No real masking with BitmapDataUnlimited

August 14th, 2008 • 3 comments ActionScript, Flash
Tags: AS3, BitmapData

It would have been too cool if there weren’t any limits with BitmapDataUnlimited, but unfortunately I have to tell you that there are limits.
For a recent project I needed an alpha mask greater than 2880px. The problem is that applying an alpha mask requires the cacheAsBitmap property of both the mask and the masked Sprite to be true, but for DisplayObjects greater than 2880px you can’t activate Bitmap caching or at least it’s ignored.

I have tried to apply a filter to the Sprites which normally forces Bitmap caching but it didn’t work out either. The next idea was to use BlendMode.ALPHA instead of a real mask but still no success. So the only working solution for the moment is to render a Bitmap and place it in front of the other layers. very oldschool but it works.

If you know a better solution please let me know.