ff:x3 lightning

by matacat 01 Apr 2010

Tags

effect lightning 闪电特效
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/**
 * Copyright matacat ( http://wonderfl.net/user/matacat )
 * MIT License ( http://www.opensource.org/licenses/mit-license.php )
 * Downloaded from: http://wonderfl.net/c/6l9G
 */

// forked from hashito's forked from: forked from: lightning
// forked from okoi's forked from: lightning
// forked from kiyobu's lightning
package
{
	import flash.display.Bitmap;
	import flash.display.BitmapData;
	import flash.display.Graphics;
	import flash.display.Shape;
	import flash.display.Sprite;
	import flash.events.Event;
	import flash.filters.BlurFilter;
	import flash.filters.GlowFilter;
	import flash.geom.ColorTransform;
	import flash.geom.Point;
	
	[SWF(width = "465", height = "465", backgroundColor = "0x000000", frameRate = "30")]
	
	public class FlashTest extends Sprite
	{
		private const LIGHT_LENGTH:int = 6;
		private const LIGHT_NUM:int    = 25;
		private const PATH_LENGTH:int  = (LIGHT_LENGTH + 1) * LIGHT_NUM << 1;
		
		private var light:Bitmap;
		private var lines:Shape;
		private var cache:BitmapData;
		
		private var ct:ColorTransform;
		private var d:Function;
		private var a:Function;
		private var o:Point;
		private var f:BlurFilter;
		private var g:Graphics;
		
		private var coms:Vector.<int>;
		private var path:Vector.<Number>;
		private var sin:Vector.<Number>;
		private var cos:Vector.<Number>;
		
		public function FlashTest()
		{
			light = new Bitmap( new BitmapData(stage.stageWidth, stage.stageHeight, false, 0) );
			addChild( light );
			
			lines         = new Shape();
			lines.filters = [ new GlowFilter(0xC080FF, 1, 64, 64, 4) ];
			
			cache = light.bitmapData.clone();
			
			ct = new ColorTransform(1, 1, 1, 1, -30, -32, -28);
			d  = cache.draw;
			a  = light.bitmapData.applyFilter;
			o  = new Point();
			f  = new BlurFilter(2, 2);
			g  = lines.graphics;
			
			coms = new Vector.<int>(PATH_LENGTH >> 1);
			for (var i:int = 0, l:int = coms.length; i < l; ) {
				coms[i++] = 1;
				for (var j:int = 0; j < LIGHT_LENGTH; j++) coms[i++] = 2;
			}
			path = new Vector.<Number>(PATH_LENGTH);
			
			sin  = new Vector.<Number>(LIGHT_NUM);
			cos  = new Vector.<Number>(LIGHT_NUM);
			var pi2:Number = Math.PI * 2;
			for (i = 0; i < LIGHT_NUM; i++) {
				sin[i] = Math.sin( i / LIGHT_NUM * pi2 );
				cos[i] = Math.cos( i / LIGHT_NUM * pi2 );
			}
			
			addEventListener(Event.ENTER_FRAME, loop);
		}
		
		public function loop(e:Event):void
		{
			lightning();
			d(light, null, ct);
			d(lines);
			a(cache, cache.rect, o, f);
		}
		
		public function lightning():void
		{
			g.clear();
			g.lineStyle(Math.random() * 2, 0xE0D0FF);
			
			for (var i:int = 0, j:int = 0; i < PATH_LENGTH; j++) {
				var xx:Number = 0;
				var yy:Number = 0;
				
				path[i++] = mouseX;
				path[i++] = mouseY;
				
				for (var l:int = 0; l < LIGHT_LENGTH ; l++) {
					xx += Math.random() * 20 * (Math.random() > 0.5 ? 1 : -1);
					yy += Math.random() * 80 ;
					
					path[i++] = cos[j] * xx - sin[j] * yy + mouseX;
					path[i++] = sin[j] * xx + cos[j] * yy + mouseY;
				}
				
			}
			
			g.drawPath(coms, path);
		}
	}
}