if(zpos > -fl)
     {
      var scale:Number = fl / (fl + zpos);
      ball.scaleX = ball.scaleY = scale;
      ball.x = vpX + xpos * scale;
      ball.y = vpY + ypos * scale;
      ball.visible = true;
     }
     else
     {
      ball.visible = false;
     }
    }
   }
  }