package {
    import flash.display.Sprite;
    import flash.events.Event;
    import flash.display.StageAlign;
    import flash.display.StageScaleMode;
 
    public class MultiBounce3D extends Sprite {
        private var balls:Array;
        private var numBalls:uint=20;
        private var fl:Number=250;
        private var vpX:Number=stage.stageWidth/2;
        private var vpY:Number=stage.stageHeight/2;
        private var top:Number=-120;
        private var bottom:Number=120;
        private var left:Number=-120;
        private var right:Number=120;
        private var front:Number=120;
        private var back:Number=-120;
        public function MultiBounce3D() {
            init();
        }
        private function init():void {
            stage.align=StageAlign.TOP_LEFT;
            stage.scaleMode=StageScaleMode.NO_SCALE;
            balls = new Array();
            for (var i:uint = 0; i < numBalls; i++) {
                var ball:Ball3D=new Ball3D(15,Math.random()*0xffffff);
                balls.push(ball);
                ball.vx=Math.random()*10-5;
                ball.vy=Math.random()*10-5;
                ball.vz=Math.random()*10-5;
                addChild(ball);
            }
            addEventListener(Event.ENTER_FRAME, onEnterFrame);
        }
        private function onEnterFrame(event:Event):void {
            vpX=stage.stageWidth/2;
            vpY=stage.stageHeight/2;
            graphics.clear();
            for (var i:uint = 0; i < numBalls; i++) {
                var ball:Ball3D=balls[i];
                move(ball);
            }
            sortZ();
        }
 
        function sortZ():void {
            balls.sortOn("zpos", Array.DESCENDING | Array.NUMERIC);
            for (var i:uint = 0; i < numBalls; i++) {
                var ball:Ball3D=balls[i];
                setChildIndex(ball, i);
            }
        }
 
        private function move(ball:Ball3D):void {
            var radius:Number=ball.radius;
            ball.xpos+=ball.vx;
            ball.ypos+=ball.vy;
            ball.zpos+=ball.vz;
 
            //6边界检测
            if (ball.xpos+radius>right) {
                ball.xpos=right-radius;
                ball.vx*=-1;
            } else if (ball.xpos - radius < left) {
                ball.xpos=left+radius;
                ball.vx*=-1;
            }
            if (ball.ypos+radius>bottom) {
                ball.ypos=bottom-radius;
                ball.vy*=-1;
            } else if (ball.ypos - radius < top) {
                ball.ypos=top+radius;
                ball.vy*=-1;
            }
            if (ball.zpos+radius>front) {
                ball.zpos=front-radius;
                ball.vz*=-1;
            } else if (ball.zpos - radius < back) {
                ball.zpos=back+radius;
                ball.vz*=-1;
            }
 
            //转换化2D坐标
            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;
            }
 
            //辅助线
            graphics.lineStyle(1,0xccccff);
            graphics.moveTo(0,stage.stageHeight/2);
            graphics.lineTo(stage.stageWidth,stage.stageHeight/2);
            graphics.lineTo(stage.stageWidth-15,stage.stageHeight/2-8);
            graphics.moveTo(stage.stageWidth,stage.stageHeight/2);
            graphics.lineTo(stage.stageWidth-15,stage.stageHeight/2+8);
 
            graphics.moveTo(0,stage.stageHeight);
            graphics.lineTo(stage.stageWidth,0);
            graphics.lineTo(stage.stageWidth-15,2);
            graphics.moveTo(stage.stageWidth,0);
            graphics.lineTo(stage.stageWidth-6,13);
 
            graphics.moveTo(stage.stageWidth/2,0);
            graphics.lineTo(stage.stageWidth/2,stage.stageHeight);
            graphics.lineTo(stage.stageWidth/2-8,stage.stageHeight-15);
            graphics.moveTo(stage.stageWidth/2,stage.stageHeight);
            graphics.lineTo(stage.stageWidth/2+8,stage.stageHeight-15);
            graphics.lineStyle(1,0xff99ff);
            graphics.moveTo(vpX,vpY);
            graphics.lineTo(ball.x,ball.y);
        }
    }
}