cocos creator自动转向

    // use this for initialization
    onLoad: function () {
        this.height = 640;
        this.width = 1136;
        this.lastPoint = cc.p(0,this.height);
        
    },
    //
    update: function (dt) {
        var curPoint = this.node.parent.getPosition();
        if (this.curPoint == this.lastPoint)  //  
        {  
            return ;  
        }  
        var dx = curPoint.x - this.lastPoint.x;  
        var dy = curPoint.y - this.lastPoint.y;  
        var angle = Math.atan(dx/dy);  
        var degree = angle*180/Math.PI;  
        if (degree) {
            if(dy<0){  
                degree += 180;  
            }  
            cc.log(degree);
            this.node.rotation = degree;  
        }
    
        this.lastPoint = curPoint;  //保存当前的坐标给下一轮刷新使用  
    },