Essentially the same way.
The only difference is that you're calculating vertexes (i.e. points (and their attributes) in 3D space) in place of fragments (2D pixels).
Have a look at the mesh.shatter example in the examples folder.
Wesley, this was the first sense of this thread.
Is there a way to access to the vertex program in the gen world ?
I already checked mesh.matter and indeed, the 2 jit.gen used aren't related to vertex programming.
if you want to manipule geometry, jit.gen is the way to go. It's not using a vertex program though. jit.gl.pix is using GLSL for pixel processing, which happens to have a vertex program as well because that's how GLSL works, but by design it's not accessible for manipulation. If there's something you need to do in the vertex program, you will need to do it some other way.