Lock mouse position

OpenRA.Game/Graphics/SoftwareCursor.cs

@@ -21,7 +21,8 @@ namespace OpenRA.Graphics
 		void Render(Renderer renderer);
 		void SetCursor(string cursor);
 		void Tick();
-		int Frame { get; }
+		void Lock();
+		void Unlock();
 	}
 
 	public sealed class SoftwareCursor : ICursor
@@ -32,6 +33,9 @@ namespace OpenRA.Graphics
 		readonly CursorProvider cursorProvider;
 		readonly SheetBuilder sheetBuilder;
 
+		bool isLocked = false;
+		int2 lockedPosition;
+
 		public SoftwareCursor(CursorProvider cursorProvider)
 		{
 			this.cursorProvider = cursorProvider;
@@ -78,7 +82,7 @@ namespace OpenRA.Graphics
 				return;
 
 			var cursorSequence = cursorProvider.GetCursorSequence(cursorName);
-			var cursorSprite = sprites[cursorName][Frame];
+			var cursorSprite = sprites[cursorName][(int)cursorFrame % cursorSequence.Length];
 			var cursorSize = CursorProvider.CursorViewportZoomed ? 2.0f * cursorSprite.Size : cursorSprite.Size;
 
 			var cursorOffset = CursorProvider.CursorViewportZoomed ?
@@ -86,19 +90,24 @@ namespace OpenRA.Graphics
 				cursorSequence.Hotspot + (0.5f * cursorSprite.Size.XY).ToInt2();
 
 			renderer.SetPalette(palette);
+			var mousePos = isLocked ? lockedPosition : Viewport.LastMousePos;
 			renderer.SpriteRenderer.DrawSprite(cursorSprite,
-				Viewport.LastMousePos - cursorOffset,
+				mousePos - cursorOffset,
 				paletteReferences[cursorSequence.Palette],
 				cursorSize);
 		}
 
-		public int Frame
+		public void Lock()
 		{
-			get
-			{
-				var cursorSequence = cursorProvider.GetCursorSequence(cursorName);
-				return (int)cursorFrame % cursorSequence.Length;
-			}
+			Game.Renderer.Window.SetRelativeMouseMode(true);
+			lockedPosition = Viewport.LastMousePos;
+			isLocked = true;
+		}
+
+		public void Unlock()
+		{
+			Game.Renderer.Window.SetRelativeMouseMode(false);
+			isLocked = false;
 		}
 
 		public void Dispose()