向心力

This code is illustrated in the following entry.
http://level0.kayac.com/2009/07/flashlite11sincos.php
@author 9re

by 9re 01 Jul 2009

• Related works: 3

Tags

cos cosを使わずに円運動 sin sin, sine を使わずに円運動を近似 円運動
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package 
{
	import flash.display.MovieClip;
	import flash.display.Shape;
	import flash.events.Event;
        import flash.events.TimerEvent;
        import flash.utils.Timer;	

	/**
	 * This code is illustrated in the following entry.
           http://level0.kayac.com/2009/07/flashlite11sincos.php
	 * @author 9re
	 */
	public class CircularMotion extends MovieClip
	{
		private const K:Number = 0.1;
		private const R:Number = 120;
		private var _shp:Shape;
		
		public function CircularMotion() 
		{
			_shp = new Shape();
			_shp.graphics.beginFill(0);
			_shp.graphics.drawCircle(0, 0, 15);
			_shp.graphics.endFill();
			
			_shp.x = stage.stageWidth / 2 + R;
			_shp.y = stage.stageHeight / 2;
			
			graphics.lineStyle(1, 0xff0000);
			graphics.moveTo(_shp.x, _shp.y);
			
			
			addChild(_shp);
			
			addEventListener(Event.ENTER_FRAME, enterFrameHandler);

                        var timer:Timer = new Timer(20000);
                        timer.addEventListener(TimerEvent.TIMER, function (e:TimerEvent):void
                         {
                             graphics.clear();
                             graphics.lineStyle(1, 0xff0000);
                             graphics.moveTo(_shp.x, _shp.y);
                         });
                        timer.start();
		}
		
		private function enterFrameHandler(e:Event):void 
		{
			
			_shp.x -= (_shp.y - stage.stageHeight / 2) * K;
			_shp.y += (_shp.x - stage.stageWidth / 2) * K;
			
			graphics.lineTo(_shp.x, _shp.y);
		}
		
	}
	
}