Is there an alternative to GLImageProcessing?

I'm playing around with GLImageProcessing from http://developer.apple.com/library/ios/#samplecode/GLImageProcessing/Introduction/Intro.html about image processing. The problem I'm having is that it can only apply one filter at a time. I'm trying to think of a solution but would like to know if there's already 开发者_如何学运维an alternative to this? Is there already that enables you to make multiple filters at once?

Thanks in advance.