Æliens

    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:animation_ch15_Ball3D = new animation_ch15_Ball3D(15);
      balls.push(ball);
      ball.xpos = Math.random() * 200 - 100;
      ball.ypos = Math.random() * 200 - 100;
      ball.zpos = Math.random() * 200 - 100;
      addChild(ball);
     }
     addEventListener(Event.ENTER_FRAME, onEnterFrame);
    }
   

    private function onEnterFrame(event:Event):void
    {
     var angleY:Number = (mouseX - vpX) * .001;
     for(var i:uint = 0; i < numBalls; i++)
     {
      var ball:animation_ch15_Ball3D = balls[i];
      rotateY(ball, angleY);
     }
     sortZ();
    }
  

    
    private function rotateY(ball:animation_ch15_Ball3D, angleY:Number):void
    {
     var cosY:Number = Math.cos(angleY);
     var sinY:Number = Math.sin(angleY);
     
     var x1:Number = ball.xpos * cosY - ball.zpos * sinY;
     var z1:Number = ball.zpos * cosY + ball.xpos * sinY;
     
     ball.xpos = x1;
     ball.zpos = z1;
     
     
     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;
     }
    }
   

    private function sortZ():void
    {
     balls.sortOn("zpos", Array.DESCENDING | Array.NUMERIC);
     for(var i:uint = 0; i < numBalls; i++)
     {
      var ball:animation_ch15_Ball3D = balls[i];
      setChildIndex(ball, i);
     }
    }
   }
  }