Sierpinski distortion

by Petri Leskinen, Espoo, Finland 5 February 2009
http://pixelero.wordpress.com

by piXelero 05 Feb 2009

Embed

package {
/*
*    by Petri Leskinen, Espoo, Finland 5 February 2009
*    http://pixelero.wordpress.com
*
*/
	import flash.display.BitmapData;
	
	import flash.display.Sprite;
	import flash.display.TriangleCulling;
	import flash.display.StageAlign;
	import flash.display.StageScaleMode;
	
	import flash.events.Event;
	import flash.events.MouseEvent;
	import flash.geom.ColorTransform;
	import flash.geom.Matrix;
	
	public class Sierpinski extends Sprite {
		
 // (new SomeImage(400,300)) as BitmapData;
		protected var w:int, 
			h:int, bmp:BitmapData,
			vertices:Vector.<Number>,
			indices:Vector.<int>,
			uvtData:Vector.<Number>,
			spr:Sprite,
			tick:Number =0.0,
			running:Boolean;
		
		protected const DEGREES120:Number = Math.PI/3;
		internal var i:int, tmp:Number;
		
		function Sierpinski() {
			init();
		}
		
		function init():void {
			w = stage.stageWidth-100;
			h = w*Math.sqrt(3)/2; // regular triangle: height=0.866*width
			bmp = new BitmapData(w,h,false,0x00);
			
			// perlinNoise for seed, could actually be any kind of image data
			bmp.perlinNoise(w,h,4,12,false,true,7,false);
			// darken the image
			bmp.draw(bmp,new Matrix(),
					new ColorTransform(0.5,0.5,0.5,1,0,0,0));
			
			addChild(spr = new Sprite());
			spr.x = 0.5*(stage.stageWidth -w); // centered
			spr.y = 0.5*(stage.stageHeight -h);
			
			stage.addEventListener(MouseEvent.CLICK, toggleAnimation);
			toggleAnimation();
		}
		
                //    a click on canvas will pause
		function toggleAnimation(e:MouseEvent=null):void {
			if (running =!running) addEventListener(Event.ENTER_FRAME, render)
			else removeEventListener(Event.ENTER_FRAME, render);
		}
		
		function render(e:Event=null):void {
			tick += 0.05;
			
			vertices = Vector.<Number>([
						  w/2,0,	//	top triangle
						  w/4,h/2,
						  0.75*w,h/2,
						  
						  w/4,h/2,	//	 Left bottom triangle 
						  0.0,h,
						  w/2,h,
						  
						  0.75*w,h/2,//	 Right bottom triangle  
						  w/2,h,
						  w,h
						 ] );
			
                        // a perspective transformation,
                        //    Math.sin in t-coordinate does the distortion
			uvtData = Vector.<Number>([
						 0.5,0.0, 1.0 +0.9*Math.sin(tmp=tick),
						 0.0,1.0, 1.0 +0.9*Math.sin(tmp+=DEGREES120),
						 1.0,1.0, 1.0 +0.9*Math.sin(tmp+=DEGREES120),
						 
						 0.5,0.0, 1.0 +0.9*Math.sin(tmp=0.5*tick) ,	
						 0.0,1.0, 1.0 +0.9*Math.sin(tmp+=DEGREES120),
						 1.0,1.0, 1.0 +0.9*Math.sin(tmp+=DEGREES120),
						 
						 0.5,0.0, 1.0 +0.9*Math.sin(tmp=0.2*tick) ,	
						 0.0,1.0, 1.0 +0.9*Math.sin(tmp+=DEGREES120),
						 1.0,1.0, 1.0 +0.9*Math.sin(tmp+=DEGREES120)
						 
					]);
			/* Vector.<Number>([	//    uvtData for a regular Sierpinski
						 0.5,0.0, 1.0 ,	
						 0.0,1.0, 1.0 ,
						 1.0,1.0, 1.0 ,
						 
						 0.5,0.0, 1.0 ,	
						 0.0,1.0, 1.0 ,
						 1.0,1.0, 1.0 ,
						 
						 0.5,0.0, 1.0 ,	
						 0.0,1.0, 1.0 ,
						 1.0,1.0, 1.0 
					]);
			*/
			indices = Vector.<int>([
						0,1,2,
						3,4,5,
						6,7,8
					]);
			
		
			var bmpTemp:BitmapData = new BitmapData(w,h,false,0xFFFFFF); // background color
			
			// Iterations, five times
			for (i = 0; i<5;i++) { 
				with (spr.graphics) {
					clear();
					beginBitmapFill( i==0 ? bmp : bmpTemp  ,
									null, 	//	no matrix
									true,	//	= repeat
									true);	
					drawTriangles(vertices, 
								  indices,
								  uvtData,
								  TriangleCulling.NONE);
					
					endFill();
				}
				bmpTemp.draw(spr);
			}
		}
		
		
		
		
		
					
		
		/////////////////////////////////

	}
}