Simple Sprite subclass with a rectangular mask in stage coordinates

ClippedSprite.as

package starling.extensions
{
    import flash.display3D.Context3D;
    import flash.geom.Point;
    import flash.geom.Rectangle;
    
    import starling.core.RenderSupport;
    import starling.core.Starling;
    import starling.display.DisplayObject;
    import starling.display.Sprite;
    import starling.errors.MissingContextError;
    
    public class ClippedSprite extends Sprite
    {
        private var mClipRect:Rectangle;
        
        public override function render(support:RenderSupport, alpha:Number):void
        {
            if (mClipRect == null) super.render(support, alpha);
            else
            {
                var context:Context3D = Starling.context;
                if (context == null) throw new MissingContextError();
                
                support.finishQuadBatch();
                support.scissorRectangle = mClipRect;
                
                super.render(support, alpha);
                
                support.finishQuadBatch();
                support.scissorRectangle = null;
            }
        }
        
        public override function hitTest(localPoint:Point, forTouch:Boolean=false):DisplayObject
        {
            // without a clip rect, the sprite should behave just like before
            if (mClipRect == null) return super.hitTest(localPoint, forTouch); 
            
            // on a touch test, invisible or untouchable objects cause the test to fail
            if (forTouch && (!visible || !touchable)) return null;
            
            if (mClipRect.containsPoint(localToGlobal(localPoint)))
                return super.hitTest(localPoint, forTouch);
            else
                return null;
        }
        
        public function get clipRect():Rectangle { return mClipRect; }
        public function set clipRect(value:Rectangle):void
        {
            if (value) 
            {
                if (mClipRect == null) mClipRect = value.clone();
                else mClipRect.setTo(value.x, value.y, value.width, value.height);
            }
            else mClipRect = null;
        }
    }
}

Hi - Thanks for this extension. Useful!
Looks like current implementation doesn't support scale -- if you scale the ClippedSprite, the clipping rect doesn't react as you'd expect (it stays the same size). Children sprites of the ClippedSprite, however, scale as you'd expect.

I'm wondering if translating the desired scale to x and y values and then updating the clipRect is ideal, or if perhaps there's a better way like using a matrix or just resetting the cliprect after the scale is complete - even though visually this wouldn't look correct during the scale.

I'll run some tests and will report back when / if I find a path. Thanks.

Daniel,

I see the ClippedSprite hasn't been updated for 7 months. Is it still compatible with latest Starling?

As of Starling 1.4 there is no need for ClippedSprite anymore, as Sprite class features a clipRect parameter that does the same thing. See http://gamua.com/blog/2013/09/starling-14/ for more info.