_mac python fix

Add checks for #3215 to hide the tab bar only if it doesn't prevent
window dragging in Wayland sessions with native decorations.

.github/workflows/build_linux.yml

@@ -16,7 +16,7 @@ jobs:
       uses: actions/checkout@v3
     - name: Install dependencies
       run: |
-        sudo apt-get install libx11-dev libxcursor-dev libxinerama-dev build-essential gettext libtool libtool-bin libpulse-dev libasound2-dev libjack-dev portaudio19-dev
+        sudo apt-get install libx11-dev libxcursor-dev libxinerama-dev build-essential gettext libtool libtool-bin libpulse-dev libasound2-dev libjack-dev portaudio19-dev libwayland-dev
     - name: Setup Vulkan
       uses: ./.github/actions/vulkan
     - name: Setup .NET
@@ -44,7 +44,7 @@ jobs:
       uses: actions/checkout@v3
     - name: Install dependencies
       run: |
-        sudo apt-get install libx11-dev libxcursor-dev libxinerama-dev
+        sudo apt-get install libx11-dev libxcursor-dev libxinerama-dev libwayland-dev
     - name: Setup Vulkan
       uses: ./.github/actions/vulkan
     - name: Setup .NET

.github/workflows/tests.yml

@@ -28,7 +28,7 @@ jobs:
         git lfs pull
     - name: Install dependencies
       run: |
-        sudo apt-get install libx11-dev libxcursor-dev libxinerama-dev build-essential gettext libtool libtool-bin libpulse-dev libasound2-dev libjack-dev portaudio19-dev
+        sudo apt-get install libx11-dev libxcursor-dev libxinerama-dev build-essential gettext libtool libtool-bin libpulse-dev libasound2-dev libjack-dev portaudio19-dev libwayland-dev
     - name: Build
       run: |
         ./GenerateProjectFiles.sh -vs2022 -log -verbose -printSDKs -dotnet=8

Flax.flaxproj

@@ -13,6 +13,7 @@
   "Configuration": {
     "UseCSharp": true,
     "UseLargeWorlds": false,
-    "UseDotNet": true
+    "UseDotNet": true,
+    "UseSDL": true
   }
 }

README.md

@@ -57,9 +57,9 @@ Follow the instructions below to compile and run the engine from source.
   * Arch: `sudo pacman -S git git-lfs`
   * `git-lfs install`
 * Install the required packages:
-  * Ubuntu: `sudo apt-get install libx11-dev libxcursor-dev libxinerama-dev zlib1g-dev`
-  * Fedora: `sudo dnf install libX11-devel libXcursor-devel  libXinerama-devel ghc-zlib-devel`
-  * Arch: `sudo pacman -S base-devel libx11 libxcursor libxinerama zlib`
+  * Ubuntu: `sudo apt-get install libx11-dev libxcursor-dev libxinerama-dev zlib1g-dev zenity wayland-protocols libportal-dev`
+  * Fedora: `sudo dnf install libX11-devel libXcursor-devel  libXinerama-devel ghc-zlib-devel zenity wayland-protocols-devel libportal`
+  * Arch: `sudo pacman -S base-devel libx11 libxcursor libxinerama zlib zenity wayland-protocols libportal`
 * Install Clang compiler (version 6 or later):
   * Ubuntu: `sudo apt-get install clang lldb lld`
   * Fedora: `sudo dnf install clang llvm lldb lld`

Source/Editor/Content/Items/ContentFolder.cs

@@ -282,7 +282,7 @@ namespace FlaxEditor.Content
 
             if (data is DragDataFiles)
                 return DragDropEffect.Copy;
-            return _dragOverItems.Effect;
+            return _dragOverItems?.Effect ?? DragDropEffect.None;
         }
 
         /// <inheritdoc />

Source/Editor/Content/Items/CppScriptItem.cs

@@ -20,7 +20,7 @@ namespace FlaxEditor.Content
         }
 
         /// <inheritdoc />
-        public override string TypeDescription => Path.EndsWith(".h") ? "C++ Header File" : "C++ Source Code";
+        public override string TypeDescription => Path.EndsWith(".h") || Path.EndsWith(".hpp") ? "C++ Header File" : "C++ Source Code";
 
         /// <inheritdoc />
         public override SpriteHandle DefaultThumbnail => Editor.Instance.Icons.CPPScript128;

Source/Editor/CustomEditors/Dedicated/LocalizationSettingsEditor.cs

@@ -190,12 +190,12 @@ namespace FlaxEditor.CustomEditors.Dedicated
                     foreach (var file in files)
                         FindNewKeysCSharp(file, newKeys, allKeys);
 
-                    // C++
-                    files = Directory.GetFiles(Globals.ProjectSourceFolder, "*.cpp", SearchOption.AllDirectories);
+                    // C/C++
+                    files = Directory.GetFiles(Globals.ProjectSourceFolder, "*.cpp", SearchOption.AllDirectories).Concat(Directory.GetFiles(Globals.ProjectSourceFolder, "*.c", SearchOption.AllDirectories)).ToArray();
                     filesCount += files.Length;
                     foreach (var file in files)
                         FindNewKeysCpp(file, newKeys, allKeys);
-                    files = Directory.GetFiles(Globals.ProjectSourceFolder, "*.h", SearchOption.AllDirectories);
+                    files = Directory.GetFiles(Globals.ProjectSourceFolder, "*.h", SearchOption.AllDirectories).Concat(Directory.GetFiles(Globals.ProjectSourceFolder, "*.hpp", SearchOption.AllDirectories)).ToArray();;
                     filesCount += files.Length;
                     foreach (var file in files)
                         FindNewKeysCpp(file, newKeys, allKeys);

Source/Editor/GUI/ContextMenu/ContextMenuBase.cs

@@ -1,7 +1,10 @@
-#if PLATFORM_WINDOWS
+#if PLATFORM_WINDOWS || PLATFORM_SDL
 #define USE_IS_FOREGROUND
 #else
 #endif
+#if PLATFORM_SDL
+#define USE_SDL_WORKAROUNDS
+#endif
 // Copyright (c) Wojciech Figat. All rights reserved.
 
 using System.Collections.Generic;
@@ -121,7 +124,7 @@ namespace FlaxEditor.GUI.ContextMenu
         }
 
         /// <summary>
-        /// Shows the empty menu popup o na screen.
+        /// Shows the empty menu popup on a screen.
         /// </summary>
         /// <param name="control">The target control.</param>
         /// <param name="area">The target control area to cover.</param>
@@ -256,7 +259,9 @@ namespace FlaxEditor.GUI.ContextMenu
                 desc.AllowMaximize = false;
                 desc.AllowDragAndDrop = false;
                 desc.IsTopmost = true;
-                desc.IsRegularWindow = false;
+                desc.Type = WindowType.Popup;
+                desc.Parent = parentWin.Window;
+                desc.Title = "ContextMenu";
                 desc.HasSizingFrame = false;
                 OnWindowCreating(ref desc);
                 _window = Platform.CreateWindow(ref desc);
@@ -265,6 +270,12 @@ namespace FlaxEditor.GUI.ContextMenu
                     _window.GotFocus += OnWindowGotFocus;
                     _window.LostFocus += OnWindowLostFocus;
                 }
+                
+#if USE_IS_FOREGROUND && USE_SDL_WORKAROUNDS
+                // The focus between popup and parent windows doesn't change, force hide the popup when clicked on parent
+                parentWin.Window.MouseDown += OnWindowMouseDown;
+                _window.Closed += () => parentWin.Window.MouseDown -= OnWindowMouseDown;
+#endif
 
                 // Attach to the window
                 _parentCM = parent as ContextMenuBase;
@@ -440,6 +451,17 @@ namespace FlaxEditor.GUI.ContextMenu
             }
         }
 
+#if USE_SDL_WORKAROUNDS
+        private void OnWindowGotFocus()
+        {
+        }
+        
+        private void OnWindowMouseDown(ref Float2 mousePosition, MouseButton button, ref bool handled)
+        {
+            // The user clicked outside the popup window
+            Hide();
+        }
+#else
         private void OnWindowGotFocus()
         {
             var child = _childCM;
@@ -453,6 +475,7 @@ namespace FlaxEditor.GUI.ContextMenu
                 });
             }
         }
+#endif
 
         private void OnWindowLostFocus()
         {
@@ -551,7 +574,12 @@ namespace FlaxEditor.GUI.ContextMenu
             // Let root context menu to check if none of the popup windows
             if (_parentCM == null && UseVisibilityControl && !IsForeground)
             {
+#if USE_SDL_WORKAROUNDS
+                if (!IsMouseOver)
+                    Hide();
+#else
                 Hide();
+#endif
             }
         }
 #endif

Source/Editor/GUI/Dialogs/ColorPickerDialog.cs

@@ -326,8 +326,11 @@ namespace FlaxEditor.GUI.Dialogs
             // Update eye dropper tool
             if (_activeEyedropper)
             {
+                // Try reading the color under the cursor in realtime if supported by the platform
                 Float2 mousePosition = Platform.MousePosition;
-                SelectedColor = ScreenUtilities.GetColorAt(mousePosition);
+                Color color = ScreenUtilities.GetColorAt(mousePosition);
+                if (color != Color.Transparent)
+                    SelectedColor = color;
             }
         }
 

Source/Editor/GUI/Docking/DockHintWindow.cs

@@ -1,545 +0,0 @@
-// Copyright (c) Wojciech Figat. All rights reserved.
-
-using System;
-using FlaxEngine;
-using FlaxEngine.GUI;
-
-namespace FlaxEditor.GUI.Docking
-{
-    /// <summary>
-    /// Helper class used to handle docking windows dragging and docking.
-    /// </summary>
-    public class DockHintWindow
-    {
-        private FloatWindowDockPanel _toMove;
-
-        private Float2 _dragOffset;
-        private Float2 _defaultWindowSize;
-        private Rectangle _rectDock;
-        private Rectangle _rectWindow;
-        private Float2 _mouse;
-        private DockState _toSet;
-        private DockPanel _toDock;
-        private bool _lateDragOffsetUpdate;
-
-        private Rectangle _rLeft, _rRight, _rBottom, _rUpper, _rCenter;
-
-        private DockHintWindow(FloatWindowDockPanel toMove)
-        {
-            _toMove = toMove;
-            _toSet = DockState.Float;
-            var window = toMove.Window.Window;
-
-            // Remove focus from drag target
-            _toMove.Focus();
-            _toMove.Defocus();
-
-            // Focus window
-            window.Focus();
-
-            // Check if window is maximized and restore window.
-            if (window.IsMaximized)
-            {
-                // Restore window and set position to mouse.
-                var mousePos = window.MousePosition;
-                var previousSize = window.Size;
-                window.Restore();
-                window.Position = Platform.MousePosition - mousePos * window.Size / previousSize;
-            }
-
-            // Calculate dragging offset and move window to the destination position
-            var mouseScreenPosition = Platform.MousePosition;
-
-            // If the _toMove window was not focused when initializing this window, the result vector only contains zeros
-            // and to prevent a failure, we need to perform an update for the drag offset at later time which will be done in the OnMouseMove event handler.
-            if (mouseScreenPosition != Float2.Zero)
-                CalculateDragOffset(mouseScreenPosition);
-            else
-                _lateDragOffsetUpdate = true;
-
-            // Get initial size
-            _defaultWindowSize = window.Size;
-
-            // Init proxy window
-            Proxy.Init(ref _defaultWindowSize);
-
-            // Bind events
-            Proxy.Window.MouseUp += OnMouseUp;
-            Proxy.Window.MouseMove += OnMouseMove;
-            Proxy.Window.LostFocus += OnLostFocus;
-
-            // Start tracking mouse
-            Proxy.Window.StartTrackingMouse(false);
-
-            // Update window GUI
-            Proxy.Window.GUI.PerformLayout();
-
-            // Update rectangles
-            UpdateRects();
-
-            // Hide base window
-            window.Hide();
-
-            // Enable hit window presentation
-            Proxy.Window.RenderingEnabled = true;
-            Proxy.Window.Show();
-            Proxy.Window.Focus();
-        }
-
-        /// <summary>
-        /// Releases unmanaged and - optionally - managed resources.
-        /// </summary>
-        public void Dispose()
-        {
-            // End tracking mouse
-            Proxy.Window.EndTrackingMouse();
-
-            // Disable rendering
-            Proxy.Window.RenderingEnabled = false;
-
-            // Unbind events
-            Proxy.Window.MouseUp -= OnMouseUp;
-            Proxy.Window.MouseMove -= OnMouseMove;
-            Proxy.Window.LostFocus -= OnLostFocus;
-
-            // Hide the proxy
-            Proxy.Hide();
-
-            if (_toMove == null)
-                return;
-
-            // Check if window won't be docked
-            if (_toSet == DockState.Float)
-            {
-                var window = _toMove.Window?.Window;
-                if (window == null)
-                    return;
-                var mouse = Platform.MousePosition;
-
-                // Move base window
-                window.Position = mouse - _dragOffset;
-
-                // Show base window
-                window.Show();
-            }
-            else
-            {
-                bool hasNoChildPanels = _toMove.ChildPanelsCount == 0;
-
-                // Check if window has only single tab
-                if (hasNoChildPanels && _toMove.TabsCount == 1)
-                {
-                    // Dock window
-                    _toMove.GetTab(0).Show(_toSet, _toDock);
-                }
-                // Check if dock as tab and has no child panels
-                else if (hasNoChildPanels && _toSet == DockState.DockFill)
-                {
-                    // Dock all tabs
-                    while (_toMove.TabsCount > 0)
-                    {
-                        _toMove.GetTab(0).Show(DockState.DockFill, _toDock);
-                    }
-                }
-                else
-                {
-                    var selectedTab = _toMove.SelectedTab;
-
-                    // Dock the first tab into the target location
-                    var firstTab = _toMove.GetTab(0);
-                    firstTab.Show(_toSet, _toDock);
-
-                    // Dock rest of the tabs
-                    while (_toMove.TabsCount > 0)
-                    {
-                        _toMove.GetTab(0).Show(DockState.DockFill, firstTab);
-                    }
-
-                    // Keep selected tab being selected
-                    selectedTab?.SelectTab();
-                }
-
-                // Focus target window
-                _toDock.Root.Focus();
-            }
-
-            _toMove = null;
-        }
-
-        /// <summary>
-        /// Creates the new dragging hit window.
-        /// </summary>
-        /// <param name="toMove">Floating dock panel to move.</param>
-        /// <returns>The dock hint window object.</returns>
-        public static DockHintWindow Create(FloatWindowDockPanel toMove)
-        {
-            if (toMove == null)
-                throw new ArgumentNullException();
-
-            return new DockHintWindow(toMove);
-        }
-
-        /// <summary>
-        /// Creates the new dragging hit window.
-        /// </summary>
-        /// <param name="toMove">Dock window to move.</param>
-        /// <returns>The dock hint window object.</returns>
-        public static DockHintWindow Create(DockWindow toMove)
-        {
-            if (toMove == null)
-                throw new ArgumentNullException();
-
-            // Show floating
-            toMove.ShowFloating();
-
-            // Move window to the mouse position (with some offset for caption bar)
-            var window = (WindowRootControl)toMove.Root;
-            var mouse = Platform.MousePosition;
-            window.Window.Position = mouse - new Float2(8, 8);
-
-            // Get floating panel
-            var floatingPanelToMove = window.GetChild(0) as FloatWindowDockPanel;
-
-            return new DockHintWindow(floatingPanelToMove);
-        }
-
-        /// <summary>
-        /// Calculates window rectangle in the dock window.
-        /// </summary>
-        /// <param name="state">Window dock state.</param>
-        /// <param name="rect">Dock panel rectangle.</param>
-        /// <returns>Calculated window rectangle.</returns>
-        public static Rectangle CalculateDockRect(DockState state, ref Rectangle rect)
-        {
-            Rectangle result = rect;
-            switch (state)
-            {
-            case DockState.DockFill:
-                result.Location.Y += Editor.Instance.Options.Options.Interface.TabHeight;
-                result.Size.Y -= Editor.Instance.Options.Options.Interface.TabHeight;
-                break;
-            case DockState.DockTop:
-                result.Size.Y *= DockPanel.DefaultSplitterValue;
-                break;
-            case DockState.DockLeft:
-                result.Size.X *= DockPanel.DefaultSplitterValue;
-                break;
-            case DockState.DockBottom:
-                result.Location.Y += result.Size.Y * (1 - DockPanel.DefaultSplitterValue);
-                result.Size.Y *= DockPanel.DefaultSplitterValue;
-                break;
-            case DockState.DockRight:
-                result.Location.X += result.Size.X * (1 - DockPanel.DefaultSplitterValue);
-                result.Size.X *= DockPanel.DefaultSplitterValue;
-                break;
-            }
-            return result;
-        }
-
-        private void CalculateDragOffset(Float2 mouseScreenPosition)
-        {
-            var baseWinPos = _toMove.Window.Window.Position;
-            _dragOffset = mouseScreenPosition - baseWinPos;
-        }
-
-        private void UpdateRects()
-        {
-            // Cache mouse position
-            _mouse = Platform.MousePosition;
-
-            // Check intersection with any dock panel
-            var uiMouse = _mouse;
-            _toDock = _toMove.MasterPanel.HitTest(ref uiMouse, _toMove);
-
-            // Check dock state to use
-            bool showProxyHints = _toDock != null;
-            bool showBorderHints = showProxyHints;
-            bool showCenterHint = showProxyHints;
-            if (showProxyHints)
-            {
-                // If moved window has not only tabs but also child panels disable docking as tab
-                if (_toMove.ChildPanelsCount > 0)
-                    showCenterHint = false;
-
-                // Disable docking windows with one or more dock panels inside
-                if (_toMove.ChildPanelsCount > 0)
-                    showBorderHints = false;
-
-                // Get dock area
-                _rectDock = _toDock.DockAreaBounds;
-
-                // Cache dock rectangles
-                var size = _rectDock.Size;
-                var offset = _rectDock.Location;
-                var borderMargin = 4.0f;
-                var hintWindowsSize = Proxy.HintWindowsSize * Platform.DpiScale;
-                var hintWindowsSize2 = hintWindowsSize * 0.5f;
-                var centerX = size.X * 0.5f;
-                var centerY = size.Y * 0.5f;
-                _rUpper = new Rectangle(centerX - hintWindowsSize2, borderMargin, hintWindowsSize, hintWindowsSize) + offset;
-                _rBottom = new Rectangle(centerX - hintWindowsSize2, size.Y - hintWindowsSize - borderMargin, hintWindowsSize, hintWindowsSize) + offset;
-                _rLeft = new Rectangle(borderMargin, centerY - hintWindowsSize2, hintWindowsSize, hintWindowsSize) + offset;
-                _rRight = new Rectangle(size.X - hintWindowsSize - borderMargin, centerY - hintWindowsSize2, hintWindowsSize, hintWindowsSize) + offset;
-                _rCenter = new Rectangle(centerX - hintWindowsSize2, centerY - hintWindowsSize2, hintWindowsSize, hintWindowsSize) + offset;
-
-                // Hit test
-                DockState toSet = DockState.Float;
-                if (showBorderHints)
-                {
-                    if (_rUpper.Contains(_mouse))
-                        toSet = DockState.DockTop;
-                    else if (_rBottom.Contains(_mouse))
-                        toSet = DockState.DockBottom;
-                    else if (_rLeft.Contains(_mouse))
-                        toSet = DockState.DockLeft;
-                    else if (_rRight.Contains(_mouse))
-                        toSet = DockState.DockRight;
-                }
-                if (showCenterHint && _rCenter.Contains(_mouse))
-                    toSet = DockState.DockFill;
-                _toSet = toSet;
-
-                // Show proxy hint windows
-                Proxy.Down.Position = _rBottom.Location;
-                Proxy.Left.Position = _rLeft.Location;
-                Proxy.Right.Position = _rRight.Location;
-                Proxy.Up.Position = _rUpper.Location;
-                Proxy.Center.Position = _rCenter.Location;
-            }
-            else
-            {
-                _toSet = DockState.Float;
-            }
-
-            // Update proxy hint windows visibility
-            Proxy.Down.IsVisible = showProxyHints & showBorderHints;
-            Proxy.Left.IsVisible = showProxyHints & showBorderHints;
-            Proxy.Right.IsVisible = showProxyHints & showBorderHints;
-            Proxy.Up.IsVisible = showProxyHints & showBorderHints;
-            Proxy.Center.IsVisible = showProxyHints & showCenterHint;
-
-            // Calculate proxy/dock/window rectangles
-            if (_toDock == null)
-            {
-                // Floating window over nothing
-                _rectWindow = new Rectangle(_mouse - _dragOffset, _defaultWindowSize);
-            }
-            else
-            {
-                if (_toSet == DockState.Float)
-                {
-                    // Floating window over dock panel
-                    _rectWindow = new Rectangle(_mouse - _dragOffset, _defaultWindowSize);
-                }
-                else
-                {
-                    // Use only part of the dock panel to show hint
-                    _rectWindow = CalculateDockRect(_toSet, ref _rectDock);
-                }
-            }
-
-            // Update proxy window
-            Proxy.Window.ClientBounds = _rectWindow;
-        }
-
-        private void OnMouseUp(ref Float2 location, MouseButton button, ref bool handled)
-        {
-            if (button == MouseButton.Left)
-            {
-                Dispose();
-            }
-        }
-
-        private void OnMouseMove(ref Float2 mousePos)
-        {
-            // Recalculate the drag offset because the current mouse screen position was invalid when we initialized the window
-            if (_lateDragOffsetUpdate)
-            {
-                // Calculate dragging offset and move window to the destination position
-                CalculateDragOffset(mousePos);
-
-                // Reset state
-                _lateDragOffsetUpdate = false;
-            }
-
-            UpdateRects();
-        }
-
-        private void OnLostFocus()
-        {
-            Dispose();
-        }
-
-        /// <summary>
-        /// Contains helper proxy windows shared across docking panels. They are used to visualize docking window locations.
-        /// </summary>
-        public static class Proxy
-        {
-            /// <summary>
-            /// The drag proxy window.
-            /// </summary>
-            public static Window Window;
-
-            /// <summary>
-            /// The left hint proxy window.
-            /// </summary>
-            public static Window Left;
-
-            /// <summary>
-            /// The right hint proxy window.
-            /// </summary>
-            public static Window Right;
-
-            /// <summary>
-            /// The up hint proxy window.
-            /// </summary>
-            public static Window Up;
-
-            /// <summary>
-            /// The down hint proxy window.
-            /// </summary>
-            public static Window Down;
-
-            /// <summary>
-            /// The center hint proxy window.
-            /// </summary>
-            public static Window Center;
-
-            /// <summary>
-            /// The hint windows size.
-            /// </summary>
-            public const float HintWindowsSize = 32.0f;
-
-            /// <summary>
-            /// Initializes the hit proxy windows. Those windows are used to indicate drag target areas (left, right, top, bottom, etc.).
-            /// </summary>
-            public static void InitHitProxy()
-            {
-                CreateProxy(ref Left, "DockHint.Left");
-                CreateProxy(ref Right, "DockHint.Right");
-                CreateProxy(ref Up, "DockHint.Up");
-                CreateProxy(ref Down, "DockHint.Down");
-                CreateProxy(ref Center, "DockHint.Center");
-            }
-
-            /// <summary>
-            /// Initializes the hint window.
-            /// </summary>
-            /// <param name="initSize">Initial size of the proxy window.</param>
-            public static void Init(ref Float2 initSize)
-            {
-                if (Window == null)
-                {
-                    var settings = CreateWindowSettings.Default;
-                    settings.Title = "DockHint.Window";
-                    settings.Size = initSize;
-                    settings.AllowInput = true;
-                    settings.AllowMaximize = false;
-                    settings.AllowMinimize = false;
-                    settings.HasBorder = false;
-                    settings.HasSizingFrame = false;
-                    settings.IsRegularWindow = false;
-                    settings.SupportsTransparency = true;
-                    settings.ShowInTaskbar = false;
-                    settings.ShowAfterFirstPaint = false;
-                    settings.IsTopmost = true;
-
-                    Window = Platform.CreateWindow(ref settings);
-                    Window.Opacity = 0.6f;
-                    Window.GUI.BackgroundColor = Style.Current.Selection;
-                    Window.GUI.AddChild<DragVisuals>();
-                }
-                else
-                {
-                    // Resize proxy
-                    Window.ClientSize = initSize;
-                }
-
-                InitHitProxy();
-            }
-
-            private sealed class DragVisuals : Control
-            {
-                public DragVisuals()
-                {
-                    AnchorPreset = AnchorPresets.StretchAll;
-                    Offsets = Margin.Zero;
-                }
-
-                public override void Draw()
-                {
-                    Render2D.DrawRectangle(new Rectangle(Float2.Zero, Size), Style.Current.SelectionBorder);
-                }
-            }
-
-            private static void CreateProxy(ref Window win, string name)
-            {
-                if (win != null)
-                    return;
-
-                var settings = CreateWindowSettings.Default;
-                settings.Title = name;
-                settings.Size = new Float2(HintWindowsSize * Platform.DpiScale);
-                settings.AllowInput = false;
-                settings.AllowMaximize = false;
-                settings.AllowMinimize = false;
-                settings.HasBorder = false;
-                settings.HasSizingFrame = false;
-                settings.IsRegularWindow = false;
-                settings.SupportsTransparency = true;
-                settings.ShowInTaskbar = false;
-                settings.ActivateWhenFirstShown = false;
-                settings.IsTopmost = true;
-                settings.ShowAfterFirstPaint = false;
-
-                win = Platform.CreateWindow(ref settings);
-                win.Opacity = 0.6f;
-                win.GUI.BackgroundColor = Style.Current.Selection;
-                win.GUI.AddChild<DragVisuals>();
-            }
-
-            /// <summary>
-            /// Hides proxy windows.
-            /// </summary>
-            public static void Hide()
-            {
-                HideProxy(ref Window);
-                HideProxy(ref Left);
-                HideProxy(ref Right);
-                HideProxy(ref Up);
-                HideProxy(ref Down);
-                HideProxy(ref Center);
-            }
-
-            private static void HideProxy(ref Window win)
-            {
-                if (win)
-                {
-                    win.Hide();
-                }
-            }
-
-            /// <summary>
-            /// Releases proxy data and windows.
-            /// </summary>
-            public static void Dispose()
-            {
-                DisposeProxy(ref Window);
-                DisposeProxy(ref Left);
-                DisposeProxy(ref Right);
-                DisposeProxy(ref Up);
-                DisposeProxy(ref Down);
-                DisposeProxy(ref Center);
-            }
-
-            private static void DisposeProxy(ref Window win)
-            {
-                if (win)
-                {
-                    win.Close(ClosingReason.User);
-                    win = null;
-                }
-            }
-        }
-    }
-}

Source/Editor/GUI/Docking/DockPanelProxy.cs

@@ -19,11 +19,7 @@ namespace FlaxEditor.GUI.Docking
         private float _tabHeight = Editor.Instance.Options.Options.Interface.TabHeight;
         private bool _useMinimumTabWidth = Editor.Instance.Options.Options.Interface.UseMinimumTabWidth;
         private float _minimumTabWidth = Editor.Instance.Options.Options.Interface.MinimumTabWidth;
-#if PLATFORM_WINDOWS
-        private readonly bool _hideTabForSingleTab = Editor.Instance.Options.Options.Interface.HideSingleTabWindowTabBars;
-#else
-        private readonly bool _hideTabForSingleTab = false;
-#endif
+        private readonly bool _hideTabForSingleTab = Utilities.Utils.HideSingleTabWindowTabBars();
 
         /// <summary>
         /// The is mouse down flag (left button).
@@ -54,6 +50,11 @@ namespace FlaxEditor.GUI.Docking
         /// The mouse position.
         /// </summary>
         public Float2 MousePosition = Float2.Minimum;
+        
+        /// <summary>
+        /// The mouse position.
+        /// </summary>
+        public Float2 MouseStartPosition = Float2.Minimum;
 
         /// <summary>
         /// The start drag asynchronous window.
@@ -198,7 +199,7 @@ namespace FlaxEditor.GUI.Docking
                 if (_panel.ChildPanelsCount == 0 && _panel.TabsCount == 1 && _panel.IsFloating)
                 {
                     // Create docking hint window but in an async manner
-                    DockHintWindow.Create(_panel as FloatWindowDockPanel);
+                    WindowDragHelper.StartDragging(_panel as FloatWindowDockPanel);
                 }
                 else
                 {
@@ -209,7 +210,7 @@ namespace FlaxEditor.GUI.Docking
                     _panel.SelectTab(index - 1);
 
                     // Create docking hint window
-                    DockHintWindow.Create(win);
+                    WindowDragHelper.StartDragging(win, _panel.RootWindow.Window);
                 }
             }
         }
@@ -395,6 +396,7 @@ namespace FlaxEditor.GUI.Docking
             if (IsSingleFloatingWindow)
                 return base.OnMouseDown(location, button);
             MouseDownWindow = GetTabAtPos(location, out IsMouseDownOverCross);
+            MouseStartPosition = location;
 
             // Check buttons
             if (button == MouseButton.Left)
@@ -481,6 +483,20 @@ namespace FlaxEditor.GUI.Docking
                         StartDrag(MouseDownWindow);
                     MouseDownWindow = null;
                 }
+                // Check if single tab is tried to be moved
+                else if (MouseDownWindow != null && _panel.TabsCount <= 1)
+                {
+                    if ((MousePosition - MouseStartPosition).Length > 3)
+                    {
+                        // Clear flag
+                        IsMouseLeftButtonDown = false;
+
+                        // Check tab under the mouse
+                        if (!IsMouseDownOverCross && MouseDownWindow != null)
+                            StartDrag(MouseDownWindow);
+                        MouseDownWindow = null;
+                    }
+                }
                 // Check if has more than one tab to change order
                 else if (MouseDownWindow != null && _panel.TabsCount > 1)
                 {

Source/Editor/GUI/Docking/DockWindow.cs

@@ -182,6 +182,25 @@ namespace FlaxEditor.GUI.Docking
         /// <param name="size">Window size, set <see cref="Float2.Zero"/> to use default.</param>
         /// <param name="position">Window location.</param>
         public void ShowFloating(Float2 location, Float2 size, WindowStartPosition position = WindowStartPosition.CenterParent)
+        {
+            CreateFloating(location, size, position, true);
+        }
+
+        /// <summary>
+        /// Creates the window in a floating state.
+        /// </summary>
+        public void CreateFloating()
+        {
+            CreateFloating(Float2.Zero, Float2.Zero);
+        }
+        /// <summary>
+        /// Creates the window in a floating state.
+        /// </summary>
+        /// <param name="location">Window location.</param>
+        /// <param name="size">Window size, set <see cref="Float2.Zero"/> to use default.</param>
+        /// <param name="position">Window location.</param>
+        /// <param name="showWindow">Window visibility.</param>
+        public void CreateFloating(Float2 location, Float2 size, WindowStartPosition position = WindowStartPosition.CenterParent, bool showWindow = false)
         {
             Undock();
 
@@ -199,14 +218,17 @@ namespace FlaxEditor.GUI.Docking
             windowGUI.UnlockChildrenRecursive();
             windowGUI.PerformLayout();
 
-            // Show
-            window.Show();
-            window.BringToFront();
-            window.Focus();
-            OnShow();
+            if (showWindow)
+            {
+                // Show
+                window.Show();
+                window.BringToFront();
+                window.Focus();
+                OnShow();
 
-            // Perform layout again
-            windowGUI.PerformLayout();
+                // Perform layout again
+                windowGUI.PerformLayout();
+            }
         }
 
         /// <summary>

Source/Editor/GUI/Docking/FloatWindowDockPanel.cs

@@ -11,6 +11,42 @@ namespace FlaxEditor.GUI.Docking
     /// <seealso cref="DockPanel" />
     public class FloatWindowDockPanel : DockPanel
     {
+        private class FloatWindowDecorations : WindowDecorations
+        {
+            private FloatWindowDockPanel _panel;
+            
+            public FloatWindowDecorations(FloatWindowDockPanel panel)
+            : base(panel.RootWindow)
+            {
+                _panel = panel;
+            }
+            
+            /// <inheritdoc />
+            public override bool OnMouseDown(Float2 location, MouseButton button)
+            {
+                if (Title.Bounds.Contains(location) && button == MouseButton.Left)
+                {
+                    _panel.BeginDrag();
+                    return true;
+                }
+                return base.OnMouseDown(location, button);
+            }
+
+#if !PLATFORM_WINDOWS
+            /// <inheritdoc />
+            protected override WindowHitCodes OnHitTest(ref Float2 mouse)
+            {
+                var hit = base.OnHitTest(ref mouse);
+                if (hit == WindowHitCodes.Caption)
+                {
+                    // Override the system behaviour when interacting with the caption area
+                    hit = WindowHitCodes.Client;
+                }
+                return hit;
+            }
+#endif
+        }
+
         private MasterDockPanel _masterPanel;
         private WindowRootControl _window;
 
@@ -40,6 +76,26 @@ namespace FlaxEditor.GUI.Docking
             Parent = window;
             _window.Window.Closing += OnClosing;
             _window.Window.LeftButtonHit += OnLeftButtonHit;
+            
+            if (Utilities.Utils.UseCustomWindowDecorations())
+            {
+                var decorations = Parent.AddChild(new FloatWindowDecorations(this));
+                decorations.SetAnchorPreset(AnchorPresets.HorizontalStretchTop, false);
+            }
+        }
+        
+        /// <inheritdoc />
+        protected override void PerformLayoutBeforeChildren()
+        {
+            base.PerformLayoutBeforeChildren();
+            
+            var decorations = Parent.GetChild<FloatWindowDecorations>();
+            if (decorations != null)
+            {
+                // Apply offset for the title bar
+                foreach (var child in Children)
+                    child.Bounds = child.Bounds with { Y = decorations.Height, Height = Parent.Height - decorations.Height };
+            }
         }
 
         /// <summary>
@@ -52,7 +108,7 @@ namespace FlaxEditor.GUI.Docking
                 return;
 
             // Create docking hint window
-            DockHintWindow.Create(this);
+            WindowDragHelper.StartDragging(this);
         }
 
         /// <summary>
@@ -71,22 +127,28 @@ namespace FlaxEditor.GUI.Docking
             settings.Title = title;
             settings.Size = size;
             settings.Position = location;
-            settings.MinimumSize = new Float2(1);
+            settings.MinimumSize = new Float2(200, 150);
             settings.MaximumSize = Float2.Zero; // Unlimited size
             settings.Fullscreen = false;
             settings.HasBorder = true;
-            settings.SupportsTransparency = false;
+            settings.SupportsTransparency = true;
             settings.ActivateWhenFirstShown = true;
             settings.AllowInput = true;
             settings.AllowMinimize = true;
             settings.AllowMaximize = true;
             settings.AllowDragAndDrop = true;
             settings.IsTopmost = false;
-            settings.IsRegularWindow = true;
+            settings.Type = WindowType.Regular;
             settings.HasSizingFrame = true;
             settings.ShowAfterFirstPaint = false;
             settings.ShowInTaskbar = true;
             settings.StartPosition = startPosition;
+            
+            if (Utilities.Utils.UseCustomWindowDecorations())
+            {
+                settings.HasBorder = false;
+                //settings.HasSizingFrame = false;
+            }
 
             // Create window
             return Platform.CreateWindow(ref settings);

Source/Editor/GUI/Docking/MasterDockPanel.cs

@@ -81,7 +81,6 @@ namespace FlaxEditor.GUI.Docking
         public DockPanel HitTest(ref Float2 position, FloatWindowDockPanel excluded)
         {
             // Check all floating windows
-            // TODO: gather windows order and take it into account when performing test
             for (int i = 0; i < FloatingPanels.Count; i++)
             {
                 var win = FloatingPanels[i];
@@ -94,9 +93,44 @@ namespace FlaxEditor.GUI.Docking
             }
 
             // Base
+            //if (!Root?.RootWindow.Window.IsFocused ?? false)
+            //    return null;
             return base.HitTest(ref position);
         }
 
+        /// <summary>
+        /// Performs hit test over dock panel.
+        /// </summary>
+        /// <param name="position">Window space position to test.</param>
+        /// <param name="excluded">Floating window to omit during searching (and all docked to that one).</param>
+        /// <param name="hitResults">Results of the hit test</param>
+        /// <returns>True if any dock panels were hit, otherwise false.</returns>
+        public bool HitTest(ref Float2 position, FloatWindowDockPanel excluded, out DockPanel[] hitResults)
+        {
+            // Check all floating windows
+            List<DockPanel> results = new(FloatingPanels.Count);
+            for (int i = 0; i < FloatingPanels.Count; i++)
+            {
+                var win = FloatingPanels[i];
+                if (win.Visible && win != excluded)
+                {
+                    var result = win.HitTest(ref position);
+                    if (result != null)
+                        results.Add(result);
+                }
+            }
+
+            // Base
+            //if (!Root?.RootWindow.Window.IsFocused ?? false)
+            //    return null;
+            var baseResult = base.HitTest(ref position);
+            if (baseResult != null)
+                results.Add(baseResult);
+
+            hitResults = results.ToArray();
+            return hitResults.Length > 0;
+        }
+
         internal void LinkWindow(DockWindow window)
         {
             // Add to the windows list

