multitouch study 1

package
{
    import caurina.transitions.Tweener;

    import flash.display.Sprite;
    import flash.events.TouchEvent;
    import flash.events.Event;
	import flash.ui.Multitouch;
	import flash.ui.MultitouchInputMode;

    [SWF(width="1024", height="600", backgroundColor="#cccccc")]
    public class MultiTouch extends Sprite
    {
        public var dots:Object = {};

        public function MultiTouch()
        {
            trace('starting MultiTouch')
			addEventListener(Event.ADDED_TO_STAGE, onAdded);
        }

        private function onAdded(event:Event):void
        {
            Multitouch.inputMode = MultitouchInputMode.TOUCH_POINT;
            stage.addEventListener(TouchEvent.TOUCH_BEGIN, onTouchBegin);
            stage.addEventListener(TouchEvent.TOUCH_END, onTouchEnd);
        }

        public const RADIUS:int = 50;
        public const CROSS:int = 75;
        private function onTouchBegin(e:TouchEvent):void
        {
            var tpid:int = e.touchPointID;

            var dot:Sprite = new Sprite();
            dot.graphics.beginFill(int(Math.random() * 0xffffff));
            dot.graphics.drawCircle(0, 0, RADIUS);
            dot.graphics.endFill();
            dot.graphics.lineStyle(0);
            dot.graphics.moveTo(-CROSS, 0);
            dot.graphics.lineTo(CROSS, 0);
            dot.graphics.moveTo(0, -CROSS);
            dot.graphics.lineTo(0, CROSS);
            this.addChild(dot);

            trace('touch', tpid);
            dot.x = e.stageX;
            dot.y = e.stageY;

            dot.startTouchDrag(tpid, true);
            dots[tpid] = dot;
        }

        private function onTouchEnd(e:TouchEvent):void
        {
            var tpid:int = e.touchPointID;
            var dot:Sprite = dots[tpid];
            dot.stopTouchDrag(tpid);
            delete dots[tpid];

            Tweener.addTween(dot, {alpha: 0, time: 1, transition: 'linear',
                onComplete: this.removeChild,
                onCompleteParams: [dot]
            });
        }
    }
}