linear transformation

/**
 * Copyright 883108 ( http://wonderfl.net/user/883108 )
 * MIT License ( http://www.opensource.org/licenses/mit-license.php )
 * Downloaded from: http://wonderfl.net/c/3nIg
 */

package{
        //一次変換を使って円周運動を表現する
	import flash.display.MovieClip;
	import flash.display.Sprite;
	
	import flash.events.Event;
	import flash.events.TimerEvent;
	
	import flash.utils.Timer;
		
	public class UzumakiTest extends MovieClip{
		private var _ball:Sprite;
		private var _base:Sprite;
		
		private var _radius = 200;
		private var _radian:Number = Math.PI * 2 / 32;
		
		private var _timer:Timer;
		
		public function UzumakiTest(){
			init();
		}
		
		private function init():void{
			_base = new Sprite;
			_base.x = stage.stageWidth / 2;
			_base.y = stage.stageHeight / 2;
			_base.graphics.clear();
			_base.graphics.beginFill(0x000000);
			_base.graphics.drawRect(-stage.stageWidth/2,-stage.stageHeight/2,stage.stageWidth, stage.stageHeight);
			_base.graphics.endFill();
                        addChild(_base);
			
			_base.addChild(_ball = new Sprite);
			_ball.graphics.clear();
			_ball.graphics.beginFill(0xffccee);
			_ball.graphics.drawCircle(0, 0, 20);
			_ball.graphics.endFill();
			
			_ball.x = _radius;
			_ball.y = 0;
			
			_timer = new Timer(33);
			_timer.addEventListener(TimerEvent.TIMER, loop);
			_timer.start();
			
		}
		
		private function loop($event:TimerEvent):void{
			var tmpX:Number = _ball.x;
			var tmpY:Number = _ball.y;
			_ball.x = tmpX * Math.cos(_radian) - tmpY * Math.sin(_radian);
			_ball.y = tmpX * Math.sin(_radian) + tmpY * Math.cos(_radian);
			
			//trace(tmpX * Math.cos(_radian) - tmpY * Math.sin(_radian), tmpX * Math.sin(_radian) + tmpY * Math.cos(_radian));
		}
	}
	
}