From 7953f6cb83c2416743c92de8202ca74f067bf55d Mon Sep 17 00:00:00 2001
From: Wojciech Figat <wojtek@figat.pl>
Date: Mon, 1 Aug 2022 16:17:34 +0200
Subject: [PATCH] Add `Engine.FocusGameViewport` to implement game menu with
 camera focus gather

---
 Source/Editor/Editor.cs                   | 11 +++++++++++
 Source/Editor/Managed/ManagedEditor.cpp   | 14 ++++++++++++++
 Source/Editor/Managed/ManagedEditor.h     |  5 +++++
 Source/Editor/Modules/SimulationModule.cs | 11 +----------
 Source/Editor/Windows/GameWindow.cs       | 17 +++++++++++++++++
 Source/Engine/Engine/Engine.cpp           | 13 +++++++++++++
 Source/Engine/Engine/Engine.h             |  5 +++++
 7 files changed, 66 insertions(+), 10 deletions(-)

diff --git a/Source/Editor/Editor.cs b/Source/Editor/Editor.cs
index 75ee0b481..fc6d72ee9 100644
--- a/Source/Editor/Editor.cs
+++ b/Source/Editor/Editor.cs
@@ -1301,6 +1301,17 @@ namespace FlaxEditor
             return false;
         }
 
+        internal void Internal_FocusGameViewport()
+        {
+            if (Windows.GameWin != null)
+            {
+                if (StateMachine.IsPlayMode && !StateMachine.PlayingState.IsPaused)
+                {
+                    Windows.GameWin.FocusGameViewport();
+                }
+            }
+        }
+
         internal void Internal_ScreenToGameViewport(ref Float2 pos)
         {
             var win = Windows.GameWin?.Root;
diff --git a/Source/Editor/Managed/ManagedEditor.cpp b/Source/Editor/Managed/ManagedEditor.cpp
index 3f0c613e8..c33e2c63e 100644
--- a/Source/Editor/Managed/ManagedEditor.cpp
+++ b/Source/Editor/Managed/ManagedEditor.cpp
@@ -27,6 +27,7 @@ MMethod* Internal_LightmapsBake = nullptr;
 MMethod* Internal_CanReloadScripts = nullptr;
 MMethod* Internal_CanAutoBuildCSG = nullptr;
 MMethod* Internal_CanAutoBuildNavMesh = nullptr;
+MMethod* Internal_FocusGameViewport = nullptr;
 MMethod* Internal_HasGameViewportFocus = nullptr;
 MMethod* Internal_ScreenToGameViewport = nullptr;
 MMethod* Internal_GameViewportToScreen = nullptr;
@@ -372,6 +373,19 @@ bool ManagedEditor::HasGameViewportFocus() const
     return result;
 }
 
+void ManagedEditor::FocusGameViewport() const
+{
+    if (HasManagedInstance())
+    {
+        if (Internal_FocusGameViewport == nullptr)
+        {
+            Internal_FocusGameViewport = GetClass()->GetMethod("Internal_FocusGameViewport");
+            ASSERT(Internal_FocusGameViewport);
+        }
+        Internal_FocusGameViewport->Invoke(GetManagedInstance(), nullptr, nullptr);
+    }
+}
+
 Float2 ManagedEditor::ScreenToGameViewport(const Float2& screenPos) const
 {
     Float2 result = screenPos;
diff --git a/Source/Editor/Managed/ManagedEditor.h b/Source/Editor/Managed/ManagedEditor.h
index c08c17e3f..8d6547377 100644
--- a/Source/Editor/Managed/ManagedEditor.h
+++ b/Source/Editor/Managed/ManagedEditor.h
@@ -100,6 +100,11 @@ public:
     /// <returns>True if game viewport is focused, otherwise false.</returns>
     bool HasGameViewportFocus() const;
 
+    /// <summary>
+    /// Gives focus to the game viewport (game can receive input).
+    /// </summary>
+    void FocusGameViewport() const;
+
     /// <summary>
     /// Converts the screen-space position to the game viewport position.
     /// </summary>
diff --git a/Source/Editor/Modules/SimulationModule.cs b/Source/Editor/Modules/SimulationModule.cs
index 0994ce9f0..07a67714a 100644
--- a/Source/Editor/Modules/SimulationModule.cs
+++ b/Source/Editor/Modules/SimulationModule.cs
@@ -191,16 +191,7 @@ namespace FlaxEditor.Modules
             // Show Game widow if hidden
             if (gameWin != null && gameWin.FocusOnPlay)
             {
-                if (!gameWin.IsDocked)
-                {
-                    gameWin.ShowFloating();
-                }
-                else if (!gameWin.IsSelected)
-                {
-                    gameWin.SelectTab(false);
-                    gameWin.RootWindow?.Window?.Focus();
-                    FlaxEngine.GUI.RootControl.GameRoot.Focus();
-                }
+                gameWin.FocusGameViewport();
             }
 
             Editor.Log("[PlayMode] Enter");
diff --git a/Source/Editor/Windows/GameWindow.cs b/Source/Editor/Windows/GameWindow.cs
index f5d6c8d45..4f9a18218 100644
--- a/Source/Editor/Windows/GameWindow.cs
+++ b/Source/Editor/Windows/GameWindow.cs
@@ -471,6 +471,23 @@ namespace FlaxEditor.Windows
             }
         }
 
+        /// <summary>
+        /// Focuses the game viewport. Shows the window if hidden or unselected.
+        /// </summary>
+        public void FocusGameViewport()
+        {
+            if (!IsDocked)
+            {
+                ShowFloating();
+            }
+            else if (!IsSelected)
+            {
+                SelectTab(false);
+                RootWindow?.Window?.Focus();
+            }
+            Focus();
+        }
+
         /// <summary>
         /// Takes the screenshot of the current viewport.
         /// </summary>
diff --git a/Source/Engine/Engine/Engine.cpp b/Source/Engine/Engine/Engine.cpp
index ae1fa0563..cf24223ea 100644
--- a/Source/Engine/Engine/Engine.cpp
+++ b/Source/Engine/Engine/Engine.cpp
@@ -409,6 +409,19 @@ JsonAsset* Engine::GetCustomSettings(const StringView& key)
     return Content::LoadAsync<JsonAsset>(assetId);
 }
 
+void Engine::FocusGameViewport()
+{
+#if USE_EDITOR
+    Editor::Managed->FocusGameViewport();
+#else
+    if (MainWindow)
+    {
+        MainWindow->BringToFront();
+        MainWindow->Focus();
+    }
+#endif
+}
+
 bool Engine::HasGameViewportFocus()
 {
 #if USE_EDITOR
diff --git a/Source/Engine/Engine/Engine.h b/Source/Engine/Engine/Engine.h
index 7fc5430f2..0e72e6b4b 100644
--- a/Source/Engine/Engine/Engine.h
+++ b/Source/Engine/Engine/Engine.h
@@ -153,6 +153,11 @@ public:
 
     static Window* MainWindow;
 
+    /// <summary>
+    /// Brings focused to the game viewport (game can receive input).
+    /// </summary>
+    API_FUNCTION() static void FocusGameViewport();
+
     /// <summary>
     /// Checks whenever the game viewport is focused by the user (eg. can receive input).
     /// </summary>