fitting ofxFx's Gray Scott Reaction Diffusion model into a shape

Hi everyone,

I’m trying to fit a shader from Patricio’s ofxFx addon into a shape. The shader works by drawing a shape that acts like a seed and starts growing in an organic micro organism-like way. This goes on until the entire allocated FBO is filled.

I would really like to use this shader to fill out a shape based on blobs from a kinect. But so far I’m out of luck, masking is possible, but then it won’t show the nice edges created by the shader as you see on the edges of the FBO. Could anyone give me some pointers in how to go about doing this?