Source/Editor/GUI/Docking/WindowDragHelper.cs

@@ -0,0 +1,458 @@
+// Copyright (c) Wojciech Figat. All rights reserved.
+
+using System;
+using FlaxEngine;
+using FlaxEngine.GUI;
+
+namespace FlaxEditor.GUI.Docking
+{
+    /// <summary>
+    /// Helper class used to handle docking windows dragging and docking.
+    /// </summary>
+    public class WindowDragHelper
+    {
+        private FloatWindowDockPanel _toMove;
+
+        private Float2 _dragOffset;
+        private Rectangle _rectDock;
+        private Float2 _mouse;
+        private DockState _toSet;
+        private DockPanel _toDock;
+        private Window _dragSourceWindow;
+
+        private Rectangle _rLeft, _rRight, _rBottom, _rUpper, _rCenter;
+        private Control _dockHintDown, _dockHintUp, _dockHintLeft, _dockHintRight, _dockHintCenter;
+
+        /// <summary>
+        /// The hint control size.
+        /// </summary>
+        public const float HintControlSize = 32.0f;
+
+        /// <summary>
+        /// The opacity of the dragged window when hint controls are shown.
+        /// </summary>
+        public const float DragWindowOpacity = 0.4f;
+        
+        /// <summary>
+        /// Returns true if any windows are being dragged.
+        /// </summary>
+        public static bool IsDragActive { get; private set; }
+
+        private WindowDragHelper(FloatWindowDockPanel toMove, Window dragSourceWindow)
+        {
+            IsDragActive = true;
+            _toMove = toMove;
+            _toSet = DockState.Float;
+            var window = toMove.Window.Window;
+
+            // Bind events
+            FlaxEngine.Scripting.Update += OnUpdate;
+            window.MouseUp += OnMouseUp;
+            
+            // Update rectangles
+            UpdateRects(Platform.MousePosition);
+            
+            // Ensure the dragged window stays on top of every other window
+            window.IsAlwaysOnTop = true;
+
+            _dragSourceWindow = dragSourceWindow;
+            if (_dragSourceWindow != null) // Detaching a tab from existing window
+            {
+                _dragOffset = new Float2(window.Size.X / 2, 10.0f);
+                
+                _dragSourceWindow.MouseUp += OnMouseUp; // The mouse up event is sent to the source window on Windows
+
+                // TODO: when detaching tab in floating window (not main window), the drag source window is still main window?
+                var dragSourceWindowWayland = toMove.MasterPanel?.RootWindow.Window ?? Editor.Instance.Windows.MainWindow;
+                window.DoDragDrop(window.Title, _dragOffset, dragSourceWindowWayland);
+            }
+            else
+            {
+                _dragOffset = window.MousePosition;
+                window.DoDragDrop(window.Title, _dragOffset, window);
+            }
+        }
+
+        /// <summary>
+        /// Releases unmanaged and - optionally - managed resources.
+        /// </summary>
+        public void Dispose()
+        {
+            IsDragActive = false;
+            var window = _toMove?.Window?.Window;
+
+            // Unbind events
+            FlaxEngine.Scripting.Update -= OnUpdate;
+            if (window != null)
+                window.MouseUp -= OnMouseUp;
+            if (_dragSourceWindow != null)
+                _dragSourceWindow.MouseUp -= OnMouseUp;
+
+            RemoveDockHints();
+
+            if (_toMove == null)
+                return;
+
+            if (window != null)
+            {
+                window.Opacity = 1.0f;
+                window.IsAlwaysOnTop = false;
+                window.BringToFront();
+            }
+
+            // Check if window won't be docked
+            if (_toSet == DockState.Float)
+            {
+                if (window == null)
+                    return;
+
+                // Show base window
+                window.Show();
+            }
+            else
+            {
+                bool hasNoChildPanels = _toMove.ChildPanelsCount == 0;
+
+                // Check if window has only single tab
+                if (hasNoChildPanels && _toMove.TabsCount == 1)
+                {
+                    // Dock window
+                    _toMove.GetTab(0).Show(_toSet, _toDock);
+                }
+                // Check if dock as tab and has no child panels
+                else if (hasNoChildPanels && _toSet == DockState.DockFill)
+                {
+                    // Dock all tabs
+                    while (_toMove.TabsCount > 0)
+                    {
+                        _toMove.GetTab(0).Show(DockState.DockFill, _toDock);
+                    }
+                }
+                else
+                {
+                    var selectedTab = _toMove.SelectedTab;
+
+                    // Dock the first tab into the target location
+                    if (_toMove.TabsCount > 0)
+                    {
+                        var firstTab = _toMove.GetTab(0);
+                        firstTab.Show(_toSet, _toDock);
+
+                        // Dock rest of the tabs
+                        while (_toMove.TabsCount > 0)
+                        {
+                            _toMove.GetTab(0).Show(DockState.DockFill, firstTab);
+                        }
+                    }
+
+                    // Keep selected tab being selected
+                    selectedTab?.SelectTab();
+                }
+
+                // Focus target window
+                _toDock.Root.Focus();
+            }
+
+            _toMove = null;
+        }
+
+        /// <summary>
+        /// Start dragging a floating dock panel.
+        /// </summary>
+        /// <param name="toMove">Floating dock panel to move.</param>
+        /// <returns>The window drag helper object.</returns>
+        public static WindowDragHelper StartDragging(FloatWindowDockPanel toMove)
+        {
+            if (toMove == null)
+                throw new ArgumentNullException();
+
+            return new WindowDragHelper(toMove, null);
+        }
+
+        /// <summary>
+        /// Start dragging a docked panel into a floating window.
+        /// </summary>
+        /// <param name="toMove">Dock window to move.</param>
+        /// <param name="dragSourceWindow">The window where dragging started from.</param>
+        /// <returns>The window drag helper object.</returns>
+        public static WindowDragHelper StartDragging(DockWindow toMove, Window dragSourceWindow)
+        {
+            if (toMove == null)
+                throw new ArgumentNullException();
+
+            // Create floating window
+            toMove.CreateFloating();
+
+            // Get floating panel
+            var window = (WindowRootControl)toMove.Root;
+            var floatingPanelToMove = window.GetChild(0) as FloatWindowDockPanel;
+
+            return new WindowDragHelper(floatingPanelToMove, dragSourceWindow);
+        }
+
+        private sealed class DragVisuals : Control
+        {
+            public DragVisuals()
+            {
+                AnchorPreset = AnchorPresets.StretchAll;
+                Offsets = Margin.Zero;
+            }
+
+            public override void Draw()
+            {
+                base.Draw();
+                Render2D.DrawRectangle(new Rectangle(Float2.Zero, Size), Style.Current.SelectionBorder);
+            }
+        }
+
+        private void AddDockHints()
+        {
+            if (_toDock == null)
+                return;
+
+            if (_toDock.RootWindow.Window != _dragSourceWindow)
+                _toDock.RootWindow.Window.MouseUp += OnMouseUp;
+
+            _dockHintDown = AddHintControl(new Float2(0.5f, 1));
+            _dockHintUp = AddHintControl(new Float2(0.5f, 0));
+            _dockHintLeft = AddHintControl(new Float2(0, 0.5f));
+            _dockHintRight = AddHintControl(new Float2(1, 0.5f));
+            _dockHintCenter = AddHintControl(new Float2(0.5f, 0.5f));
+
+            Control AddHintControl(Float2 pivot)
+            {
+                DragVisuals hintControl = _toDock.AddChild<DragVisuals>();
+                hintControl.Size = new Float2(HintControlSize);
+                hintControl.BackgroundColor = Style.Current.Selection.AlphaMultiplied(0.6f);
+                hintControl.Pivot = pivot;
+                hintControl.PivotRelative = true;
+                return hintControl;
+            }
+        }
+        
+        private void RemoveDockHints()
+        {
+            if (_toDock == null)
+                return;
+
+            if (_toDock.RootWindow.Window != _dragSourceWindow)
+                _toDock.RootWindow.Window.MouseUp -= OnMouseUp;
+
+            _dockHintDown?.Parent.RemoveChild(_dockHintDown);
+            _dockHintUp?.Parent.RemoveChild(_dockHintUp);
+            _dockHintLeft?.Parent.RemoveChild(_dockHintLeft);
+            _dockHintRight?.Parent.RemoveChild(_dockHintRight);
+            _dockHintCenter?.Parent.RemoveChild(_dockHintCenter);
+            _dockHintDown = _dockHintUp = _dockHintLeft = _dockHintRight = _dockHintCenter = null;
+        }
+
+        private void UpdateRects(Float2 mousePos)
+        {
+            // Cache mouse position
+            _mouse = mousePos;
+
+            // Check intersection with any dock panel
+            DockPanel dockPanel = null;
+            if (_toMove.MasterPanel.HitTest(ref _mouse, _toMove, out var hitResults))
+            {
+                dockPanel = hitResults[0];
+
+                // Prefer panel which currently has focus
+                foreach (var hit in hitResults)
+                {
+                    if (hit.RootWindow.Window.IsFocused)
+                    {
+                        dockPanel = hit;
+                        break;
+                    }
+                }
+
+                // Prefer panel in the same window we hit earlier
+                if (dockPanel?.RootWindow != _toDock?.RootWindow)
+                {
+                    foreach (var hit in hitResults)
+                    {
+                        if (hit.RootWindow == _toDock?.RootWindow)
+                        {
+                            dockPanel = _toDock;
+                            break;
+                        }
+                    }
+                }
+            }
+            
+            if (dockPanel != _toDock)
+            {
+                RemoveDockHints();
+                _toDock = dockPanel;
+                AddDockHints();
+
+                // Make sure the all the dock hint areas are not under other windows
+                _toDock?.RootWindow.Window.BringToFront();
+                //_toDock?.RootWindow.Window.Focus();
+
+                // Make the dragged window transparent when dock hints are visible
+                _toMove.Window.Window.Opacity = _toDock == null ? 1.0f : DragWindowOpacity;
+            }
+            
+            // Check dock state to use
+            bool showProxyHints = _toDock != null;
+            bool showBorderHints = showProxyHints;
+            bool showCenterHint = showProxyHints;
+            Control hoveredHintControl = null;
+            Float2 hoveredSizeOverride = Float2.Zero;
+            if (showProxyHints)
+            {
+                // If moved window has not only tabs but also child panels disable docking as tab
+                if (_toMove.ChildPanelsCount > 0)
+                    showCenterHint = false;
+
+                // Disable docking windows with one or more dock panels inside
+                if (_toMove.ChildPanelsCount > 0)
+                    showBorderHints = false;
+
+                // Get dock area
+                _rectDock = _toDock.DockAreaBounds;
+
+                // Cache dock rectangles
+                var size = _rectDock.Size / Platform.DpiScale;
+                var offset = _toDock.PointFromScreen(_rectDock.Location);
+                var borderMargin = 4.0f;
+                var hintWindowsSize = HintControlSize;
+                var hintWindowsSize2 = hintWindowsSize * 0.5f;
+                var hintPreviewSize = new Float2(Math.Max(HintControlSize * 2, size.X * 0.5f), Math.Max(HintControlSize * 2, size.Y * 0.5f));
+                var centerX = size.X * 0.5f;
+                var centerY = size.Y * 0.5f;
+                _rUpper = new Rectangle(centerX - hintWindowsSize2, borderMargin, hintWindowsSize, hintWindowsSize) + offset;
+                _rBottom = new Rectangle(centerX - hintWindowsSize2, size.Y - hintWindowsSize - borderMargin, hintWindowsSize, hintWindowsSize) + offset;
+                _rLeft = new Rectangle(borderMargin, centerY - hintWindowsSize2, hintWindowsSize, hintWindowsSize) + offset;
+                _rRight = new Rectangle(size.X - hintWindowsSize - borderMargin, centerY - hintWindowsSize2, hintWindowsSize, hintWindowsSize) + offset;
+                _rCenter = new Rectangle(centerX - hintWindowsSize2, centerY - hintWindowsSize2, hintWindowsSize, hintWindowsSize) + offset;
+
+                // Hit test, and calculate the approximation for filled area when hovered over the hint
+                DockState toSet = DockState.Float;
+                if (showBorderHints)
+                {
+                    if (_rUpper.Contains(_toDock.PointFromScreen(_mouse)))
+                    {
+                        toSet = DockState.DockTop;
+                        hoveredHintControl = _dockHintUp;
+                        hoveredSizeOverride = new Float2(size.X, hintPreviewSize.Y);
+                    }
+                    else if (_rBottom.Contains(_toDock.PointFromScreen(_mouse)))
+                    {
+                        toSet = DockState.DockBottom;
+                        hoveredHintControl = _dockHintDown;
+                        hoveredSizeOverride = new Float2(size.X, hintPreviewSize.Y);
+                    }
+                    else if (_rLeft.Contains(_toDock.PointFromScreen(_mouse)))
+                    {
+                        toSet = DockState.DockLeft;
+                        hoveredHintControl = _dockHintLeft;
+                        hoveredSizeOverride = new Float2(hintPreviewSize.X, size.Y);
+                    }
+                    else if (_rRight.Contains(_toDock.PointFromScreen(_mouse)))
+                    {
+                        toSet = DockState.DockRight;
+                        hoveredHintControl = _dockHintRight;
+                        hoveredSizeOverride = new Float2(hintPreviewSize.X, size.Y);
+                    }
+                }
+                if (showCenterHint && _rCenter.Contains(_toDock.PointFromScreen(_mouse)))
+                {
+                    toSet = DockState.DockFill;
+                    hoveredHintControl = _dockHintCenter;
+                    hoveredSizeOverride = new Float2(size.X, size.Y);
+                }
+
+                _toSet = toSet;
+            }
+            else
+            {
+                _toSet = DockState.Float;
+            }
+            
+            // Update sizes and opacity of hint controls
+            if (_toDock != null)
+            {
+                if (hoveredHintControl != _dockHintDown)
+                {
+                    _dockHintDown.Size = new Float2(HintControlSize);
+                    _dockHintDown.BackgroundColor = Style.Current.Selection.AlphaMultiplied(0.6f);
+                }
+                if (hoveredHintControl != _dockHintLeft)
+                {
+                    _dockHintLeft.Size = new Float2(HintControlSize);
+                    _dockHintLeft.BackgroundColor = Style.Current.Selection.AlphaMultiplied(0.6f);
+                }
+                if (hoveredHintControl != _dockHintRight)
+                {
+                    _dockHintRight.Size = new Float2(HintControlSize);
+                    _dockHintRight.BackgroundColor = Style.Current.Selection.AlphaMultiplied(0.6f);
+                }
+                if (hoveredHintControl != _dockHintUp)
+                {
+                    _dockHintUp.Size = new Float2(HintControlSize);
+                    _dockHintUp.BackgroundColor = Style.Current.Selection.AlphaMultiplied(0.6f);
+                }
+                if (hoveredHintControl != _dockHintCenter)
+                {
+                    _dockHintCenter.Size = new Float2(HintControlSize);
+                    _dockHintCenter.BackgroundColor = Style.Current.Selection.AlphaMultiplied(0.6f);
+                }
+
+                if (_toSet != DockState.Float)
+                {
+                    if (hoveredHintControl != null)
+                    {
+                        hoveredHintControl.BackgroundColor = Style.Current.Selection.AlphaMultiplied(1.0f);
+                        hoveredHintControl.Size = hoveredSizeOverride;
+                    }
+                }
+            }
+
+            // Update hint controls visibility and location
+            if (showProxyHints)
+            {
+                if (hoveredHintControl != _dockHintDown)
+                    _dockHintDown.Location = _rBottom.Location;
+                if (hoveredHintControl != _dockHintLeft)
+                    _dockHintLeft.Location = _rLeft.Location;
+                if (hoveredHintControl != _dockHintRight)
+                    _dockHintRight.Location = _rRight.Location;
+                if (hoveredHintControl != _dockHintUp)
+                    _dockHintUp.Location = _rUpper.Location;
+                if (hoveredHintControl != _dockHintCenter)
+                    _dockHintCenter.Location = _rCenter.Location;
+                
+                _dockHintDown.Visible = showProxyHints & showBorderHints;
+                _dockHintLeft.Visible = showProxyHints & showBorderHints;
+                _dockHintRight.Visible = showProxyHints & showBorderHints;
+                _dockHintUp.Visible = showProxyHints & showBorderHints;
+                _dockHintCenter.Visible = showProxyHints & showCenterHint;
+            }
+        }
+
+        private void OnMouseUp(ref Float2 location, MouseButton button, ref bool handled)
+        {
+            if (button == MouseButton.Left)
+                Dispose();
+        }
+
+        private void OnUpdate()
+        {
+            var mousePos = Platform.MousePosition;
+
+            if (_mouse != mousePos)
+                OnMouseMove(mousePos);
+        }
+        
+        private void OnMouseMove(Float2 mousePos)
+        {
+            if (_dragSourceWindow != null)
+                _toMove.Window.Window.Position = mousePos - _dragOffset;
+
+            UpdateRects(mousePos);
+        }
+    }
+}

Source/Editor/GUI/Input/ValueBox.cs

@@ -266,6 +266,7 @@ namespace FlaxEditor.GUI.Input
             return base.OnMouseDown(location, button);
         }
 
+#if !PLATFORM_SDL
         /// <inheritdoc />
         public override void OnMouseMove(Float2 location)
         {
@@ -292,13 +293,45 @@ namespace FlaxEditor.GUI.Input
             base.OnMouseMove(location);
         }
 
+#else
+
+        /// <inheritdoc />
+        public override void OnMouseMoveRelative(Float2 mouseMotion)
+        {
+            var location = Root.TrackingMouseOffset;
+            if (_isSliding)
+            {
+                // Update sliding
+                ApplySliding(Root.TrackingMouseOffset.X * _slideSpeed);
+                return;
+            }
+
+            // Update cursor type so user knows they can slide value
+            if (CanUseSliding && SlideRect.Contains(location) && !_isSliding)
+            {
+                Cursor = CursorType.SizeWE;
+                _cursorChanged = true;
+            }
+            else if (_cursorChanged && !_isSliding)
+            {
+                Cursor = CursorType.Default;
+                _cursorChanged = false;
+            }
+
+            base.OnMouseMoveRelative(mouseMotion);
+        }
+
+#endif
+
         /// <inheritdoc />
         public override bool OnMouseUp(Float2 location, MouseButton button)
         {
             if (button == MouseButton.Left && _isSliding)
             {
+#if !PLATFORM_SDL
                 // End sliding and return mouse to original location
                 RootWindow.MousePosition = _mouseClickedPosition;
+#endif
                 EndSliding();
                 return true;
             }

Source/Editor/GUI/MainMenu.cs

@@ -12,16 +12,6 @@ namespace FlaxEditor.GUI
     /// <seealso cref="FlaxEngine.GUI.ContainerControl" />
     public sealed class MainMenu : ContainerControl
     {
-#if PLATFORM_WINDOWS
-        private bool _useCustomWindowSystem;
-        private Image _icon;
-        private Label _title;
-        private Button _closeButton;
-        private Button _minimizeButton;
-        private Button _maximizeButton;
-        private LocalizedString _charChromeRestore, _charChromeMaximize;
-        private Window _window;
-#endif
         private MainMenuButton _selected;
 
         /// <summary>
@@ -60,200 +50,12 @@ namespace FlaxEditor.GUI
         /// <summary>
         /// Initializes a new instance of the <see cref="MainMenu"/> class.
         /// </summary>
-        /// <param name="mainWindow">The main window.</param>
-        public MainMenu(RootControl mainWindow)
+        public MainMenu()
         : base(0, 0, 0, 20)
         {
             AutoFocus = false;
             AnchorPreset = AnchorPresets.HorizontalStretchTop;
-
-#if PLATFORM_WINDOWS
-            _useCustomWindowSystem = !Editor.Instance.Options.Options.Interface.UseNativeWindowSystem;
-            if (_useCustomWindowSystem)
-            {
-                BackgroundColor = Style.Current.LightBackground;
-                Height = 28;
-
-                var windowIcon = FlaxEngine.Content.LoadAsyncInternal<Texture>(EditorAssets.WindowIcon);
-                FontAsset windowIconsFont = FlaxEngine.Content.LoadAsyncInternal<FontAsset>(EditorAssets.WindowIconsFont);
-                Font iconFont = windowIconsFont?.CreateFont(9);
-
-                _window = mainWindow.RootWindow.Window;
-                _window.HitTest += OnHitTest;
-                _window.Closed += OnWindowClosed;
-
-                ScriptsBuilder.GetBinariesConfiguration(out _, out _, out _, out var configuration);
-
-                _icon = new Image
-                {
-                    Margin = new Margin(6, 6, 6, 6),
-                    Brush = new TextureBrush(windowIcon),
-                    Color = Style.Current.Foreground,
-                    KeepAspectRatio = false,
-                    TooltipText = string.Format("{0}\nVersion {1}\nConfiguration {3}\nGraphics {2}", _window.Title, Globals.EngineVersion, GPUDevice.Instance.RendererType, configuration),
-                    Parent = this,
-                };
-
-                _title = new Label(0, 0, Width, Height)
-                {
-                    Text = _window.Title,
-                    HorizontalAlignment = TextAlignment.Center,
-                    VerticalAlignment = TextAlignment.Center,
-                    ClipText = true,
-                    TextColor = Style.Current.ForegroundGrey,
-                    TextColorHighlighted = Style.Current.ForegroundGrey,
-                    Parent = this,
-                };
-
-                _closeButton = new Button
-                {
-                    Text = ((char)EditorAssets.SegMDL2Icons.ChromeClose).ToString(),
-                    Font = new FontReference(iconFont),
-                    BackgroundColor = Color.Transparent,
-                    BorderColor = Color.Transparent,
-                    BorderColorHighlighted = Color.Transparent,
-                    BorderColorSelected = Color.Transparent,
-                    TextColor = Style.Current.Foreground,
-                    Width = 46,
-                    BackgroundColorHighlighted = Color.Red,
-                    BackgroundColorSelected = Color.Red.RGBMultiplied(1.3f),
-                    Parent = this,
-                };
-                _closeButton.Clicked += () => _window.Close(ClosingReason.User);
-
-                _minimizeButton = new Button
-                {
-                    Text = ((char)EditorAssets.SegMDL2Icons.ChromeMinimize).ToString(),
-                    Font = new FontReference(iconFont),
-                    BackgroundColor = Color.Transparent,
-                    BorderColor = Color.Transparent,
-                    BorderColorHighlighted = Color.Transparent,
-                    BorderColorSelected = Color.Transparent,
-                    TextColor = Style.Current.Foreground,
-                    Width = 46,
-                    BackgroundColorHighlighted = Style.Current.LightBackground.RGBMultiplied(1.3f),
-                    Parent = this,
-                };
-                _minimizeButton.Clicked += () => _window.Minimize();
-
-                _maximizeButton = new Button
-                {
-                    Text = ((char)(_window.IsMaximized ? EditorAssets.SegMDL2Icons.ChromeRestore : EditorAssets.SegMDL2Icons.ChromeMaximize)).ToString(),
-                    Font = new FontReference(iconFont),
-                    BackgroundColor = Color.Transparent,
-                    BorderColor = Color.Transparent,
-                    BorderColorHighlighted = Color.Transparent,
-                    BorderColorSelected = Color.Transparent,
-                    TextColor = Style.Current.Foreground,
-                    Width = 46,
-                    BackgroundColorHighlighted = Style.Current.LightBackground.RGBMultiplied(1.3f),
-                    Parent = this,
-                };
-                _maximizeButton.Clicked += () =>
-                {
-                    if (_window.IsMaximized)
-                        _window.Restore();
-                    else
-                        _window.Maximize();
-                };
-                _charChromeRestore = ((char)EditorAssets.SegMDL2Icons.ChromeRestore).ToString();
-                _charChromeMaximize = ((char)EditorAssets.SegMDL2Icons.ChromeMaximize).ToString();
-            }
-            else
-#endif
-            {
-                BackgroundColor = Style.Current.LightBackground;
-            }
-        }
-
-#if PLATFORM_WINDOWS
-        /// <inheritdoc />
-        public override void Update(float deltaTime)
-        {
-            base.Update(deltaTime);
-
-            if (_maximizeButton != null)
-            {
-                _maximizeButton.Text = _window.IsMaximized ? _charChromeRestore : _charChromeMaximize;
-            }
-        }
-
-        private void OnWindowClosed()
-        {
-            if (_window != null)
-            {
-                _window.HitTest = null;
-                _window = null;
-            }
-        }
-
-        private WindowHitCodes OnHitTest(ref Float2 mouse)
-        {
-            var dpiScale = _window.DpiScale;
-
-            if (_window.IsMinimized)
-                return WindowHitCodes.NoWhere;
-
-            if (!_window.IsMaximized)
-            {
-                var pos = _window.ScreenToClient(mouse * dpiScale); // pos is not DPI adjusted
-                var winSize = _window.Size;
-
-                // Distance from which the mouse is considered to be on the border/corner
-                float distance = 5.0f * dpiScale;
-
-                if (pos.Y > winSize.Y - distance && pos.X < distance)
-                    return WindowHitCodes.BottomLeft;
-
-                if (pos.X > winSize.X - distance && pos.Y > winSize.Y - distance)
-                    return WindowHitCodes.BottomRight;
-
-                if (pos.Y < distance && pos.X < distance)
-                    return WindowHitCodes.TopLeft;
-
-                if (pos.Y < distance && pos.X > winSize.X - distance)
-                    return WindowHitCodes.TopRight;
-
-                if (pos.X > winSize.X - distance)
-                    return WindowHitCodes.Right;
-
-                if (pos.X < distance)
-                    return WindowHitCodes.Left;
-
-                if (pos.Y < distance)
-                    return WindowHitCodes.Top;
-
-                if (pos.Y > winSize.Y - distance)
-                    return WindowHitCodes.Bottom;
-            }
-
-            var mousePos = PointFromScreen(mouse * dpiScale);
-            var controlUnderMouse = GetChildAt(mousePos);
-            var isMouseOverSth = controlUnderMouse != null && controlUnderMouse != _title;
-            var rb = GetRightButton();
-            if (rb != null && _minimizeButton != null && new Rectangle(rb.UpperRight, _minimizeButton.BottomLeft - rb.UpperRight).Contains(ref mousePos) && !isMouseOverSth)
-                return WindowHitCodes.Caption;
-
-            return WindowHitCodes.Client;
-        }
-#endif
-
-        /// <summary>
-        /// Return the rightmost button.
-        /// </summary>
-        /// <returns>Rightmost button, null if there is no <see cref="MainMenuButton"/></returns>
-        private MainMenuButton GetRightButton()
-        {
-            MainMenuButton b = null;
-            foreach (var control in Children)
-            {
-                if (b == null && control is MainMenuButton)
-                    b = (MainMenuButton)control;
-
-                if (control is MainMenuButton && control.Right > b.Right)
-                    b = (MainMenuButton)control;
-            }
-            return b;
+            BackgroundColor = Style.Current.LightBackground;
         }
 
         /// <summary>
@@ -298,26 +100,6 @@ namespace FlaxEditor.GUI
             return result;
         }
 
-        /// <inheritdoc />
-        public override bool OnMouseDoubleClick(Float2 location, MouseButton button)
-        {
-            if (base.OnMouseDoubleClick(location, button))
-                return true;
-
-#if PLATFORM_WINDOWS
-            var child = GetChildAtRecursive(location);
-            if (_useCustomWindowSystem && child is not Button && child is not MainMenuButton)
-            {
-                if (_window.IsMaximized)
-                    _window.Restore();
-                else
-                    _window.Maximize();
-            }
-#endif
-
-            return true;
-        }
-
         /// <inheritdoc />
         public override bool OnKeyDown(KeyboardKeys key)
         {
@@ -333,16 +115,8 @@ namespace FlaxEditor.GUI
         protected override void PerformLayoutAfterChildren()
         {
             float x = 0;
-
-#if PLATFORM_WINDOWS
-            if (_useCustomWindowSystem)
-            {
-                // Icon
-                _icon.X = x;
-                _icon.Size = new Float2(Height);
-                x += _icon.Width;
-            }
-#endif
+            WindowDecorations decorations = Parent.GetChild<WindowDecorations>();
+            x += decorations?.Icon?.Width ?? 0;
 
             // Arrange controls
             MainMenuButton rightMostButton = null;
@@ -361,37 +135,21 @@ namespace FlaxEditor.GUI
                     x += b.Width;
                 }
             }
-
-#if PLATFORM_WINDOWS
-            if (_useCustomWindowSystem)
-            {
-                // Buttons
-                _closeButton.Height = Height;
-                _closeButton.X = Width - _closeButton.Width;
-                _maximizeButton.Height = Height;
-                _maximizeButton.X = _closeButton.X - _maximizeButton.Width;
-                _minimizeButton.Height = Height;
-                _minimizeButton.X = _maximizeButton.X - _minimizeButton.Width;
-
-                // Title
-                _title.Bounds = new Rectangle(x + 2, 0, _minimizeButton.Left - x - 4, Height);
-                //_title.Text = _title.Width < 300.0f ? Editor.Instance.ProjectInfo.Name : _window.Title;
-            }
-#endif
+            
+            // Fill the right side if title and buttons are not present
+            if (decorations?.Title == null)
+                Width = Parent.Width;
+            else
+                Width = x;
         }
 
-#if PLATFORM_WINDOWS
         /// <inheritdoc />
         public override void OnDestroy()
         {
             base.OnDestroy();
-
-            if (_window != null)
-            {
-                _window.Closed -= OnWindowClosed;
-                OnWindowClosed();
-            }
+            
+            if (_selected != null)
+                Selected = null;
         }
-#endif
     }
 }

Source/Editor/GUI/MainMenuButton.cs

@@ -42,14 +42,12 @@ namespace FlaxEditor.GUI
             Text = text;
 
             var style = Style.Current;
-#if PLATFORM_WINDOWS
-            if (Editor.Instance.Options.Options.Interface.UseNativeWindowSystem)
+            if (!Utilities.Utils.UseCustomWindowDecorations())
             {
                 BackgroundColorMouseOver = style.BackgroundHighlighted;
                 BackgroundColorMouseOverOpened = style.Background;
             }
             else
-#endif
             {
                 BackgroundColorMouseOver = BackgroundColorMouseOverOpened = style.LightBackground * 1.3f;
             }

Source/Editor/GUI/WindowDecorations.cs

@@ -0,0 +1,342 @@
+// Copyright (c) Wojciech Figat. All rights reserved.
+
+using System;
+using FlaxEditor.GUI.Docking;
+using FlaxEditor.Options;
+using FlaxEngine;
+using FlaxEngine.GUI;
+
+namespace FlaxEditor.GUI;
+
+/// <summary>
+/// Represents the title bar of the window with buttons.
+/// </summary>
+/// <seealso cref="FlaxEngine.GUI.ContainerControl" />
+public class WindowDecorations : ContainerControl
+{
+    private Image _icon;
+    private Label _title;
+    private Button _closeButton;
+    private Button _minimizeButton;
+    private Button _maximizeButton;
+    private LocalizedString _charChromeRestore, _charChromeMaximize;
+    private Window _window;
+
+    /// <summary>
+    /// The title label in the title bar.
+    /// </summary>
+    public Label Title => _title;
+    
+    /// <summary>
+    /// The icon used in the title bar.
+    /// </summary>
+    public Image Icon => _icon;
+    
+    /// <summary>
+    /// The tooltip shown when hovering over the icon.
+    /// </summary>
+    public string IconTooltipText
+    {
+        get => _icon?.TooltipText ?? null;
+        set
+        {
+            if (_icon != null)
+                _icon.TooltipText = value;
+        }
+    }
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="WindowDecorations"/> class.
+    /// </summary>
+    /// <param name="window">The window.</param>
+    /// <param name="iconOnly">When set, omit drawing title and buttons.</param>
+    public WindowDecorations(RootControl window, bool iconOnly = false)
+    : base(0, 0, 0, 20)
+    {
+        _window = window.RootWindow.Window;
+        
+        AutoFocus = false;
+        AnchorPreset = AnchorPresets.HorizontalStretchTop;
+        BackgroundColor = Color.Transparent;
+
+        var windowIcon = FlaxEngine.Content.LoadAsyncInternal<Texture>(EditorAssets.WindowIcon);
+
+        _icon = new Image
+        {
+            Margin = new Margin(4, 4, 4, 4),
+            Brush = new TextureBrush(windowIcon),
+            Color = Style.Current.Foreground,
+            BackgroundColor = Style.Current.LightBackground,
+            KeepAspectRatio = false,
+            Parent = this,
+        };
+
+        if (!iconOnly)
+        {
+            _icon.Margin = new Margin(6, 6, 6, 6);
+            Height = 28;
+            
+            _window.HitTest += OnHitTest;
+            _window.Closed += OnWindowClosed;
+            
+            FontAsset windowIconsFont = FlaxEngine.Content.LoadAsyncInternal<FontAsset>(EditorAssets.WindowIconsFont);
+            Font iconFont = windowIconsFont?.CreateFont(9);
+            
+            _title = new Label(0, 0, Width, Height)
+            {
+                Text = _window.Title,
+                HorizontalAlignment = TextAlignment.Center,
+                VerticalAlignment = TextAlignment.Center,
+                ClipText = true,
+                TextColor = Style.Current.ForegroundGrey,
+                TextColorHighlighted = Style.Current.ForegroundGrey,
+                BackgroundColor = Style.Current.LightBackground,
+                Parent = this,
+            };
+
+            _closeButton = new Button
+            {
+                Text = ((char)EditorAssets.SegMDL2Icons.ChromeClose).ToString(),
+                Font = new FontReference(iconFont),
+                BackgroundColor = Style.Current.LightBackground,
+                BorderColor = Color.Transparent,
+                BorderColorHighlighted = Color.Transparent,
+                BorderColorSelected = Color.Transparent,
+                TextColor = Style.Current.Foreground,
+                Width = 46,
+                BackgroundColorHighlighted = Color.Red,
+                BackgroundColorSelected = Color.Red.RGBMultiplied(1.3f),
+                Parent = this,
+            };
+            _closeButton.Clicked += () => _window.Close(ClosingReason.User);
+
+            _minimizeButton = new Button
+            {
+                Text = ((char)EditorAssets.SegMDL2Icons.ChromeMinimize).ToString(),
+                Font = new FontReference(iconFont),
+                BackgroundColor = Style.Current.LightBackground,
+                BorderColor = Color.Transparent,
+                BorderColorHighlighted = Color.Transparent,
+                BorderColorSelected = Color.Transparent,
+                TextColor = Style.Current.Foreground,
+                Width = 46,
+                BackgroundColorHighlighted = Style.Current.LightBackground.RGBMultiplied(1.3f),
+                Parent = this,
+            };
+            _minimizeButton.Clicked += () => _window.Minimize();
+
+            _maximizeButton = new Button
+            {
+                Text = ((char)(_window.IsMaximized ? EditorAssets.SegMDL2Icons.ChromeRestore : EditorAssets.SegMDL2Icons.ChromeMaximize)).ToString(),
+                Font = new FontReference(iconFont),
+                BackgroundColor = Style.Current.LightBackground,
+                BorderColor = Color.Transparent,
+                BorderColorHighlighted = Color.Transparent,
+                BorderColorSelected = Color.Transparent,
+                TextColor = Style.Current.Foreground,
+                Width = 46,
+                BackgroundColorHighlighted = Style.Current.LightBackground.RGBMultiplied(1.3f),
+                Parent = this,
+            };
+            _maximizeButton.Clicked += () =>
+            {
+                if (_window.IsMaximized)
+                    _window.Restore();
+                else
+                    _window.Maximize();
+            };
+
+            _charChromeRestore = ((char)EditorAssets.SegMDL2Icons.ChromeRestore).ToString();
+            _charChromeMaximize = ((char)EditorAssets.SegMDL2Icons.ChromeMaximize).ToString();
+        }
+    }
+    
+    /// <inheritdoc />
+    public override void Update(float deltaTime)
+    {
+        base.Update(deltaTime);
+
+        if (_maximizeButton != null)
+        {
+            var maximizeText = _window.IsMaximized ? _charChromeRestore : _charChromeMaximize;
+            if (_maximizeButton.Text != maximizeText)
+                _maximizeButton.Text = maximizeText;
+        }
+    }
+
+    private void OnWindowClosed()
+    {
+        if (_window != null)
+        {
+            _window.HitTest -= OnHitTest;
+            _window = null;
+        }
+    }
+
+    /// <summary>
+    /// Perform hit test on the window.
+    /// </summary>
+    /// <param name="mouse">The mouse position</param>
+    /// <returns>The hit code for given position.</returns>
+    protected virtual WindowHitCodes OnHitTest(ref Float2 mouse)
+    {
+        if (_window.IsMinimized)
+            return WindowHitCodes.NoWhere;
+
+        var dpiScale = _window.DpiScale;
+        var pos = _window.ScreenToClient(mouse * dpiScale); // pos is not DPI adjusted
+        if (!_window.IsMaximized)
+        {
+            var winSize = _window.Size;
+
+            // Distance from which the mouse is considered to be on the border/corner
+            float distance = 5.0f * dpiScale;
+
+            if (pos.Y > winSize.Y - distance && pos.X < distance)
+                return WindowHitCodes.BottomLeft;
+
+            if (pos.X > winSize.X - distance && pos.Y > winSize.Y - distance)
+                return WindowHitCodes.BottomRight;
+
+            if (pos.Y < distance && pos.X < distance)
+                return WindowHitCodes.TopLeft;
+
+            if (pos.Y < distance && pos.X > winSize.X - distance)
+                return WindowHitCodes.TopRight;
+
+            if (pos.X > winSize.X - distance)
+                return WindowHitCodes.Right;
+
+            if (pos.X < distance)
+                return WindowHitCodes.Left;
+
+            if (pos.Y < distance)
+                return WindowHitCodes.Top;
+
+            if (pos.Y > winSize.Y - distance)
+                return WindowHitCodes.Bottom;
+        }
+        
+        var controlUnderMouse = GetChildAt(pos, control => control != _title);
+        if (_title.Bounds.Contains(pos) && controlUnderMouse == null)
+            return WindowHitCodes.Caption;
+
+        return WindowHitCodes.Client;
+    }
+    
+    /// <inheritdoc />
+    public override bool OnMouseDoubleClick(Float2 location, MouseButton button)
+    {
+        // These may not work with main window due to SDL not passing mouse events
+        // when interacting with hit tests on caption area...
+        
+        if (Title.Bounds.Contains(location) && button == MouseButton.Left)
+        {
+            if (_window.IsMaximized)
+                _window.Restore();
+            else
+                _window.Maximize();
+            return true;
+        }
+        else if (Icon.Bounds.Contains(location) && button == MouseButton.Left)
+        {
+            _window.Close(ClosingReason.User);
+            return true;
+        }
+        return base.OnMouseDoubleClick(location, button);
+    }
+
+    /// <inheritdoc />
+    protected override void PerformLayoutAfterChildren()
+    {
+        // Calculate extents for title bounds area excluding the icon and main menu area
+        float x = 0;
+        
+        // Icon
+        if (_icon != null)
+        {
+            _icon.X = x;
+            _icon.Size = new Float2(Height);
+            x += _icon.Width;
+        }
+
+        // Main menu if present
+        if (Parent.GetChild<MainMenu>() is MainMenu mainMenu)
+        {
+            for (int i = 0; i < mainMenu.Children.Count; i++)
+            {
+                var c = mainMenu.Children[i];
+                if (c is MainMenuButton b && c.Visible)
+                {
+                    b.Bounds = new Rectangle(x, 0, b.Width, Height);
+                    x += b.Width;
+                }
+            }
+        }
+     
+        // Buttons
+        float rightMostButtonX = Width;
+        if (_closeButton != null)
+        {
+            _closeButton.Height = Height;
+            _closeButton.X = rightMostButtonX - _closeButton.Width;
+            rightMostButtonX = _closeButton.X;
+        }
+        if (_maximizeButton != null)
+        {
+            _maximizeButton.Height = Height;
+            _maximizeButton.X = rightMostButtonX - _maximizeButton.Width;
+            rightMostButtonX = _maximizeButton.X;
+        }
+        if (_minimizeButton != null)
+        {
+            _minimizeButton.Height = Height;
+            _minimizeButton.X = rightMostButtonX - _minimizeButton.Width;
+            rightMostButtonX = _minimizeButton.X;
+        }
+
+        // Title
+        if (_title != null)
+        {
+            _title.Text = _window.Title;
+            _title.Bounds = new Rectangle(x, 0, rightMostButtonX - x, Height);
+        }
+    }
+    
+    /// <inheritdoc />
+    public override void Draw()
+    {
+        base.Draw();
+        DrawBorders();
+    }
+
+    /// <summary>
+    /// Draw borders around the window.
+    /// </summary>
+    public virtual void DrawBorders()
+    {
+        var win = RootWindow.Window;
+        if (win.IsMaximized)
+            return;
+
+        if (Editor.Instance.UI.StatusBar == null)
+            return;
+        
+        const float thickness = 1.0f;
+        Color color = Editor.Instance.UI.StatusBar.StatusColor;
+        Rectangle rect = new Rectangle(thickness * 0.5f, thickness * 0.5f, Parent.Width - thickness, Parent.Height - thickness);
+        Render2D.DrawRectangle(rect, color);
+    }
+
+    /// <inheritdoc />
+    public override void OnDestroy()
+    {
+        base.OnDestroy();
+
+        if (_window != null)
+        {
+            _window.Closed -= OnWindowClosed;
+            OnWindowClosed();
+        }
+    }
+}

