public MainLayer()
        {
            rnd = new Random();
            var batchnode = new CCSpriteBatchNode("Images/sprites.png",10);
            Add (batchnode, -1, (int)Tags.SpriteManager);

            var background = new CCSprite(batchnode.Texture, new RectangleF(0,0,320,480)) {Position = new PointF (160,240)};
            batchnode.Add (background);
        }
        public override void OnEnter()
        {
            base.OnEnter ();

            InitPhysics ();

            var parent = new CCSpriteBatchNode ("grossini_dance_atlas.png", 100);
            Add (parent, 0, parentnode);

            AddNewSpriteAt (new PointF (200, 200));
            ScheduleUpdate ();
        }