package
  {
          import flash.display.Sprite;
          import flash.display.StageAlign;
          import flash.display.StageScaleMode;
          import flash.events.Event;
          
          public class @ax-animation-ch06-Friction2 extends Sprite
          {
                  private var ball:animation_ch06_Ball;
                  private var vx:Number = 0;
                  private var vy:Number = 0;
                  private var friction:Number = 0.9;
                  
                  public function @ax-animation-ch06-Friction2()
                  {
                          init();
                  }
                  
                  private function init():void
                  {
                          stage.scaleMode = StageScaleMode.NO_SCALE;
                          stage.align=StageAlign.TOP_LEFT;
  
                          ball = new animation_ch06_Ball();
                          ball.x = stage.stageWidth / 2;
                          ball.y = stage.stageHeight / 2;
                          vx = Math.random() * 10 - 5;
                          vy = Math.random() * 10 - 5;
                          addChild(ball);
                          addEventListener(Event.ENTER_FRAME, onEnterFrame);
                  }
                  
                  private function onEnterFrame(event:Event):void
                  {
                          vx *= friction;
                          vy *= friction;
                          ball.x += vx;
                          ball.y += vy;
                  }
          }
  }