放物螺旋

r = a * sqrt(n);

by cpu_t 29 Jan 2010

Embed

/**
 * Copyright cpu_t ( http://wonderfl.net/user/cpu_t )
 * MIT License ( http://www.opensource.org/licenses/mit-license.php )
 * Downloaded from: http://wonderfl.net/c/sh8X
 */

// r = a * sqrt(n);
package {
	import flash.display.*;
	import flash.events.*;
	[SWF(width = 400, height = 400, backgroundColor = 0x000000)]
    public class FlashTest extends Sprite {
		private const size:int = 400;
		private var isStop:Boolean;
		public function FlashTest() {
			addEventListener(Event.ENTER_FRAME, enterFrameHandler);
			isStop = false;
			stage.addEventListener(MouseEvent.MOUSE_DOWN, function(e:Event):void {
				isStop = !isStop;
			});
        }
		private var n:Number = 0;
		private function enterFrameHandler(e:Event):void 
		{
			if(!isStop){
			var g:Graphics = this.graphics;
			var x:Number = size / 2 + Math.cos(n / 180 * Math.PI) * Math.sqrt(n) * 2;
			var y:Number = size / 2 + Math.sin(n / 180 * Math.PI) * Math.sqrt(n) * 2;
			g.lineStyle(-1, 0x00FF00);
			g.moveTo(x, y);
			n+=3;
			x = size / 2 + Math.cos(n / 180 * Math.PI) * Math.sqrt(n) * 2;
			y = size / 2 + Math.sin(n / 180 * Math.PI) * Math.sqrt(n) * 2;
			g.lineTo(x, y);
			}
		}
		
    }
}