# Need help with PerlinNoise and masks

**URL:** <https://forum.kirupa.com/t/need-help-with-perlinnoise-and-masks/236788>\
**Category:** Uncategorized\
**Created:** [August 23, 2007, 5:23pm UTC](https://forum.kirupa.com/t/need-help-with-perlinnoise-and-masks/236788 "2007-08-23T17:23:51Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![Aquilonian](https://avatars.discourse-cdn.com/v4/letter/a/97f17d/32.png) [@Aquilonian](https://forum.kirupa.com/u/Aquilonian)\
**Post date:** [August 23, 2007, 5:23pm UTC](https://forum.kirupa.com/t/need-help-with-perlinnoise-and-masks/236788/1 "2007-08-23T17:23:51Z")

</div>

All i want is to create a Bitmap with some ramdom noise in the alpha channel and  
use it as a mask for another Bitmap but this is not working:

```php

import flash.display.BitmapData;
import flash.geom.Point;
var bitmapData_1g:BitmapData = new BitmapData(400, 400, false, 0xFF00FF00);
var bitmapData_2r:BitmapData = new BitmapData(100, 100, false, 0xFFFF0000);
var b1:Bitmap = new Bitmap(bitmapData_1g);
var b2:Bitmap = new Bitmap(bitmapData_2r);
addChild(b1);
addChild(b2);
var seed:Number = Math.floor(Math.random() * 10);
var channels:uint = BitmapDataChannel.ALPHA | BitmapDataChannel.BLUE;
bitmapData_2r.perlinNoise(100, 80, 6, seed, false, true, channels, false, null);
b1.mask = b2;

```

it works kinda of full size, i want it to be an alpha mask with the clouds  
Does anyone knows why?Tnaks