It uses a 3d noise map to determin the xy coordinates and over time it shifts the texture by going through the values for each vert. It looks like it uses the enviroment map (skybox cube) to texture it.

I don't know that much about these shaders or how much you can do in them but there dosn't seem to be an obvious way to do what you want with a texture.

I certianly don't know of a algorithm that will produce a hex grid. Technically it should be possible since you have distance of the the current pixel to the impact point but maybe there is way to use the coordinates?

It would also be originating at the impact point if you uses that distance code. But im not good enough at math to work out how to do it either.

I can do silly little circles though!

Damn now im all interested and stuff...