Source/Editor/Managed/ManagedEditor.Internal.cpp

@@ -402,10 +402,11 @@ DEFINE_INTERNAL_CALL(void) EditorInternal_RunVisualScriptBreakpointLoopTick(floa
                 break;
             }
         }
+        WindowsManager::WindowsLocker.Unlock();
         for (const auto& e : inputEvents)
         {
             auto window = e.Target ? e.Target : defaultWindow;
-            if (!window)
+            if (!window || window->IsClosed())
                 continue;
             switch (e.Type)
             {
@@ -435,12 +436,14 @@ DEFINE_INTERNAL_CALL(void) EditorInternal_RunVisualScriptBreakpointLoopTick(floa
             case InputDevice::EventType::MouseMove:
                 window->OnMouseMove(window->ScreenToClient(e.MouseData.Position));
                 break;
+            case InputDevice::EventType::MouseMoveRelative:
+                window->OnMouseMoveRelative(e.MouseMovementData.PositionRelative);
+                break;
             case InputDevice::EventType::MouseLeave:
                 window->OnMouseLeave();
                 break;
             }
         }
-        WindowsManager::WindowsLocker.Unlock();
     }
     WindowsManager::WindowsLocker.Lock();
     Array<Window*, InlinedAllocation<32>> windows;

Source/Editor/Modules/ContentDatabaseModule.cs

@@ -1013,7 +1013,7 @@ namespace FlaxEditor.Modules
                     ContentItem item;
                     if (path.EndsWith(".cs"))
                         item = new CSharpScriptItem(path);
-                    else if (path.EndsWith(".cpp") || path.EndsWith(".h"))
+                    else if (path.EndsWith(".cpp") || path.EndsWith(".h") || path.EndsWith(".c") || path.EndsWith(".hpp"))
                         item = new CppScriptItem(path);
                     else if (path.EndsWith(".shader") || path.EndsWith(".hlsl"))
                         item = new ShaderSourceItem(path);

Source/Editor/Modules/ContentImportingModule.cs

@@ -222,7 +222,7 @@ namespace FlaxEditor.Modules
                 outputExtension = extension;
 
                 // Check if can place source files here
-                if (!targetLocation.CanHaveScripts && (extension == ".cs" || extension == ".cpp" || extension == ".h"))
+                if (!targetLocation.CanHaveScripts && (extension == ".cs" || extension == ".cpp" || extension == ".h" || extension == ".c" || extension == ".hpp"))
                 {
                     // Error
                     Editor.LogWarning(string.Format("Cannot import \'{0}\' to \'{1}\'. The target directory cannot have scripts.", inputPath, targetLocation.Node.Path));

Source/Editor/Modules/SimulationModule.cs

@@ -267,7 +267,7 @@ namespace FlaxEditor.Modules
         }
 
         /// <inheritdoc />
-        public override void OnPlayBegin()
+        public override void OnPlayBeginning()
         {
             Editor.Windows.FlashMainWindow();
 

Source/Editor/Modules/UIModule.cs

@@ -16,7 +16,6 @@ using FlaxEditor.Windows;
 using FlaxEngine;
 using FlaxEngine.GUI;
 using FlaxEngine.Json;
-using DockHintWindow = FlaxEditor.GUI.Docking.DockHintWindow;
 using MasterDockPanel = FlaxEditor.GUI.Docking.MasterDockPanel;
 using FlaxEditor.Content.Settings;
 using FlaxEditor.Options;
@@ -29,6 +28,40 @@ namespace FlaxEditor.Modules
     /// <seealso cref="FlaxEditor.Modules.EditorModule" />
     public sealed class UIModule : EditorModule
     {
+        private class MainWindowDecorations : WindowDecorations
+        {
+            public MainWindowDecorations(RootControl window, bool iconOnly) 
+            : base(window, iconOnly)
+            {
+            }
+
+            /// <inheritdoc />
+            public override bool OnKeyDown(KeyboardKeys key)
+            {
+                if (base.OnKeyDown(key))
+                    return true;
+
+                // Fallback to the edit window for shortcuts
+                var editor = Editor.Instance;
+                return editor.Windows.EditWin.InputActions.Process(editor, this, key);
+            }
+            
+            /// <inheritdoc />
+            public override void DrawBorders()
+            {
+                // Draw main window borders if using a custom style
+                var win = RootWindow.Window;
+                if (win.IsMaximized)
+                    return;
+
+                var color = Editor.Instance.UI.StatusBar.StatusColor;
+                var rect = new Rectangle(0.5f, 0.5f, Parent.Width - 1.0f, Parent.Height - 1.0f - StatusBar.DefaultHeight);
+                Render2D.DrawLine(rect.UpperLeft, rect.UpperRight, color);
+                Render2D.DrawLine(rect.UpperLeft, rect.BottomLeft, color);
+                Render2D.DrawLine(rect.UpperRight, rect.BottomRight, color);
+            }
+        }
+        
         private Label _progressLabel;
         private ProgressBar _progressBar;
         private Button _outputLogButton;
@@ -144,6 +177,11 @@ namespace FlaxEditor.Modules
         /// </summary>
         public MainMenu MainMenu;
 
+        /// <summary>
+        /// The window decorations (title bar with buttons)
+        /// </summary>
+        public WindowDecorations WindowDecorations;
+
         /// <summary>
         /// The tool strip control.
         /// </summary>
@@ -426,19 +464,11 @@ namespace FlaxEditor.Modules
             InitToolstrip(mainWindow);
             InitStatusBar(mainWindow);
             InitDockPanel(mainWindow);
+            InitWindowDecorations(mainWindow);
 
             Editor.Options.OptionsChanged += OnOptionsChanged;
-
-            // Add dummy control for drawing the main window borders if using a custom style
-#if PLATFORM_WINDOWS
-            if (!Editor.Options.Options.Interface.UseNativeWindowSystem)
-#endif
-            {
-                mainWindow.AddChild(new CustomWindowBorderControl
-                {
-                    Size = Float2.Zero,
-                });
-            }
+            
+            mainWindow.PerformLayout(true);
         }
 
         private void InitViewportScaleOptions()
@@ -510,23 +540,6 @@ namespace FlaxEditor.Modules
             }
         }
 
-        private class CustomWindowBorderControl : Control
-        {
-            /// <inheritdoc />
-            public override void Draw()
-            {
-                var win = RootWindow.Window;
-                if (win.IsMaximized)
-                    return;
-
-                var color = Editor.Instance.UI.StatusBar.StatusColor;
-                var rect = new Rectangle(0.5f, 0.5f, Parent.Width - 1.0f, Parent.Height - 1.0f - StatusBar.DefaultHeight);
-                Render2D.DrawLine(rect.UpperLeft, rect.UpperRight, color);
-                Render2D.DrawLine(rect.UpperLeft, rect.BottomLeft, color);
-                Render2D.DrawLine(rect.UpperRight, rect.BottomRight, color);
-            }
-        }
-
         /// <inheritdoc />
         public override void OnEndInit()
         {
@@ -558,13 +571,6 @@ namespace FlaxEditor.Modules
             UpdateToolstrip();
         }
 
-        /// <inheritdoc />
-        public override void OnExit()
-        {
-            // Cleanup dock panel hint proxy windows (Flax will destroy them by var but it's better to clear them earlier)
-            DockHintWindow.Proxy.Dispose();
-        }
-
         private IColorPickerDialog ShowPickColorDialog(Control targetControl, Color initialValue, ColorValueBox.ColorPickerEvent colorChanged, ColorValueBox.ColorPickerClosedEvent pickerClosed, bool useDynamicEditing)
         {
             var dialog = new ColorPickerDialog(initialValue, colorChanged, pickerClosed, useDynamicEditing);
@@ -618,10 +624,12 @@ namespace FlaxEditor.Modules
 
         private void InitMainMenu(RootControl mainWindow)
         {
-            MainMenu = new MainMenu(mainWindow)
+            MainMenu = new MainMenu()
             {
                 Parent = mainWindow
             };
+            if (Utilities.Utils.UseCustomWindowDecorations(isMainWindow: true))
+                MainMenu.Height = 28;
 
             var inputOptions = Editor.Options.Options.Input;
 
@@ -762,6 +770,20 @@ namespace FlaxEditor.Modules
             cm.AddButton("Information about Flax", () => new AboutDialog().Show());
         }
 
+        private void InitWindowDecorations(RootControl mainWindow)
+        {
+            ScriptsBuilder.GetBinariesConfiguration(out _, out _, out _, out var configuration);
+            var driver = Platform.DisplayServer;
+            if (!string.IsNullOrEmpty(driver))
+                driver = $" ({driver})";
+            
+            WindowDecorations = new MainWindowDecorations(mainWindow, !Utilities.Utils.UseCustomWindowDecorations(isMainWindow: true))
+            {
+                Parent = mainWindow,
+                IconTooltipText = $"{mainWindow.RootWindow.Title}\nVersion {Globals.EngineVersion}\nConfiguration {configuration}\nGraphics {GPUDevice.Instance.RendererType}{driver}",
+            };
+        }
+        
         private void OnOptionsChanged(EditorOptions options)
         {
             var inputOptions = options.Input;
@@ -1182,6 +1204,7 @@ namespace FlaxEditor.Modules
         {
             // Clear UI references (GUI cannot be used after window closing)
             MainMenu = null;
+            WindowDecorations = null;
             ToolStrip = null;
             MasterPanel = null;
             StatusBar = null;

Source/Editor/Modules/WindowsModule.cs

@@ -10,7 +10,6 @@ using System.Text;
 using System.Xml;
 using FlaxEditor.Content;
 using FlaxEditor.GUI.Dialogs;
-using FlaxEditor.GUI.Docking;
 using FlaxEditor.Windows;
 using FlaxEditor.Windows.Assets;
 using FlaxEditor.Windows.Profiler;
@@ -758,17 +757,19 @@ namespace FlaxEditor.Modules
             var settings = CreateWindowSettings.Default;
             settings.Title = "Flax Editor";
             settings.Size = Platform.DesktopSize * 0.75f;
+            settings.MinimumSize = new Float2(200, 150);
             settings.StartPosition = WindowStartPosition.CenterScreen;
             settings.ShowAfterFirstPaint = true;
-#if PLATFORM_WINDOWS
-            if (!Editor.Instance.Options.Options.Interface.UseNativeWindowSystem)
+            
+            if (Utilities.Utils.UseCustomWindowDecorations(isMainWindow: true))
             {
                 settings.HasBorder = false;
-
+#if PLATFORM_WINDOWS && !PLATFORM_SDL
                 // Skip OS sizing frame and implement it using LeftButtonHit
                 settings.HasSizingFrame = false;
+#endif
             }
-#elif PLATFORM_LINUX
+#if PLATFORM_LINUX && !PLATFORM_SDL
             settings.HasBorder = false;
 #endif
             MainWindow = Platform.CreateWindow(ref settings);

Source/Editor/Options/InterfaceOptions.cs

@@ -179,6 +179,34 @@ namespace FlaxEditor.Options
             GameWindowThenRestore,
         }
 
+        /// <summary>
+        /// Options for type of window decorations to use.
+        /// </summary>
+        public enum WindowDecorationsType
+        {
+            /// <summary>
+            /// Determined automatically based on the system and any known compatibility issues with native decorations.
+            /// </summary>
+            Auto,
+            
+            /// <summary>
+            /// Automatically choose most compatible window decorations for child windows, prefer custom decorations on main window.
+            /// </summary>
+            [EditorDisplay(Name = "Auto (Child Only)")]
+            AutoChildOnly,
+            
+            /// <summary>
+            /// Use native system window decorations on all windows.
+            /// </summary>
+            Native,
+            
+            /// <summary>
+            /// Use custom client-side window decorations on all windows.
+            /// </summary>
+            [EditorDisplay(Name = "Client-side")]
+            ClientSide,
+        }
+
         /// <summary>
         /// Gets or sets the Editor User Interface scale. Applied to all UI elements, windows and text. Can be used to scale the interface up on a bigger display. Editor restart required.
         /// </summary>
@@ -268,7 +296,14 @@ namespace FlaxEditor.Options
         [EditorDisplay("Interface"), EditorOrder(322)]
         public bool ScrollToScriptOnAdd { get; set; } = true;
 
-#if PLATFORM_WINDOWS
+#if PLATFORM_SDL
+        /// <summary>
+        /// Gets or sets a value indicating whether use native window title bar decorations in child windows. Editor restart required.
+        /// </summary>
+        [DefaultValue(WindowDecorationsType.AutoChildOnly)]
+        [EditorDisplay("Interface"), EditorOrder(70), Tooltip("Determines whether use native window title bar decorations. Editor restart required.")]
+        public WindowDecorationsType WindowDecorations { get; set; } = WindowDecorationsType.AutoChildOnly;
+#elif PLATFORM_WINDOWS
         /// <summary>
         /// Gets or sets a value indicating whether use native window title bar. Editor restart required.
         /// </summary>
@@ -277,7 +312,7 @@ namespace FlaxEditor.Options
         public bool UseNativeWindowSystem { get; set; } = false;
 #endif
 
-#if PLATFORM_WINDOWS
+#if PLATFORM_SDL || PLATFORM_WINDOWS
         /// <summary>
         /// Gets or sets a value indicating whether a window containing a single tabs hides the tab bar. Editor restart recommended.
         /// </summary>

Source/Editor/Scripting/ScriptsBuilder.cpp

@@ -120,9 +120,13 @@ void ScriptsBuilderImpl::sourceDirEvent(const String& path, FileSystemAction act
     // Discard non-source files or generated files
     if ((!path.EndsWith(TEXT(".cs")) &&
         !path.EndsWith(TEXT(".cpp")) &&
+        !path.EndsWith(TEXT(".c")) &&
+        !path.EndsWith(TEXT(".hpp")) &&
         !path.EndsWith(TEXT(".h"))) ||
         path.EndsWith(TEXT(".Gen.cs")))
+    {
         return;
+    }
 
     ScopeLock scopeLock(_locker);
     _lastSourceCodeEdited = DateTime::Now();

Source/Editor/Utilities/ScreenUtilities.cpp

@@ -1,131 +0,0 @@
-// Copyright (c) Wojciech Figat. All rights reserved.
-
-#include "ScreenUtilities.h"
-#include "Engine/Core/Math/Vector2.h"
-#include "Engine/Core/Delegate.h"
-#include "Engine/Core/Log.h"
-#include "Engine/Profiler/ProfilerCPU.h"
-
-Delegate<Color32> ScreenUtilities::PickColorDone;
-
-#if PLATFORM_WINDOWS
-
-#include <Windows.h>
-
-#pragma comment(lib, "Gdi32.lib")
-
-static HHOOK MouseCallbackHook;
-
-LRESULT CALLBACK OnScreenUtilsMouseCallback(_In_ int nCode, _In_ WPARAM wParam, _In_ LPARAM lParam)
-{
-    if (nCode >= 0 && wParam == WM_LBUTTONDOWN)
-    {
-        UnhookWindowsHookEx(MouseCallbackHook);
-
-        // Push event with the picked color
-        const Float2 cursorPos = Platform::GetMousePosition();
-        const Color32 colorPicked = ScreenUtilities::GetColorAt(cursorPos);
-        ScreenUtilities::PickColorDone(colorPicked);
-        return 1;
-    }
-    return CallNextHookEx(NULL, nCode, wParam, lParam);
-}
-
-Color32 ScreenUtilities::GetColorAt(const Float2& pos)
-{
-    PROFILE_CPU();
-    HDC deviceContext = GetDC(NULL);
-    COLORREF color = GetPixel(deviceContext, (int)pos.X, (int)pos.Y);
-    ReleaseDC(NULL, deviceContext);
-    return Color32(GetRValue(color), GetGValue(color), GetBValue(color), 255);
-}
-
-void ScreenUtilities::PickColor()
-{
-    MouseCallbackHook = SetWindowsHookEx(WH_MOUSE_LL, OnScreenUtilsMouseCallback, NULL, NULL);
-    if (MouseCallbackHook == NULL)
-    {
-        LOG(Warning, "Failed to set mouse hook.");
-        LOG(Warning, "Error: {0}", GetLastError());
-    }
-}
-
-#elif PLATFORM_LINUX
-
-#include "Engine/Platform/Linux/LinuxPlatform.h"
-#include "Engine/Platform/Linux/IncludeX11.h"
-
-Color32 ScreenUtilities::GetColorAt(const Float2& pos)
-{
-    X11::XColor color;
-    
-    X11::Display* display = (X11::Display*) LinuxPlatform::GetXDisplay();
-    int defaultScreen = X11::XDefaultScreen(display);
-
-    X11::XImage* image;
-    image = X11::XGetImage(display, X11::XRootWindow(display, defaultScreen), (int)pos.X, (int)pos.Y, 1, 1, AllPlanes, XYPixmap);
-    color.pixel = XGetPixel(image, 0, 0);
-    X11::XFree(image);
-
-    X11::XQueryColor(display, X11::XDefaultColormap(display, defaultScreen), &color);
-
-    Color32 outputColor;
-    outputColor.R = color.red / 256;
-    outputColor.G = color.green / 256;
-    outputColor.B = color.blue / 256;
-    outputColor.A = 255;
-    return outputColor;
-}
-
-void OnScreenUtilsXEventCallback(void* eventPtr)
-{
-    X11::XEvent* event = (X11::XEvent*) eventPtr;
-    X11::Display* display = (X11::Display*)LinuxPlatform::GetXDisplay();
-    if (event->type == ButtonPress)
-    {
-        const Float2 cursorPos = Platform::GetMousePosition();
-        const Color32 colorPicked = ScreenUtilities::GetColorAt(cursorPos);
-        X11::XUngrabPointer(display, CurrentTime);
-        ScreenUtilities::PickColorDone(colorPicked);
-        LinuxPlatform::xEventRecieved.Unbind(OnScreenUtilsXEventCallback);
-    }
-}
-
-void ScreenUtilities::PickColor()
-{
-    PROFILE_CPU();
-    X11::Display* display = (X11::Display*) LinuxPlatform::GetXDisplay();
-    X11::Window rootWindow = X11::XRootWindow(display, X11::XDefaultScreen(display));
-
-    X11::Cursor cursor = XCreateFontCursor(display, 130);
-    int grabbedPointer = X11::XGrabPointer(display, rootWindow, 0,  ButtonPressMask, GrabModeAsync, GrabModeAsync, rootWindow, cursor, CurrentTime);
-    if (grabbedPointer != GrabSuccess)
-    {
-        LOG(Error, "Failed to grab cursor for events.");
-        X11::XFreeCursor(display, cursor);
-        return;
-    }
-
-    X11::XFreeCursor(display, cursor);
-    LinuxPlatform::xEventRecieved.Bind(OnScreenUtilsXEventCallback);
-}
-
-#elif PLATFORM_MAC
-
-#include <Cocoa/Cocoa.h>
-#include <AppKit/AppKit.h>
-
-Color32 ScreenUtilities::GetColorAt(const Float2& pos)
-{
-    // TODO: implement ScreenUtilities for macOS
-    return { 0, 0, 0, 255 };
-}
-
-void ScreenUtilities::PickColor()
-{
-    // This is what C# calls to start the color picking sequence
-    // This should stop mouse clicks from working for one click, and that click is on the selected color
-    // There is a class called NSColorSample that might implement that for you, but maybe not.
-}
-
-#endif

Source/Editor/Utilities/ScreenUtilities.h

@@ -2,32 +2,4 @@
 
 #pragma once
 
-#include "Engine/Core/Types/BaseTypes.h"
-#include "Engine/Core/Math/Color32.h"
-#include "Engine/Core/Math/Vector2.h"
-#include "Engine/Core/Delegate.h"
-
-/// <summary>
-/// Platform-dependent screen utilities.
-/// </summary>
-API_CLASS(Static) class FLAXENGINE_API ScreenUtilities
-{
-    DECLARE_SCRIPTING_TYPE_MINIMAL(ScreenUtilities);
-
-    /// <summary>
-    /// Gets the pixel color at the specified coordinates.
-    /// </summary>
-    /// <param name="pos">Screen-space coordinate to read.</param>
-    /// <returns>Pixel color at the specified coordinates.</returns>
-    API_FUNCTION() static Color32 GetColorAt(const Float2& pos);
-
-    /// <summary>
-    /// Starts async color picking. Color will be returned through PickColorDone event when the actions ends (user selected the final color with a mouse). When action is active, GetColorAt can be used to read the current value.
-    /// </summary>
-    API_FUNCTION() static void PickColor();
-
-    /// <summary>
-    /// Called when PickColor action is finished.
-    /// </summary>
-    API_EVENT() static Delegate<Color32> PickColorDone;
-};
+#include "Engine/Platform/ScreenUtilities.h"

Source/Editor/Utilities/Utils.cs

@@ -1583,5 +1583,31 @@ namespace FlaxEditor.Utilities
                 c = c.Parent;
             return c as ISceneEditingContext;
         }
+
+        internal static bool UseCustomWindowDecorations(bool isMainWindow = false)
+        {
+            return Editor.Instance.Options.Options.Interface.WindowDecorations switch
+            {
+                Options.InterfaceOptions.WindowDecorationsType.Auto => !Platform.SupportsNativeDecorations,
+                Options.InterfaceOptions.WindowDecorationsType.AutoChildOnly => !isMainWindow ? !Platform.SupportsNativeDecorations : true,
+                Options.InterfaceOptions.WindowDecorationsType.Native => false,
+                Options.InterfaceOptions.WindowDecorationsType.ClientSide => true,
+                _ => throw new ArgumentOutOfRangeException()
+            };
+        }
+
+        internal static bool HideSingleTabWindowTabBars()
+        {
+#if PLATFORM_SDL
+            // We should not hide the tab bars if tab handle is the only way to dock the window
+            bool clientSideDecorations = UseCustomWindowDecorations(false);
+            bool draggableDecorations = clientSideDecorations || Platform.SupportsNativeDecorationDragging;
+            return draggableDecorations && Editor.Instance.Options.Options.Interface.HideSingleTabWindowTabBars;
+#elif PLATFORM_WINDOWS
+            return Editor.Instance.Options.Options.Interface.HideSingleTabWindowTabBars;
+#else
+            return false;
+#endif
+        }
     }
 }

Source/Editor/Viewport/EditorGizmoViewport.cs

@@ -77,7 +77,7 @@ namespace FlaxEditor.Viewport
         public bool SnapToVertex => ContainsFocus && Editor.Instance.Options.Options.Input.SnapToVertex.Process(Root);
 
         /// <inheritdoc />
-        public Float2 MouseDelta => _mouseDelta;
+        public Float2 MouseDelta => FlaxEngine.Input.MousePositionDelta;
 
         /// <inheritdoc />
         public bool UseSnapping => Root?.GetKey(KeyboardKeys.Control) ?? false;

Source/Editor/Viewport/EditorViewport.cs

@@ -4,6 +4,7 @@ using System;
 using System.Linq;
 using FlaxEditor.Content.Settings;
 using FlaxEditor.GUI.ContextMenu;
+using FlaxEditor.GUI.Docking;
 using FlaxEditor.GUI.Input;
 using FlaxEditor.Options;
 using FlaxEditor.Viewport.Cameras;
@@ -158,18 +159,22 @@ namespace FlaxEditor.Viewport
         private float _movementSpeed;
         private float _minMovementSpeed;
         private float _maxMovementSpeed;
+#if !PLATFORM_SDL
         private float _mouseAccelerationScale;
         private bool _useMouseFiltering;
         private bool _useMouseAcceleration;
+#endif
 
         // Input
 
         internal bool _disableInputUpdate;
         private bool _isControllingMouse, _isViewportControllingMouse, _wasVirtualMouseRightDown, _isVirtualMouseRightDown;
-        private int _deltaFilteringStep;
         private Float2 _startPos;
+#if !PLATFORM_SDL
         private Float2 _mouseDeltaLast;
+        private int _deltaFilteringStep;
         private Float2[] _deltaFilteringBuffer = new Float2[FpsCameraFilteringFrames];
+#endif
 
         /// <summary>
         /// The previous input (from the previous update).
@@ -522,10 +527,11 @@ namespace FlaxEditor.Viewport
         : base(task)
         {
             _editor = Editor.Instance;
-
+#if !PLATFORM_SDL
             _mouseAccelerationScale = 0.1f;
             _useMouseFiltering = false;
             _useMouseAcceleration = false;
+#endif
             _camera = camera;
             if (_camera != null)
                 _camera.Viewport = this;
@@ -1525,7 +1531,9 @@ namespace FlaxEditor.Viewport
             // Hide cursor and start tracking mouse movement
             win.StartTrackingMouse(false);
             win.Cursor = CursorType.Hidden;
+            win.MouseMoveRelative += OnMouseMoveRelative;
 
+#if !PLATFORM_SDL
             // Center mouse position if it's too close to the edge
             var size = Size;
             var center = Float2.Round(size * 0.5f);
@@ -1534,6 +1542,7 @@ namespace FlaxEditor.Viewport
                 _viewMousePos = center;
                 win.MousePosition = PointToWindow(_viewMousePos);
             }
+#endif
         }
 
         /// <summary>
@@ -1545,6 +1554,7 @@ namespace FlaxEditor.Viewport
             // Restore cursor and stop tracking mouse movement
             win.Cursor = CursorType.Default;
             win.EndTrackingMouse();
+            win.MouseMoveRelative -= OnMouseMoveRelative;
         }
 
         /// <summary>
@@ -1626,18 +1636,15 @@ namespace FlaxEditor.Viewport
 
             // Get parent window
             var win = (WindowRootControl)Root;
-
-            // Get current mouse position in the view
+            if (win.IsFocused)
             {
-                // When the window is not focused, the position in window does not return sane values
-                Float2 pos = PointFromWindow(win.MousePosition);
-                if (!float.IsInfinity(pos.LengthSquared))
-                    _viewMousePos = pos;
+                // Get current mouse position in the view
+                _viewMousePos = PointFromWindow(win.MousePosition);
             }
 
             // Update input
             var window = win.Window;
-            var canUseInput = window != null && window.IsFocused && window.IsForegroundWindow;
+            var canUseInput = window != null && window.IsFocused && window.IsForegroundWindow && !WindowDragHelper.IsDragActive;
             {
                 // Get input buttons and keys (skip if viewport has no focus or mouse is over a child control)
                 var isViewportControllingMouse = canUseInput && IsControllingMouse;
@@ -1649,9 +1656,17 @@ namespace FlaxEditor.Viewport
                     else
                         EndMouseCapture();
                 }
-                bool useMouse = IsControllingMouse || (Mathf.IsInRange(_viewMousePos.X, 0, Width) && Mathf.IsInRange(_viewMousePos.Y, 0, Height));
+                
                 _prevInput = _input;
+#if PLATFORM_SDL
+                bool useMouse = IsControllingMouse || ContainsPoint(ref _viewMousePos) || _prevInput.IsControllingMouse;
                 var hit = GetChildAt(_viewMousePos, c => c.Visible && !(c is CanvasRootControl) && !(c is UIEditorRoot));
+                if (_prevInput.IsControllingMouse)
+                    hit = null;
+#else
+                bool useMouse = IsControllingMouse || ContainsPoint(ref _viewMousePos);
+                var hit = GetChildAt(_viewMousePos, c => c.Visible && !(c is CanvasRootControl) && !(c is UIEditorRoot));
+#endif
                 if (canUseInput && ContainsFocus && hit == null)
                     _input.Gather(win.Window, useMouse, ref _prevInput);
                 else
@@ -1764,6 +1779,10 @@ namespace FlaxEditor.Viewport
                 if (_input.IsControlDown)
                     moveDelta *= 0.3f;
 
+#if PLATFORM_SDL
+                var mouseDelta = _mouseDelta;
+                _mouseDelta = Float2.Zero;
+#else
                 // Calculate smooth mouse delta not dependant on viewport size
                 var offset = _viewMousePos - _startPos;
                 if (_input.IsZooming && !_input.IsMouseRightDown && !_input.IsMouseLeftDown && !_input.IsMouseMiddleDown && !_isOrtho && !rmbWheel && !_isVirtualMouseRightDown)
@@ -1805,6 +1824,7 @@ namespace FlaxEditor.Viewport
                     mouseDelta += _mouseDeltaLast * _mouseAccelerationScale;
                     _mouseDeltaLast = currentDelta;
                 }
+#endif
 
                 // Update
                 moveDelta *= dt * (60.0f * 4.0f);
@@ -1813,12 +1833,14 @@ namespace FlaxEditor.Viewport
                     mouseDelta *= new Float2(1, -1);
                 UpdateView(dt, ref moveDelta, ref mouseDelta, out var centerMouse);
 
+#if !PLATFORM_SDL
                 // Move mouse back to the root position
                 if (centerMouse && (_input.IsMouseRightDown || _input.IsMouseLeftDown || _input.IsMouseMiddleDown || _isVirtualMouseRightDown))
                 {
                     var center = PointToWindow(_startPos);
                     win.MousePosition = center;
                 }
+#endif
 
                 // Change Ortho size on mouse scroll
                 if (_isOrtho && !rmbWheel)
@@ -1830,6 +1852,8 @@ namespace FlaxEditor.Viewport
             }
             else
             {
+#if PLATFORM_SDL
+#else
                 if (_input.IsMouseLeftDown || _input.IsMouseRightDown || _isVirtualMouseRightDown)
                 {
                     // Calculate smooth mouse delta not dependant on viewport size
@@ -1844,6 +1868,7 @@ namespace FlaxEditor.Viewport
                     _mouseDelta = Float2.Zero;
                 }
                 _mouseDeltaLast = Float2.Zero;
+#endif
 
                 if (ContainsFocus)
                 {
@@ -1893,6 +1918,12 @@ namespace FlaxEditor.Viewport
             _input.MouseWheelDelta = 0;
         }
 
+        /// <inheritdoc />
+        public void OnMouseMoveRelative(ref Float2 mouseMotion)
+        {
+            _mouseDelta += mouseMotion;
+        }
+
         /// <inheritdoc />
         public override bool OnMouseDown(Float2 location, MouseButton button)
         {
@@ -1958,7 +1989,8 @@ namespace FlaxEditor.Viewport
 
             if (_isControllingMouse)
             {
-                OnControlMouseEnd(RootWindow.Window);
+                if (RootWindow?.Window != null)
+                    OnControlMouseEnd(RootWindow.Window);
                 _isControllingMouse = false;
                 _isVirtualMouseRightDown = false;
             }

Source/Editor/Viewport/MainEditorGizmoViewport.cs

@@ -604,16 +604,25 @@ namespace FlaxEditor.Viewport
 
             // Don't allow rubber band selection when gizmo is controlling mouse, vertex painting mode, or cloth painting is enabled
             bool canStart = !(IsControllingMouse || IsRightMouseButtonDown || IsAltKeyDown) &&
-                            Gizmos?.Active is TransformGizmo && !Gizmos.Active.IsControllingMouse;
+                            Gizmos?.Active is TransformGizmo;
             _rubberBandSelector.TryCreateRubberBand(canStart, _viewMousePos);
         }
 
+        /// <inheritdoc />
+        protected override void OnControlMouseBegin(Window win)
+        {
+            _rubberBandSelector.ReleaseRubberBandSelection();
+
+            base.OnControlMouseBegin(win);
+        }
+
         /// <inheritdoc />
         protected override void OnLeftMouseButtonDown()
         {
             base.OnLeftMouseButtonDown();
 
-            _rubberBandSelector.TryStartingRubberBandSelection();
+            if (!IsAltKeyDown)
+                _rubberBandSelector.TryStartingRubberBandSelection();
         }
 
         /// <inheritdoc />

Source/Editor/Windows/AboutDialog.cs

@@ -130,6 +130,9 @@ namespace FlaxEditor.Windows
                 "Mono Project - www.mono-project.com",
 #if USE_NETCORE
                 ".NET - www.dotnet.microsoft.com",
+#endif
+#if PLATFORM_SDL
+                "Simple DirectMedia Layer - www.libsdl.org",
 #endif
                 "FreeType Project - www.freetype.org",
                 "Assimp - www.assimp.sourceforge.net",

