Editor updates mouse position while game widget is unfocused

Author: aidencurtis

engine/Sandbox.Engine/Systems/Input/InputRouter.Input.cs

@@ -87,30 +87,34 @@ internal static void OnMouseMotion( float dx, float dy )
 	/// </summary>
 	internal static void OnMousePositionChange( float x, float y, float dx, float dy )
 	{
-		var delta = new Vector2( 0, 0 );
+		ApplyAbsoluteMousePosition( new Vector2( x, y ), new Vector2( dx, dy ) );
+	}
+
+	/// <summary>
+	/// Shared absolute-position path for native and editor-driven mouse updates.
+	/// </summary>
+	internal static void ApplyAbsoluteMousePosition( Vector2 pos, Vector2 delta )
+	{
+		MouseCursorPosition = pos;
 
-		// if we're not in relative mode - take the delta from this
-		if ( !NativeEngine.InputSystem.GetRelativeMouseMode() )
+		if ( InputSystem.GetRelativeMouseMode() )
 		{
-			delta = new Vector2( dx, dy );
-			MouseCursorDelta += delta;
+			delta = Vector2.Zero;
 		}
 
-		MouseCursorPosition = new Vector2( x, y );
-
-		// if this is set, we're in capture mode - so just update the position
-		// which will update the position of the cursor when we come out of it
+		// If this is set, we're in capture mode - so just update the position
+		// cache we restore when capture ends. This intentionally records the
+		// latest absolute position without moving the OS cursor.
 		if ( mouseCapturePosition is not null )
 		{
 			mouseCapturePosition = MouseCursorPosition;
 			return;
 		}
 
+		MouseCursorDelta += delta;
+
 		var mouse = Contexts.FirstOrDefault( x => x.MouseState != InputContext.InputState.Ignore );
-		if ( mouse is not null )
-		{
-			mouse.In_MousePosition( MouseCursorPosition, delta );
-		}
+		mouse?.In_MousePosition( MouseCursorPosition, delta );
 	}
 
 	internal static void OnGameControllerButton( int deviceId, GameControllerCode button, bool down )

engine/Sandbox.Tools/GameMode.cs

@@ -1,9 +1,10 @@
-using Native;
+using Sandbox.Engine;
 
 namespace Editor;
 
 /// <summary>
-/// Registers a widget with the input system, so it uses SDL.
+/// Registers a widget with the input system to use SDL and manages
+/// inputs and focus as it relates to the editor's game widget.
 /// </summary>
 public static class GameMode
 {
@@ -50,6 +51,9 @@ public static void ClearPlayMode()
 	/// </summary>
 	private static void WidgetFocused( FocusChangeReason reason )
 	{
+		if ( _inPlay is null )
+			return;
+
 		NativeEngine.InputSystem.OnEditorGameFocusChange( _inPlay._widget.winId(), true );
 	}
 
@@ -58,6 +62,28 @@ private static void WidgetFocused( FocusChangeReason reason )
 	/// </summary>
 	private static void WidgetBlurred( FocusChangeReason reason )
 	{
+		if ( _inPlay is null )
+			return;
+
 		NativeEngine.InputSystem.OnEditorGameFocusChange( _inPlay._widget.winId(), false );
 	}
+
+	internal static void Tick()
+	{
+		// Keep game mouse position updated while the play widget is unfocused.
+		var playWidget = _inPlay;
+		if ( playWidget is null || playWidget.IsFocused )
+			return;
+
+		var local = playWidget.FromScreen( Application.CursorPosition );
+
+		// Don't snap to borders if cursor isn't over the widget.
+		if ( local.x < 0 || local.y < 0 || local.x >= playWidget.Size.x || local.y >= playWidget.Size.y )
+			return;
+
+		var pos = new Vector2( (int)local.x, (int)local.y );
+		var delta = pos - InputRouter.MouseCursorPosition;
+
+		InputRouter.ApplyAbsoluteMousePosition( pos, delta );
+	}
 }

engine/Sandbox.Tools/ToolsDll.cs

@@ -260,6 +260,8 @@ public void Tick()
 			Time.Update( scene.TimeNow, scene.TimeDelta );
 		}
 
+		GameMode.Tick();
+
 		// Escape was pressed in game and wasn't swallowed
 		// so lets change focus from the game window to the main editor
 		// window, which is going to free the mouse cursor from being captured