[AS3]as3的时间问题time源代码

[AS3]as3的时间问题time源代码

显示代码 
package { 
    import flash.display.Sprite; 
    import flash.events.Event; 
    import flash.geom.Point; 
 
    public class MouseAvoider extends Sprite { 
 
        private const SPRING:Number=0.1;//弹性系数 
        private const FRICTION:Number=0.9;//摩擦系数 
        private const FEAR_DISTANCE:Number=150;//安全距离(小于该距离则发生躲避行为) 
        private const MAX_AVOID_FORCE:uint=10;//最大躲避速度 
 
        private var _destinationPoint:Point;//目标静止点(鼠标远离该物体时，物体最终会静止的坐标点) 
        private var _speed:Point=new Point(0,0);//速度矢量(_speed.x即相当于vx,_speed.y即相当于vy) 
 
        public function MouseAvoider():void { 
            drawStuff(); 
        } 
 
        private function drawStuff():void { 
            //默认先画一个半径为10的圆 
            graphics.beginFill(Math.random() * 0xFFFFFF); 
            //graphics.beginFill(0xFFFFFF); 
            graphics.drawCircle(0, 0, 5); 
            graphics.endFill(); 
        } 
 
        //只写属性(设置目标点) 
        public function set destinationPoint(value:Point):void { 
            _destinationPoint=value; 
            addEventListener(Event.ENTER_FRAME, enterFrameHandler); 
        } 
         
         
        protected function enterFrameHandler(e:Event):void { 
            moveToDestination();//先移动到目标点 
            avoidMouse();//躲避鼠标 
            applyFriction();//应用摩擦力 
            updatePosition();//更新位置 
        } 
 
        //以弹性运动方式移动到目标点 
        private function moveToDestination():void { 
            _speed.x += (_destinationPoint.x - x) * SPRING; 
            _speed.y += (_destinationPoint.y - y) * SPRING; 
        } 
 
        //躲避鼠标 
        private function avoidMouse():void { 
            var currentPosition:Point=new Point(x,y);//确定当前位置 
            var mousePosition:Point=new Point(stage.mouseX,stage.mouseY);//确实鼠标位置 
            var distance:uint=Point.distance(currentPosition,mousePosition);//计算鼠标与当前位置的距离 
             
            //如果低于安全距离 
            if (distance<FEAR_DISTANCE) { 
                var force:Number = (1 - distance / FEAR_DISTANCE) * MAX_AVOID_FORCE;//计算(每单位时间的)躲避距离--即躲避速率 
                var gamma:Number=Math.atan2(currentPosition.y- mousePosition.y,currentPosition.x- mousePosition.x);//计算鼠标所在位置与当前位置所成的夹角 
                 
                var avoidVector:Point=Point.polar(force,gamma);//将极坐标转换为普通(笛卡尔)坐标--其实相当于vx = force*Math.cos(gamma),vy = force*Math.sin(gamma) 
                 
                //加速 躲避逃开 
                _speed.x+=avoidVector.x; 
                _speed.y+=avoidVector.y; 
            } 
        } 
         
        //应用摩擦力 
        private function applyFriction():void { 
 
            _speed.x*=FRICTION; 
            _speed.y*=FRICTION; 
        } 
         
        //最终更新自身的位置 
        private function updatePosition():void { 
 
            x+=_speed.x; 
            y+=_speed.y; 
        } 
 
    } 
} 

[AS3]as3的时间问题time源代码