Source/Editor/Windows/GameWindow.cs

@@ -767,7 +767,7 @@ namespace FlaxEditor.Windows
                 _cursorVisible = Screen.CursorVisible;
                 _cursorLockMode = Screen.CursorLock;
                 Screen.CursorVisible = true;
-                if (Screen.CursorLock == CursorLockMode.Clipped)
+                if (Screen.CursorLock == CursorLockMode.Clipped || Screen.CursorLock == CursorLockMode.Locked)
                     Screen.CursorLock = CursorLockMode.None;
 
                 // Defocus
@@ -856,8 +856,11 @@ namespace FlaxEditor.Windows
 
             if (Editor.StateMachine.IsPlayMode && !Editor.StateMachine.PlayingState.IsPaused)
             {
+                // Make sure the cursor is always in the viewport when cursor is locked
+                bool forceCenter = _cursorLockMode != CursorLockMode.None && !IsMouseOver;
+
                 // Center mouse in play mode
-                if (CenterMouseOnFocus)
+                if (CenterMouseOnFocus || forceCenter)
                 {
                     var center = PointToWindow(Size * 0.5f);
                     Root.MousePosition = center;
@@ -882,9 +885,10 @@ namespace FlaxEditor.Windows
                 _cursorVisible = Screen.CursorVisible;
                 _cursorLockMode = Screen.CursorLock;
 
-                // Restore cursor visibility (could be hidden by the game)
+                // Restore cursor state, could be hidden or locked by the game
                 if (!_cursorVisible)
                     Screen.CursorVisible = true;
+                Screen.CursorLock = CursorLockMode.None;
             }
         }
 

Source/Editor/Windows/SceneTreeWindow.cs

@@ -26,7 +26,6 @@ namespace FlaxEditor.Windows
         private Tree _tree;
         private Panel _sceneTreePanel;
         private bool _isUpdatingSelection;
-        private bool _isMouseDown;
         private bool _blockSceneTreeScroll = false;
 
         private DragAssets _dragAssets;
@@ -374,10 +373,7 @@ namespace FlaxEditor.Windows
                 return true;
 
             if (buttons == MouseButton.Right)
-            {
-                _isMouseDown = true;
                 return true;
-            }
 
             return false;
         }
@@ -388,10 +384,8 @@ namespace FlaxEditor.Windows
             if (base.OnMouseUp(location, buttons))
                 return true;
 
-            if (_isMouseDown && buttons == MouseButton.Right)
+            if (buttons == MouseButton.Right)
             {
-                _isMouseDown = false;
-
                 if (Editor.StateMachine.CurrentState.CanEditScene)
                 {
                     // Show context menu
@@ -416,14 +410,6 @@ namespace FlaxEditor.Windows
             return false;
         }
 
-        /// <inheritdoc />
-        public override void OnLostFocus()
-        {
-            _isMouseDown = false;
-
-            base.OnLostFocus();
-        }
-
         /// <inheritdoc />
         public override DragDropEffect OnDragEnter(ref Float2 location, DragData data)
         {

Source/Editor/Windows/SplashScreen.cpp

@@ -29,7 +29,7 @@ const Char* SplashScreenQuotes[] =
 #elif PLATFORM_LINUX
     TEXT("Try it on a Raspberry"),
     TEXT("Trying to exit vim"),
-    TEXT("Sudo flax --loadproject"),
+    TEXT("sudo flax --project HelloWorld.flaxproj"),
 #elif PLATFORM_MAC
     TEXT("don't compare Macbooks to oranges."),
     TEXT("Why does macbook heat up?\nBecause it doesn't have windows"),
@@ -105,6 +105,7 @@ const Char* SplashScreenQuotes[] =
     TEXT("You have my bow.\nAnd my axe!"),
     TEXT("To the bridge of Khazad-dum."),
     TEXT("One ring to rule them all.\nOne ring to find them."),
+    TEXT("Where there's a whip, there's a way."),
     TEXT("That's what she said"),
     TEXT("We could be compiling shaders here"),
     TEXT("Hello There"),
@@ -165,7 +166,7 @@ void SplashScreen::Show()
     settings.AllowMaximize = false;
     settings.AllowDragAndDrop = false;
     settings.IsTopmost = false;
-    settings.IsRegularWindow = false;
+    settings.Type = WindowType::Utility;
     settings.HasSizingFrame = false;
     settings.ShowAfterFirstPaint = true;
     settings.StartPosition = WindowStartPosition::CenterScreen;

Source/Engine/Engine/CommandLine.cpp

@@ -145,6 +145,12 @@ bool CommandLine::Parse(const Char* cmdLine)
     PARSE_BOOL_SWITCH("-monolog ", MonoLog);
     PARSE_BOOL_SWITCH("-mute ", Mute);
     PARSE_BOOL_SWITCH("-lowdpi ", LowDPI);
+
+#if PLATFORM_LINUX && PLATFORM_SDL
+    PARSE_BOOL_SWITCH("-wayland ", Wayland);
+    PARSE_BOOL_SWITCH("-x11 ", X11);
+#endif
+
 #if USE_EDITOR
     PARSE_BOOL_SWITCH("-clearcache ", ClearCache);
     PARSE_BOOL_SWITCH("-clearcooker ", ClearCookerCache);

Source/Engine/Engine/CommandLine.h

@@ -127,6 +127,20 @@ public:
         /// </summary>
         Nullable<bool> LowDPI;
 
+#if PLATFORM_LINUX && PLATFORM_SDL
+
+        /// <summary>
+        /// -wayland (prefer Wayland over X11 as display server)
+        /// </summary>
+        Nullable<bool> Wayland;
+
+        /// <summary>
+        /// -x11 (prefer X11 over Wayland as display server)
+        /// </summary>
+        Nullable<bool> X11;
+
+#endif
+
 #if USE_EDITOR
         /// <summary>
         /// -project !path! (Startup project path)

Source/Engine/Engine/Engine.cpp

@@ -99,13 +99,14 @@ int32 Engine::Main(const Char* cmdLine)
     CommandLine::Options.Std = true;
 #endif
 
+    Platform::SetHighDpiAwarenessEnabled(!CommandLine::Options.LowDPI.IsTrue());
+
     if (Platform::Init())
     {
         Platform::Fatal(TEXT("Cannot init platform."));
         return -1;
     }
 
-    Platform::SetHighDpiAwarenessEnabled(!CommandLine::Options.LowDPI.IsTrue());
     Time::StartupTime = DateTime::Now();
     Globals::StartupFolder = Globals::BinariesFolder = Platform::GetMainDirectory();
 #if USE_EDITOR

Source/Engine/Engine/Screen.cpp

@@ -6,6 +6,8 @@
 #include "Engine/Core/Types/Nullable.h"
 #include "Engine/Platform/Window.h"
 #include "Engine/Engine/EngineService.h"
+#include "Engine/Input/Input.h"
+#include "Engine/Input/Mouse.h"
 #if USE_EDITOR
 #include "Editor/Editor.h"
 #include "Editor/Managed/ManagedEditor.h"
@@ -13,10 +15,14 @@
 #include "Engine/Engine/Engine.h"
 #endif
 
-Nullable<bool> Fullscreen;
-Nullable<Float2> Size;
-bool CursorVisible = true;
-CursorLockMode CursorLock = CursorLockMode::None;
+namespace
+{
+    Nullable<bool> Fullscreen;
+    Nullable<Float2> Size;
+    bool CursorVisible = true;
+    CursorLockMode CursorLock = CursorLockMode::None;
+    bool LastGameViewportFocus = false;
+}
 
 class ScreenService : public EngineService
 {
@@ -101,9 +107,9 @@ void Screen::SetCursorVisible(const bool value)
 	const auto win = Engine::MainWindow;
 #endif
     if (win && Engine::HasGameViewportFocus())
-    {
         win->SetCursor(value ? CursorType::Default : CursorType::Hidden);
-    }
+    else if (win)
+        win->SetCursor(CursorType::Default);
     CursorVisible = value;
 }
 
@@ -116,21 +122,31 @@ void Screen::SetCursorLock(CursorLockMode mode)
 {
 #if USE_EDITOR
     const auto win = Editor::Managed->GetGameWindow(true);
+    Rectangle bounds(Editor::Managed->GameViewportToScreen(Float2::Zero), Editor::Managed->GetGameWindowSize());
+    if (win)
+        bounds = Rectangle(win->ScreenToClient(bounds.GetTopLeft()), bounds.Size);
 #else
     const auto win = Engine::MainWindow;
+    Rectangle bounds = win != nullptr ? win->GetClientBounds() : Rectangle();
 #endif
-    if (win && mode == CursorLockMode::Clipped)
+    if (win)
     {
-#if USE_EDITOR
-        Rectangle bounds(Editor::Managed->GameViewportToScreen(Float2::Zero), Editor::Managed->GetGameWindowSize());
-#else
-        Rectangle bounds = win->GetClientBounds();
-#endif
-        win->StartClippingCursor(bounds);
-    }
-    else if (win && CursorLock == CursorLockMode::Clipped)
-    {
-        win->EndClippingCursor();
+        bool inRelativeMode = Input::Mouse->IsRelative();
+        if (mode == CursorLockMode::Clipped)
+            win->StartClippingCursor(bounds);
+        else if (mode == CursorLockMode::Locked)
+        {
+            // Use mouse clip region to restrict the cursor in one spot
+            win->StartClippingCursor(Rectangle(bounds.GetCenter(), Float2(1, 1)));
+        }
+        else if (CursorLock == CursorLockMode::Locked || CursorLock == CursorLockMode::Clipped)
+            win->EndClippingCursor();
+
+        // Enable relative mode when cursor is restricted
+        if (mode != CursorLockMode::None)
+            Input::Mouse->SetRelativeMode(true, win);
+        else if (mode == CursorLockMode::None && inRelativeMode)
+            Input::Mouse->SetRelativeMode(false, win);
     }
     CursorLock = mode;
 }
@@ -190,7 +206,11 @@ void ScreenService::Update()
 {
 #if USE_EDITOR
     // Sync current cursor state in Editor (eg. when viewport focus can change)
-    Screen::SetCursorVisible(CursorVisible);
+    const auto win = Editor::Managed->GetGameWindow(true);
+    bool gameViewportFocus = win && Engine::HasGameViewportFocus();
+    if (gameViewportFocus != LastGameViewportFocus)
+        Screen::SetCursorVisible(CursorVisible);
+    LastGameViewportFocus = gameViewportFocus;
 #endif
 }
 

Source/Engine/Engine/Time.h

@@ -16,6 +16,7 @@ API_CLASS(Static, Attributes="DebugCommand") class FLAXENGINE_API Time
     friend class Engine;
     friend class TimeService;
     friend class PhysicsSettings;
+    friend Window;
 
 public:
     /// <summary>

Source/Engine/GraphicsDevice/Vulkan/Android/AndroidVulkanPlatform.cpp

@@ -4,6 +4,7 @@
 
 #include "AndroidVulkanPlatform.h"
 #include "../RenderToolsVulkan.h"
+#include "Engine/Platform/Window.h"
 
 void AndroidVulkanPlatform::GetInstanceExtensions(Array<const char*>& extensions, Array<const char*>& layers)
 {
@@ -17,8 +18,10 @@ void AndroidVulkanPlatform::GetDeviceExtensions(Array<const char*>& extensions,
 	extensions.Add(VK_KHR_ANDROID_SURFACE_EXTENSION_NAME);
 }
 
-void AndroidVulkanPlatform::CreateSurface(void* windowHandle, VkInstance instance, VkSurfaceKHR* surface)
+void AndroidVulkanPlatform::CreateSurface(Window* window, GPUDeviceVulkan* device, VkInstance instance, VkSurfaceKHR* surface)
 {
+    ASSERT(window);
+    void* windowHandle = window->GetNativePtr();
     ASSERT(windowHandle);
     VkAndroidSurfaceCreateInfoKHR surfaceCreateInfo;
     RenderToolsVulkan::ZeroStruct(surfaceCreateInfo, VK_STRUCTURE_TYPE_ANDROID_SURFACE_CREATE_INFO_KHR);

Source/Engine/GraphicsDevice/Vulkan/Android/AndroidVulkanPlatform.h

@@ -9,6 +9,8 @@
 // Support more backbuffers in case driver decides to use more
 #define VULKAN_BACK_BUFFERS_COUNT_MAX 8
 
+class GPUDeviceVulkan;
+
 /// <summary>
 /// The implementation for the Vulkan API support for Android platform.
 /// </summary>
@@ -17,7 +19,7 @@ class AndroidVulkanPlatform : public VulkanPlatformBase
 public:
 	static void GetInstanceExtensions(Array<const char*>& extensions, Array<const char*>& layers);
 	static void GetDeviceExtensions(Array<const char*>& extensions, Array<const char*>& layers);
-	static void CreateSurface(void* windowHandle, VkInstance instance, VkSurfaceKHR* surface);
+	static void CreateSurface(Window* window, GPUDeviceVulkan* device, VkInstance instance, VkSurfaceKHR* surface);
 };
 
 typedef AndroidVulkanPlatform VulkanPlatform;

Source/Engine/GraphicsDevice/Vulkan/GPUSwapChainVulkan.cpp

@@ -192,7 +192,7 @@ bool GPUSwapChainVulkan::CreateSwapChain(int32 width, int32 height)
     ASSERT_LOW_LAYER(_backBuffers.Count() == 0);
 
     // Create platform-dependent surface
-    VulkanPlatform::CreateSurface(windowHandle, GPUDeviceVulkan::Instance, &_surface);
+    VulkanPlatform::CreateSurface(_window, _device, GPUDeviceVulkan::Instance, &_surface);
     if (_surface == VK_NULL_HANDLE)
     {
         LOG(Warning, "Failed to create Vulkan surface.");
@@ -349,13 +349,22 @@ bool GPUSwapChainVulkan::CreateSwapChain(int32 width, int32 height)
         LOG(Error, "Vulkan swapchain dimensions are invalid {}x{} (minImageExtent={}x{}, maxImageExtent={}x{})", width, height, surfProperties.minImageExtent.width, surfProperties.minImageExtent.height, surfProperties.maxImageExtent.width, surfProperties.maxImageExtent.height);
         return true;
     }
+
+    uint32_t backbuffersCount = VULKAN_BACK_BUFFERS_COUNT;
+#if PLATFORM_SDL && PLATFORM_LINUX && USE_EDITOR
+    // Wayland compositor might block one of the backbuffers while the window is minimized or fully occluded,
+    // make sure we have at least 3 backbuffers available so double-buffering can be used while we are blocked.
+    if (Platform::UsesWayland())
+        backbuffersCount = Math::Max<uint32_t>(backbuffersCount, 3);
+#endif
+    
     ASSERT(surfProperties.minImageCount <= VULKAN_BACK_BUFFERS_COUNT_MAX);
     VkSwapchainCreateInfoKHR swapChainInfo;
     RenderToolsVulkan::ZeroStruct(swapChainInfo, VK_STRUCTURE_TYPE_SWAPCHAIN_CREATE_INFO_KHR);
     swapChainInfo.surface = _surface;
     swapChainInfo.minImageCount = surfProperties.maxImageCount > 0 // A value of 0 means that there is no limit on the number of image
-                                      ? Math::Min<uint32_t>(VULKAN_BACK_BUFFERS_COUNT, surfProperties.maxImageCount)
-                                      : VULKAN_BACK_BUFFERS_COUNT;
+                                      ? Math::Min<uint32_t>(backbuffersCount, surfProperties.maxImageCount)
+                                      : backbuffersCount;
     swapChainInfo.minImageCount = Math::Max<uint32_t>(swapChainInfo.minImageCount, surfProperties.minImageCount);
     swapChainInfo.minImageCount = Math::Min<uint32_t>(swapChainInfo.minImageCount, VULKAN_BACK_BUFFERS_COUNT_MAX);
     swapChainInfo.imageFormat = result.format;
@@ -374,7 +383,9 @@ bool GPUSwapChainVulkan::CreateSwapChain(int32 width, int32 height)
     swapChainInfo.presentMode = presentMode;
     swapChainInfo.clipped = VK_TRUE;
     swapChainInfo.compositeAlpha = VK_COMPOSITE_ALPHA_INHERIT_BIT_KHR;
-    if (surfProperties.supportedCompositeAlpha & VK_COMPOSITE_ALPHA_OPAQUE_BIT_KHR)
+    if (_window->GetSettings().SupportsTransparency && surfProperties.supportedCompositeAlpha & VK_COMPOSITE_ALPHA_PRE_MULTIPLIED_BIT_KHR)
+        swapChainInfo.compositeAlpha = VK_COMPOSITE_ALPHA_PRE_MULTIPLIED_BIT_KHR;
+    else if (surfProperties.supportedCompositeAlpha & VK_COMPOSITE_ALPHA_OPAQUE_BIT_KHR)
         swapChainInfo.compositeAlpha = VK_COMPOSITE_ALPHA_OPAQUE_BIT_KHR;
 
     // Create swap chain

Source/Engine/GraphicsDevice/Vulkan/Linux/LinuxVulkanPlatform.cpp

@@ -4,62 +4,61 @@
 
 #include "LinuxVulkanPlatform.h"
 #include "../RenderToolsVulkan.h"
+#include "Engine/Platform/Window.h"
 
-// Contents of vulkan\vulkan_xlib.h inlined here to prevent typename collisions with engine types due to X11 types
 #include "Engine/Platform/Linux/IncludeX11.h"
-#ifdef __cplusplus
-extern "C" {
-#endif
-#define VK_KHR_xlib_surface 1
-#define VK_KHR_XLIB_SURFACE_SPEC_VERSION  6
-#define VK_KHR_XLIB_SURFACE_EXTENSION_NAME "VK_KHR_xlib_surface"
-typedef VkFlags VkXlibSurfaceCreateFlagsKHR;
+#define Display X11::Display
+#define Window X11::Window
+#define VisualID X11::VisualID
+#include "vulkan/vulkan_xlib.h"
+#undef Display
+#undef Window
+#undef VisualID
 
-typedef struct VkXlibSurfaceCreateInfoKHR
-{
-	VkStructureType sType;
-	const void* pNext;
-	VkXlibSurfaceCreateFlagsKHR flags;
-	X11::Display* dpy;
-	X11::Window window;
-} VkXlibSurfaceCreateInfoKHR;
+#include "vulkan/vulkan_wayland.h"
 
-typedef VkResult (VKAPI_PTR *PFN_vkCreateXlibSurfaceKHR)(VkInstance instance, const VkXlibSurfaceCreateInfoKHR* pCreateInfo, const VkAllocationCallbacks* pAllocator, VkSurfaceKHR* pSurface);
-typedef VkBool32 (VKAPI_PTR *PFN_vkGetPhysicalDeviceXlibPresentationSupportKHR)(VkPhysicalDevice physicalDevice, uint32_t queueFamilyIndex, X11::Display* dpy, X11::VisualID visualID);
-#ifndef VK_NO_PROTOTYPES
-VKAPI_ATTR VkResult VKAPI_CALL vkCreateXlibSurfaceKHR(
-    VkInstance                                  instance,
-    const VkXlibSurfaceCreateInfoKHR*           pCreateInfo,
-    const VkAllocationCallbacks*                pAllocator,
-    VkSurfaceKHR*                               pSurface);
-VKAPI_ATTR VkBool32 VKAPI_CALL vkGetPhysicalDeviceXlibPresentationSupportKHR(
-    VkPhysicalDevice                            physicalDevice,
-    uint32_t                                    queueFamilyIndex,
-    Display*                                    dpy,
-    VisualID                                    visualID);
-#endif
-#ifdef __cplusplus
-}
-#endif
-//
-
-// Export X11 surface extension from volk
+// Export extension from volk
 extern PFN_vkCreateXlibSurfaceKHR vkCreateXlibSurfaceKHR;
 extern PFN_vkGetPhysicalDeviceXlibPresentationSupportKHR vkGetPhysicalDeviceXlibPresentationSupportKHR;
+extern PFN_vkCreateWaylandSurfaceKHR vkCreateWaylandSurfaceKHR;
+extern PFN_vkGetPhysicalDeviceWaylandPresentationSupportKHR vkGetPhysicalDeviceWaylandPresentationSupportKHR;
 
 void LinuxVulkanPlatform::GetInstanceExtensions(Array<const char*>& extensions, Array<const char*>& layers)
 {
 	extensions.Add(VK_KHR_SURFACE_EXTENSION_NAME);
 	extensions.Add(VK_KHR_XLIB_SURFACE_EXTENSION_NAME);
+    extensions.Add(VK_KHR_WAYLAND_SURFACE_EXTENSION_NAME);
 }
 
-void LinuxVulkanPlatform::CreateSurface(void* windowHandle, VkInstance instance, VkSurfaceKHR* surface)
+void LinuxVulkanPlatform::CreateSurface(Window* window, GPUDeviceVulkan* device, VkInstance instance, VkSurfaceKHR* surface)
 {
+#if !PLATFORM_SDL
+    void* windowHandle = window->GetNativePtr();
 	VkXlibSurfaceCreateInfoKHR surfaceCreateInfo;
 	RenderToolsVulkan::ZeroStruct(surfaceCreateInfo, VK_STRUCTURE_TYPE_XLIB_SURFACE_CREATE_INFO_KHR);
-	surfaceCreateInfo.dpy = (X11::Display*)LinuxPlatform::GetXDisplay();
+	surfaceCreateInfo.dpy = (X11::Display*)Platform::GetXDisplay();
 	surfaceCreateInfo.window = (X11::Window)windowHandle;
 	VALIDATE_VULKAN_RESULT(vkCreateXlibSurfaceKHR(instance, &surfaceCreateInfo, nullptr, surface));
+#else
+    SDLWindow* sdlWindow = static_cast<Window*>(window);
+    void* windowHandle = window->GetNativePtr();
+    if (SDLPlatform::UsesWayland())
+    {
+        VkWaylandSurfaceCreateInfoKHR surfaceCreateInfo;
+        RenderToolsVulkan::ZeroStruct(surfaceCreateInfo, VK_STRUCTURE_TYPE_WAYLAND_SURFACE_CREATE_INFO_KHR);
+        surfaceCreateInfo.display = (wl_display*)sdlWindow->GetWaylandDisplay();
+        surfaceCreateInfo.surface = (wl_surface*)windowHandle;
+        VALIDATE_VULKAN_RESULT(vkCreateWaylandSurfaceKHR(instance, &surfaceCreateInfo, nullptr, surface));
+    }
+    else if (SDLPlatform::UsesX11())
+    {
+        VkXlibSurfaceCreateInfoKHR surfaceCreateInfo;
+        RenderToolsVulkan::ZeroStruct(surfaceCreateInfo, VK_STRUCTURE_TYPE_XLIB_SURFACE_CREATE_INFO_KHR);
+        surfaceCreateInfo.dpy = (X11::Display*)sdlWindow->GetX11Display();
+        surfaceCreateInfo.window = (X11::Window)windowHandle;
+        VALIDATE_VULKAN_RESULT(vkCreateXlibSurfaceKHR(instance, &surfaceCreateInfo, nullptr, surface));
+    }
+#endif
 }
 
 #endif

Source/Engine/GraphicsDevice/Vulkan/Linux/LinuxVulkanPlatform.h

@@ -12,6 +12,8 @@
 // Prevent wierd error 'Invalid VkValidationCacheEXT Object'
 #define VULKAN_USE_VALIDATION_CACHE 0
 
+class GPUDeviceVulkan;
+
 /// <summary>
 /// The implementation for the Vulkan API support for Linux platform.
 /// </summary>
@@ -19,7 +21,7 @@ class LinuxVulkanPlatform : public VulkanPlatformBase
 {
 public:
 	static void GetInstanceExtensions(Array<const char*>& extensions, Array<const char*>& layers);
-	static void CreateSurface(void* windowHandle, VkInstance instance, VkSurfaceKHR* outSurface);
+	static void CreateSurface(Window* window, GPUDeviceVulkan* device, VkInstance instance, VkSurfaceKHR* outSurface);
 };
 
 typedef LinuxVulkanPlatform VulkanPlatform;

Source/Engine/GraphicsDevice/Vulkan/Mac/MacVulkanPlatform.cpp

@@ -4,21 +4,40 @@
 
 #include "MacVulkanPlatform.h"
 #include "../RenderToolsVulkan.h"
+#include "Engine/Platform/Window.h"
+#include "Engine/GraphicsDevice/Vulkan/GPUDeviceVulkan.h"
 #include <Cocoa/Cocoa.h>
+#include <QuartzCore/CAMetalLayer.h>
 
 void MacVulkanPlatform::GetInstanceExtensions(Array<const char*>& extensions, Array<const char*>& layers)
 {
     extensions.Add(VK_KHR_SURFACE_EXTENSION_NAME);
-	extensions.Add(VK_MVK_MACOS_SURFACE_EXTENSION_NAME);
+    extensions.Add(VK_MVK_MACOS_SURFACE_EXTENSION_NAME);
+    extensions.Add(VK_EXT_METAL_SURFACE_EXTENSION_NAME);
 }
 
-void MacVulkanPlatform::CreateSurface(void* windowHandle, VkInstance instance, VkSurfaceKHR* surface)
+void MacVulkanPlatform::CreateSurface(Window* window, GPUDeviceVulkan* device, VkInstance instance, VkSurfaceKHR* surface)
 {
-    NSWindow* window = (NSWindow*)windowHandle;
-	VkMacOSSurfaceCreateInfoMVK surfaceCreateInfo;
-	RenderToolsVulkan::ZeroStruct(surfaceCreateInfo, VK_STRUCTURE_TYPE_MACOS_SURFACE_CREATE_INFO_MVK);
-	surfaceCreateInfo.pView = (void*)window.contentView;
-	VALIDATE_VULKAN_RESULT(vkCreateMacOSSurfaceMVK(instance, &surfaceCreateInfo, nullptr, surface));
+    void* windowHandle = window->GetNativePtr();
+    NSWindow* nswindow = (NSWindow*)windowHandle;
+#if PLATFORM_SDL
+    nswindow.contentView.wantsLayer = YES;
+    nswindow.contentView.layer = [CAMetalLayer layer];
+#endif
+    if (device->InstanceExtensions.Contains(VK_EXT_METAL_SURFACE_EXTENSION_NAME))
+    {
+        VkMetalSurfaceCreateInfoEXT surfaceCreateInfo;
+        RenderToolsVulkan::ZeroStruct(surfaceCreateInfo, VK_STRUCTURE_TYPE_METAL_SURFACE_CREATE_INFO_EXT);
+        surfaceCreateInfo.pLayer = (CAMetalLayer*)nswindow.contentView.layer;
+        VALIDATE_VULKAN_RESULT(vkCreateMetalSurfaceEXT(instance, &surfaceCreateInfo, nullptr, surface));
+    }
+    else
+    {
+        VkMacOSSurfaceCreateInfoMVK surfaceCreateInfo;
+        RenderToolsVulkan::ZeroStruct(surfaceCreateInfo, VK_STRUCTURE_TYPE_MACOS_SURFACE_CREATE_INFO_MVK);
+        surfaceCreateInfo.pView = (void*)nswindow.contentView;
+        VALIDATE_VULKAN_RESULT(vkCreateMacOSSurfaceMVK(instance, &surfaceCreateInfo, nullptr, surface));
+    }
 }
 
 #endif

Source/Engine/GraphicsDevice/Vulkan/Mac/MacVulkanPlatform.h

@@ -11,6 +11,8 @@
 // General/Validation Error:0 VK_ERROR_INITIALIZATION_FAILED: Could not create MTLCounterSampleBuffer for query pool of type VK_QUERY_TYPE_TIMESTAMP. Reverting to emulated behavior. (Error code 0): Cannot allocate sample buffer
 #define VULKAN_USE_QUERIES 0
 
+class GPUDeviceVulkan;
+
 /// <summary>
 /// The implementation for the Vulkan API support for Mac platform.
 /// </summary>
@@ -18,7 +20,7 @@ class MacVulkanPlatform : public VulkanPlatformBase
 {
 public:
 	static void GetInstanceExtensions(Array<const char*>& extensions, Array<const char*>& layers);
-	static void CreateSurface(void* windowHandle, VkInstance instance, VkSurfaceKHR* outSurface);
+	static void CreateSurface(Window* window, GPUDeviceVulkan* device, VkInstance instance, VkSurfaceKHR* outSurface);
 };
 
 typedef MacVulkanPlatform VulkanPlatform;

Source/Engine/GraphicsDevice/Vulkan/Win32/Win32VulkanPlatform.cpp

@@ -6,6 +6,7 @@
 
 #include "../RenderToolsVulkan.h"
 #include "Engine/Graphics/GPUDevice.h"
+#include "Engine/Platform/Window.h"
 
 void Win32VulkanPlatform::GetInstanceExtensions(Array<const char*>& extensions, Array<const char*>& layers)
 {
@@ -13,8 +14,9 @@ void Win32VulkanPlatform::GetInstanceExtensions(Array<const char*>& extensions,
     extensions.Add(VK_KHR_WIN32_SURFACE_EXTENSION_NAME);
 }
 
-void Win32VulkanPlatform::CreateSurface(void* windowHandle, VkInstance instance, VkSurfaceKHR* surface)
+void Win32VulkanPlatform::CreateSurface(Window* window, GPUDeviceVulkan* device, VkInstance instance, VkSurfaceKHR* surface)
 {
+    void* windowHandle = window->GetNativePtr();
     VkWin32SurfaceCreateInfoKHR surfaceCreateInfo;
     RenderToolsVulkan::ZeroStruct(surfaceCreateInfo, VK_STRUCTURE_TYPE_WIN32_SURFACE_CREATE_INFO_KHR);
     surfaceCreateInfo.hinstance = GetModuleHandle(nullptr);

Source/Engine/GraphicsDevice/Vulkan/Win32/Win32VulkanPlatform.h

@@ -10,6 +10,8 @@
 #define VULKAN_USE_PLATFORM_WIN32_KHX 1
 #define VULKAN_USE_CREATE_WIN32_SURFACE 1
 
+class GPUDeviceVulkan;
+
 /// <summary>
 /// The implementation for the Vulkan API support for Win32 platform.
 /// </summary>
@@ -17,7 +19,7 @@ class Win32VulkanPlatform : public VulkanPlatformBase
 {
 public:
     static void GetInstanceExtensions(Array<const char*>& extensions, Array<const char*>& layers);
-    static void CreateSurface(void* windowHandle, VkInstance instance, VkSurfaceKHR* surface);
+    static void CreateSurface(Window* window, GPUDeviceVulkan* device, VkInstance instance, VkSurfaceKHR* surface);
 };
 
 typedef Win32VulkanPlatform VulkanPlatform;

Source/Engine/GraphicsDevice/Vulkan/iOS/iOSVulkanPlatform.cpp

@@ -5,6 +5,7 @@
 #include "iOSVulkanPlatform.h"
 #include "../RenderToolsVulkan.h"
 #include "Engine/Core/Delegate.h"
+#include "Engine/Platform/Window.h"
 #include <UIKit/UIKit.h>
 
 void iOSVulkanPlatform::GetInstanceExtensions(Array<const char*>& extensions, Array<const char*>& layers)
@@ -13,8 +14,9 @@ void iOSVulkanPlatform::GetInstanceExtensions(Array<const char*>& extensions, Ar
 	extensions.Add(VK_MVK_IOS_SURFACE_EXTENSION_NAME);
 }
 
-void iOSVulkanPlatform::CreateSurface(void* windowHandle, VkInstance instance, VkSurfaceKHR* surface)
+void iOSVulkanPlatform::CreateSurface(Window* window, GPUDeviceVulkan* device, VkInstance instance, VkSurfaceKHR* surface)
 {
+    void* windowHandle = window->GetNativePtr();
 	// Create surface on a main UI Thread
 	Function<void()> func = [&windowHandle, &instance, &surface]()
 	{

Source/Engine/GraphicsDevice/Vulkan/iOS/iOSVulkanPlatform.h

@@ -11,6 +11,8 @@
 // General/Validation Error:0 VK_ERROR_INITIALIZATION_FAILED: Could not create MTLCounterSampleBuffer for query pool of type VK_QUERY_TYPE_TIMESTAMP. Reverting to emulated behavior. (Error code 0): Cannot allocate sample buffer
 #define VULKAN_USE_QUERIES 0
 
+class GPUDeviceVulkan;
+
 /// <summary>
 /// The implementation for the Vulkan API support for iOS platform.
 /// </summary>
@@ -18,7 +20,7 @@ class iOSVulkanPlatform : public VulkanPlatformBase
 {
 public:
 	static void GetInstanceExtensions(Array<const char*>& extensions, Array<const char*>& layers);
-	static void CreateSurface(void* windowHandle, VkInstance instance, VkSurfaceKHR* outSurface);
+	static void CreateSurface(Window* window, GPUDeviceVulkan* device, VkInstance instance, VkSurfaceKHR* outSurface);
 };
 
 typedef iOSVulkanPlatform VulkanPlatform;

Source/Engine/Input/Input.cpp

@@ -78,6 +78,7 @@ Delegate<const Float2&, MouseButton> Input::MouseUp;
 Delegate<const Float2&, MouseButton> Input::MouseDoubleClick;
 Delegate<const Float2&, float> Input::MouseWheel;
 Delegate<const Float2&> Input::MouseMove;
+Delegate<const Float2&> Input::MouseMoveRelative;
 Action Input::MouseLeave;
 Delegate<const Float2&, int32> Input::TouchDown;
 Delegate<const Float2&, int32> Input::TouchMove;
@@ -208,6 +209,14 @@ void Mouse::OnMouseMove(const Float2& position, Window* target)
     e.MouseData.Position = position;
 }
 
+void Mouse::OnMouseMoveRelative(const Float2& positionRelative, Window* target)
+{
+    Event& e = _queue.AddOne();
+    e.Type = EventType::MouseMoveRelative;
+    e.Target = target;
+    e.MouseMovementData.PositionRelative = positionRelative;
+}
+
 void Mouse::OnMouseLeave(Window* target)
 {
     Event& e = _queue.AddOne();
@@ -273,6 +282,11 @@ bool Mouse::Update(EventQueue& queue)
             _state.MousePosition = e.MouseData.Position;
             break;
         }
+        case EventType::MouseMoveRelative:
+        {
+            _state.MousePosition += e.MouseMovementData.PositionRelative;
+            break;
+        }
         case EventType::MouseLeave:
         {
             break;
@@ -899,11 +913,10 @@ void InputService::Update()
     WindowsManager::WindowsLocker.Unlock();
 
     // Send input events for the focused window
-    WindowsManager::WindowsLocker.Lock();
     for (const auto& e : InputEvents)
     {
         auto window = e.Target ? e.Target : defaultWindow;
-        if (!window || !WindowsManager::Windows.Contains(window))
+        if (!window || window->IsClosed())
             continue;
         switch (e.Type)
         {
@@ -933,6 +946,9 @@ void InputService::Update()
         case InputDevice::EventType::MouseMove:
             window->OnMouseMove(window->ScreenToClient(e.MouseData.Position));
             break;
+        case InputDevice::EventType::MouseMoveRelative:
+            window->OnMouseMoveRelative(e.MouseMovementData.PositionRelative);
+            break;
         case InputDevice::EventType::MouseLeave:
             window->OnMouseLeave();
             break;
@@ -948,7 +964,6 @@ void InputService::Update()
             break;
         }
     }
-    WindowsManager::WindowsLocker.Unlock();
 
     // Skip if game has no focus to handle the input
     if (!Engine::HasGameViewportFocus())
@@ -989,6 +1004,9 @@ void InputService::Update()
         case InputDevice::EventType::MouseMove:
             Input::MouseMove(e.MouseData.Position);
             break;
+        case InputDevice::EventType::MouseMoveRelative:
+            Input::MouseMoveRelative(e.MouseMovementData.PositionRelative);
+            break;
         case InputDevice::EventType::MouseLeave:
             Input::MouseLeave();
             break;
@@ -1202,6 +1220,7 @@ void InputService::Update()
         }
     }
 
+#if !PLATFORM_SDL
     // Lock mouse if need to
     const auto lockMode = Screen::GetCursorLock();
     if (lockMode == CursorLockMode::Locked)
@@ -1210,6 +1229,7 @@ void InputService::Update()
                            Screen::ScreenToGameViewport(Float2::Zero);
         Input::SetMousePosition(pos);
     }
+#endif
 
     // Send events for the active actions and axes (send events only in play mode)
     if (!Time::GetGamePaused())

Source/Engine/Input/Input.h

@@ -108,6 +108,11 @@ public:
     /// </summary>
     API_EVENT() static Delegate<const Float2&> MouseMove;
 
+    /// <summary>
+    /// Event fired when mouse moves while in relative mode.
+    /// </summary>
+    API_EVENT() static Delegate<const Float2&> MouseMoveRelative;
+
     /// <summary>
     /// Event fired when mouse leaves window.
     /// </summary>

Source/Engine/Input/InputDevice.h

@@ -25,6 +25,7 @@ public:
         MouseDoubleClick,
         MouseWheel,
         MouseMove,
+        MouseMoveRelative,
         MouseLeave,
         TouchDown,
         TouchMove,
@@ -54,6 +55,11 @@ public:
                 Float2 Position;
             } MouseData;
 
+            struct
+            {
+                Float2 PositionRelative;
+            } MouseMovementData;
+
             struct
             {
                 float WheelDelta;

