package
{
 import flash.display.Sprite;
 import flash.events.Event;
 
 public class animation_ch03_Wave2 extends Sprite {
  private var angle:Number = 0;
  private var centerY:Number = 200;
  private var range:Number = 50;
  private var xspeed:Number = 1;
  private var yspeed:Number = .05;
  private var xpos:Number;
  private var ypos:Number;
  
  public function animation_ch03_Wave2() {
   init();
  }
//@ init(s)
  private function init():void {
   xpos = 0;
   graphics.lineStyle(1, 0, 1);
   graphics.moveTo(0, centerY);
   addEventListener(Event.ENTER_FRAME, onEnterFrame);
  }
//@ frame(s)
  public function onEnterFrame(event:Event):void {
   xpos += xspeed;
   angle += yspeed;
   ypos = centerY + Math.sin(angle) * range;
   graphics.lineTo(xpos, ypos);
  }
 }
}