Expose Main Window to c# through Screen class.

Source/Engine/Engine/Screen.cpp

@@ -181,6 +181,15 @@ void Screen::SetGameWindowMode(GameWindowMode windowMode)
 #endif
 }
 
+Window* Screen::GetMainWindow()
+{
+    Window* win = nullptr;
+#if !USE_EDITOR
+    win = Engine::MainWindow;
+#endif
+    return win;
+}
+
 void ScreenService::Update()
 {
 #if USE_EDITOR

Source/Engine/Engine/Screen.h

@@ -96,4 +96,10 @@ DECLARE_SCRIPTING_TYPE_NO_SPAWN(Screen);
     /// </remarks>
     /// <param name="windowMode">The window mode.</param>
     API_PROPERTY() static void SetGameWindowMode(GameWindowMode windowMode);
+
+    /// <summary>
+    /// Gets the main window. Only during built game.
+    /// </summary>
+    /// <returns>The current window. Will be null if fails.</returns>
+    API_PROPERTY() static Window* GetMainWindow();
 };