AS3运动学基础-正弦运动2

package 
{
	import flash.display.Sprite;
	import flash.events.Event;
	import flash.events.MouseEvent;
	import flash.filters.BlurFilter;
	import flash.filters.GlowFilter;
	
	/**
	 * ...
	 * @author hacker47
	 */
	
	 [SWF(backgroundColor="0x000000")]
	public class Main3 extends Sprite 
	{
		private var angle:Number = 0;
		private var speed:Number = .05;
		private var range:Number = 200;
		private var vx:Number = 2;
		
		private var startx:Number=100;
		private var starty:Number=300;
		
		private var canvas:Sprite;
		private var ball:Ball;
		
		public function Main3():void 
		{
			if (stage) init();
			else addEventListener(Event.ADDED_TO_STAGE, init);
		}
		
		private function init(e:Event = null):void 
		{
			removeEventListener(Event.ADDED_TO_STAGE, init);
			
			canvas = new Sprite();
			addChild(canvas);
			canvas.filters = [new BlurFilter(10, 10, 1)];
			
			ball = new Ball();
			addChild(ball);
			ball.x = startx;
			ball.y = starty;
			// entry point
			canvas.graphics.lineStyle(2,0xffffff,1,true);
			canvas.graphics.moveTo(startx, starty);
			addEventListener(Event.ENTER_FRAME, function running(e:Event):void {
				var dx:Number = startx + vx;
				var sin:Number = Math.sin(angle);
				if (sin > 0) sin *= -1;
				var dy:Number = starty+sin * range;
				angle += speed;
				
				canvas.graphics.lineTo(dx, dy);
				canvas.filters = [new BlurFilter(5*Math.abs(sin), 5*Math.abs(sin), 1),new GlowFilter(0xff0000,Math.abs(sin),5*Math.abs(sin),5*Math.abs(sin))];
				
				startx = dx;
				if ((angle * 180 / Math.PI) > 180) {
					range-= 30;
					angle = 0;
					trace("一个周期");
					if (range < 0) {
						removeEventListener(Event.ENTER_FRAME, running);
					}
				}
				
				ball.x = startx;
			    ball.y = dy;
			});
		}
		
	}
	
}

package  
{
	import flash.display.Sprite;
	
	/**
	 * ...
	 * @author hacker47
	 */
	public class Ball extends Sprite 
	{
		private var _radius:Number = 20;
		
		public function Ball() 
		{
			this.graphics.lineStyle(1);
			this.graphics.moveTo(0, 0);
			this.graphics.beginFill(0xCCCCCC);
			this.graphics.drawCircle(_radius >> 1, _radius >> 1, _radius);
			this.graphics.endFill();
		}
	}

}