3d缓动,弹性实例

package com.ddd
{
    import flash.display.Sprite;
    import flash.events.Event;
    import flash.events.MouseEvent;

    public class Easing3D extends Sprite
    {
        private var ball:Ball;
        private var tx:Number=0;
        private var ty:Number=0;
        private var tz:Number=0;

        private var vpX:Number=stage.stageWidth / 2;
        private var vpY:Number=stage.stageHeight / 2;

        //缓动系数
        private var easing:Number=.08;
        //弹性系数 一般比缓动系数大,但都小于1
        private var fir:Number=.6;
        private var fl:Number=250;

        public function Easing3D()
        {
            super();
            init();
        }

        private function init():void
        {

            ball=new Ball;
            this.addChild(ball);

            tx=Math.random() * 500 - 250;
            ty=Math.random() * 500 - 250;
            tz=Math.random() * 500;

            this.addEventListener(Event.ENTER_FRAME, onEnterFrame)
            stage.addEventListener(MouseEvent.MOUSE_DOWN, onMouseDown)
        }

        private function onMouseDown(e:MouseEvent):void
        {
            tx=Math.random() * 500 - 250;
            ty=Math.random() * 500 - 250;
            tz=Math.random() * 500;
        }

        private function onEnterFrame(e:Event):void
        {
            var dx:Number=tx - ball.xpos;
            var dy:Number=ty - ball.ypos;
            var dz:Number=tz - ball.zpos;

            dx*=easing;
            dy*=easing;
            dz*=easing;

            ball.vx+=dx;
            ball.vy+=dy;
            ball.vz+=dz;

            ball.xpos+=ball.vx;
            ball.ypos+=ball.vy;
            ball.zpos+=ball.vz;

            ball.vx*=fir;
            ball.vy*=fir;
            ball.vz*=fir;

            if (ball.zpos > -fl)
            {

                var scale:Number=fl / (fl + ball.zpos);

                ball.scaleX=ball.scaleY=scale;

                ball.x=vpX + ball.xpos * scale;
                ball.y=vpY + ball.ypos * scale;

                ball.visible=true;
            }
            else
            {
                ball.visible=false;
            }

        }

    }
}