package
  {
          import flash.display.Sprite;
          import flash.display.StageAlign;
          import flash.display.StageScaleMode;
          import flash.events.Event;
          import flash.events.MouseEvent;
          
          public class @ax-animation-ch07-DragAndMove2 extends Sprite
          {
                  private var ball:animation_ch07_Ball;
                  private var vx:Number;
                  private var vy:Number;
                  private var bounce:Number = -0.7;
                  private var gravity:Number = .5;
                  
                  public function @ax-animation-ch07-DragAndMove2()
                  {
                          init();
                  }
                  
                  private function init():void
                  {
                          stage.scaleMode = StageScaleMode.NO_SCALE;
                          stage.align=StageAlign.TOP_LEFT;
  
                          ball = new animation_ch07_Ball();
                          ball.x = stage.stageWidth / 2;
                          ball.y = stage.stageHeight / 2;
                          vx = Math.random() * 10 - 5;
                          vy = -10;
                          addChild(ball);
                          ball.addEventListener(MouseEvent.MOUSE_DOWN, onMouseDown);
                          addEventListener(Event.ENTER_FRAME, onEnterFrame);
                  }
                  
                  private function onEnterFrame(event:Event):void
                  {
                          vy += gravity;
                          ball.x += vx;
                          ball.y += vy;
                          var left:Number = 0;
                          var right:Number = stage.stageWidth;
                          var top:Number = 0;
                          var bottom:Number = stage.stageHeight;
                          
                          if(ball.x + ball.radius > right)
                          {
                                  ball.x = right - ball.radius;
                                  vx *= bounce;
                          }
                          else if(ball.x - ball.radius < left)
                          {
                                  ball.x = left + ball.radius;
                                  vx *= bounce;
                          }
                          if(ball.y + ball.radius > bottom)
                          {
                                  ball.y = bottom - ball.radius;
                                  vy *= bounce;
                          }
                          else if(ball.y - ball.radius < top)
                          {
                                  ball.y = top + ball.radius;
                                  vy *= bounce;
                          }
                  }
                  
                  private function onMouseDown(event:MouseEvent):void
                  {
                          //vx = 0;
                          //vy = 0;
                          stage.addEventListener(MouseEvent.MOUSE_UP, onMouseUp);
                          ball.startDrag();
                          removeEventListener(Event.ENTER_FRAME, onEnterFrame);
                  }
                  
                  private function onMouseUp(event:MouseEvent):void
                  {
                          stage.removeEventListener(MouseEvent.MOUSE_UP, onMouseUp);
                          ball.stopDrag();
                          addEventListener(Event.ENTER_FRAME, onEnterFrame);
                  }
          }
  }