Source/Engine/Input/Mouse.h

@@ -46,12 +46,14 @@ public:
 protected:
     State _state;
     State _prevState;
+    bool _relativeMode;
 
     explicit Mouse()
         : InputDevice(SpawnParams(Guid::New(), TypeInitializer), TEXT("Mouse"))
     {
         _state.Clear();
         _prevState.Clear();
+        _relativeMode = false;
     }
 
 public:
@@ -114,6 +116,16 @@ public:
         return !_state.MouseButtons[static_cast<int32>(button)] && _prevState.MouseButtons[static_cast<int32>(button)];
     }
 
+    /// <summary>
+    /// Gets the current state of mouse relative mode. 
+    /// </summary>
+    /// <param name="window">The window to check against, or null to check for any window.</param>
+    /// <returns>True if mouse is in relative mode, otherwise false.</returns>
+    API_FUNCTION() virtual bool IsRelative(Window* window = nullptr) const
+    {
+        return _relativeMode;
+    }
+
 public:
     /// <summary>
     /// Sets the mouse position.
@@ -121,6 +133,17 @@ public:
     /// <param name="newPosition">The new position.</param>
     virtual void SetMousePosition(const Float2& newPosition) = 0;
 
+    /// <summary>
+    /// Sets the mouse relative mode state. While enabled, the mouse movement tracking becomes more accurate.
+    /// The cursor will be hidden while in relative mode.
+    /// </summary>
+    /// <param name="relativeMode">The new relative mode state.</param>
+    /// <param name="window">The window.</param>
+    virtual void SetRelativeMode(bool relativeMode, Window* window)
+    {
+        _relativeMode = relativeMode;
+    }
+
     /// <summary>
     /// Called when mouse cursor gets moved by the application. Invalidates the previous cached mouse position to prevent mouse jitter when locking the cursor programmatically.
     /// </summary>
@@ -158,6 +181,13 @@ public:
     /// <param name="target">The target window to receive this event, otherwise input system will pick the window automatically.</param>
     void OnMouseMove(const Float2& position, Window* target = nullptr);
 
+    /// <summary>
+    /// Called when mouse moves in relative mode.
+    /// </summary>
+    /// <param name="positionRelative">The mouse position change.</param>
+    /// <param name="target">The target window to receive this event, otherwise input system will pick the window automatically.</param>
+    void OnMouseMoveRelative(const Float2& positionRelative, Window* target = nullptr);
+
     /// <summary>
     /// Called when mouse leaves the input source area.
     /// </summary>

Source/Engine/Platform/Base/Enums.h

@@ -0,0 +1,251 @@
+// Copyright (c) Wojciech Figat. All rights reserved.
+
+#pragma once
+
+#include "Engine/Core/Config.h"
+
+/// <summary>
+/// Window closing reasons.
+/// </summary>
+API_ENUM() enum class ClosingReason
+{
+    /// <summary>
+    /// The unknown.
+    /// </summary>
+    Unknown = 0,
+
+    /// <summary>
+    /// The user.
+    /// </summary>
+    User,
+
+    /// <summary>
+    /// The engine exit.
+    /// </summary>
+    EngineExit,
+
+    /// <summary>
+    /// The close event.
+    /// </summary>
+    CloseEvent,
+};
+
+/// <summary>
+/// Types of default cursors.
+/// </summary>
+API_ENUM() enum class CursorType
+{
+    /// <summary>
+    /// The default.
+    /// </summary>
+    Default = 0,
+
+    /// <summary>
+    /// The cross.
+    /// </summary>
+    Cross,
+
+    /// <summary>
+    /// The hand.
+    /// </summary>
+    Hand,
+
+    /// <summary>
+    /// The help icon
+    /// </summary>
+    Help,
+
+    /// <summary>
+    /// The I beam.
+    /// </summary>
+    IBeam,
+
+    /// <summary>
+    /// The blocking image.
+    /// </summary>
+    No,
+
+    /// <summary>
+    /// The wait.
+    /// </summary>
+    Wait,
+
+    /// <summary>
+    /// The size all sides.
+    /// </summary>
+    SizeAll,
+
+    /// <summary>
+    /// The size NE-SW.
+    /// </summary>
+    SizeNESW,
+
+    /// <summary>
+    /// The size NS.
+    /// </summary>
+    SizeNS,
+
+    /// <summary>
+    /// The size NW-SE.
+    /// </summary>
+    SizeNWSE,
+
+    /// <summary>
+    /// The size WE.
+    /// </summary>
+    SizeWE,
+
+    /// <summary>
+    /// The cursor is hidden.
+    /// </summary>
+    Hidden,
+
+    MAX
+};
+
+/// <summary>
+/// Data drag and drop effects.
+/// </summary>
+API_ENUM() enum class DragDropEffect
+{
+    /// <summary>
+    /// The none.
+    /// </summary>
+    None = 0,
+
+    /// <summary>
+    /// The copy.
+    /// </summary>
+    Copy,
+
+    /// <summary>
+    /// The move.
+    /// </summary>
+    Move,
+
+    /// <summary>
+    /// The link.
+    /// </summary>
+    Link,
+};
+
+/// <summary>
+/// Window hit test codes. Note: they are 1:1 mapping for Win32 values.
+/// </summary>
+API_ENUM() enum class WindowHitCodes
+{
+    /// <summary>
+    /// The transparent area.
+    /// </summary>
+    Transparent = -1,
+
+    /// <summary>
+    /// The no hit.
+    /// </summary>
+    NoWhere = 0,
+
+    /// <summary>
+    /// The client area.
+    /// </summary>
+    Client = 1,
+
+    /// <summary>
+    /// The caption area.
+    /// </summary>
+    Caption = 2,
+
+    /// <summary>
+    /// The system menu.
+    /// </summary>
+    SystemMenu = 3,
+
+    /// <summary>
+    /// The grow box
+    /// </summary>
+    GrowBox = 4,
+
+    /// <summary>
+    /// The menu.
+    /// </summary>
+    Menu = 5,
+
+    /// <summary>
+    /// The horizontal scroll.
+    /// </summary>
+    HScroll = 6,
+
+    /// <summary>
+    /// The vertical scroll.
+    /// </summary>
+    VScroll = 7,
+
+    /// <summary>
+    /// The minimize button.
+    /// </summary>
+    MinButton = 8,
+
+    /// <summary>
+    /// The maximize button.
+    /// </summary>
+    MaxButton = 9,
+
+    /// <summary>
+    /// The left side;
+    /// </summary>
+    Left = 10,
+
+    /// <summary>
+    /// The right side.
+    /// </summary>
+    Right = 11,
+
+    /// <summary>
+    /// The top side.
+    /// </summary>
+    Top = 12,
+
+    /// <summary>
+    /// The top left corner.
+    /// </summary>
+    TopLeft = 13,
+
+    /// <summary>
+    /// The top right corner.
+    /// </summary>
+    TopRight = 14,
+
+    /// <summary>
+    /// The bottom side.
+    /// </summary>
+    Bottom = 15,
+
+    /// <summary>
+    /// The bottom left corner.
+    /// </summary>
+    BottomLeft = 16,
+
+    /// <summary>
+    /// The bottom right corner.
+    /// </summary>
+    BottomRight = 17,
+
+    /// <summary>
+    /// The border.
+    /// </summary>
+    Border = 18,
+
+    /// <summary>
+    /// The object.
+    /// </summary>
+    Object = 19,
+
+    /// <summary>
+    /// The close button.
+    /// </summary>
+    Close = 20,
+
+    /// <summary>
+    /// The help button.
+    /// </summary>
+    Help = 21,
+};

Source/Engine/Platform/Base/PlatformBase.cpp

@@ -45,6 +45,7 @@ static_assert(sizeof(double) == 8, "Invalid double type size.");
 static_assert((PLATFORM_THREADS_LIMIT & (PLATFORM_THREADS_LIMIT - 1)) == 0, "Threads limit must be power of two.");
 static_assert(PLATFORM_THREADS_LIMIT % 4 == 0, "Threads limit must be multiple of 4.");
 
+const Char* PlatformBase::ApplicationClassName = TEXT("FlaxWindow");
 float PlatformBase::CustomDpiScale = 1.0f;
 Array<User*, FixedAllocation<8>> PlatformBase::Users;
 Delegate<User*> PlatformBase::UserAdded;
@@ -261,6 +262,29 @@ PlatformType PlatformBase::GetPlatformType()
     return PLATFORM_TYPE;
 }
 
+#if !PLATFORM_SDL
+
+String PlatformBase::GetDisplayServer()
+{
+    return String::Empty;
+}
+
+bool PlatformBase::SupportsNativeDecorations()
+{
+    return true;
+}
+
+bool PlatformBase::SupportsNativeDecorationDragging()
+{
+#if PLATFORM_LINUX
+    return false;
+#else
+    return true;
+#endif
+}
+
+#endif
+
 bool PlatformBase::Is64BitApp()
 {
 #if PLATFORM_64BITS

Source/Engine/Platform/Base/PlatformBase.h

@@ -190,6 +190,13 @@ DECLARE_SCRIPTING_TYPE_MINIMAL(PlatformBase);
     /// </summary>
     static void Exit();
 
+public:
+
+    /// <summary>
+    /// Application windows class name.
+    /// </summary>
+    static const Char* ApplicationClassName;
+
 public:
     /// <summary>
     /// Copy memory region
@@ -362,6 +369,21 @@ public:
     /// </summary>
     API_PROPERTY() static PlatformType GetPlatformType();
 
+    /// <summary>
+    /// Returns the display server name on Linux.
+    /// </summary>
+    API_PROPERTY() static String GetDisplayServer();
+
+    /// <summary>
+    /// Returns true if system provides decorations for windows.
+    /// </summary>
+    API_PROPERTY() static bool SupportsNativeDecorations();
+
+    /// <summary>
+    /// Returns true if system provides support for native window dragging events.
+    /// </summary>
+    API_PROPERTY() static bool SupportsNativeDecorationDragging();
+
     /// <summary>
     /// Returns true if is running 64 bit application (otherwise 32 bit). It's compile-time constant.
     /// </summary>

Source/Engine/Platform/Base/ScreenUtilitiesBase.h

@@ -0,0 +1,42 @@
+// Copyright (c) Wojciech Figat. All rights reserved.
+
+#pragma once
+
+#include "Engine/Core/Types/BaseTypes.h"
+#include "Engine/Core/Math/Color32.h"
+#include "Engine/Core/Math/Vector2.h"
+#include "Engine/Core/Delegate.h"
+
+API_INJECT_CODE(cpp, "#include \"Engine/Platform/ScreenUtilities.h\"");
+
+/// <summary>
+/// Platform-dependent screen utilities.
+/// </summary>
+API_CLASS(Static, Name="ScreenUtilities", Tag="NativeInvokeUseName")
+class FLAXENGINE_API ScreenUtilitiesBase
+{
+public:
+    static struct FLAXENGINE_API ScriptingTypeInitializer TypeInitializer;
+    
+    /// <summary>
+    /// Gets the pixel color at the specified coordinates.
+    /// </summary>
+    /// <param name="pos">Screen-space coordinate to read.</param>
+    /// <returns>Pixel color at the specified coordinates, or transparent color when color couldn't be picked up.</returns>
+    API_FUNCTION() static Color32 GetColorAt(const Float2& pos)
+    {
+        return Color32::Transparent;
+    }
+
+    /// <summary>
+    /// Starts async color picking. Color will be returned through PickColorDone event when the actions ends (user selected the final color with a mouse). When action is active, GetColorAt can be used to read the current value.
+    /// </summary>
+    API_FUNCTION() static void PickColor()
+    {
+    }
+
+    /// <summary>
+    /// Called when PickColor action is finished.
+    /// </summary>
+    API_EVENT() static Delegate<Color32> PickColorDone;
+};

Source/Engine/Platform/Base/WindowBase.cpp

@@ -106,7 +106,7 @@ WindowBase::WindowBase(const CreateWindowSettings& settings)
     if (settings.StartPosition == WindowStartPosition::CenterParent
         || settings.StartPosition == WindowStartPosition::CenterScreen)
     {
-        Rectangle parentBounds = Rectangle(Float2::Zero, Platform::GetDesktopSize());
+        Rectangle parentBounds = Platform::GetMonitorBounds(Float2::Minimum);
         if (settings.Parent != nullptr && settings.StartPosition == WindowStartPosition::CenterParent)
             parentBounds = settings.Parent->GetClientBounds();
 
@@ -164,6 +164,15 @@ void WindowBase::SetIsVisible(bool isVisible)
     }
 }
 
+bool WindowBase::IsAlwaysOnTop() const
+{
+    return false;
+}
+
+void WindowBase::SetIsAlwaysOnTop(bool isAlwaysOnTop)
+{
+}
+
 String WindowBase::ToString() const
 {
     return GetTitle();
@@ -257,6 +266,13 @@ void WindowBase::OnMouseMove(const Float2& mousePosition)
     INVOKE_EVENT_PARAMS_1(OnMouseMove, (void*)&mousePosition);
 }
 
+void WindowBase::OnMouseMoveRelative(const Float2& mousePositionRelative)
+{
+    PROFILE_CPU_NAMED("GUI.OnMouseMoveRelative");
+    MouseMoveRelative(mousePositionRelative);
+    INVOKE_EVENT_PARAMS_1(OnMouseMoveRelative, (void*)&mousePositionRelative);
+}
+
 void WindowBase::OnMouseLeave()
 {
     PROFILE_CPU_NAMED("GUI.OnMouseLeave");

Source/Engine/Platform/Base/WindowBase.h

@@ -8,6 +8,7 @@
 #include "Engine/Scripting/ScriptingObject.h"
 #include "Engine/Input/KeyboardKeys.h"
 #include "Engine/Input/Enums.h"
+#include "Enums.h"
 
 class Input;
 class Engine;
@@ -17,252 +18,6 @@ class GPUSwapChain;
 class TextureData;
 class IGuiData;
 
-/// <summary>
-/// Window closing reasons.
-/// </summary>
-API_ENUM() enum class ClosingReason
-{
-    /// <summary>
-    /// The unknown.
-    /// </summary>
-    Unknown = 0,
-
-    /// <summary>
-    /// The user.
-    /// </summary>
-    User,
-
-    /// <summary>
-    /// The engine exit.
-    /// </summary>
-    EngineExit,
-
-    /// <summary>
-    /// The close event.
-    /// </summary>
-    CloseEvent,
-};
-
-/// <summary>
-/// Types of default cursors.
-/// </summary>
-API_ENUM() enum class CursorType
-{
-    /// <summary>
-    /// The default.
-    /// </summary>
-    Default = 0,
-
-    /// <summary>
-    /// The cross.
-    /// </summary>
-    Cross,
-
-    /// <summary>
-    /// The hand.
-    /// </summary>
-    Hand,
-
-    /// <summary>
-    /// The help icon
-    /// </summary>
-    Help,
-
-    /// <summary>
-    /// The I beam.
-    /// </summary>
-    IBeam,
-
-    /// <summary>
-    /// The blocking image.
-    /// </summary>
-    No,
-
-    /// <summary>
-    /// The wait.
-    /// </summary>
-    Wait,
-
-    /// <summary>
-    /// The size all sides.
-    /// </summary>
-    SizeAll,
-
-    /// <summary>
-    /// The size NE-SW.
-    /// </summary>
-    SizeNESW,
-
-    /// <summary>
-    /// The size NS.
-    /// </summary>
-    SizeNS,
-
-    /// <summary>
-    /// The size NW-SE.
-    /// </summary>
-    SizeNWSE,
-
-    /// <summary>
-    /// The size WE.
-    /// </summary>
-    SizeWE,
-
-    /// <summary>
-    /// The cursor is hidden.
-    /// </summary>
-    Hidden,
-
-    MAX
-};
-
-/// <summary>
-/// Data drag and drop effects.
-/// </summary>
-API_ENUM() enum class DragDropEffect
-{
-    /// <summary>
-    /// The none.
-    /// </summary>
-    None = 0,
-
-    /// <summary>
-    /// The copy.
-    /// </summary>
-    Copy,
-
-    /// <summary>
-    /// The move.
-    /// </summary>
-    Move,
-
-    /// <summary>
-    /// The link.
-    /// </summary>
-    Link,
-};
-
-/// <summary>
-/// Window hit test codes. Note: they are 1:1 mapping for Win32 values.
-/// </summary>
-API_ENUM() enum class WindowHitCodes
-{
-    /// <summary>
-    /// The transparent area.
-    /// </summary>
-    Transparent = -1,
-
-    /// <summary>
-    /// The no hit.
-    /// </summary>
-    NoWhere = 0,
-
-    /// <summary>
-    /// The client area.
-    /// </summary>
-    Client = 1,
-
-    /// <summary>
-    /// The caption area.
-    /// </summary>
-    Caption = 2,
-
-    /// <summary>
-    /// The system menu.
-    /// </summary>
-    SystemMenu = 3,
-
-    /// <summary>
-    /// The grow box
-    /// </summary>
-    GrowBox = 4,
-
-    /// <summary>
-    /// The menu.
-    /// </summary>
-    Menu = 5,
-
-    /// <summary>
-    /// The horizontal scroll.
-    /// </summary>
-    HScroll = 6,
-
-    /// <summary>
-    /// The vertical scroll.
-    /// </summary>
-    VScroll = 7,
-
-    /// <summary>
-    /// The minimize button.
-    /// </summary>
-    MinButton = 8,
-
-    /// <summary>
-    /// The maximize button.
-    /// </summary>
-    MaxButton = 9,
-
-    /// <summary>
-    /// The left side;
-    /// </summary>
-    Left = 10,
-
-    /// <summary>
-    /// The right side.
-    /// </summary>
-    Right = 11,
-
-    /// <summary>
-    /// The top side.
-    /// </summary>
-    Top = 12,
-
-    /// <summary>
-    /// The top left corner.
-    /// </summary>
-    TopLeft = 13,
-
-    /// <summary>
-    /// The top right corner.
-    /// </summary>
-    TopRight = 14,
-
-    /// <summary>
-    /// The bottom side.
-    /// </summary>
-    Bottom = 15,
-
-    /// <summary>
-    /// The bottom left corner.
-    /// </summary>
-    BottomLeft = 16,
-
-    /// <summary>
-    /// The bottom right corner.
-    /// </summary>
-    BottomRight = 17,
-
-    /// <summary>
-    /// The border.
-    /// </summary>
-    Border = 18,
-
-    /// <summary>
-    /// The object.
-    /// </summary>
-    Object = 19,
-
-    /// <summary>
-    /// The close button.
-    /// </summary>
-    Close = 20,
-
-    /// <summary>
-    /// The help button.
-    /// </summary>
-    Help = 21,
-};
-
 API_INJECT_CODE(cpp, "#include \"Engine/Platform/Window.h\"");
 
 /// <summary>
@@ -290,6 +45,7 @@ protected:
     bool _isHorizontalFlippingMouse = false;
     bool _isVerticalFlippingMouse = false;
     bool _isClippingCursor = false;
+    bool _restoreRelativeMode = false;
 
     explicit WindowBase(const CreateWindowSettings& settings);
     virtual ~WindowBase();
@@ -402,6 +158,17 @@ public:
         return _maximized;
     }
 
+    /// <summary>
+    /// Gets a value that indicates whether a window is always on top of other windows.
+    /// </summary>
+    API_PROPERTY() virtual bool IsAlwaysOnTop() const;
+
+    /// <summary>
+    /// Sets a value that indicates whether a window is always on top of other windows.
+    /// </summary>
+    /// <param name="isAlwaysOnTop">True if always on top.</param>
+    API_PROPERTY() virtual void SetIsAlwaysOnTop(bool isAlwaysOnTop);
+
     /// <summary>
     /// Gets the native window handle.
     /// </summary>
@@ -663,7 +430,7 @@ public:
 
 public:
     /// <summary>
-    /// Starts drag and drop operation
+    /// Starts a drag and drop operation.
     /// </summary>
     /// <param name="data">The data.</param>
     /// <returns>The result.</returns>
@@ -672,6 +439,18 @@ public:
         return DragDropEffect::None;
     }
 
+    /// <summary>
+    /// Starts a window drag and drop operation.
+    /// </summary>
+    /// <param name="data">The data.</param>
+    /// <param name="offset">The offset for positioning the window from cursor.</param>
+    /// <param name="dragSourceWindow">The window where dragging started.</param>
+    /// <returns>The result.</returns>
+    API_FUNCTION() virtual DragDropEffect DoDragDrop(const StringView& data, const Float2& offset, Window* dragSourceWindow)
+    {
+        return DragDropEffect::None;
+    }
+
     /// <summary>
     /// Starts the mouse tracking.
     /// </summary>
@@ -742,6 +521,17 @@ public:
     {
     }
 
+    /// <summary>
+    /// Gets the mouse position in window coordinates.
+    /// </summary>
+    API_PROPERTY() virtual Float2 GetMousePosition() const;
+
+    /// <summary>
+    /// Sets the mouse position in window coordinates.
+    /// </summary>
+    /// <param name="position">Mouse position to set on</param>
+    API_PROPERTY() virtual void SetMousePosition(const Float2& position) const;
+
     /// <summary>
     /// Gets the mouse cursor.
     /// </summary>
@@ -837,6 +627,12 @@ public:
     MouseDelegate MouseMove;
     void OnMouseMove(const Float2& mousePosition);
 
+    /// <summary>
+    /// Event fired when mouse moves in relative mode.
+    /// </summary>
+    MouseDelegate MouseMoveRelative;
+    void OnMouseMoveRelative(const Float2& mousePositionRelative);
+
     /// <summary>
     /// Event fired when mouse leaves window.
     /// </summary>
@@ -932,16 +728,6 @@ public:
     API_FUNCTION() bool GetKeyUp(KeyboardKeys key) const;
 
 public:
-    /// <summary>
-    /// Gets the mouse position in window coordinates.
-    /// </summary>
-    API_PROPERTY() Float2 GetMousePosition() const;
-
-    /// <summary>
-    /// Sets the mouse position in window coordinates.
-    /// </summary>
-    /// <param name="position">Mouse position to set on</param>
-    API_PROPERTY() void SetMousePosition(const Float2& position) const;
 
     /// <summary>
     /// Gets the mouse position change during the last frame.

Source/Engine/Platform/Clipboard.h

@@ -2,7 +2,9 @@
 
 #pragma once
 
-#if PLATFORM_WINDOWS
+#if PLATFORM_SDL && PLATFORM_LINUX
+#include "SDL/SDLClipboard.h"
+#elif PLATFORM_WINDOWS
 #include "Windows/WindowsClipboard.h"
 #elif PLATFORM_LINUX
 #include "Linux/LinuxClipboard.h"

Source/Engine/Platform/CreateWindowSettings.cs

@@ -11,7 +11,7 @@ namespace FlaxEngine
         {
             Position = new Float2(100, 100),
             Size = new Float2(640, 480),
-            MinimumSize = Float2.One,
+            MinimumSize = new Float2(8, 8),
             MaximumSize = Float2.Zero, // Unlimited size
             StartPosition = WindowStartPosition.CenterParent,
             HasBorder = true,
@@ -21,7 +21,7 @@ namespace FlaxEngine
             AllowMinimize = true,
             AllowMaximize = true,
             AllowDragAndDrop = true,
-            IsRegularWindow = true,
+            Type = WindowType.Regular,
             HasSizingFrame = true,
             ShowAfterFirstPaint = true,
         };

Source/Engine/Platform/CreateWindowSettings.h

@@ -26,6 +26,32 @@ API_ENUM() enum class WindowStartPosition
     Manual,
 };
 
+/// <summary>
+/// Specifies the type of the window.
+/// </summary>
+API_ENUM() enum class WindowType
+{
+    /// <summary>
+    /// Regular window.
+    /// </summary>
+    Regular,
+
+    /// <summary>
+    /// Utility window.
+    /// </summary>
+    Utility,
+
+    /// <summary>
+    /// Tooltip window.
+    /// </summary>
+    Tooltip,
+
+    /// <summary>
+    /// Popup window.
+    /// </summary>
+    Popup,
+};
+
 /// <summary>
 /// Settings for new window.
 /// </summary>
@@ -119,9 +145,15 @@ DECLARE_SCRIPTING_TYPE_MINIMAL(CreateWindowSettings);
     API_FIELD() bool IsTopmost = false;
 
     /// <summary>
-    /// True if it's a regular window, false for tooltips, contextmenu and other utility windows.
+    /// True if it's a regular window, false for tooltips, context menu and other utility windows.
     /// </summary>
-    API_FIELD() bool IsRegularWindow = true;
+    API_FIELD() DEPRECATED("Use Type instead") bool IsRegularWindow = true;
+
+    /// <summary>
+    /// The type of window. The type affects the behaviour of the window in system level.
+    /// Note: Tooltip and Popup windows require Parent to be set.
+    /// </summary>
+    API_FIELD() WindowType Type = WindowType::Regular;
 
     /// <summary>
     /// Enable/disable window sizing frame.

Source/Engine/Platform/Defines.h

@@ -140,6 +140,9 @@ API_ENUM() enum class ArchitectureType
 #if !defined(PLATFORM_SWITCH)
 #define PLATFORM_SWITCH 0
 #endif
+#if !defined(PLATFORM_SDL)
+#define PLATFORM_SDL 0
+#endif
 
 #if PLATFORM_WINDOWS
 #include "Windows/WindowsDefines.h"

Source/Engine/Platform/GDK/GDKPlatform.cpp

@@ -30,7 +30,6 @@ inline bool operator==(const APP_LOCAL_DEVICE_ID& l, const APP_LOCAL_DEVICE_ID&
     return Platform::MemoryCompare(&l, &r, sizeof(APP_LOCAL_DEVICE_ID)) == 0;
 }
 
-const Char* GDKPlatform::ApplicationWindowClass = TEXT("FlaxWindow");
 void* GDKPlatform::Instance = nullptr;
 Delegate<> GDKPlatform::Suspended;
 Delegate<> GDKPlatform::Resumed;
@@ -317,7 +316,7 @@ void GDKPlatform::PreInit(void* hInstance)
     windowsClass.style = CS_HREDRAW | CS_VREDRAW;
     windowsClass.lpfnWndProc = WndProc;
     windowsClass.hInstance = (HINSTANCE)Instance;
-    windowsClass.lpszClassName = ApplicationWindowClass;
+    windowsClass.lpszClassName = ApplicationClassName;
     if (!RegisterClassW(&windowsClass))
     {
         Error(TEXT("Window class registration failed!"));
@@ -477,7 +476,7 @@ void GDKPlatform::Exit()
     if (PlmSignalResume)
         CloseHandle(PlmSignalResume);
 
-    UnregisterClassW(ApplicationWindowClass, nullptr);
+    UnregisterClassW(ApplicationClassName, nullptr);
 
     XGameRuntimeUninitialize();
 }

Source/Engine/Platform/GDK/GDKPlatform.h

@@ -13,11 +13,6 @@ class FLAXENGINE_API GDKPlatform : public Win32Platform
 {
 public:
 
-    /// <summary>
-    /// Win32 application windows class name.
-    /// </summary>
-    static const Char* ApplicationWindowClass;
-
     /// <summary>
     /// Handle to Win32 application instance.
     /// </summary>

Source/Engine/Platform/GDK/GDKWindow.cpp

@@ -71,7 +71,7 @@ GDKWindow::GDKWindow(const CreateWindowSettings& settings)
     // Creating the window
     _handle = CreateWindowExW(
         exStyle,
-        Platform::ApplicationWindowClass,
+        Platform::ApplicationClassName,
         settings.Title.GetText(),
         style,
         x,

Source/Engine/Platform/Linux/IncludeX11.h

@@ -21,6 +21,7 @@ namespace X11
 #include <X11/Xresource.h>
 #include <X11/extensions/Xinerama.h>
 #include <X11/Xcursor/Xcursor.h>
+#include <X11/extensions/Xfixes.h>
 }
 
 // Helper macros

Source/Engine/Platform/Linux/LinuxPlatform.cpp

@@ -97,7 +97,9 @@ X11::Cursor Cursors[(int32)CursorType::MAX];
 X11::XcursorImage* CursorsImg[(int32)CursorType::MAX];
 Dictionary<StringAnsi, X11::KeyCode> KeyNameMap;
 Array<KeyboardKeys> KeyCodeMap;
-Delegate<void*> LinuxPlatform::xEventRecieved;
+#if !PLATFORM_SDL
+Delegate<void*> LinuxPlatform::xEventReceived;
+#endif
 Window* MouseTrackingWindow = nullptr;
 
 // Message boxes configuration
@@ -655,7 +657,11 @@ static int X11_MessageBoxLoop(MessageBoxData* data)
 	return 0;
 }
 
+#if !PLATFORM_SDL
 DialogResult MessageBox::Show(Window* parent, const StringView& text, const StringView& caption, MessageBoxButtons buttons, MessageBoxIcon icon)
+#else
+DialogResult MessageBox::ShowFallback(Window* parent, const StringView& text, const StringView& caption, MessageBoxButtons buttons, MessageBoxIcon icon)
+#endif
 {
     if (CommandLine::Options.Headless.IsTrue())
         return DialogResult::None;
@@ -842,6 +848,8 @@ DialogResult MessageBox::Show(Window* parent, const StringView& text, const Stri
 	return data.resultButtonIndex == -1 ? DialogResult::None : data.buttons[data.resultButtonIndex].result;
 }
 
+#if !PLATFORM_SDL
+
 int X11ErrorHandler(X11::Display* display, X11::XErrorEvent* event)
 {
     if (event->error_code == 5)
@@ -852,6 +860,8 @@ int X11ErrorHandler(X11::Display* display, X11::XErrorEvent* event)
 	return 0;
 }
 
+#endif
+
 int32 CalculateDpi()
 {
 	int dpi = 96;
@@ -1207,17 +1217,20 @@ public:
     }
 };
 
+#if !PLATFORM_SDL
 struct Property
 {
-	unsigned char* data;
-	int format, nitems;
-	X11::Atom type;
+    unsigned char* data;
+    int format, nitems;
+    X11::Atom type;
 };
+#endif
 
 namespace Impl
 {
 	LinuxKeyboard* Keyboard;
 	LinuxMouse* Mouse;
+#if !PLATFORM_SDL
     StringAnsi ClipboardText;
 
     void ClipboardGetText(String& result, X11::Atom source, X11::Atom atom, X11::Window window)
@@ -1332,6 +1345,7 @@ namespace Impl
         X11::XQueryPointer(display, w, &wtmp, &child, &tmp, &tmp, &tmp, &tmp, &utmp);
         return FindAppWindow(display, child);
     }
+#endif
 
     Dictionary<String, String> LoadConfigFile(StringView path)
 	{
@@ -1361,6 +1375,7 @@ namespace Impl
 	}
 }
 
+#if !PLATFORM_SDL
 class LinuxDropFilesData : public IGuiData
 {
 public:
@@ -1398,7 +1413,7 @@ public:
     }
 };
 
-DragDropEffect LinuxWindow::DoDragDrop(const StringView& data)
+DragDropEffect Window::DoDragDrop(const StringView& data)
 {
     if (CommandLine::Options.Headless.IsTrue())
         return DragDropEffect::None;
@@ -1412,13 +1427,14 @@ DragDropEffect LinuxWindow::DoDragDrop(const StringView& data)
     StringAnsi dataAnsi(data);
     LinuxDropTextData dropData;
     dropData.Text = data;
+    unsigned long mainWindow = _window;
 
     // Begin dragging
 	auto screen = X11::XDefaultScreen(xDisplay);
 	auto rootWindow = X11::XRootWindow(xDisplay, screen);
-    if (X11::XGrabPointer(xDisplay, _window, 1, Button1MotionMask | ButtonReleaseMask, GrabModeAsync, GrabModeAsync, rootWindow, cursorWrong, CurrentTime) != GrabSuccess)
+    if (X11::XGrabPointer(xDisplay, mainWindow, 1, Button1MotionMask | ButtonReleaseMask, GrabModeAsync, GrabModeAsync, rootWindow, cursorWrong, CurrentTime) != GrabSuccess)
 	    return DragDropEffect::None;
-    X11::XSetSelectionOwner(xDisplay, xAtomXdndSelection, _window, CurrentTime);
+    X11::XSetSelectionOwner(xDisplay, xAtomXdndSelection, mainWindow, CurrentTime);
 
     // Process events
     X11::XEvent event;
@@ -1526,7 +1542,7 @@ DragDropEffect LinuxWindow::DoDragDrop(const StringView& data)
                     m.window = previousWindow;
                     m.message_type = xAtomXdndLeave;
                     m.format = 32;
-                    m.data.l[0] = _window;
+                    m.data.l[0] = mainWindow;
                     m.data.l[1] = 0;
                     m.data.l[2] = 0;
                     m.data.l[3] = 0;
@@ -1555,7 +1571,7 @@ DragDropEffect LinuxWindow::DoDragDrop(const StringView& data)
                     m.window = window;
                     m.message_type = xAtomXdndEnter;
                     m.format = 32;
-                    m.data.l[0] = _window;
+                    m.data.l[0] = mainWindow;
                     m.data.l[1] = Math::Min(5, version) << 24  | (formats.Count() > 3);
                     m.data.l[2] = formats.Count() > 0 ? formats[0] : 0;
                     m.data.l[3] = formats.Count() > 1 ? formats[1] : 0;
@@ -1590,7 +1606,7 @@ DragDropEffect LinuxWindow::DoDragDrop(const StringView& data)
                     m.window = window;
                     m.message_type = xAtomXdndPosition;
                     m.format = 32;
-                    m.data.l[0] = _window;
+                    m.data.l[0] = mainWindow;
                     m.data.l[1] = 0;
                     m.data.l[2] = (x << 16) | y;
                     m.data.l[3] = CurrentTime;
@@ -1633,7 +1649,7 @@ DragDropEffect LinuxWindow::DoDragDrop(const StringView& data)
                     m.window = previousWindow;
                     m.message_type = xAtomXdndDrop;
                     m.format = 32;
-                    m.data.l[0] = _window;
+                    m.data.l[0] = mainWindow;
                     m.data.l[1] = 0;
                     m.data.l[2] = CurrentTime;
                     m.data.l[3] = 0;
@@ -1680,7 +1696,7 @@ DragDropEffect LinuxWindow::DoDragDrop(const StringView& data)
             m.window = previousWindow;
             m.message_type = xAtomXdndLeave;
             m.format = 32;
-            m.data.l[0] = _window;
+            m.data.l[0] = mainWindow;
             m.data.l[1] = 0;
             m.data.l[2] = 0;
             m.data.l[3] = 0;
@@ -1706,7 +1722,7 @@ void LinuxClipboard::SetText(const StringView& text)
 {
     if (CommandLine::Options.Headless.IsTrue())
         return;
-    auto mainWindow = (LinuxWindow*)Engine::MainWindow;
+    auto mainWindow = Engine::MainWindow;
     if (!mainWindow)
         return;
     X11::Window window = (X11::Window)mainWindow->GetNativePtr();
@@ -1729,7 +1745,7 @@ String LinuxClipboard::GetText()
     if (CommandLine::Options.Headless.IsTrue())
         return String::Empty;
     String result;
-    auto mainWindow = (LinuxWindow*)Engine::MainWindow;
+    auto mainWindow = Engine::MainWindow;
     if (!mainWindow)
         return result;
     X11::Window window = (X11::Window)mainWindow->GetNativePtr();
@@ -1758,9 +1774,11 @@ Array<String> LinuxClipboard::GetFiles()
     return Array<String>();
 }
 
+#endif
+
 void* LinuxPlatform::GetXDisplay()
 {
-	return xDisplay;
+    return xDisplay;
 }
 
 bool LinuxPlatform::CreateMutex(const Char* name)
@@ -2090,6 +2108,7 @@ bool LinuxPlatform::Init()
 
     UnixGetMacAddress(MacAddress);
 
+#if !PLATFORM_SDL
     // Get user locale string
     setlocale(LC_ALL, "");
     const char* locale = setlocale(LC_CTYPE, NULL);
@@ -2099,6 +2118,7 @@ bool LinuxPlatform::Init()
     UserLocale.Replace('_', '-');
     if (UserLocale == TEXT("C"))
         UserLocale = TEXT("en");
+#endif
 
     // Get computer name string
     gethostname(buffer, UNIX_APP_BUFF_SIZE);
@@ -2142,7 +2162,11 @@ bool LinuxPlatform::Init()
     // Skip setup if running in headless mode (X11 might not be available on servers)
     if (CommandLine::Options.Headless.IsTrue())
         return false;
-
+#if PLATFORM_SDL
+    xDisplay = X11::XOpenDisplay(nullptr);
+#endif
+    
+#if !PLATFORM_SDL
 	X11::XInitThreads();
 
 	xDisplay = X11::XOpenDisplay(nullptr);
@@ -2281,7 +2305,7 @@ bool LinuxPlatform::Init()
     Input::Mouse = Impl::Mouse = New<LinuxMouse>();
     Input::Keyboard = Impl::Keyboard = New<LinuxKeyboard>();
 	LinuxInput::Init();
-
+#endif
     return false;
 }
 
