Lafortune BSDF and Albedo

[DanBode]

I've been going through the different primitive BSDFs to try to get a better understanding of what they each look like. The Lafortune has no documentation though. I know it can take two vectors and a float. I'm assuming that the first vector is the normal and that the float is an exponent, but I have no idea what the middle vector is. Can anyone enlighten me?

I have a similar question with the Albedo function. I know when passed a BSDF it returns the portion of reflected light. Albedo can also accept two vectors and an int. I'm guessing the int is for one of the masks defined in pbr.h, but I'm not sure what the two vectors are.

Thank you for any help,

Dan

[edward]

I have no idea what the middle vector is

Wild guess, it's the "C" vector in equation 4 of the paper:

http://www.graphics....1997/LFTG97.pdf

(some example values for it are given in Table 1

For some way cooler coefficients see:

http://www.graphics....ts/reflectance/

(look for the "coefficient" links)

[DanBode]

Oh wow. Thanks for the link! A lot of great information.

While poking around in pbr.h I noticed this line:

hitAlbedo = luminance(albedo(hitF, -hitI, hitNg, indirect_bounces));

So I'm guessing the extended call to albedo isn't something I'll be needing often for writing PBR shaders.

thanks again!

Dan