The easiest way to use two input images is stack them on top
of each other and apply the filter as a blend mode of the top
There's a good example of applying a Pixel Bender blend mode
Bender blend mode example.. Instead of using two shape objects,
you would instead apply the pixel bender shader to the bitmaps that
If this doesn't work for you, you can always use the
ShaderJob directly and set the ShaderInput objects; however, this
can be a lot of code.