@@ -2291,6 +2315,7 @@ void LinuxPlatform::BeforeRun()
 
 void LinuxPlatform::Tick()
 {
+#if !PLATFORM_SDL
 	UnixPlatform::Tick();
 
 	LinuxInput::UpdateState();
@@ -2307,9 +2332,9 @@ void LinuxPlatform::Tick()
 			continue;
 
         // External event handling
-		xEventRecieved(&event);
+		xEventReceived(&event);
 
-		LinuxWindow* window;
+		Window* window;
 		switch (event.type)
 		{
 			case ClientMessage:
@@ -2641,6 +2666,7 @@ void LinuxPlatform::Tick()
 	}
 
 	//X11::XFlush(xDisplay);
+#endif
 }
 
 void LinuxPlatform::BeforeExit()
@@ -2649,6 +2675,7 @@ void LinuxPlatform::BeforeExit()
 
 void LinuxPlatform::Exit()
 {
+#if !PLATFORM_SDL
 	for (int32 i = 0; i < (int32)CursorType::MAX; i++)
 	{
 		if (Cursors[i])
@@ -2674,6 +2701,7 @@ void LinuxPlatform::Exit()
 		X11::XCloseDisplay(xDisplay);
 		xDisplay = nullptr;
 	}
+#endif
 }
 
 String LinuxPlatform::GetSystemName()
@@ -2695,6 +2723,7 @@ Version LinuxPlatform::GetSystemVersion()
     return Version(0, 0);
 }
 
+#if !PLATFORM_SDL
 int32 LinuxPlatform::GetDpi()
 {
     return SystemDpi;
@@ -2704,6 +2733,7 @@ String LinuxPlatform::GetUserLocaleName()
 {
     return UserLocale;
 }
+#endif
 
 String LinuxPlatform::GetComputerName()
 {
@@ -2911,10 +2941,12 @@ bool LinuxPlatform::SetWorkingDirectory(const String& path)
     return chdir(StringAsANSI<>(*path).Get()) != 0;
 }
 
+#if !PLATFORM_SDL
 Window* LinuxPlatform::CreateWindow(const CreateWindowSettings& settings)
 {
     return New<LinuxWindow>(settings);
 }
+#endif
 
 extern char **environ;
 

Source/Engine/Platform/Linux/LinuxPlatform.h

@@ -36,7 +36,7 @@ public:
     /// <summary>
     /// An event that is fired when an XEvent is received during platform tick.
     /// </summary>
-    static Delegate<void*> xEventRecieved;
+    static Delegate<void*> xEventReceived;
 
 public:
 
@@ -123,8 +123,10 @@ public:
     static void Tick();
     static void BeforeExit();
     static void Exit();
+#if !PLATFORM_SDL
     static int32 GetDpi();
     static String GetUserLocaleName();
+#endif
     static String GetComputerName();
     static bool GetHasFocus();
     static bool CanOpenUrl(const StringView& url);
@@ -139,7 +141,9 @@ public:
     static Guid GetUniqueDeviceId();
     static String GetWorkingDirectory();
     static bool SetWorkingDirectory(const String& path);
+#if !PLATFORM_SDL
     static Window* CreateWindow(const CreateWindowSettings& settings);
+#endif
     static void GetEnvironmentVariables(Dictionary<String, String, HeapAllocation>& result);
     static bool GetEnvironmentVariable(const String& name, String& value);
     static bool SetEnvironmentVariable(const String& name, const String& value);

Source/Engine/Platform/Linux/LinuxScreenUtilities.cpp

@@ -0,0 +1,164 @@
+// Copyright (c) Wojciech Figat. All rights reserved.
+
+#if PLATFORM_LINUX
+
+#include "Engine/Platform/Types.h"
+#include "Engine/Platform/ScreenUtilities.h"
+#include "Engine/Core/Math/Vector2.h"
+#include "Engine/Core/Delegate.h"
+#include "Engine/Core/Log.h"
+#include "Engine/Core/Math/Vector4.h"
+#include "Engine/Profiler/ProfilerCPU.h"
+#include "Engine/Platform/Linux/LinuxPlatform.h"
+#include "Engine/Platform/Linux/IncludeX11.h"
+
+#if PLATFORM_SDL
+#include <libportal/portal-enums.h>
+#include <libportal/screenshot.h>
+
+namespace PortalImpl
+{
+    XdpPortal* Portal = nullptr;
+    int64 MainLoopReady = 0;
+
+    gpointer GLibMainLoop(gpointer data);
+    void PickColorCallback(GObject* source, GAsyncResult* result, gpointer data);
+}
+#endif
+
+Delegate<Color32> ScreenUtilitiesBase::PickColorDone;
+
+Color32 LinuxScreenUtilities::GetColorAt(const Float2& pos)
+{
+    X11::Display* display = (X11::Display*)Platform::GetXDisplay();
+    if (display)
+    {
+        int defaultScreen = X11::XDefaultScreen(display);
+        X11::Window rootWindow = X11::XRootWindow(display, defaultScreen);
+        X11::XImage* image = X11::XGetImage(display, rootWindow, (int)pos.X, (int)pos.Y, 1, 1, AllPlanes, XYPixmap);
+        if (image)
+        {
+            X11::XColor color;
+            color.pixel = XGetPixel(image, 0, 0);
+            X11::XFree(image);
+
+            X11::XQueryColor(display, X11::XDefaultColormap(display, defaultScreen), &color);
+
+            Color32 outputColor;
+            outputColor.R = color.red / 256;
+            outputColor.G = color.green / 256;
+            outputColor.B = color.blue / 256;
+            outputColor.A = 255;
+            return outputColor;
+        }
+        else
+        {
+            // XWayland doesn't support XGetImage
+        }
+    }
+
+    return Color32::Transparent;
+}
+
+void OnScreenUtilsXEventCallback(void* eventPtr)
+{
+    X11::XEvent* event = (X11::XEvent*) eventPtr;
+    X11::Display* display = (X11::Display*)Platform::GetXDisplay();
+    if (event->type == ButtonPress)
+    {
+        const Float2 cursorPos = Platform::GetMousePosition();
+        const Color32 colorPicked = ScreenUtilities::GetColorAt(cursorPos);
+        X11::XUngrabPointer(display, CurrentTime);
+        ScreenUtilities::PickColorDone(colorPicked);
+        LinuxPlatform::xEventReceived.Unbind(OnScreenUtilsXEventCallback);
+    }
+}
+
+void LinuxScreenUtilities::PickColor()
+{
+    PROFILE_CPU();
+    X11::Display* display = (X11::Display*)Platform::GetXDisplay();
+    if (display)
+    {
+        X11::Window rootWindow = X11::XRootWindow(display, X11::XDefaultScreen(display));
+
+        X11::Cursor cursor = XCreateFontCursor(display, 130);
+        int grabbedPointer = X11::XGrabPointer(display, rootWindow, 0,  ButtonPressMask, GrabModeAsync, GrabModeAsync, rootWindow, cursor, CurrentTime);
+        if (grabbedPointer != GrabSuccess)
+        {
+            LOG(Error, "Failed to grab cursor for events.");
+            X11::XFreeCursor(display, cursor);
+            return;
+        }
+
+        X11::XFreeCursor(display, cursor);
+        LinuxPlatform::xEventReceived.Bind(OnScreenUtilsXEventCallback);
+        return;
+    }
+#if PLATFORM_SDL
+    if (PortalImpl::MainLoopReady == 0)
+    {
+        // Initialize portal
+        GError* error = nullptr;
+        PortalImpl::Portal = xdp_portal_initable_new(&error);
+        if (error != nullptr)
+        {
+            PortalImpl::MainLoopReady = 2;
+            LOG(Error, "Failed to initialize XDP Portal");
+            return;
+        }
+
+        // Run the GLib main loop in other thread in order to process asynchronous callbacks
+        g_thread_new(nullptr, PortalImpl::GLibMainLoop, nullptr);
+        while (Platform::AtomicRead(&PortalImpl::MainLoopReady) != 1)
+            Platform::Sleep(1);
+    }
+    
+    if (PortalImpl::Portal != nullptr)
+    {
+        // Enter color picking mode, the callback receives the final color
+        xdp_portal_pick_color(PortalImpl::Portal, nullptr, nullptr, PortalImpl::PickColorCallback, nullptr);
+    }
+#endif
+}
+
+#if PLATFORM_SDL
+
+gpointer PortalImpl::GLibMainLoop(gpointer data)
+{
+    GMainContext* mainContext = g_main_context_get_thread_default();
+    GMainLoop* mainLoop = g_main_loop_new(mainContext, false);
+
+    Platform::AtomicStore(&PortalImpl::MainLoopReady, 1);
+    
+    g_main_loop_run(mainLoop);
+    g_main_loop_unref(mainLoop);
+    return nullptr;
+}
+
+void PortalImpl::PickColorCallback(GObject* source, GAsyncResult* result, gpointer data)
+{
+    GError* error = nullptr;
+    GVariant* variant = xdp_portal_pick_color_finish(PortalImpl::Portal, result, &error);
+    if (error)
+    {
+        if (g_error_matches(error, G_IO_ERROR, G_IO_ERROR_CANCELLED))
+            LOG(Info, "XDP Portal pick color cancelled");
+        else
+            LOG(Error, "XDP Portal pick color failed: {}", String(error->message));
+        return;
+    }
+
+    // The color is stored in a triple double variant, extract the values
+    Double4 colorDouble;
+    g_variant_get(variant, "(ddd)", &colorDouble.X, &colorDouble.Y, &colorDouble.Z);
+    g_variant_unref(variant);
+    colorDouble.W = 1.0f;
+    Vector4 colorVector = colorDouble;
+    Color32 color = Color32(colorVector);
+
+    ScreenUtilities::PickColorDone(color);
+}
+#endif
+
+#endif

Source/Engine/Platform/Linux/LinuxScreenUtilities.h

@@ -0,0 +1,24 @@
+// Copyright (c) Wojciech Figat. All rights reserved.
+
+#pragma once
+
+#if PLATFORM_LINUX
+
+#include "Engine/Platform/Base/ScreenUtilitiesBase.h"
+#include "Engine/Core/Types/BaseTypes.h"
+#include "Engine/Core/Math/Color32.h"
+#include "Engine/Core/Delegate.h"
+
+/// <summary>
+/// Platform-dependent screen utilities.
+/// </summary>
+class FLAXENGINE_API LinuxScreenUtilities : public ScreenUtilitiesBase
+{
+public:
+    
+    // [ScreenUtilitiesBase]
+    static Color32 GetColorAt(const Float2& pos);
+    static void PickColor();
+};
+
+#endif

Source/Engine/Platform/Linux/LinuxWindow.cpp

@@ -1,6 +1,6 @@
 // Copyright (c) Wojciech Figat. All rights reserved.
 
-#if PLATFORM_LINUX
+#if PLATFORM_LINUX && !PLATFORM_SDL
 
 #include "../Window.h"
 #include "Engine/Input/Input.h"
@@ -616,7 +616,7 @@ void LinuxWindow::OnButtonPress(void* event)
 	}
 
 	// Handle double-click
-	if (buttonEvent->button == Button1)
+	if (buttonEvent->button == Button1 && !Input::Mouse->IsRelative())
 	{
 		if (
 			buttonEvent->time < (MouseLastButtonPressTime + MouseDoubleClickTime) &&

Source/Engine/Platform/Linux/LinuxWindow.h

@@ -89,6 +89,7 @@ public:
 	void Focus() override;
 	void SetTitle(const StringView& title) override;
 	DragDropEffect DoDragDrop(const StringView& data) override;
+    using WindowBase::DoDragDrop;
 	void StartTrackingMouse(bool useMouseScreenOffset) override;
 	void EndTrackingMouse() override;
 	void SetCursor(CursorType type) override;

Source/Engine/Platform/Mac/MacPlatform.cpp

@@ -273,6 +273,7 @@ bool MacPlatform::Init()
         CFRelease(computerName);
     }
 
+#if !PLATFORM_SDL
     // Find the maximum scale of the display to handle high-dpi displays scaling factor
     {
 	    NSArray* screenArray = [NSScreen screens];
@@ -297,6 +298,7 @@ bool MacPlatform::Init()
 
     Input::Mouse = New<MacMouse>();
     Input::Keyboard = New<MacKeyboard>();
+#endif
 
     return false;
 }
@@ -423,11 +425,15 @@ String MacPlatform::GetMainDirectory()
     return path;
 }
 
+#if !PLATFORM_SDL
+
 Window* MacPlatform::CreateWindow(const CreateWindowSettings& settings)
 {
     return New<MacWindow>(settings);
 }
 
+#endif
+
 int32 MacPlatform::CreateProcess(CreateProcessSettings& settings)
 {
     LOG(Info, "Command: {0} {1}", settings.FileName, settings.Arguments);

Source/Engine/Platform/Mac/MacScreenUtilities.cpp

@@ -0,0 +1,29 @@
+// Copyright (c) Wojciech Figat. All rights reserved.
+
+#if USE_EDITOR && PLATFORM_MAC
+
+#include "Engine/Platform/Types.h"
+#include "Engine/Platform/ScreenUtilities.h"
+#include "Engine/Core/Math/Vector2.h"
+#include "Engine/Core/Delegate.h"
+#include "Engine/Core/Log.h"
+
+#include <Cocoa/Cocoa.h>
+#include <AppKit/AppKit.h>
+
+Delegate<Color32> ScreenUtilitiesBase::PickColorDone;
+
+Color32 MacScreenUtilities::GetColorAt(const Float2& pos)
+{
+    // TODO: implement ScreenUtilities for macOS
+    return { 0, 0, 0, 255 };
+}
+
+void MacScreenUtilities::PickColor()
+{
+    // This is what C# calls to start the color picking sequence
+    // This should stop mouse clicks from working for one click, and that click is on the selected color
+    // There is a class called NSColorSample that might implement that for you, but maybe not.
+}
+
+#endif

Source/Engine/Platform/Mac/MacScreenUtilities.h

@@ -0,0 +1,25 @@
+// Copyright (c) Wojciech Figat. All rights reserved.
+
+#pragma once
+
+#if USE_EDITOR && PLATFORM_MAC
+
+#include "Engine/Platform/Base/ScreenUtilitiesBase.h"
+#include "Engine/Core/Types/BaseTypes.h"
+#include "Engine/Core/Math/Color32.h"
+#include "Engine/Core/Math/Vector2.h"
+#include "Engine/Core/Delegate.h"
+
+/// <summary>
+/// Platform-dependent screen utilities.
+/// </summary>
+class FLAXENGINE_API MacScreenUtilities : public ScreenUtilitiesBase
+{
+public:
+
+    // [ScreenUtilitiesBase]
+    static Color32 GetColorAt(const Float2& pos);
+    static void PickColor();
+};
+
+#endif

Source/Engine/Platform/Mac/MacWindow.cpp

@@ -1,6 +1,6 @@
 // Copyright (c) Wojciech Figat. All rights reserved.
 
-#if PLATFORM_MAC
+#if PLATFORM_MAC && !PLATFORM_SDL
 
 #include "../Window.h"
 #include "Engine/Platform/Apple/AppleUtils.h"
@@ -507,7 +507,7 @@ static void ConvertNSRect(NSScreen *screen, NSRect *r)
 	Float2 mousePos = GetMousePosition(Window, event);
     mousePos = Window->ClientToScreen(mousePos);
     MouseButton mouseButton = MouseButton::Left;
-    if ([event clickCount] == 2)
+    if ([event clickCount] == 2 && !Input::Mouse->IsRelative())
         Input::Mouse->OnMouseDoubleClick(mousePos, mouseButton, Window);
     else
 	    Input::Mouse->OnMouseDown(mousePos, mouseButton, Window);
@@ -544,7 +544,7 @@ static void ConvertNSRect(NSScreen *screen, NSRect *r)
     if (IsWindowInvalid(Window)) return;
 	Float2 mousePos = GetMousePosition(Window, event);
     MouseButton mouseButton = MouseButton::Right;
-    if ([event clickCount] == 2)
+    if ([event clickCount] == 2 && !Input::Mouse->IsRelative())
         Input::Mouse->OnMouseDoubleClick(Window->ClientToScreen(mousePos), mouseButton, Window);
     else
 	    Input::Mouse->OnMouseDown(Window->ClientToScreen(mousePos), mouseButton, Window);
@@ -582,7 +582,7 @@ static void ConvertNSRect(NSScreen *screen, NSRect *r)
     default:
         return;
     }
-    if ([event clickCount] == 2)
+    if ([event clickCount] == 2 && !Input::Mouse->IsRelative())
         Input::Mouse->OnMouseDoubleClick(Window->ClientToScreen(mousePos), mouseButton, Window);
     else
 	    Input::Mouse->OnMouseDown(Window->ClientToScreen(mousePos), mouseButton, Window);

Source/Engine/Platform/Mac/MacWindow.h

@@ -55,6 +55,7 @@ public:
     void Focus() override;
     void SetTitle(const StringView& title) override;
 	DragDropEffect DoDragDrop(const StringView& data) override;
+    using WindowBase::DoDragDrop;
     void StartTrackingMouse(bool useMouseScreenOffset) override;
     void EndTrackingMouse() override;
 	void SetCursor(CursorType type) override;

Source/Engine/Platform/MessageBox.h

@@ -237,4 +237,9 @@ DECLARE_SCRIPTING_TYPE_NO_SPAWN(MessageBox);
     /// <param name="icon">One of the MessageBoxIcon values that specifies which icon to display in the message box.</param>
     /// <returns>The message box dialog result.</returns>
     API_FUNCTION() static DialogResult Show(Window* parent, const StringView& text, const StringView& caption, MessageBoxButtons buttons, MessageBoxIcon icon);
+
+private:
+#if PLATFORM_SDL && PLATFORM_LINUX
+    static DialogResult ShowFallback(Window* parent, const StringView& text, const StringView& caption, MessageBoxButtons buttons, MessageBoxIcon icon);
+#endif
 };

Source/Engine/Platform/Platform.Build.cs

@@ -89,6 +89,21 @@ public class Platform : EngineModule
             break;
         default: throw new InvalidPlatformException(options.Platform.Target);
         }
+
+        if (EngineConfiguration.WithSDL(options))
+        {
+            switch (options.Platform.Target)
+            {
+            case TargetPlatform.Windows:
+            case TargetPlatform.Linux:
+            case TargetPlatform.Mac:
+                options.PublicDependencies.Add("SDL");
+                options.SourcePaths.Add(Path.Combine(FolderPath, "SDL"));
+                break;
+            }
+            if (options.Platform.Target == TargetPlatform.Linux)
+                options.PublicDependencies.Add("Wayland");
+        }
         if (options.Target.IsEditor)
         {
             // Include platform settings headers

Source/Engine/Platform/Platform.h

@@ -8,7 +8,9 @@
 #include "Types.h"
 #include "Defines.h"
 
-#if PLATFORM_WINDOWS
+#if PLATFORM_SDL
+#include "SDL/SDLPlatform.h"
+#elif PLATFORM_WINDOWS
 #include "Windows/WindowsPlatform.h"
 #elif PLATFORM_UWP
 #include "UWP/UWPPlatform.h"

Source/Engine/Platform/SDL/SDLClipboard.h

@@ -0,0 +1,26 @@
+// Copyright (c) Wojciech Figat. All rights reserved.
+
+#pragma once
+
+#if PLATFORM_SDL && PLATFORM_LINUX
+
+#include "Engine/Platform/Base/ClipboardBase.h"
+
+/// <summary>
+/// SDL implementation of the clipboard service for Linux platform.
+/// </summary>
+class FLAXENGINE_API SDLClipboard : public ClipboardBase
+{
+public:
+
+    // [ClipboardBase]
+    static void Clear();
+    static void SetText(const StringView& text);
+    static void SetRawData(const Span<byte>& data);
+    static void SetFiles(const Array<String>& files);
+    static String GetText();
+    static Array<byte> GetRawData();
+    static Array<String> GetFiles();
+};
+
+#endif

