Fix CursorLockMode.Locked not working

Source/Engine/Engine/Screen.cpp

@@ -106,25 +106,11 @@ void Screen::SetCursorVisible(const bool value)
 #else
 	const auto win = Engine::MainWindow;
 #endif
-    bool focused = false;
     if (win && Engine::HasGameViewportFocus())
-    {
         win->SetCursor(value ? CursorType::Default : CursorType::Hidden);
-        focused = true;
-    }
     else if (win)
         win->SetCursor(CursorType::Default);
     CursorVisible = value;
-
-    // Just enable relative mode when cursor is constrained and not visible
-    if (CursorLock != CursorLockMode::None && !CursorVisible && focused)
-    {
-        Input::Mouse->SetRelativeMode(true, win);
-    }
-    else if (CursorLock == CursorLockMode::None || CursorVisible || !focused)
-    {
-        Input::Mouse->SetRelativeMode(false, win);
-    }
 }
 
 CursorLockMode Screen::GetCursorLock()
@@ -136,34 +122,35 @@ 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());
 #else
     const auto win = Engine::MainWindow;
+    Rectangle bounds = win != nullptr ? win->GetClientBounds() : Rectangle();
 #endif
+    bool inRelativeMode = Input::Mouse->IsRelative();
     if (win && mode == CursorLockMode::Clipped)
-    {
-#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 && mode == CursorLockMode::Locked)
-    else if (win && CursorLock == CursorLockMode::Clipped)
     {
-        win->EndClippingCursor();
+        // Use mouse clip region to restrict the cursor in one spot
+        Rectangle centerBounds;
+        auto mousePosition = win->GetMousePosition();
+        if (bounds.Contains(mousePosition))
+            centerBounds = Rectangle(mousePosition, Float2(1, 1));
+        else
+            centerBounds = Rectangle(bounds.GetCenter(), Float2(1, 1));
+        win->StartClippingCursor(centerBounds);
     }
+    else if (win && (CursorLock == CursorLockMode::Locked || CursorLock == CursorLockMode::Clipped))
+        win->EndClippingCursor();
     CursorLock = mode;
 
-    // Just enable relative mode when cursor is constrained and not visible
+    // Enable relative mode when cursor is restricted
     bool focused = win && Engine::HasGameViewportFocus();
-    if (CursorLock != CursorLockMode::None && !CursorVisible && focused)
+    if (CursorLock != CursorLockMode::None)
-    {
         Input::Mouse->SetRelativeMode(true, win);
-    }
+    else if (CursorLock == CursorLockMode::None && inRelativeMode)
-    else if (CursorLock == CursorLockMode::None || CursorVisible || !focused)
-    {
         Input::Mouse->SetRelativeMode(false, win);
-    }
 }
 
 GameWindowMode Screen::GetGameWindowMode()

Source/Engine/Platform/SDL/SDLInput.cpp

@@ -357,9 +357,9 @@ public:
 class SDLMouse : public Mouse
 {
 private:
-    Float2 oldPosition = Float2::Zero;
+    Float2 _oldPosition = Float2::Zero;
-    Window* relativeModeWindow = nullptr;
+    Window* _relativeModeWindow = nullptr;
-    const SDL_Rect* oldScreenRect = nullptr;
+    const SDL_Rect* _oldScreenRect = nullptr;
 public:
 
     /// <summary>
@@ -377,8 +377,8 @@ public:
     /// </summary>
     Float2 GetOldMousePosition() const
     {
-        ASSERT(relativeModeWindow != nullptr);
+        ASSERT(_relativeModeWindow != nullptr);
-        return relativeModeWindow->ClientToScreen(oldPosition);
+        return _relativeModeWindow->ClientToScreen(_oldPosition);
     }
 
     // [Mouse]
@@ -405,27 +405,27 @@ public:
         auto windowHandle = static_cast<SDLWindow*>(window)->_window;
         if (relativeMode)
         {
-            relativeModeWindow = window;
+            _relativeModeWindow = window;
-            SDL_GetMouseState(&oldPosition.X, &oldPosition.Y);
+            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 };
+                SDL_Rect clipRect = { (int)_oldPosition.X, (int)_oldPosition.Y, 1, 1 };
-                oldScreenRect = SDL_GetWindowMouseRect(windowHandle);
+                _oldScreenRect = SDL_GetWindowMouseRect(windowHandle);
                 SDL_SetWindowMouseRect(windowHandle, &clipRect);
             }
         }
         else
         {
-            if (relativeModeWindow != window)
+            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);
+            SDL_WarpMouseInWindow(windowHandle, _oldPosition.X, _oldPosition.Y);
-            oldScreenRect = nullptr;
+            _oldScreenRect = nullptr;
-            relativeModeWindow = nullptr;
+            _relativeModeWindow = nullptr;
         }
 
