Reverse Engineering Noise

Trying to find the algorithm that generates noise.

This sketch shows how "random" values repeat depending on their offset in the bitmap.

by Quasimondo 04 Oct 2010

Tags

bitmapData noise 楽しい動き
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/**
 * Copyright Quasimondo ( http://wonderfl.net/user/Quasimondo )
 * MIT License ( http://www.opensource.org/licenses/mit-license.php )
 * Downloaded from: http://wonderfl.net/c/oMXM
 */

package {
    import flash.display.Bitmap;
    import flash.display.BitmapData;
    import flash.display.Sprite;
    public class AnalyzeNoise extends Sprite {
        public function AnalyzeNoise() {
            test();
        }
        
        private function test():void
        {
            
            var b:BitmapData = new BitmapData( 64 * 16, 64 * 16,  false,0 );
            var n:BitmapData = new BitmapData( 256, 1, false, 0 );
            var gridSize:int = 40;   
            var p:int;
            var offset:int = 0;
            for ( var yy:int = 0; yy < 16; yy++ )
            {
                for ( var xx:int = 0; xx < 16; xx++ )
                {
                    var seed:int = 1;
                    for ( var y:int = 0; y < gridSize; y++ )
                    {
                        for ( var x:int = 0; x < gridSize; x++ )
                        {
                            n.noise( seed++,0,255,4,false);    
                            b.setPixel( xx * gridSize + x, yy * gridSize + y, ( p = (n.getPixel( offset, 0 ) & 0xff ) ) | ( p << 16 ) | ( p << 8));
                        }
                    }
                    offset++;
                }
            }
            
            addChild( new Bitmap( b ) );
        }

    }
}