求助!!等距tiledmap获取tiled问题

例如我把鼠标放在(0,0)位置
怎么透过屏幕坐标取到(0,0)这个位置的tiled对象?

getTilePos(posInPixel): cc.Vec2 {
    var mapSize = this.tiledMap.node.getContentSize();
    var tileSize = this.tiledMap.getTileSize();
    var x = Math.floor(posInPixel.x / tileSize.width);
    var y = Math.floor((mapSize.height - posInPixel.y) / tileSize.height);
    return cc.v2(x, y);
}