使Sprite朝向旋转到鼠标点击方向

var mySprite = new cc.Sprite(res.paotai_png);mySprite.setPosition(cc.winSize.width>>1,100);this.addChild(mySprite);var that = this;var listener = cc.EventListener.create({    event:cc.EventListener.TOUCH_ONE_BY_ONE,    swallowTouches: true,    onTouchBegan: function (touch, event) {        var locationInNode = touch.getLocation();        var o = locationInNode.x - mySprite.x;        var a = locationInNode.y - mySprite.y;        var at = Math.atan(o / a) * 180 / Math.PI;        if (a < 0) {            if (o < 0){                at = 180 + Math.abs(at);            }else{                at = 180 - Math.abs(at);            }        }        //at -= 90;                           //横板设置        var rotate = cc.rotateTo(0.2, at);   //缓动        mySprite.runAction(rotate)    }});cc.eventManager.addListener(listener, this);