         Mouse::SetRelativeMode(relativeMode, window);

Source/Engine/Platform/SDL/SDLPlatform.cpp

@@ -70,7 +70,7 @@ bool SDLPlatform::Init()
     
     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"); // 
+    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
@@ -118,6 +118,7 @@ bool SDLPlatform::Init()
     }
 
     SDLInput::Init();
+    SDLWindow::Init();
 
     SystemDpi = (int)(SDL_GetDisplayContentScale(SDL_GetPrimaryDisplay()) * DefaultDPI);
 

Source/Engine/Platform/SDL/SDLWindow.cpp

@@ -73,6 +73,10 @@ void* GetNativeWindowPointer(SDL_Window* window)
     return windowPtr;
 }
 
+void SDLWindow::Init()
+{
+}
+
 SDLWindow::SDLWindow(const CreateWindowSettings& settings)
     : WindowBase(settings)
     , _handle(nullptr)
@@ -420,26 +424,29 @@ void SDLWindow::HandleEvent(SDL_Event& event)
     case SDL_EVENT_WINDOW_FOCUS_GAINED:
     {
         OnGotFocus();
-        if (IsPopupWindow(_settings.Type))
-            _window = _window;
         if (_settings.AllowInput && !SDLPlatform::UsesX11())
             SDL_StartTextInput(_window);
-        const SDL_Rect* currentClippingRect = SDL_GetWindowMouseRect(_window);
+        if (_isClippingCursor)
-        if (_isClippingCursor && currentClippingRect == nullptr)
         {
+            // The relative mode needs to be disabled for clipping to take effect
+            bool inRelativeMode = Input::Mouse->IsRelative(this) || _restoreRelativeMode;
+            if (inRelativeMode)
+                Input::Mouse->SetRelativeMode(false, this);
+
+            // Restore previous clipping region
             SDL_Rect rect{ (int)_clipCursorRect.GetX(), (int)_clipCursorRect.GetY(), (int)_clipCursorRect.GetWidth(), (int)_clipCursorRect.GetHeight() };
             SDL_SetWindowMouseRect(_window, &rect);
+
+            if (inRelativeMode)
+                Input::Mouse->SetRelativeMode(true, this);
         }
         return;
     }
     case SDL_EVENT_WINDOW_FOCUS_LOST:
     {
-        if (IsPopupWindow(_settings.Type))
-            _window = _window;
         if (_settings.AllowInput && !SDLPlatform::UsesX11())
             SDL_StopTextInput(_window);
-        const SDL_Rect* currentClippingRect = SDL_GetWindowMouseRect(_window);
+        if (_isClippingCursor)
-        if (currentClippingRect != nullptr)
             SDL_SetWindowMouseRect(_window, nullptr);
         OnLostFocus();
         return;
@@ -802,9 +809,23 @@ void SDLWindow::StartClippingCursor(const Rectangle& bounds)
     if (!IsFocused())
         return;
 
+#if PLATFORM_LINUX
+    {
+        auto oldValue = SDL_GetHint(SDL_HINT_MOUSE_RELATIVE_WARP_MOTION);
+        SDL_SetHint(SDL_HINT_MOUSE_RELATIVE_WARP_MOTION, "1");
+        
+        // The cursor is not fully constrained when positioned outside of the clip region...
+        Float2 center = bounds.GetCenter();
+        SDL_WarpMouseInWindow(_window, center.X, center.Y);
+
+        SDL_SetHint(SDL_HINT_MOUSE_RELATIVE_WARP_MOTION, oldValue);
+    }
+#endif
+
     _isClippingCursor = true;
     SDL_Rect rect{ (int)bounds.GetX(), (int)bounds.GetY(), (int)bounds.GetWidth(), (int)bounds.GetHeight() };
     SDL_SetWindowMouseRect(_window, &rect);
+    _clipCursorRect = bounds;
 }
 
 void SDLWindow::EndClippingCursor()

Source/Engine/Platform/SDL/SDLWindow.h

@@ -40,6 +40,9 @@ private:
     Rectangle _clipCursorRect;
     Rectangle _cachedClientRectangle;
 
+public:
+    static void Init();
+
 public:
     /// <summary>
     /// Initializes a new instance of the <see cref="SDLWindow"/> class.