package {    import flash.display.Bitmap;    import flash.display.BitmapData;    import flash.display.Sprite;    import flash.events.Event;    import flash.events.MouseEvent;    import flash.geom.Point;    [SWF(width="500",height="400")]    public class SmokeFog extends Sprite {        private var vectormap:BitmapData;        private var bmpdata:BitmapData;        private var oy:int = 0;        private var w:int;                public function SmokeFog(){            w = 200;            vectormap = new BitmapData(w, w);            bmpdata = new BitmapData(w, w, false, 0);            addChild(new Bitmap(bmpdata));            stage.addEventListener(Event.ENTER_FRAME, reset);        }                private function reset(e:Event):void {            vectormap.perlinNoise(w * .5, w * .5, 3, 1, false, true, 7, false, [new Point(0, oy++)]);            bmpdata.fillRect(bmpdata.rect, 0);            for (var y:int = 0; y < vectormap.height; y++){                for (var x:int = 0; x < vectormap.width; x++){                    var px:uint = vectormap.getPixel(x, y);                    var r:int = px >> 16 & 0xFF;                    var g:int = px >> 8 & 0xFF;                    var b:int = px & 0xFF;                    var tx:int = x + (g / 0xFF - .5) * w;                    var ty:int = y + (b / 0xFF - .5) * w;                                        if (ty < 0 || ty >= bmpdata.height || tx < 0 || tx >= bmpdata.width)                        continue;                    var col:uint = bmpdata.getPixel(tx, ty);                    col += 0x010101 * (int)(r * .2);                    if (col > 0xFFFFFF)                        col = 0xFFFFFF;                    bmpdata.setPixel(tx, ty, col);                }            }        }    }}