Source/Engine/Platform/SDL/SDLInput.cpp

@@ -0,0 +1,836 @@
+// Copyright (c) Wojciech Figat. All rights reserved.
+
+#if PLATFORM_SDL
+
+#include "SDLInput.h"
+#include "SDLWindow.h"
+#include "Engine/Core/Collections/Dictionary.h"
+#include "Engine/Core/Log.h"
+#include "Engine/Input/Input.h"
+#include "Engine/Input/Mouse.h"
+#include "Engine/Input/Keyboard.h"
+#include "Engine/Input/Gamepad.h"
+#include "Engine/Engine/Engine.h"
+#include "Engine/Engine/Screen.h"
+#if USE_EDITOR
+#include "Editor/Editor.h"
+#include "Editor/Managed/ManagedEditor.h"
+#endif
+
+#include <SDL3/SDL_events.h>
+
+class SDLMouse;
+class SDLKeyboard;
+class SDLGamepad;
+
+// TODO: Turn these into customizable values
+#define TRIGGER_THRESHOLD 30
+#define LEFT_STICK_THRESHOLD 7849
+#define RIGHT_STICK_THRESHOLD 8689
+
+namespace SDLInputImpl
+{
+    SDLMouse* Mouse = nullptr;
+    SDLKeyboard* Keyboard = nullptr;
+    Dictionary<SDL_JoystickID, SDLGamepad*> Gamepads;
+}
+
+static const KeyboardKeys SDL_TO_FLAX_KEYS_MAP[] =
+{
+    KeyboardKeys::None, // SDL_SCANCODE_UNKNOWN
+    KeyboardKeys::None,
+    KeyboardKeys::None,
+    KeyboardKeys::None,
+    KeyboardKeys::A,
+    KeyboardKeys::B,
+    KeyboardKeys::C,
+    KeyboardKeys::D,
+    KeyboardKeys::E,
+    KeyboardKeys::F,
+    KeyboardKeys::G,
+    KeyboardKeys::H,
+    KeyboardKeys::I,
+    KeyboardKeys::J,
+    KeyboardKeys::K,
+    KeyboardKeys::L,
+    KeyboardKeys::M,
+    KeyboardKeys::N,
+    KeyboardKeys::O,
+    KeyboardKeys::P,
+    KeyboardKeys::Q,
+    KeyboardKeys::R,
+    KeyboardKeys::S,
+    KeyboardKeys::T,
+    KeyboardKeys::U,
+    KeyboardKeys::V,
+    KeyboardKeys::W,
+    KeyboardKeys::X,
+    KeyboardKeys::Y,
+    KeyboardKeys::Z, // 29
+    KeyboardKeys::Alpha1,
+    KeyboardKeys::Alpha2,
+    KeyboardKeys::Alpha3,
+    KeyboardKeys::Alpha4,
+    KeyboardKeys::Alpha5,
+    KeyboardKeys::Alpha6,
+    KeyboardKeys::Alpha7,
+    KeyboardKeys::Alpha8,
+    KeyboardKeys::Alpha9,
+    KeyboardKeys::Alpha0, // 39
+    KeyboardKeys::Return,
+    KeyboardKeys::Escape,
+    KeyboardKeys::Backspace,
+    KeyboardKeys::Tab,
+    KeyboardKeys::Spacebar,
+    KeyboardKeys::Minus,
+    KeyboardKeys::None, //KeyboardKeys::Equals, // ?
+    KeyboardKeys::LeftBracket,
+    KeyboardKeys::RightBracket,
+    KeyboardKeys::Backslash, // SDL_SCANCODE_BACKSLASH ?
+    KeyboardKeys::Oem102, // SDL_SCANCODE_NONUSHASH ?
+    KeyboardKeys::Colon, // SDL_SCANCODE_SEMICOLON ?
+    KeyboardKeys::Quote, // SDL_SCANCODE_APOSTROPHE
+    KeyboardKeys::BackQuote, // SDL_SCANCODE_GRAVE
+    KeyboardKeys::Comma,
+    KeyboardKeys::Period,
+    KeyboardKeys::Slash,
+    KeyboardKeys::Capital,
+    KeyboardKeys::F1,
+    KeyboardKeys::F2,
+    KeyboardKeys::F3,
+    KeyboardKeys::F4,
+    KeyboardKeys::F5,
+    KeyboardKeys::F6,
+    KeyboardKeys::F7,
+    KeyboardKeys::F8,
+    KeyboardKeys::F9,
+    KeyboardKeys::F10,
+    KeyboardKeys::F11,
+    KeyboardKeys::F12,
+    KeyboardKeys::PrintScreen,
+    KeyboardKeys::Scroll,
+    KeyboardKeys::Pause,
+    KeyboardKeys::Insert,
+    KeyboardKeys::Home,
+    KeyboardKeys::PageUp,
+    KeyboardKeys::Delete,
+    KeyboardKeys::End,
+    KeyboardKeys::PageDown,
+    KeyboardKeys::ArrowRight,
+    KeyboardKeys::ArrowLeft,
+    KeyboardKeys::ArrowDown,
+    KeyboardKeys::ArrowUp,
+    KeyboardKeys::Numlock,
+    KeyboardKeys::NumpadDivide,
+    KeyboardKeys::NumpadMultiply,
+    KeyboardKeys::NumpadSubtract,
+    KeyboardKeys::NumpadAdd,
+    KeyboardKeys::Return, // SDL_SCANCODE_KP_ENTER ?
+    KeyboardKeys::Numpad1,
+    KeyboardKeys::Numpad2,
+    KeyboardKeys::Numpad3,
+    KeyboardKeys::Numpad4,
+    KeyboardKeys::Numpad5,
+    KeyboardKeys::Numpad6,
+    KeyboardKeys::Numpad7,
+    KeyboardKeys::Numpad8,
+    KeyboardKeys::Numpad9,
+    KeyboardKeys::Numpad0, //98
+    KeyboardKeys::NumpadDecimal, // SDL_SCANCODE_KP_PERIOD
+    KeyboardKeys::Backslash, // SDL_SCANCODE_NONUSBACKSLASH ?
+    KeyboardKeys::Applications,
+    KeyboardKeys::Sleep, // SDL_SCANCODE_POWER ?
+    KeyboardKeys::None, // SDL_SCANCODE_KP_EQUALS ?
+    KeyboardKeys::F13,
+    KeyboardKeys::F14,
+    KeyboardKeys::F15,
+    KeyboardKeys::F16,
+    KeyboardKeys::F17,
+    KeyboardKeys::F18,
+    KeyboardKeys::F19,
+    KeyboardKeys::F20,
+    KeyboardKeys::F21,
+    KeyboardKeys::F22,
+    KeyboardKeys::F23,
+    KeyboardKeys::F24,
+    KeyboardKeys::Execute,
+    KeyboardKeys::Help,
+    KeyboardKeys::LeftMenu, // SDL_SCANCODE_MENU ?
+    KeyboardKeys::Select,
+    KeyboardKeys::None, // SDL_SCANCODE_STOP
+    KeyboardKeys::None, // SDL_SCANCODE_AGAIN
+    KeyboardKeys::None, // SDL_SCANCODE_UNDO
+    KeyboardKeys::None, // SDL_SCANCODE_CUT
+    KeyboardKeys::None, // SDL_SCANCODE_COPY
+    KeyboardKeys::None, // SDL_SCANCODE_PASTE
+    KeyboardKeys::None, // SDL_SCANCODE_FIND
+    KeyboardKeys::None, // SDL_SCANCODE_MUTE
+    KeyboardKeys::None, // SDL_SCANCODE_VOLUMEUP
+    KeyboardKeys::None, // SDL_SCANCODE_VOLUMEDOWN
+    KeyboardKeys::None,
+    KeyboardKeys::None,
+    KeyboardKeys::None,
+    KeyboardKeys::NumpadSeparator, // SDL_SCANCODE_KP_COMMA ?
+    KeyboardKeys::None, // SDL_SCANCODE_KP_EQUALSAS400
+    KeyboardKeys::None, // SDL_SCANCODE_INTERNATIONAL1
+    KeyboardKeys::None, // SDL_SCANCODE_INTERNATIONAL2
+    KeyboardKeys::None, // SDL_SCANCODE_INTERNATIONAL3
+    KeyboardKeys::None, // SDL_SCANCODE_INTERNATIONAL4
+    KeyboardKeys::None, // SDL_SCANCODE_INTERNATIONAL5
+    KeyboardKeys::None, // SDL_SCANCODE_INTERNATIONAL6
+    KeyboardKeys::None, // SDL_SCANCODE_INTERNATIONAL7
+    KeyboardKeys::None, // SDL_SCANCODE_INTERNATIONAL8
+    KeyboardKeys::None, // SDL_SCANCODE_INTERNATIONAL9
+    KeyboardKeys::None, // SDL_SCANCODE_LANG1
+    KeyboardKeys::None, // SDL_SCANCODE_LANG2
+    KeyboardKeys::None, // SDL_SCANCODE_LANG3
+    KeyboardKeys::None, // SDL_SCANCODE_LANG4
+    KeyboardKeys::None, // SDL_SCANCODE_LANG5
+    KeyboardKeys::None, // SDL_SCANCODE_LANG6
+    KeyboardKeys::None, // SDL_SCANCODE_LANG7
+    KeyboardKeys::None, // SDL_SCANCODE_LANG8
+    KeyboardKeys::None, // SDL_SCANCODE_LANG9
+    KeyboardKeys::None, // SDL_SCANCODE_ALTERASE
+    KeyboardKeys::None, // SDL_SCANCODE_SYSREQ
+    KeyboardKeys::None, // SDL_SCANCODE_CANCEL
+    KeyboardKeys::Clear, // SDL_SCANCODE_CLEAR
+    KeyboardKeys::None, // SDL_SCANCODE_PRIOR
+    KeyboardKeys::None, // SDL_SCANCODE_RETURN2
+    KeyboardKeys::None, // SDL_SCANCODE_SEPARATOR
+    KeyboardKeys::None, // SDL_SCANCODE_OUT
+    KeyboardKeys::None, // SDL_SCANCODE_OPER
+    KeyboardKeys::None, // SDL_SCANCODE_CLEARAGAIN
+    KeyboardKeys::None, // SDL_SCANCODE_CRSEL
+    KeyboardKeys::None, // SDL_SCANCODE_EXSEL
+    KeyboardKeys::None,
+    KeyboardKeys::None,
+    KeyboardKeys::None,
+    KeyboardKeys::None,
+    KeyboardKeys::None,
+    KeyboardKeys::None,
+    KeyboardKeys::None,
+    KeyboardKeys::None,
+    KeyboardKeys::None,
+    KeyboardKeys::None,
+    KeyboardKeys::None,
+    KeyboardKeys::None, // SDL_SCANCODE_KP_00
+    KeyboardKeys::None, // SDL_SCANCODE_KP_000
+    KeyboardKeys::None, // SDL_SCANCODE_THOUSANDSSEPARATOR
+    KeyboardKeys::None, // SDL_SCANCODE_DECIMALSEPARATOR
+    KeyboardKeys::None, // SDL_SCANCODE_CURRENCYUNIT
+    KeyboardKeys::None, // SDL_SCANCODE_CURRENCYSUBUNIT
+    KeyboardKeys::None, // SDL_SCANCODE_KP_LEFTPAREN = 182,
+    KeyboardKeys::None, // SDL_SCANCODE_KP_RIGHTPAREN = 183,
+    KeyboardKeys::None, // SDL_SCANCODE_KP_LEFTBRACE = 184,
+    KeyboardKeys::None, // SDL_SCANCODE_KP_RIGHTBRACE = 185,
+    KeyboardKeys::None, // SDL_SCANCODE_KP_TAB = 186,
+    KeyboardKeys::None, // SDL_SCANCODE_KP_BACKSPACE = 187,
+    KeyboardKeys::None, // SDL_SCANCODE_KP_A = 188,
+    KeyboardKeys::None, // SDL_SCANCODE_KP_B = 189,
+    KeyboardKeys::None, // SDL_SCANCODE_KP_C = 190,
+    KeyboardKeys::None, // SDL_SCANCODE_KP_D = 191,
+    KeyboardKeys::None, // SDL_SCANCODE_KP_E = 192,
+    KeyboardKeys::None, // SDL_SCANCODE_KP_F = 193,
+    KeyboardKeys::None, // SDL_SCANCODE_KP_XOR = 194,
+    KeyboardKeys::None, // SDL_SCANCODE_KP_POWER = 195,
+    KeyboardKeys::None, // SDL_SCANCODE_KP_PERCENT = 196,
+    KeyboardKeys::None, // SDL_SCANCODE_KP_LESS = 197,
+    KeyboardKeys::None, // SDL_SCANCODE_KP_GREATER = 198,
+    KeyboardKeys::None, // SDL_SCANCODE_KP_AMPERSAND = 199,
+    KeyboardKeys::None, // SDL_SCANCODE_KP_DBLAMPERSAND = 200,
+    KeyboardKeys::None, // SDL_SCANCODE_KP_VERTICALBAR = 201,
+    KeyboardKeys::None, // SDL_SCANCODE_KP_DBLVERTICALBAR = 202,
+    KeyboardKeys::None, // SDL_SCANCODE_KP_COLON = 203,
+    KeyboardKeys::None, // SDL_SCANCODE_KP_HASH = 204,
+    KeyboardKeys::None, // SDL_SCANCODE_KP_SPACE = 205,
+    KeyboardKeys::None, // SDL_SCANCODE_KP_AT = 206,
+    KeyboardKeys::None, // SDL_SCANCODE_KP_EXCLAM = 207,
+    KeyboardKeys::None, // SDL_SCANCODE_KP_MEMSTORE = 208,
+    KeyboardKeys::None, // SDL_SCANCODE_KP_MEMRECALL = 209,
+    KeyboardKeys::None, // SDL_SCANCODE_KP_MEMCLEAR = 210,
+    KeyboardKeys::None, // SDL_SCANCODE_KP_MEMADD = 211,
+    KeyboardKeys::None, // SDL_SCANCODE_KP_MEMSUBTRACT = 212,
+    KeyboardKeys::None, // SDL_SCANCODE_KP_MEMMULTIPLY = 213,
+    KeyboardKeys::None, // SDL_SCANCODE_KP_MEMDIVIDE = 214,
+    KeyboardKeys::None, // SDL_SCANCODE_KP_PLUSMINUS = 215,
+    KeyboardKeys::None, // SDL_SCANCODE_KP_CLEAR = 216,
+    KeyboardKeys::None, // SDL_SCANCODE_KP_CLEARENTRY = 217,
+    KeyboardKeys::None, // SDL_SCANCODE_KP_BINARY = 218,
+    KeyboardKeys::None, // SDL_SCANCODE_KP_OCTAL = 219,
+    KeyboardKeys::None, // SDL_SCANCODE_KP_DECIMAL = 220,
+    KeyboardKeys::None, // SDL_SCANCODE_KP_HEXADECIMAL = 221,
+    KeyboardKeys::None,
+    KeyboardKeys::None,
+    KeyboardKeys::Control, // SDL_SCANCODE_LCTRL = 224,
+    KeyboardKeys::Shift, // SDL_SCANCODE_LSHIFT = 225,
+    KeyboardKeys::Alt, // SDL_SCANCODE_LALT = 226,
+    KeyboardKeys::LeftMenu, // SDL_SCANCODE_LGUI = 227,
+    KeyboardKeys::Control, // SDL_SCANCODE_RCTRL = 228,
+    KeyboardKeys::Shift, // SDL_SCANCODE_RSHIFT = 229,
+    KeyboardKeys::Alt, // SDL_SCANCODE_RALT = 230,
+    KeyboardKeys::RightMenu, // SDL_SCANCODE_RGUI = 231,
+    KeyboardKeys::None,
+    KeyboardKeys::None,
+    KeyboardKeys::None,
+    KeyboardKeys::None,
+    KeyboardKeys::None,
+    KeyboardKeys::None,
+    KeyboardKeys::None,
+    KeyboardKeys::None,
+    KeyboardKeys::None,
+    KeyboardKeys::None,
+    KeyboardKeys::None,
+    KeyboardKeys::None,
+    KeyboardKeys::None,
+    KeyboardKeys::None,
+    KeyboardKeys::None,
+    KeyboardKeys::None,
+    KeyboardKeys::None,
+    KeyboardKeys::None,
+    KeyboardKeys::None,
+    KeyboardKeys::None,
+    KeyboardKeys::None,
+    KeyboardKeys::None,
+    KeyboardKeys::None,
+    KeyboardKeys::None,
+    KeyboardKeys::None,
+    KeyboardKeys::Modechange, // SDL_SCANCODE_MODE
+    KeyboardKeys::Sleep, // SDL_SCANCODE_SLEEP
+    KeyboardKeys::None, // SDL_SCANCODE_WAKE
+    KeyboardKeys::None, // SDL_SCANCODE_CHANNEL_INCREMENT = 260,
+    KeyboardKeys::None, // SDL_SCANCODE_CHANNEL_DECREMENT = 261,
+    KeyboardKeys::None, // SDL_SCANCODE_MEDIA_PLAY = 262,
+    KeyboardKeys::None, // SDL_SCANCODE_MEDIA_PAUSE = 263,
+    KeyboardKeys::None, // SDL_SCANCODE_MEDIA_RECORD = 264,
+    KeyboardKeys::None, // SDL_SCANCODE_MEDIA_FAST_FORWARD = 265,
+    KeyboardKeys::None, // SDL_SCANCODE_MEDIA_REWIND = 266,
+    KeyboardKeys::MediaNextTrack, // SDL_SCANCODE_MEDIA_NEXT_TRACK = 267,
+    KeyboardKeys::MediaPrevTrack, // SDL_SCANCODE_MEDIA_PREVIOUS_TRACK = 268,
+    KeyboardKeys::MediaStop, // SDL_SCANCODE_MEDIA_STOP = 269,
+    KeyboardKeys::None, // SDL_SCANCODE_MEDIA_EJECT = 270,
+    KeyboardKeys::MediaPlayPause, // SDL_SCANCODE_MEDIA_PLAY_PAUSE = 271,
+    KeyboardKeys::None, // SDL_SCANCODE_MEDIA_SELECT = 272,
+    KeyboardKeys::None, // SDL_SCANCODE_AC_NEW = 273,
+    KeyboardKeys::None, // SDL_SCANCODE_AC_OPEN = 274,
+    KeyboardKeys::None, // SDL_SCANCODE_AC_CLOSE = 275,
+    KeyboardKeys::None, // SDL_SCANCODE_AC_EXIT = 276,
+    KeyboardKeys::None, // SDL_SCANCODE_AC_SAVE = 277,
+    KeyboardKeys::None, // SDL_SCANCODE_AC_PRINT = 278,
+    KeyboardKeys::None, // SDL_SCANCODE_AC_PROPERTIES = 279,
+    KeyboardKeys::None, // SDL_SCANCODE_AC_SEARCH = 280,
+    KeyboardKeys::None, // SDL_SCANCODE_AC_HOME = 281,
+    KeyboardKeys::None, // SDL_SCANCODE_AC_BACK = 282,
+    KeyboardKeys::None, // SDL_SCANCODE_AC_FORWARD = 283,
+    KeyboardKeys::None, // SDL_SCANCODE_AC_STOP = 284,
+    KeyboardKeys::None, // SDL_SCANCODE_AC_REFRESH = 285,
+    KeyboardKeys::None, // SDL_SCANCODE_AC_BOOKMARKS = 286,
+    KeyboardKeys::None, // SDL_SCANCODE_SOFTLEFT = 287,
+    KeyboardKeys::None, // SDL_SCANCODE_SOFTRIGHT = 288,
+    KeyboardKeys::None, // SDL_SCANCODE_CALL = 289,
+    KeyboardKeys::None, // SDL_SCANCODE_ENDCALL = 290
+};
+
+/// <summary>
+/// Implementation of the keyboard device for Windows platform.
+/// </summary>
+/// <seealso cref="Keyboard" />
+class SDLKeyboard : public Keyboard
+{
+public:
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="SDLKeyboard"/> class.
+    /// </summary>
+    explicit SDLKeyboard()
+        : Keyboard()
+    {
+    }
+
+public:
+
+};
+
+/// <summary>
+/// Implementation of the mouse device for SDL platform.
+/// </summary>
+/// <seealso cref="Mouse" />
+class SDLMouse : public Mouse
+{
+private:
+    Float2 _oldPosition = Float2::Zero;
+    Window* _relativeModeWindow = nullptr;
+    const SDL_Rect* _oldScreenRect = nullptr;
+public:
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="SDLMouse"/> class.
+    /// </summary>
+    explicit SDLMouse()
+        : Mouse()
+    {
+    }
+
+public:
+
+    /// <summary>
+    /// Returns the previous known position of the mouse before entering relative mode.
+    /// </summary>
+    Float2 GetOldMousePosition() const
+    {
+        ASSERT(_relativeModeWindow != nullptr);
+        return _relativeModeWindow->ClientToScreen(_oldPosition);
+    }
+
+    // [Mouse]
+    void SetMousePosition(const Float2& screenPosition) final override
+    {
+#if USE_EDITOR
+        auto window = Editor::Managed->GetGameWindow();
+        if (window == nullptr)
+            window = Engine::MainWindow;
+#else
+        auto window = Engine::MainWindow;
+#endif
+        Float2 position = window->ScreenToClient(screenPosition);
+        SDL_WarpMouseInWindow(static_cast<SDLWindow*>(window)->_window, position.X, position.Y);
+
+        OnMouseMoved(screenPosition);
+    }
+
+    void SetRelativeMode(bool relativeMode, Window* window) final override
+    {
+        ASSERT(window != nullptr);
+        if (relativeMode == _relativeMode)
+            return;
+
+        auto windowHandle = static_cast<SDLWindow*>(window)->_window;
+        if (relativeMode)
+        {
+            _relativeModeWindow = window;
+            SDL_GetMouseState(&_oldPosition.X, &_oldPosition.Y);
+            if (!SDL_CursorVisible())
+            {
+                // Trap the cursor in current location
+                SDL_Rect clipRect = { (int)_oldPosition.X, (int)_oldPosition.Y, 1, 1 };
+                _oldScreenRect = SDL_GetWindowMouseRect(windowHandle);
+                SDL_SetWindowMouseRect(windowHandle, &clipRect);
+            }
+        }
+        else
+        {
+            if (_relativeModeWindow != window)
+            {
+                // FIXME: When floating game window is focused and editor viewport activated, the relative mode gets stuck
+                return;
+            }
+            SDL_SetWindowMouseRect(windowHandle, nullptr);//oldScreenRect);
+            SDL_WarpMouseInWindow(windowHandle, _oldPosition.X, _oldPosition.Y);
+            _oldScreenRect = nullptr;
+            _relativeModeWindow = nullptr;
+        }
+
+        Mouse::SetRelativeMode(relativeMode, window);
+        if (!SDL_SetWindowRelativeMouseMode(windowHandle, relativeMode))
+            LOG(Error, "Failed to set mouse relative mode: {0}", String(SDL_GetError()));
+
+#if PLATFORM_MAC
+        // Warping right before entering relative mode seems to generate motion event for relative mode
+        SDL_PumpEvents();
+        SDL_FlushEvent(SDL_EVENT_MOUSE_MOTION);
+#endif
+    }
+
+    bool IsRelative(Window* window) const override
+    {
+        if (window == nullptr)
+            return _relativeMode;
+        return _relativeModeWindow == window && _relativeMode;
+    }
+};
+
+/// <summary>
+/// Implementation of the gamepad device for SDL platform.
+/// </summary>
+/// <seealso cref="Gamepad" />
+class SDLGamepad : public Gamepad
+{
+private:
+
+    SDL_Gamepad* _gamepad = nullptr;
+    SDL_JoystickID _instanceId;
+
+public:
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="SDLGamepad"/> class.
+    /// </summary>
+    /// <param name="userIndex">The joystick.</param>
+    explicit SDLGamepad(SDL_JoystickID instanceId);
+
+    /// <summary>
+    /// Finalizes an instance of the <see cref="SDLGamepad"/> class.
+    /// </summary>
+    ~SDLGamepad();
+
+private:
+
+    SDLGamepad(SDL_Gamepad* gamepad, SDL_JoystickID instanceId);
+
+public:
+
+    static SDLGamepad* GetGamepadById(SDL_JoystickID id)
+    {
+        SDLGamepad* gamepad = nullptr;
+        SDLInputImpl::Gamepads.TryGet(id, gamepad);
+        return gamepad;
+    }
+
+    SDL_JoystickID GetJoystickInstanceId() const
+    {
+        return _instanceId;
+    }
+
+    void OnAxisMotion(SDL_GamepadAxis axis, int16 value);
+
+    void OnButtonState(SDL_GamepadButton axis, bool pressed);
+
+    // [Gamepad]
+    void SetVibration(const GamepadVibrationState& state) override;
+
+protected:
+
+    // [Gamepad]
+    bool UpdateState() override;
+};
+
+void SDLInput::Init()
+{
+    Input::Mouse = SDLInputImpl::Mouse = New<SDLMouse>();
+    Input::Keyboard = SDLInputImpl::Keyboard = New<SDLKeyboard>();
+}
+
+void SDLInput::Update()
+{
+}
+
+float NormalizeAxisValue(const int16 axisVal)
+{
+    // Normalize [-32768..32767] -> [-1..1]
+    const float norm = axisVal <= 0 ? 32768.0f : 32767.0f;
+    return float(axisVal) / norm;
+}
+
+bool SDLInput::HandleEvent(SDLWindow* window, SDL_Event& event)
+{
+    switch (event.type)
+    {
+    case SDL_EVENT_MOUSE_MOTION:
+    {
+        if (Input::Mouse->IsRelative())
+        {
+            const Float2 mouseDelta(event.motion.xrel, event.motion.yrel);
+            Input::Mouse->OnMouseMoveRelative(mouseDelta, window);
+        }
+        else
+        {
+            const Float2 mousePos = window->ClientToScreen({ event.motion.x, event.motion.y });
+            Input::Mouse->OnMouseMove(mousePos, window);
+        }
+        return true;
+    }
+    case SDL_EVENT_WINDOW_MOUSE_LEAVE:
+    {
+        Input::Mouse->OnMouseLeave(window);
+        return true;
+    }
+    case SDL_EVENT_MOUSE_BUTTON_DOWN:
+    case SDL_EVENT_MOUSE_BUTTON_UP:
+    {
+        Float2 mousePos = window->ClientToScreen({ event.button.x, event.button.y });
+
+        // In case of activating the window from non-focused state, we might not have received the motion event yet
+        if (!Input::Mouse->IsRelative() && event.button.down)
+            Input::Mouse->OnMouseMove(mousePos, window);
+
+        MouseButton button = MouseButton::None;
+        if (event.button.button == SDL_BUTTON_LEFT)
+            button = MouseButton::Left;
+        else if (event.button.button == SDL_BUTTON_RIGHT)
+            button = MouseButton::Right;
+        else if (event.button.button == SDL_BUTTON_MIDDLE)
+            button = MouseButton::Middle;
+        else if (event.button.button == SDL_BUTTON_X1)
+            button = MouseButton::Extended1;
+        else if (event.button.button == SDL_BUTTON_X2)
+            button = MouseButton::Extended2;
+
+        if (Input::Mouse->IsRelative())
+        {
+            // Use the previous visible mouse position here, the event or global
+            // mouse position would cause input to trigger in other editor windows.
+            mousePos = SDLInputImpl::Mouse->GetOldMousePosition();
+        }
+
+        if (!event.button.down)
+            Input::Mouse->OnMouseUp(mousePos, button, window);
+        // Prevent sending multiple mouse down event when double-clicking UI elements
+        else if (event.button.clicks % 2 == 1)
+            Input::Mouse->OnMouseDown(mousePos, button, window);
+        else
+            Input::Mouse->OnMouseDoubleClick(mousePos, button, window);
+
+        return true;
+    }
+    case SDL_EVENT_MOUSE_WHEEL:
+    {
+        Float2 mousePos = window->ClientToScreen({ event.wheel.mouse_x, event.wheel.mouse_y });
+        const float delta = event.wheel.y;
+
+        if (Input::Mouse->IsRelative())
+        {
+            // Use the previous visible mouse position here, the event or global
+            // mouse position would cause input to trigger in other editor windows.
+            mousePos = SDLInputImpl::Mouse->GetOldMousePosition();
+        }
+
+        Input::Mouse->OnMouseWheel(mousePos, delta, window);
+        return true;
+    }
+    case SDL_EVENT_KEY_DOWN:
+    case SDL_EVENT_KEY_UP:
+    {
+        // TODO: scancode support
+        KeyboardKeys key = SDL_TO_FLAX_KEYS_MAP[event.key.scancode];
+        //event.key.mod
+        if (!event.key.down)
+            Input::Keyboard->OnKeyUp(key, window);
+        else
+            Input::Keyboard->OnKeyDown(key, window);
+        return true;
+    }
+    case SDL_EVENT_TEXT_EDITING:
+    {
+        auto edit = event.edit;
+        return true;
+    }
+    case SDL_EVENT_TEXT_INPUT:
+    {
+        String text(event.text.text);
+        for (int i = 0; i < text.Length(); i++)
+        {
+            Input::Keyboard->OnCharInput(text[i], window);
+        }
+        return true;
+    }
+    case SDL_EVENT_GAMEPAD_AXIS_MOTION:
+    {
+        SDLGamepad* gamepad = SDLGamepad::GetGamepadById(event.gaxis.which);
+        SDL_GamepadAxis axis = (SDL_GamepadAxis)event.gaxis.axis;
+        gamepad->OnAxisMotion(axis, event.gaxis.value);
+        break;
+    }
+    case SDL_EVENT_GAMEPAD_BUTTON_DOWN:
+    case SDL_EVENT_GAMEPAD_BUTTON_UP:
+    {
+        SDLGamepad* gamepad = SDLGamepad::GetGamepadById(event.gbutton.which);
+        SDL_GamepadButton button = (SDL_GamepadButton)event.gbutton.button;
+        gamepad->OnButtonState(button, event.gbutton.down);
+        break;
+    }
+    case SDL_EVENT_GAMEPAD_ADDED:
+    {
+        Input::Gamepads.Add(New<SDLGamepad>(event.gdevice.which));
+        Input::OnGamepadsChanged();
+        break;
+    }
+    case SDL_EVENT_GAMEPAD_REMOVED:
+    {
+        for (int i = 0; i < Input::Gamepads.Count(); i++)
+        {
+            SDLGamepad* gamepad = static_cast<SDLGamepad*>(Input::Gamepads[i]);
+            if (gamepad->GetJoystickInstanceId() == event.gdevice.which)
+            {
+                Input::Gamepads[i]->DeleteObject();
+                Input::Gamepads.RemoveAtKeepOrder(i);
+                Input::OnGamepadsChanged();
+                break;
+            }
+        }
+        break;
+    }
+    case SDL_EVENT_GAMEPAD_REMAPPED:
+    {
+        auto ev = event.gdevice;
+        LOG(Info, "TODO: SDL_EVENT_GAMEPAD_REMAPPED");
+        break;
+    }
+    case SDL_EVENT_GAMEPAD_TOUCHPAD_DOWN:
+    {
+        LOG(Info, "TODO: SDL_EVENT_GAMEPAD_TOUCHPAD_DOWN");
+        break;
+    }
+    case SDL_EVENT_GAMEPAD_TOUCHPAD_MOTION:
+    {
+        LOG(Info, "TODO: SDL_EVENT_GAMEPAD_TOUCHPAD_MOTION");
+        break;
+    }
+    case SDL_EVENT_GAMEPAD_TOUCHPAD_UP:
+    {
+        LOG(Info, "TODO: SDL_EVENT_GAMEPAD_TOUCHPAD_UP");
+        break;
+    }
+    case SDL_EVENT_GAMEPAD_SENSOR_UPDATE:
+    {
+        LOG(Info, "TODO: SDL_EVENT_GAMEPAD_SENSOR_UPDATE");
+        break;
+    }
+    case SDL_EVENT_GAMEPAD_STEAM_HANDLE_UPDATED:
+    {
+        auto ev = event.gdevice;
+        LOG(Info, "TODO: SDL_EVENT_GAMEPAD_STEAM_HANDLE_UPDATED");
+        break;
+    }
+    }
+    return false;
+}
+
+Guid GetGamepadGuid(SDL_JoystickID instanceId)
+{
+    SDL_GUID joystickGuid = SDL_GetGamepadGUIDForID(instanceId);
+    Guid guid;
+    Platform::MemoryCopy(&guid.Raw, joystickGuid.data, sizeof(uint8) * 16);
+    return guid;
+}
+
+SDLGamepad::SDLGamepad(SDL_JoystickID instanceId)
+    : SDLGamepad(SDL_OpenGamepad(instanceId), instanceId)
+{
+    LOG(Info, "Gamepad connected: {}", String(SDL_GetGamepadName(_gamepad)));
+}
+
+SDLGamepad::SDLGamepad(SDL_Gamepad* gamepad, SDL_JoystickID instanceId)
+    : Gamepad(GetGamepadGuid(instanceId), String(SDL_GetGamepadName(gamepad)))
+    , _gamepad(gamepad)
+    , _instanceId(instanceId)
+{
+    SDLInputImpl::Gamepads.Add(_instanceId, this);
+}
+
+SDLGamepad::~SDLGamepad()
+{
+    SDL_CloseGamepad(_gamepad);
+    SDLInputImpl::Gamepads.Remove(_instanceId);
+}
+
+void SDLGamepad::SetVibration(const GamepadVibrationState& state)
+{
+    Gamepad::SetVibration(state);
+    LOG(Info, "TODO: SDLGamepad::SetVibration");
+}
+
+bool SDLGamepad::UpdateState()
+{
+    return false;
+}
+
+void SDLGamepad::OnAxisMotion(SDL_GamepadAxis sdlAxis, int16 value)
+{
+    GamepadAxis axis;
+    int16 deadzone = 1; // SDL reports -1 for centered axis?
+    float valueNormalized = NormalizeAxisValue(value);
+    switch (sdlAxis)
+    {
+    case SDL_GAMEPAD_AXIS_LEFTX:
+        axis = GamepadAxis::LeftStickX;
+        deadzone = LEFT_STICK_THRESHOLD;
+        _state.Buttons[(int32)GamepadButton::LeftStickLeft] = value > LEFT_STICK_THRESHOLD;
+        _state.Buttons[(int32)GamepadButton::LeftStickRight] = value < -LEFT_STICK_THRESHOLD;
+        break;
+    case SDL_GAMEPAD_AXIS_LEFTY:
+        axis = GamepadAxis::LeftStickY;
+        deadzone = LEFT_STICK_THRESHOLD;
+        _state.Buttons[(int32)GamepadButton::LeftStickUp] = value < -LEFT_STICK_THRESHOLD;
+        _state.Buttons[(int32)GamepadButton::LeftStickDown] = value > LEFT_STICK_THRESHOLD;
+        valueNormalized = -valueNormalized;
+        break;
+    case SDL_GAMEPAD_AXIS_RIGHTX:
+        deadzone = RIGHT_STICK_THRESHOLD;
+        axis = GamepadAxis::RightStickX;
+        _state.Buttons[(int32)GamepadButton::RightStickLeft] = value > RIGHT_STICK_THRESHOLD;
+        _state.Buttons[(int32)GamepadButton::RightStickRight] = value < -RIGHT_STICK_THRESHOLD;
+        break;
+    case SDL_GAMEPAD_AXIS_RIGHTY:
+        deadzone = RIGHT_STICK_THRESHOLD;
+        axis = GamepadAxis::RightStickY;
+        _state.Buttons[(int32)GamepadButton::RightStickUp] = value < -RIGHT_STICK_THRESHOLD;
+        _state.Buttons[(int32)GamepadButton::RightStickDown] = value > RIGHT_STICK_THRESHOLD;
+        valueNormalized = -valueNormalized;
+        break;
+    case SDL_GAMEPAD_AXIS_LEFT_TRIGGER:
+        deadzone = TRIGGER_THRESHOLD;
+        axis = GamepadAxis::LeftTrigger;
+        _state.Buttons[(int32)GamepadButton::LeftTrigger] = value > TRIGGER_THRESHOLD;
+        break;
+    case SDL_GAMEPAD_AXIS_RIGHT_TRIGGER:
+        deadzone = TRIGGER_THRESHOLD;
+        axis = GamepadAxis::RightTrigger;
+        _state.Buttons[(int32)GamepadButton::RightTrigger] = value > TRIGGER_THRESHOLD;
+        break;
+    default:
+        return;
+    }
+    if (value <= deadzone && value >= -deadzone)
+        valueNormalized = 0.0f;
+    _state.Axis[(int32)axis] = valueNormalized;
+}
+
+void SDLGamepad::OnButtonState(SDL_GamepadButton sdlButton, bool pressed)
+{
+    switch (sdlButton)
+    {
+    case SDL_GamepadButton::SDL_GAMEPAD_BUTTON_SOUTH:
+        _state.Buttons[(int32)GamepadButton::A] = pressed;
+        break;
+    case SDL_GamepadButton::SDL_GAMEPAD_BUTTON_EAST:
+        _state.Buttons[(int32)GamepadButton::B] = pressed;
+        break;
+    case SDL_GamepadButton::SDL_GAMEPAD_BUTTON_WEST:
+        _state.Buttons[(int32)GamepadButton::X] = pressed;
+        break;
+    case SDL_GamepadButton::SDL_GAMEPAD_BUTTON_NORTH:
+        _state.Buttons[(int32)GamepadButton::Y] = pressed;
+        break;
+    case SDL_GamepadButton::SDL_GAMEPAD_BUTTON_LEFT_SHOULDER:
+        _state.Buttons[(int32)GamepadButton::LeftShoulder] = pressed;
+        break;
+    case SDL_GamepadButton::SDL_GAMEPAD_BUTTON_RIGHT_SHOULDER:
+        _state.Buttons[(int32)GamepadButton::RightShoulder] = pressed;
+        break;
+    case SDL_GamepadButton::SDL_GAMEPAD_BUTTON_BACK:
+        _state.Buttons[(int32)GamepadButton::Back] = pressed;
+        break;
+    case SDL_GamepadButton::SDL_GAMEPAD_BUTTON_START:
+        _state.Buttons[(int32)GamepadButton::Start] = pressed;
+        break;
+    case SDL_GamepadButton::SDL_GAMEPAD_BUTTON_LEFT_STICK:
+        _state.Buttons[(int32)GamepadButton::LeftThumb] = pressed;
+        break;
+    case SDL_GamepadButton::SDL_GAMEPAD_BUTTON_RIGHT_STICK:
+        _state.Buttons[(int32)GamepadButton::RightThumb] = pressed;
+        break;
+    case SDL_GamepadButton::SDL_GAMEPAD_BUTTON_DPAD_UP:
+        _state.Buttons[(int32)GamepadButton::DPadUp] = pressed;
+        break;
+    case SDL_GamepadButton::SDL_GAMEPAD_BUTTON_DPAD_DOWN:
+        _state.Buttons[(int32)GamepadButton::DPadDown] = pressed;
+        break;
+    case SDL_GamepadButton::SDL_GAMEPAD_BUTTON_DPAD_LEFT:
+        _state.Buttons[(int32)GamepadButton::DPadLeft] = pressed;
+        break;
+    case SDL_GamepadButton::SDL_GAMEPAD_BUTTON_DPAD_RIGHT:
+        _state.Buttons[(int32)GamepadButton::DPadRight] = pressed;
+        break;
+    }
+}
+
+#endif

Source/Engine/Platform/SDL/SDLInput.h

@@ -0,0 +1,22 @@
+// Copyright (c) Wojciech Figat. All rights reserved.
+
+#pragma once
+
+#if PLATFORM_SDL
+
+class SDLWindow;
+union SDL_Event;
+
+/// <summary>
+/// SDL specific implementation of the input system parts.
+/// </summary>
+class SDLInput
+{
+public:
+
+    static void Init();
+    static void Update();
+    static bool HandleEvent(SDLWindow* window, SDL_Event& event);
+};
+
+#endif

Source/Engine/Platform/SDL/SDLPlatform.Mac.cpp

@@ -0,0 +1,82 @@
+// Copyright (c) Wojciech Figat. All rights reserved.
+
+#if PLATFORM_SDL && PLATFORM_MAC
+
+#include "SDLWindow.h"
+#include "Engine/Core/Log.h"
+#include "Engine/Core/Collections/Array.h"
+#include "Engine/Engine/CommandLine.h"
+#include "Engine/Engine/Engine.h"
+#include "Engine/Engine/Time.h"
+#include "Engine/Graphics/RenderTask.h"
+#include "Engine/Input/Input.h"
+#include "Engine/Input/Mouse.h"
+#include "Engine/Platform/IGuiData.h"
+#include "Engine/Platform/MessageBox.h"
+#include "Engine/Platform/Platform.h"
+#include "Engine/Platform/WindowsManager.h"
+#include "Engine/Platform/Base/DragDropHelper.h"
+#include "Engine/Platform/SDL/SDLClipboard.h"
+#include "Engine/Platform/Unix/UnixFile.h"
+#include "Engine/Profiler/ProfilerCPU.h"
+
+#include "Engine/Platform/Linux/IncludeX11.h"
+
+#include <SDL3/SDL_events.h>
+#include <SDL3/SDL_hints.h>
+#include <SDL3/SDL_messagebox.h>
+#include <SDL3/SDL_mouse.h>
+#include <SDL3/SDL_system.h>
+#include <SDL3/SDL_timer.h>
+#include <SDL3/SDL_video.h>
+
+bool SDLPlatform::InitInternal()
+{
+    return false;
+}
+
+bool SDLPlatform::UsesWindows()
+{
+    return false;
+}
+
+bool SDLPlatform::UsesWayland()
+{
+    return false;
+}
+
+bool SDLPlatform::UsesX11()
+{
+    return false;
+}
+
+void SDLPlatform::PreHandleEvents()
+{
+}
+
+void SDLPlatform::PostHandleEvents()
+{
+}
+
+bool SDLWindow::HandleEventInternal(SDL_Event& event)
+{
+    return false;
+}
+
+void SDLPlatform::SetHighDpiAwarenessEnabled(bool enable)
+{
+    // TODO: This is now called before Platform::Init, ensure the scaling is changed accordingly during Platform::Init (see ApplePlatform::SetHighDpiAwarenessEnabled)
+}
+
+DragDropEffect SDLWindow::DoDragDrop(const StringView& data)
+{
+    return DragDropEffect::None;
+}
+
+DragDropEffect SDLWindow::DoDragDrop(const StringView& data, const Float2& offset, Window* dragSourceWindow)
+{
+    Show();
+    return DragDropEffect::None;
+}
+
+#endif

Source/Engine/Platform/SDL/SDLPlatform.Windows.cpp

@@ -0,0 +1,259 @@
+// Copyright (c) Wojciech Figat. All rights reserved.
+
+#if PLATFORM_SDL && PLATFORM_WINDOWS
+
+#include "SDLPlatform.h"
+#include "SDLInput.h"
+
+#include "Engine/Core/Collections/Array.h"
+#include "Engine/Platform/WindowsManager.h"
+#include "Engine/Platform/Win32/IncludeWindowsHeaders.h"
+#include "Engine/Input/Mouse.h"
+#include "Engine/Core/Log.h"
+#include "Engine/Engine/Engine.h"
+
+#include <SDL3/SDL_hints.h>
+#include <SDL3/SDL_init.h>
+#include <SDL3/SDL_system.h>
+#include <SDL3/SDL_timer.h>
+
+#if USE_EDITOR
+#include <oleidl.h>
+#endif
+
+namespace WinImpl
+{
+    Window* DraggedWindow;
+    Float2 DraggedWindowStartPosition = Float2::Zero;
+    Float2 DraggedWindowMousePosition = Float2::Zero;
+    Float2 DraggedWindowSize = Float2::Zero;
+}
+
+// The events for releasing the mouse during window dragging are missing, handle the mouse release event here
+bool SDLCALL SDLPlatform::EventMessageHook(void* userdata, MSG* msg)
+{
+    if (msg->message == WM_NCLBUTTONDOWN)
+    {
+        Window* window = WindowsManager::GetByNativePtr(msg->hwnd);
+        Float2 mousePosition(static_cast<float>(static_cast<LONG>(WINDOWS_GET_X_LPARAM(msg->lParam))), static_cast<float>(static_cast<LONG>(WINDOWS_GET_Y_LPARAM(msg->lParam))));
+
+        WinImpl::DraggedWindow = window;
+        WinImpl::DraggedWindowStartPosition = window->GetClientPosition();
+        WinImpl::DraggedWindowMousePosition = mousePosition - WinImpl::DraggedWindowStartPosition;
+        WinImpl::DraggedWindowSize = window->GetClientSize();
+
+        bool result = false;
+        WindowHitCodes hit = static_cast<WindowHitCodes>(msg->wParam);
+        window->OnHitTest(mousePosition, hit, result);
+        //if (result && hit != WindowHitCodes::Caption)
+        //    return false;
+
+        if (hit == WindowHitCodes::Caption)
+        {
+            SDL_Event event{ 0 };
+            event.button.type = SDL_EVENT_MOUSE_BUTTON_DOWN;
+            event.button.down = true;
+            event.button.timestamp = SDL_GetTicksNS();
+            event.button.windowID = SDL_GetWindowID(window->GetSDLWindow());
+            event.button.button = SDL_BUTTON_LEFT;
+            event.button.clicks = 1;
+            event.button.x = WinImpl::DraggedWindowMousePosition.X;
+            event.button.y = WinImpl::DraggedWindowMousePosition.Y;
+
+            SDL_PushEvent(&event);
+        }
+    }
+    return true;
+}
+
+bool SDLPlatform::InitInternal()
+{
+    // Workaround required for handling window dragging events properly
+    SDL_SetWindowsMessageHook(&EventMessageHook, nullptr);
+
+    if (WindowsPlatform::Init())
+        return true;
+
+    return false;
+}
+
+bool SDLPlatform::EventFilterCallback(void* userdata, SDL_Event* event)
+{
+    Window* draggedWindow = *(Window**)userdata;
+    if (draggedWindow == nullptr)
+        return true;
+
+    // When the window is being dragged on Windows, the internal message loop is blocking
+    // the SDL event queue. We need to handle all relevant events in this event watch callback
+    // to ensure dragging related functionality doesn't break due to engine not getting updated.
+    // This also happens to fix the engine freezing during the dragging operation.
+
+    SDLWindow* window = SDLWindow::GetWindowFromEvent(*event);
+    if (event->type == SDL_EVENT_WINDOW_EXPOSED)
+    {
+        // The internal timer is sending exposed events every ~16ms
+        Engine::OnUpdate(); // For docking updates
+        Engine::OnDraw();
+        return false;
+    }
+    else if (event->type == SDL_EVENT_MOUSE_BUTTON_DOWN)
+    {
+        if (window)
+        {
+            bool result = false;
+            window->OnLeftButtonHit(WindowHitCodes::Caption, result);
+            //if (result)
+            //    return false;
+            window->HandleEvent(*event);
+        }
+        return false;
+    }
+    else if (event->type == SDL_EVENT_WINDOW_MOVED)
+    {
+        if (window)
+        {
+            window->HandleEvent(*event);
+
+            Float2 windowSize = window->GetClientSize();
+            if (WinImpl::DraggedWindowSize != windowSize)
+            {
+                // The window size changed while dragging, most likely due to maximized window restoring back to previous size.
+                WinImpl::DraggedWindowMousePosition = WinImpl::DraggedWindowStartPosition + WinImpl::DraggedWindowMousePosition - window->GetClientPosition();
+                WinImpl::DraggedWindowStartPosition = window->GetClientPosition();
+                WinImpl::DraggedWindowSize = windowSize;
+            }
+            Float2 windowPosition = Float2(static_cast<float>(event->window.data1), static_cast<float>(event->window.data2));
+            Float2 mousePosition = WinImpl::DraggedWindowMousePosition;
+
+            // Generate mouse movement events while dragging the window around
+            SDL_Event mouseMovedEvent{ 0 };
+            mouseMovedEvent.motion.type = SDL_EVENT_MOUSE_MOTION;
+            mouseMovedEvent.motion.windowID = SDL_GetWindowID(WinImpl::DraggedWindow->GetSDLWindow());
+            mouseMovedEvent.motion.timestamp = SDL_GetTicksNS();
+            mouseMovedEvent.motion.state = SDL_BUTTON_LEFT;
+            mouseMovedEvent.motion.x = mousePosition.X;
+            mouseMovedEvent.motion.y = mousePosition.Y;
+            window->HandleEvent(mouseMovedEvent);
+        }
+        return false;
+    }
+    if (window)
+        window->HandleEvent(*event);
+    
+    return false;
+}
+
+void SDLPlatform::PreHandleEvents()
+{
+    SDL_AddEventWatch(EventFilterCallback, &WinImpl::DraggedWindow);
+}
+
+void SDLPlatform::PostHandleEvents()
+{
+    SDL_RemoveEventWatch(EventFilterCallback, &WinImpl::DraggedWindow);
+
+    // Handle window dragging release here
+    if (WinImpl::DraggedWindow != nullptr)
+    {
+        Float2 mousePosition;
+        auto buttons = SDL_GetGlobalMouseState(&mousePosition.X, &mousePosition.Y);
+
+        // Send simulated mouse up event
+        SDL_Event buttonUpEvent { 0 };
+        buttonUpEvent.motion.type = SDL_EVENT_MOUSE_BUTTON_UP;
+        buttonUpEvent.button.down = false;
+        buttonUpEvent.motion.windowID = SDL_GetWindowID(WinImpl::DraggedWindow->GetSDLWindow());
+        buttonUpEvent.motion.timestamp = SDL_GetTicksNS();
+        buttonUpEvent.motion.state = SDL_BUTTON_LEFT;
+        buttonUpEvent.button.clicks = 1;
+        buttonUpEvent.motion.x = mousePosition.X;
+        buttonUpEvent.motion.y = mousePosition.Y;
+        WinImpl::DraggedWindow->HandleEvent(buttonUpEvent);
+        WinImpl::DraggedWindow = nullptr;
+    }
+}
+
+bool SDLWindow::HandleEventInternal(SDL_Event& event)
+{
+    switch (event.type)
+    {
+    case SDL_EVENT_WINDOW_DESTROYED:
+    {
+#if USE_EDITOR
+        // Disable file dropping
+        if (_settings.AllowDragAndDrop)
+        {
+            const auto result = RevokeDragDrop((HWND)_handle);
+            if (result != S_OK)
+                LOG(Warning, "Window drag and drop service error: 0x{0:x}:{1}", result, 2);
+        }
+#endif
+        break;
+    }
+    case SDL_EVENT_MOUSE_BUTTON_UP:
+    {
+        if (WinImpl::DraggedWindow != nullptr && WinImpl::DraggedWindow->_windowId != event.button.windowID)
+        {
+            // Send the button event to dragged window as well
+            Float2 mousePos = ClientToScreen({ event.button.x, event.button.y });
+            Float2 clientPos = WinImpl::DraggedWindow->ScreenToClient(mousePos);
+
+            SDL_Event event2 = event;
+            event2.button.windowID = WinImpl::DraggedWindow->_windowId;
+            event2.button.x = clientPos.X;
+            event2.button.y = clientPos.Y;
+
+            SDLInput::HandleEvent(WinImpl::DraggedWindow, event2);
+        }
+        break;
+    }
+    default:
+        break;
+    }
+    
+    return false;
+}
+
+bool SDLPlatform::UsesWindows()
+{
+    return true;
+}
+
+bool SDLPlatform::UsesWayland()
+{
+    return false;
+}
+
+bool SDLPlatform::UsesX11()
+{
+    return false;
+}
+
+void SDLWindow::Focus()
+{
+    auto activateWhenRaised = SDL_GetHint(SDL_HINT_WINDOW_ACTIVATE_WHEN_RAISED);
+    SDL_SetHint(SDL_HINT_WINDOW_ACTIVATE_WHEN_RAISED, "1");
+
+    // Forcing the window to focus causes issues with opening context menus while window is maximized
+    //auto forceRaiseWindow = SDL_GetHint(SDL_HINT_FORCE_RAISEWINDOW);
+    //SDL_SetHint(SDL_HINT_FORCE_RAISEWINDOW, "1");
+
+    SDL_RaiseWindow(_window);
+
+    SDL_SetHint(SDL_HINT_WINDOW_ACTIVATE_WHEN_RAISED, activateWhenRaised);
+    //SDL_SetHint(SDL_HINT_FORCE_RAISEWINDOW, forceRaiseWindow);
+}
+
+void SDLPlatform::SetHighDpiAwarenessEnabled(bool enable)
+{
+    // Other supported values: "permonitor", "permonitorv2"
+    SDL_SetHint("SDL_WINDOWS_DPI_AWARENESS", enable ? "system" : "unaware");
+}
+
+DragDropEffect SDLWindow::DoDragDrop(const StringView& data, const Float2& offset, Window* dragSourceWindow)
+{
+    Show();
+    return DragDropEffect::None;
+}
+
+#endif

