Forked from:: arithma's swarms

persistent swarms

...
@author ...

forked:3
favorite:2
lines:76
license : MIT License
modified : 2010-03-04 17:46:49

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package 
{
	import flash.display.Bitmap;
	import flash.display.BitmapData;
	import flash.display.MovieClip;
	import flash.display.Sprite;
	import flash.events.Event;
	import flash.geom.ColorTransform;
	import flash.geom.Point;
	
	/**
	 * ...
	 * @author ...
	 */
	public class Main extends Sprite 
	{
		public const N:int = 200;
		public var points:Array;
		public var bmp:Bitmap;
		public var bmpdata:BitmapData;
		public var sprite:Sprite;
		
		public function Main():void 
		{
			if (stage) init();
			else addEventListener(Event.ADDED_TO_STAGE, init);
		}
		
		private function init(e:Event = null):void 
		{
			removeEventListener(Event.ADDED_TO_STAGE, init);
			// entry point
			stage.frameRate = 120;
			bmpdata = new BitmapData(stage.stageWidth, stage.stageHeight);
			bmp = new Bitmap(bmpdata);
			addChild(bmp);
			
			sprite = new Sprite();
			
			points = new Array();
			
			for (var i:int = 0; i < N; i++) {
				var arrw:MovieClip = new MovieClip();
				arrw.x = Math.random() * stage.stageWidth;
				arrw.y = Math.random() * stage.stageHeight;
				arrw.graphics.beginFill(Math.random() * 0xFFFFFF);
				arrw.graphics.moveTo( -Math.sin(Math.PI / 10)*10, (.5 - Math.cos(Math.PI / 10)) * 10);
				arrw.graphics.lineTo( +Math.sin(Math.PI / 10)*10, (.5 - Math.cos(Math.PI / 10)) * 10);
				arrw.graphics.lineTo( 0, .5 * 10);
				arrw.graphics.endFill();
				arrw.rotation = Math.atan2(arrw.vy, arrw.vx) * 180 / Math.PI - 90;
				sprite.addChild(arrw);
				points.push(arrw);
			}
			
			addEventListener(Event.ENTER_FRAME, frame);
		}
		
		private function frame(e:Event = null):void {
			for each(var arrw:MovieClip in points) {
				var vx:Number = 0;
				var vy:Number = 0;
				for each(var other:MovieClip in points) {
					if (other != arrw) {
						var dist2:Number =	(arrw.x - other.x) * (arrw.x - other.x) +
											(arrw.y - other.y) * (arrw.y - other.y);
											
						var dist:Number = Math.sqrt(dist2);
						vx += 1 * (Math.exp(-dist*.05)) * (other.x - arrw.x) / dist;
						vy += 1 * (Math.exp(-dist*.05)) * (other.y - arrw.y) / dist;
						
						vx += -20 * (Math.exp(-dist2*.005)) * (other.x - arrw.x) / dist;
						vy += -20 * (Math.exp(-dist2*.005)) * (other.y - arrw.y) / dist;
						
						vx -= .15 * (Math.exp( -dist2 * .001)) * (other.y - arrw.y);
						vy += .15 * (Math.exp( -dist2 * .001)) * (other.x - arrw.x);
					}
				}
				arrw.x += .2*vx;
				arrw.y += .2*vy;
				arrw.rotation = Math.atan2(vy, vx) * 180 / Math.PI - 90;
			}
			
			var result:Sprite = new Sprite();
			result.addChild(bmp);
			bmp.transform.colorTransform = new ColorTransform(.99, .99, .99, 1, .01);
			result.addChild(sprite);
			bmpdata.draw(result);
			addChild(bmp);
			bmp.transform.colorTransform = new ColorTransform();
		}
		
	}
	
}

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