>2 Octaves of Noise in a vertex shader ?

[pocketmoon]

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...

Rob J.

[AdrianD]

Check out the NVIDIA SDK there is an example for Perlin Noise in HW.

[pocketmoon]

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 http://www.opengl.org/discussion_boards/ubb/wink.gif

[kon]

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:
http://graphics.cs.uiuc.edu/~jch/mpnoise.zip

kon