Source/Engine/Platform/SDL/SDLPlatform.cpp

@@ -0,0 +1,319 @@
+// Copyright (c) Wojciech Figat. All rights reserved.
+
+#if PLATFORM_SDL
+
+#include "SDLPlatform.h"
+#include "SDLWindow.h"
+#include "Engine/Core/Log.h"
+#include "Engine/Input/Input.h"
+#include "Engine/Input/Mouse.h"
+#include "Engine/Platform/BatteryInfo.h"
+#include "Engine/Platform/WindowsManager.h"
+#include "Engine/Platform/SDL/SDLInput.h"
+#include "Engine/Engine/Engine.h"
+
+#include <SDL3/SDL_hints.h>
+#include <SDL3/SDL_init.h>
+#include <SDL3/SDL_misc.h>
+#include <SDL3/SDL_power.h>
+#include <SDL3/SDL_revision.h>
+#include <SDL3/SDL_system.h>
+#include <SDL3/SDL_version.h>
+#include <SDL3/SDL_locale.h>
+
+#if PLATFORM_LINUX
+#include "Engine/Engine/CommandLine.h"
+#endif
+
+#define DefaultDPI 96
+
+namespace SDLImpl
+{
+    int32 SystemDpi = 96;
+    String UserLocale("en");
+    bool WindowDecorationsSupported = true;
+    bool SupportsDecorationDragging = true;
+    String WaylandDisplayEnv;
+    String XDGCurrentDesktop;
+}
+
+bool SDLPlatform::Init()
+{
+#if PLATFORM_LINUX
+    bool waylandSession = false;
+    if (!GetEnvironmentVariable(String("WAYLAND_DISPLAY"), SDLImpl::WaylandDisplayEnv))
+        waylandSession = true;
+    GetEnvironmentVariable(String("XDG_CURRENT_DESKTOP"), SDLImpl::XDGCurrentDesktop);
+    
+    if (CommandLine::Options.X11.IsTrue())
+    {
+        SDL_SetHintWithPriority(SDL_HINT_VIDEO_DRIVER, "x11", SDL_HINT_OVERRIDE);
+        waylandSession = false;
+    }
+    else if (CommandLine::Options.Wayland.IsTrue())
+        SDL_SetHintWithPriority(SDL_HINT_VIDEO_DRIVER, "wayland", SDL_HINT_OVERRIDE);
+    else if (waylandSession)
+    {
+        // Override the X11 preference when running in Wayland session
+        SDL_SetHintWithPriority(SDL_HINT_VIDEO_DRIVER, "wayland", SDL_HINT_OVERRIDE);
+    }
+
+    // Workaround for libdecor in Gnome+Wayland causing freezes when interacting with the native decorations
+    if (waylandSession && SDLImpl::XDGCurrentDesktop.Compare(String("GNOME"), StringSearchCase::IgnoreCase) == 0)
+    {
+        SDL_SetHint(SDL_HINT_VIDEO_WAYLAND_ALLOW_LIBDECOR, "0");
+        SDLImpl::WindowDecorationsSupported = false;
+    }
+    if (waylandSession)
+        SupportsDecorationDragging = false;
+#endif
+
+#if PLATFORM_LINUX
+    // The name follows the .desktop entry specification, this is used to get a fallback icon on Wayland:
+    // https://specifications.freedesktop.org/desktop-entry-spec/latest/file-naming.html
+#if USE_EDITOR
+    SDL_SetHint(SDL_HINT_APP_ID, StringAnsi("com.FlaxEngine.FlaxEditor").Get());
+#else
+    // TODO: This should be read from the platform configuration (needed for desktop icon handling)
+    SDL_SetHint(SDL_HINT_APP_ID, StringAnsi("com.FlaxEngine.FlaxGame").Get());
+#endif
+#else
+    SDL_SetHint(SDL_HINT_APP_ID, StringAnsi(ApplicationClassName).Get());
+#endif
+
+    SDL_SetHint(SDL_HINT_WINDOW_ACTIVATE_WHEN_SHOWN, "0");
+    SDL_SetHint(SDL_HINT_WINDOW_ACTIVATE_WHEN_RAISED, "0");
+    SDL_SetHint(SDL_HINT_MOUSE_FOCUS_CLICKTHROUGH, "1"); // Fixes context menu focus issues when clicking unfocused menus
+    SDL_SetHint(SDL_HINT_WINDOWS_ERASE_BACKGROUND_MODE, "0");
+    SDL_SetHint(SDL_HINT_TIMER_RESOLUTION, "0"); // Already handled during platform initialization
+    SDL_SetHint("SDL_BORDERLESS_RESIZABLE_STYLE", "1"); // Allow borderless windows to be resizable on Windows
+    //SDL_SetHint("SDL_BORDERLESS_WINDOWED_STYLE", "1"); 
+    
+    SDL_SetHint(SDL_HINT_MOUSE_RELATIVE_WARP_MOTION, "0");
+    SDL_SetHint(SDL_HINT_MOUSE_RELATIVE_CURSOR_VISIBLE, "1"); // Needed for tracking mode
+    SDL_SetHint(SDL_HINT_MOUSE_RELATIVE_MODE_CENTER, "0"); // Relative mode can be active when cursor is shown and clipped
+    SDL_SetHint(SDL_HINT_MOUSE_DOUBLE_CLICK_RADIUS, "8"); // Reduce the default mouse double-click radius
+
+    //SDL_SetHint(SDL_HINT_MOUSE_RELATIVE_MODE_WARP, "1"); // Disables raw mouse input
+    SDL_SetHint(SDL_HINT_WINDOWS_RAW_KEYBOARD, "1");
+
+    SDL_SetHint(SDL_HINT_VIDEO_WAYLAND_SCALE_TO_DISPLAY, "1");
+
+    //if (InitInternal())
+    //    return true;
+
+    if (!SDL_InitSubSystem(SDL_INIT_VIDEO | SDL_INIT_GAMEPAD))
+        Platform::Fatal(String::Format(TEXT("Failed to initialize SDL: {0}."), String(SDL_GetError())));
+
+    int localesCount = 0;
+    auto locales = SDL_GetPreferredLocales(&localesCount);
+    for (int i = 0; i < localesCount; i++)
+    {
+        auto language = StringAnsiView(locales[i]->language);
+        auto country = StringAnsiView(locales[i]->country);
+        if (language.StartsWith("en"))
+        {
+            if (country != nullptr)
+                SDLImpl::UserLocale = String::Format(TEXT("{0}-{1}"), String(language), String(locales[i]->country));
+            else
+                SDLImpl::UserLocale = String(language);
+            break;
+        }
+    }
+    SDL_free(locales);
+
+    if (InitInternal())
+        return true;
+
+#if !PLATFORM_MAC
+    if (!UsesWayland())
+    {
+        // Disable SDL clipboard support
+        SDL_SetEventEnabled(SDL_EVENT_CLIPBOARD_UPDATE, false);
+
+        // Disable SDL drag and drop support
+        SDL_SetEventEnabled(SDL_EVENT_DROP_FILE, false);
+        SDL_SetEventEnabled(SDL_EVENT_DROP_TEXT, false);
+        SDL_SetEventEnabled(SDL_EVENT_DROP_BEGIN, false);
+        SDL_SetEventEnabled(SDL_EVENT_DROP_COMPLETE, false);
+        SDL_SetEventEnabled(SDL_EVENT_DROP_POSITION, false);
+    }
+#endif
+
+    SDLInput::Init();
+    SDLWindow::Init();
+
+    SDLImpl::SystemDpi = (int)(SDL_GetDisplayContentScale(SDL_GetPrimaryDisplay()) * DefaultDPI);
+
+    //SDL_StartTextInput(); // TODO: Call this only when text input is expected (shows virtual keyboard in some cases)
+
+    return base::Init();
+}
+
+void SDLPlatform::LogInfo()
+{
+    base::LogInfo();
+
+    const int32 runtimeVersion = SDL_GetVersion();
+    LOG(Info, "Using SDL version {}.{}.{} ({}), runtime: {}.{}.{} ({})",
+        SDL_VERSIONNUM_MAJOR(SDL_VERSION), SDL_VERSIONNUM_MINOR(SDL_VERSION), SDL_VERSIONNUM_MICRO(SDL_VERSION), String(SDL_REVISION),
+        SDL_VERSIONNUM_MAJOR(runtimeVersion), SDL_VERSIONNUM_MINOR(runtimeVersion), SDL_VERSIONNUM_MICRO(runtimeVersion), String(SDL_GetRevision()));
+
+    LOG(Info, "SDL video driver: {}", String(SDL_GetCurrentVideoDriver()));
+}
+
+void SDLPlatform::Tick()
+{
+    SDLInput::Update();
+
+    PreHandleEvents();
+    
+    SDL_PumpEvents();
+    SDL_Event events[32];
+    int count = SDL_PeepEvents(events, SDL_arraysize(events), SDL_GETEVENT, SDL_EVENT_FIRST, SDL_EVENT_LAST);
+    for (int i = 0; i < count; ++i)
+    {
+        SDLWindow* window = SDLWindow::GetWindowFromEvent(events[i]);
+        if (window)
+            window->HandleEvent(events[i]);
+        else if (events[i].type >= SDL_EVENT_JOYSTICK_AXIS_MOTION && events[i].type <= SDL_EVENT_GAMEPAD_STEAM_HANDLE_UPDATED)
+            SDLInput::HandleEvent(nullptr, events[i]);
+        else
+            HandleEvent(events[i]);
+    }
+
+    PostHandleEvents();
+}
+
+bool SDLPlatform::HandleEvent(SDL_Event& event)
+{
+    return true;
+}
+
+String SDLPlatform::GetDisplayServer()
+{
+#if PLATFORM_LINUX
+    String driver(SDL_GetCurrentVideoDriver());
+    if (driver.Length() > 0)
+        driver[0] = StringUtils::ToUpper(driver[0]);
+    return driver;
+#else
+    return String::Empty;
+#endif
+}
+
+bool SDLPlatform::SupportsNativeDecorations()
+{
+    return SDLImpl::WindowDecorationsSupported;
+}
+
+bool SDLPlatform::SupportsNativeDecorationDragging()
+{
+    return SDLImpl::SupportsDecorationDragging;
+}
+
+BatteryInfo SDLPlatform::GetBatteryInfo()
+{
+    BatteryInfo info;
+    int percentage;
+    SDL_PowerState powerState = SDL_GetPowerInfo(nullptr, &percentage);
+
+    if (percentage < 0)
+        info.BatteryLifePercent = 1.0f;
+    else
+        info.BatteryLifePercent = (float)percentage / 100.0f;
+
+    switch (powerState)
+    {
+    case SDL_POWERSTATE_CHARGING:
+        info.State = BatteryInfo::States::BatteryCharging;
+        break;
+    case SDL_POWERSTATE_ON_BATTERY:
+        info.State = BatteryInfo::States::BatteryDischarging;
+        break;
+    case SDL_POWERSTATE_CHARGED:
+        info.State = BatteryInfo::States::Connected;
+        break;
+    default:
+        info.State = BatteryInfo::States::Unknown;
+    }
+    return info;
+}
+
+int32 SDLPlatform::GetDpi()
+{
+    return SDLImpl::SystemDpi;
+}
+
+String SDLPlatform::GetUserLocaleName()
+{
+    return SDLImpl::UserLocale;
+}
+
+void SDLPlatform::OpenUrl(const StringView& url)
+{
+    StringAnsi urlStr(url);
+    SDL_OpenURL(urlStr.GetText());
+}
+
+Float2 SDLPlatform::GetMousePosition()
+{
+#if PLATFORM_LINUX
+    if (UsesWayland())
+    {
+        // Wayland doesn't support reporting global mouse position,
+        // use the last known reported position we got from received window events.
+        return Input::GetMouseScreenPosition();
+    }
+#endif
+    Float2 pos;
+    SDL_GetGlobalMouseState(&pos.X, &pos.Y);
+    return pos;
+}
+
+void SDLPlatform::SetMousePosition(const Float2& pos)
+{
+    SDL_WarpMouseGlobal(pos.X, pos.Y);
+}
+
+Float2 SDLPlatform::GetDesktopSize()
+{
+    SDL_Rect rect;
+    SDL_GetDisplayBounds(SDL_GetPrimaryDisplay(), &rect);
+    return Float2(static_cast<float>(rect.w), static_cast<float>(rect.h));
+}
+
+Rectangle SDLPlatform::GetMonitorBounds(const Float2& screenPos)
+{
+    SDL_Point point{ (int32)screenPos.X, (int32)screenPos.Y };
+    SDL_DisplayID display = SDL_GetDisplayForPoint(&point);
+    SDL_Rect rect;
+    SDL_GetDisplayBounds(display, &rect);
+    return Rectangle(static_cast<float>(rect.x), static_cast<float>(rect.y), static_cast<float>(rect.w), static_cast<float>(rect.h));
+}
+
+Rectangle SDLPlatform::GetVirtualDesktopBounds()
+{
+    int count;
+    const SDL_DisplayID* displays = SDL_GetDisplays(&count);
+    if (displays == nullptr)
+        return Rectangle::Empty;
+
+    Rectangle bounds = Rectangle::Empty;
+    for (int i = 0; i < count; i++)
+    {
+        SDL_DisplayID display = displays[i];
+        SDL_Rect rect;
+        SDL_GetDisplayBounds(display, &rect);
+        bounds = Rectangle::Union(bounds, Rectangle(static_cast<float>(rect.x), static_cast<float>(rect.y), static_cast<float>(rect.w), static_cast<float>(rect.h)));
+    }
+    SDL_free((void*)displays);
+    return bounds;
+}
+
+Window* SDLPlatform::CreateWindow(const CreateWindowSettings& settings)
+{
+    return New<SDLWindow>(settings);
+}
+
+#endif

Source/Engine/Platform/SDL/SDLPlatform.h

@@ -0,0 +1,92 @@
+// Copyright (c) Wojciech Figat. All rights reserved.
+
+#pragma once
+
+#if PLATFORM_SDL
+
+#include "Engine/Platform/Base/Enums.h"
+#if PLATFORM_WINDOWS
+#include "Engine/Platform/Windows/WindowsPlatform.h"
+typedef struct tagMSG MSG;
+#elif PLATFORM_LINUX
+#include "Engine/Platform/Linux/LinuxPlatform.h"
+union _XEvent;
+#elif PLATFORM_MAC
+#include "Engine/Platform/Mac/MacPlatform.h"
+#else
+static_assert(false, "Unsupported Platform");
+#endif
+
+class SDLWindow;
+union SDL_Event;
+
+/// <summary>
+/// The SDL platform implementation and application management utilities.
+/// </summary>
+class FLAXENGINE_API SDLPlatform
+#if PLATFORM_WINDOWS
+    : public WindowsPlatform
+{
+    using base = WindowsPlatform;
+#elif PLATFORM_LINUX
+    : public LinuxPlatform
+{
+    using base = LinuxPlatform;
+#elif PLATFORM_MAC
+: public MacPlatform
+{
+    using base = MacPlatform;
+#else
+{
+    static_assert(false, "Unsupported Platform");
+#endif
+    friend SDLWindow;
+
+private:
+    static bool InitInternal();
+#if PLATFORM_LINUX
+    static bool InitX11(void* display);
+#endif
+    static bool HandleEvent(SDL_Event& event);
+#if PLATFORM_WINDOWS
+    static bool EventMessageHook(void* userdata, MSG* msg);
+    static bool EventFilterCallback(void* userdata, SDL_Event* event);
+#elif PLATFORM_LINUX
+    static bool X11EventHook(void* userdata, _XEvent* xevent);
+#elif PLATFORM_MAC
+    static bool EventFilterCallback(void* userdata, SDL_Event* event);
+#endif
+    static void PreHandleEvents();
+    static void PostHandleEvents();
+
+public:
+#if PLATFORM_LINUX
+    static void* GetXDisplay();
+#endif
+    static bool UsesWindows();
+    static bool UsesWayland();
+    static bool UsesX11();
+
+public:
+
+    // [PlatformBase]
+    static bool Init();
+    static void LogInfo();
+    static void Tick();
+    static String GetDisplayServer();
+    static bool SupportsNativeDecorations();
+    static bool SupportsNativeDecorationDragging();
+    static void SetHighDpiAwarenessEnabled(bool enable);
+    static BatteryInfo GetBatteryInfo();
+    static int32 GetDpi();
+    static String GetUserLocaleName();
+    static void OpenUrl(const StringView& url);
+    static Float2 GetMousePosition();
+    static void SetMousePosition(const Float2& pos);
+    static Float2 GetDesktopSize();
+    static Rectangle GetMonitorBounds(const Float2& screenPos);
+    static Rectangle GetVirtualDesktopBounds();
+    static Window* CreateWindow(const CreateWindowSettings& settings);
+};
+
+#endif

Source/Engine/Platform/SDL/SDLWindow.h

@@ -0,0 +1,130 @@
+// Copyright (c) Wojciech Figat. All rights reserved.
+
+#pragma once
+
+#if PLATFORM_SDL
+
+#include "Engine/Platform/Base/WindowBase.h"
+
+struct SDL_Window;
+union SDL_Event;
+#if PLATFORM_LINUX
+class MessageBox;
+#endif
+
+/// <summary>
+/// Implementation of the window class for SDL platform
+/// </summary>
+class FLAXENGINE_API SDLWindow : public WindowBase
+#if USE_EDITOR && PLATFORM_WINDOWS
+    , public Windows::IDropTarget
+#endif
+{
+    friend SDLPlatform;
+    friend class SDLMouse;
+#if PLATFORM_LINUX
+    friend LinuxPlatform;
+    friend MessageBox;
+#endif
+    
+private:
+    void* _handle; // Opaque, platform specific window handle
+#if USE_EDITOR && PLATFORM_WINDOWS
+    Windows::ULONG _refCount;
+#endif
+#if PLATFORM_LINUX
+    bool _dragOver;
+#endif
+    SDL_Window* _window;
+    uint32 _windowId;
+    Rectangle _clipCursorRect;
+    Rectangle _cachedClientRectangle;
+
+public:
+    static void Init();
+
+public:
+    /// <summary>
+    /// Initializes a new instance of the <see cref="SDLWindow"/> class.
+    /// </summary>
+    /// <param name="settings">The initial window settings.</param>
+    SDLWindow(const CreateWindowSettings& settings);
+
+    /// <summary>
+    /// Finalizes an instance of the <see cref="SDLWindow"/> class.
+    /// </summary>
+    ~SDLWindow();
+
+private:
+    static SDLWindow* GetWindowFromEvent(const SDL_Event& event);
+    static SDLWindow* GetWindowWithSDLWindow(SDL_Window* window);
+    void HandleEvent(SDL_Event& event);
+    bool HandleEventInternal(SDL_Event& event);
+    void CheckForWindowResize();
+    void UpdateCursor();
+
+public:
+    SDL_Window* GetSDLWindow() const;
+#if PLATFORM_LINUX
+    void* GetWaylandDisplay() const;
+    void* GetX11Display() const;
+#endif
+    WindowHitCodes OnWindowHit(const Float2 point);
+
+    // [WindowBase]
+    void* GetNativePtr() const override;
+    void Show() override;
+    void Hide() override;
+    void Minimize() override;
+    void Maximize() override;
+    void SetBorderless(bool isBorderless, bool maximized = false) override;
+    void Restore() override;
+    bool IsClosed() const override;
+    bool IsForegroundWindow() const override;
+    void BringToFront(bool force = false) override;
+    void SetClientBounds(const Rectangle& clientArea) override;
+    void SetPosition(const Float2& position) override;
+    void SetClientPosition(const Float2& position) override;
+    void SetIsFullscreen(bool isFullscreen) override;
+    bool IsAlwaysOnTop() const override;
+    void SetIsAlwaysOnTop(bool isAlwaysOnTop) override;
+    Float2 GetPosition() const override;
+    Float2 GetSize() const override;
+    Float2 GetClientSize() const override;
+    Float2 ScreenToClient(const Float2& screenPos) const override;
+    Float2 ClientToScreen(const Float2& clientPos) const override;
+    void FlashWindow() override;
+    float GetOpacity() const override;
+    void SetOpacity(float opacity) override;
+    void Focus() override;
+    String GetTitle() const override;
+    void SetTitle(const StringView& title) override;
+    DragDropEffect DoDragDrop(const StringView& data) override;
+    DragDropEffect DoDragDrop(const StringView& data, const Float2& offset, Window* dragSourceWindow) override;
+    void StartTrackingMouse(bool useMouseScreenOffset) override;
+    void EndTrackingMouse() override;
+    void StartClippingCursor(const Rectangle& bounds) override;
+    void EndClippingCursor() override;
+    void SetMousePosition(const Float2& position) const override;
+    void SetCursor(CursorType type) override;
+    void SetIcon(TextureData& icon) override;
+
+#if USE_EDITOR && PLATFORM_WINDOWS
+    // [IUnknown]
+    Windows::HRESULT __stdcall QueryInterface(const Windows::IID& id, void** ppvObject) override;
+    Windows::ULONG __stdcall AddRef() override;
+    Windows::ULONG __stdcall Release() override;
+
+    // [Windows::IDropTarget]
+    Windows::HRESULT __stdcall DragEnter(Windows::IDataObject* pDataObj, Windows::DWORD grfKeyState, Windows::POINTL pt, Windows::DWORD* pdwEffect) override;
+    Windows::HRESULT __stdcall DragOver(Windows::DWORD grfKeyState, Windows::POINTL pt, Windows::DWORD* pdwEffect) override;
+    Windows::HRESULT __stdcall DragLeave() override;
+    Windows::HRESULT __stdcall Drop(Windows::IDataObject* pDataObj, Windows::DWORD grfKeyState, Windows::POINTL pt, Windows::DWORD* pdwEffect) override;
+#endif
+#if PLATFORM_LINUX
+    DragDropEffect DoDragDropWayland(const StringView& data, Window* dragSourceWindow = nullptr, Float2 dragOffset = Float2::Zero);
+    DragDropEffect DoDragDropX11(const StringView& data);
+#endif
+};
+
+#endif

Source/Engine/Platform/ScreenUtilities.h

@@ -0,0 +1,15 @@
+// Copyright (c) Wojciech Figat. All rights reserved.
+
+#pragma once
+
+#if PLATFORM_WINDOWS
+#include "Windows/WindowsScreenUtilities.h"
+#elif PLATFORM_LINUX
+#include "Linux/LinuxScreenUtilities.h"
+#elif PLATFORM_MAC
+#include "Mac/MacScreenUtilities.h"
+#else
+#include "Base/ScreenUtilitiesBase.h"
+#endif
+
+#include "Types.h"

Source/Engine/Platform/Types.h

@@ -4,8 +4,6 @@
 
 #if PLATFORM_WINDOWS
 
-class WindowsClipboard;
-typedef WindowsClipboard Clipboard;
 class Win32CriticalSection;
 typedef Win32CriticalSection CriticalSection;
 class Win32ConditionVariable;
@@ -16,21 +14,25 @@ class WindowsFileSystemWatcher;
 typedef WindowsFileSystemWatcher FileSystemWatcher;
 class Win32File;
 typedef Win32File File;
-class WindowsPlatform;
-typedef WindowsPlatform Platform;
 class Win32Thread;
 typedef Win32Thread Thread;
+class WindowsClipboard;
+typedef WindowsClipboard Clipboard;
+#if !PLATFORM_SDL
+class WindowsPlatform;
+typedef WindowsPlatform Platform;
 class WindowsWindow;
 typedef WindowsWindow Window;
+#endif
 class Win32Network;
 typedef Win32Network Network;
 class UserBase;
 typedef UserBase User;
+class WindowsScreenUtilities;
+typedef WindowsScreenUtilities ScreenUtilities;
 
 #elif PLATFORM_UWP
 
-class ClipboardBase;
-typedef ClipboardBase Clipboard;
 class Win32CriticalSection;
 typedef Win32CriticalSection CriticalSection;
 class Win32ConditionVariable;
@@ -41,21 +43,23 @@ class FileSystemWatcherBase;
 typedef FileSystemWatcherBase FileSystemWatcher;
 class Win32File;
 typedef Win32File File;
-class UWPPlatform;
-typedef UWPPlatform Platform;
 class Win32Thread;
 typedef Win32Thread Thread;
+class ClipboardBase;
+typedef ClipboardBase Clipboard;
+class UWPPlatform;
+typedef UWPPlatform Platform;
 class UWPWindow;
 typedef UWPWindow Window;
 class Win32Network;
 typedef Win32Network Network;
 class UserBase;
 typedef UserBase User;
+class ScreenUtilitiesBase;
+typedef ScreenUtilitiesBase ScreenUtilities;
 
 #elif PLATFORM_LINUX
 
-class LinuxClipboard;
-typedef LinuxClipboard Clipboard;
 class UnixCriticalSection;
 typedef UnixCriticalSection CriticalSection;
 class UnixConditionVariable;
@@ -66,21 +70,25 @@ class LinuxFileSystemWatcher;
 typedef LinuxFileSystemWatcher FileSystemWatcher;
 class UnixFile;
 typedef UnixFile File;
-class LinuxPlatform;
-typedef LinuxPlatform Platform;
 class LinuxThread;
 typedef LinuxThread Thread;
+#if !PLATFORM_SDL
+class LinuxClipboard;
+typedef LinuxClipboard Clipboard;
+class LinuxPlatform;
+typedef LinuxPlatform Platform;
 class LinuxWindow;
 typedef LinuxWindow Window;
+#endif
 class UnixNetwork;
 typedef UnixNetwork Network;
 class UserBase;
 typedef UserBase User;
+class LinuxScreenUtilities;
+typedef LinuxScreenUtilities ScreenUtilities;
 
 #elif PLATFORM_PS4
 
-class ClipboardBase;
-typedef ClipboardBase Clipboard;
 class UnixCriticalSection;
 typedef UnixCriticalSection CriticalSection;
 class UnixConditionVariable;
@@ -91,21 +99,23 @@ class FileSystemWatcherBase;
 typedef FileSystemWatcherBase FileSystemWatcher;
 class UnixFile;
 typedef UnixFile File;
-class PS4Platform;
-typedef PS4Platform Platform;
 class PS4Thread;
 typedef PS4Thread Thread;
+class ClipboardBase;
+typedef ClipboardBase Clipboard;
+class PS4Platform;
+typedef PS4Platform Platform;
 class PS4Window;
 typedef PS4Window Window;
 class PS4Network;
 typedef PS4Network Network;
 class PS4User;
 typedef PS4User User;
+class ScreenUtilitiesBase;
+typedef ScreenUtilitiesBase ScreenUtilities;
 
 #elif PLATFORM_PS5
 
-class ClipboardBase;
-typedef ClipboardBase Clipboard;
 class UnixCriticalSection;
 typedef UnixCriticalSection CriticalSection;
 class UnixConditionVariable;
@@ -116,21 +126,23 @@ class FileSystemWatcherBase;
 typedef FileSystemWatcherBase FileSystemWatcher;
 class UnixFile;
 typedef UnixFile File;
-class PS5Platform;
-typedef PS5Platform Platform;
+class ClipboardBase;
+typedef ClipboardBase Clipboard;
 class PS5Thread;
 typedef PS5Thread Thread;
+class PS5Platform;
+typedef PS5Platform Platform;
 class PS5Window;
 typedef PS5Window Window;
 class PS5Network;
 typedef PS5Network Network;
 class PS5User;
 typedef PS5User User;
+class ScreenUtilitiesBase;
+typedef ScreenUtilitiesBase ScreenUtilities;
 
 #elif PLATFORM_XBOX_ONE
 
-class ClipboardBase;
-typedef ClipboardBase Clipboard;
 class Win32CriticalSection;
 typedef Win32CriticalSection CriticalSection;
 class Win32ConditionVariable;
@@ -141,21 +153,23 @@ class FileSystemWatcherBase;
 typedef FileSystemWatcherBase FileSystemWatcher;
 class Win32File;
 typedef Win32File File;
-class XboxOnePlatform;
-typedef XboxOnePlatform Platform;
 class Win32Thread;
 typedef Win32Thread Thread;
+class ClipboardBase;
+typedef ClipboardBase Clipboard;
+class XboxOnePlatform;
+typedef XboxOnePlatform Platform;
 class GDKWindow;
 typedef GDKWindow Window;
 class Win32Network;
 typedef Win32Network Network;
 class GDKUser;
 typedef GDKUser User;
+class ScreenUtilitiesBase;
+typedef ScreenUtilitiesBase ScreenUtilities;
 
 #elif PLATFORM_XBOX_SCARLETT
 
-class ClipboardBase;
-typedef ClipboardBase Clipboard;
 class Win32CriticalSection;
 typedef Win32CriticalSection CriticalSection;
 class Win32ConditionVariable;
@@ -166,21 +180,23 @@ class FileSystemWatcherBase;
 typedef FileSystemWatcherBase FileSystemWatcher;
 class Win32File;
 typedef Win32File File;
-class XboxScarlettPlatform;
-typedef XboxScarlettPlatform Platform;
 class Win32Thread;
 typedef Win32Thread Thread;
+class ClipboardBase;
+typedef ClipboardBase Clipboard;
+class XboxScarlettPlatform;
+typedef XboxScarlettPlatform Platform;
 class GDKWindow;
 typedef GDKWindow Window;
 class Win32Network;
 typedef Win32Network Network;
 class GDKUser;
 typedef GDKUser User;
+class ScreenUtilitiesBase;
+typedef ScreenUtilitiesBase ScreenUtilities;
 
 #elif PLATFORM_ANDROID
 
-class ClipboardBase;
-typedef ClipboardBase Clipboard;
 class UnixCriticalSection;
 typedef UnixCriticalSection CriticalSection;
 class UnixConditionVariable;
@@ -191,21 +207,23 @@ class FileSystemWatcherBase;
 typedef FileSystemWatcherBase FileSystemWatcher;
 class AndroidFile;
 typedef AndroidFile File;
-class AndroidPlatform;
-typedef AndroidPlatform Platform;
 class AndroidThread;
 typedef AndroidThread Thread;
+class ClipboardBase;
+typedef ClipboardBase Clipboard;
+class AndroidPlatform;
+typedef AndroidPlatform Platform;
 class AndroidWindow;
 typedef AndroidWindow Window;
 class UnixNetwork;
 typedef UnixNetwork Network;
 class UserBase;
 typedef UserBase User;
+class ScreenUtilitiesBase;
+typedef ScreenUtilitiesBase ScreenUtilities;
 
 #elif PLATFORM_SWITCH
 
-class ClipboardBase;
-typedef ClipboardBase Clipboard;
 class SwitchCriticalSection;
 typedef SwitchCriticalSection CriticalSection;
 class SwitchConditionVariable;
@@ -216,21 +234,23 @@ class FileSystemWatcherBase;
 typedef FileSystemWatcherBase FileSystemWatcher;
 class SwitchFile;
 typedef SwitchFile File;
-class SwitchPlatform;
-typedef SwitchPlatform Platform;
 class SwitchThread;
 typedef SwitchThread Thread;
+class ClipboardBase;
+typedef ClipboardBase Clipboard;
+class SwitchPlatform;
+typedef SwitchPlatform Platform;
 class SwitchWindow;
 typedef SwitchWindow Window;
 class SwitchNetwork;
 typedef SwitchNetwork Network;
 class SwitchUser;
 typedef SwitchUser User;
+class ScreenUtilitiesBase;
+typedef ScreenUtilitiesBase ScreenUtilities;
 
 #elif PLATFORM_MAC
 
-class MacClipboard;
-typedef MacClipboard Clipboard;
 class UnixCriticalSection;
 typedef UnixCriticalSection CriticalSection;
 class UnixConditionVariable;
@@ -241,21 +261,25 @@ class MacFileSystemWatcher;
 typedef MacFileSystemWatcher FileSystemWatcher;
 class UnixFile;
 typedef UnixFile File;
-class MacPlatform;
-typedef MacPlatform Platform;
 class AppleThread;
 typedef AppleThread Thread;
+class MacClipboard;
+typedef MacClipboard Clipboard;
+#if !PLATFORM_SDL
+class MacPlatform;
+typedef MacPlatform Platform;
 class MacWindow;
 typedef MacWindow Window;
+#endif
 class UnixNetwork;
 typedef UnixNetwork Network;
 class UserBase;
 typedef UserBase User;
+class MacScreenUtilities;
+typedef MacScreenUtilities ScreenUtilities;
 
 #elif PLATFORM_IOS
 
-class ClipboardBase;
-typedef ClipboardBase Clipboard;
 class UnixCriticalSection;
 typedef UnixCriticalSection CriticalSection;
 class UnixConditionVariable;
@@ -266,19 +290,34 @@ class FileSystemWatcherBase;
 typedef FileSystemWatcherBase FileSystemWatcher;
 class iOSFile;
 typedef iOSFile File;
-class iOSPlatform;
-typedef iOSPlatform Platform;
 class AppleThread;
 typedef AppleThread Thread;
+class ClipboardBase;
+typedef ClipboardBase Clipboard;
+class iOSPlatform;
+typedef iOSPlatform Platform;
 class iOSWindow;
 typedef iOSWindow Window;
 class UnixNetwork;
 typedef UnixNetwork Network;
 class UserBase;
 typedef UserBase User;
+class ScreenUtilitiesBase;
+typedef ScreenUtilitiesBase ScreenUtilities;
 
 #else
 
 #error Missing Types implementation!
 
 #endif
+
+#if PLATFORM_SDL
+#if PLATFORM_LINUX
+class SDLClipboard;
+typedef SDLClipboard Clipboard;
+#endif
+class SDLPlatform;
+typedef SDLPlatform Platform;
+class SDLWindow;
+typedef SDLWindow Window;
+#endif

Source/Engine/Platform/UWP/UWPWindow.h

@@ -183,6 +183,7 @@ public:
     void Focus() override;
     void SetTitle(const StringView& title) override;
     DragDropEffect DoDragDrop(const StringView& data) override;
+    using WindowBase::DoDragDrop;
     void StartTrackingMouse(bool useMouseScreenOffset) override;
     void EndTrackingMouse() override;
     void SetCursor(CursorType type) override;

Source/Engine/Platform/Window.cs

@@ -17,31 +17,37 @@ namespace FlaxEngine
         /// <summary>
         /// Perform window hit test delegate.
         /// </summary>
-        /// <param name="mouse">The mouse position. The coordinate is relative to the upper-left corner of the screen. Use <see cref="ScreenToClient"/> to convert position into client space coordinates.</param>
+        /// <param name="mousePosition">The mouse position. The coordinate is relative to the upper-left corner of the screen. Use <see cref="ScreenToClient"/> to convert position into client space coordinates.</param>
         /// <returns>Hit result.</returns>
-        public delegate WindowHitCodes HitTestDelegate(ref Float2 mouse);
+        public delegate WindowHitCodes HitTestDelegate(ref Float2 mousePosition);
 
         /// <summary>
         /// Perform mouse buttons action.
         /// </summary>
-        /// <param name="mouse">The mouse position.</param>
+        /// <param name="mousePosition">The mouse position.</param>
         /// <param name="button">The mouse buttons state.</param>
         /// <param name="handled">The flag that indicated that event has been handled by the custom code and should not be passed further. By default it is set to false.</param>
-        public delegate void MouseButtonDelegate(ref Float2 mouse, MouseButton button, ref bool handled);
+        public delegate void MouseButtonDelegate(ref Float2 mousePosition, MouseButton button, ref bool handled);
 
         /// <summary>
         /// Perform mouse move action.
         /// </summary>
-        /// <param name="mouse">The mouse position.</param>
-        public delegate void MouseMoveDelegate(ref Float2 mouse);
+        /// <param name="mousePosition">The mouse position.</param>
+        public delegate void MouseMoveDelegate(ref Float2 mousePosition);
+        
+        /// <summary>
+        /// Perform mouse move action in relative mode.
+        /// </summary>
+        /// <param name="mouseMotion">The relative mouse motion.</param>
+        public delegate void MouseMoveRelativeDelegate(ref Float2 mouseMotion);
 
         /// <summary>
         /// Perform mouse wheel action.
         /// </summary>
-        /// <param name="mouse">The mouse position.</param>
+        /// <param name="mousePosition">The mouse position.</param>
         /// <param name="delta">The mouse wheel move delta (can be positive or negative; normalized to [-1;1] range).</param>
         /// <param name="handled">The flag that indicated that event has been handled by the custom code and should not be passed further. By default it is set to false.</param>
-        public delegate void MouseWheelDelegate(ref Float2 mouse, float delta, ref bool handled);
+        public delegate void MouseWheelDelegate(ref Float2 mousePosition, float delta, ref bool handled);
 
         /// <summary>
         /// Perform touch action.
@@ -99,9 +105,14 @@ namespace FlaxEngine
         public event MouseWheelDelegate MouseWheel;
 
         /// <summary>
-        /// Event fired when mouse moves
+        /// Event fired when mouse moves.
         /// </summary>
         public event MouseMoveDelegate MouseMove;
+        
+        /// <summary>
+        /// Event fired when mouse moves in relative mode.
+        /// </summary>
+        public event MouseMoveRelativeDelegate MouseMoveRelative;
 
         /// <summary>
         /// Event fired when mouse leaves window.
@@ -273,6 +284,12 @@ namespace FlaxEngine
             MouseMove?.Invoke(ref pos);
             GUI.OnMouseMove(pos);
         }
+        
+        internal void Internal_OnMouseMoveRelative(ref Float2 mouseMotion)
+        {
+            MouseMoveRelative?.Invoke(ref mouseMotion);
+            GUI.OnMouseMoveRelative(mouseMotion);
+        }
 
         internal void Internal_OnMouseLeave()
         {

Source/Engine/Platform/Window.h

@@ -2,7 +2,9 @@
 
 #pragma once
 
-#if PLATFORM_WINDOWS
+#if PLATFORM_SDL
+#include "SDL/SDLWindow.h"
+#elif PLATFORM_WINDOWS
 #include "Windows/WindowsWindow.h"
 #elif PLATFORM_UWP
 #include "UWP/UWPWindow.h"