跟踪导弹

function(targetPosition){

    // 让物体朝目标移动的方法

    var speed = 5;

    var targetPoint = targetPosition;

    var thisPoint = cc.p(this.x, this.y);

    //求两点的差值，事实上就是两点的坐标相减

    var delta = cc.pSub(targetPoint, thisPoint);

    // 求当前对象和目标两点间的距离

    var distance = cc.pDistance(thisPoint, targetPoint);

    // 计算行走后的点xy坐标

    var x2 = thisPoint.x +speed *delta.x /distance;

    var y2 = thisPoint.y + speed *delta.y/distance;

    if(100>=distance){

        return true;

    }

    // 改动当前对象的位置

    var newPosition = cc.p(x2, y2);

    this.setPosition(newPosition);

    // 旋转对应的角度

    var x1 = thisPoint.x;

    var y1 = thisPoint.y;

    var deltaRotation = 90-Math.atan2(y2-y1,x2-x1)*180/Math.PI;

    this.setRotation(deltaRotation);

    return false;

}效果请看游戏地址 http://www.seraph-fd.cn/games/1/index.html