Lights, loops, and tangent space

Graphics and GPU Programming Programming

Started by harveypekar February 09, 2008 02:01 PM

3 comments, last by harveypekar 16 years, 2 months ago

219

Author

February 09, 2008 02:01 PM

Hey everyone, I have hit a wall when trying to implement bump mapping for a small amount of lights. I would like to take advantage of the loop instruction in later shader models, but when I use bump mapping I naturally have to pass the light information between VS and FS. Is there a way to combine looping and accessing the lights info from TEXCOORDS?

PfhorSlayer

316

February 10, 2008 04:32 PM

It might be easier for you to just pass the TBN->World matrix into your pixel shader and transform the tangent space normal into world space, and do your lighting there. A constant 3 texcoords used, as opposed to n coords for n lights.

harveypekar

219

Author

February 11, 2008 04:26 PM

Wouldn't that be inefficient? I get good quality with the interpolators, and I would rather unroll the loop myself, and just take the hit in program size? How is everyone here passing their lighting information for tangent space calculations?