flash on 2010-4-26

/**
 * Copyright 084 ( http://wonderfl.net/user/084 )
 * MIT License ( http://www.opensource.org/licenses/mit-license.php )
 * Downloaded from: http://wonderfl.net/c/3NAO
 */

package {
import flash.display.Sprite;
import flash.events.Event;
	public class Spring1 extends Sprite {
		private var ball:Ball;
		private var spring:Number = 0.1;
		private var targetX:Number = stage.stageWidth / 2;
		private var vx:Number = 0;
		
		public function Spring1() {
			init();
		}
		
		private function init():void {
			ball = new Ball();
			addChild(ball);
			ball.y = stage.stageHeight / 2;
			addEventListener(Event.ENTER_FRAME, onEnterFrame);
		}
		private function onEnterFrame(event:Event):void {
			var dx:Number = targetX -ball.x;
			var ax:Number = dx * spring;
			vx += ax;
			ball.x += vx;
		}
	}
}
import flash.display.Sprite;
	class Ball extends Sprite {
		public var radius:Number;
		public var color:uint;
		public var vx:Number = 0;
		public var vy:Number = 0;
			
		public function Ball(radius:Number = 40,color:uint=0xff0000 ):void {
			this.radius = radius;
			this.color = color;
		    init();
		}
		public function init():void {
			graphics.beginFill(color);
			graphics.drawCircle(0, 0, radius);
			graphics.endFill();
		}
	}