I think i’m going mad…
I’m sure I have read a presentation somewhere where somebody implemented a Perlin Noise function in a vertex shader with more than 2 octaves of noise. I think it may have been 8 (!)
anyone come across such an article ?
perhaps I dreamt it…
Check out the NVIDIA SDK there is an example for Perlin Noise in HW.
The NVSDK version codes 2 octaves. I’m so sure I’ve seen more than this elsewhere…
Perhaps I should should just have a go at it myself
Have a look at http://graphics.cs.uiuc.edu/~jch/papers/papers.html . There is a paper ‘Perlin Noise Pixel Shaders’.
On Geforce boards the algorithm uses the registercombiners and multiple passes (a lot of!).
On SGI machines it uses PixelTransfer and Pixelmap, which aren’t HW-accelerated on Geforce boards (didn’t tested myself but the author tells so).
Source code can be downloaded from here: