UDK - Math - Rho Formula (any tips)?

Ace-Angel

Hey to all,

I have been trying for the better part of the day to find the formula for Rho, in a simple manner that would make me avoid having to make a manual texture lookup for it in UDK.

However, most of the them use math which I'm unable to translate in UDK or didn't quite grasp.

Does anyone have the HLSL/shader formula for Rho or point me as to where to find it? This is what I found so far for HLSL:

rho = dot(light.Direction, L)

Cheers.

ambershee

Rho is just a character, it doesn't have any meaning other than what you apply to it. What is it supposed to represent? I can't really work it out from your snippet - it's usually something like Density or Radius.

Ace-Angel

Argh, really? Guess I misunderstood it then...

I was reading up on nvidia's GPU Gem's webpage: http://http.developer.nvidia.com/GPUGems3/gpugems3_ch14.html

I guess I mistook Beckmann's texture for Rho, since I saw other sites referring to the code as Rho.

Ooops, sorry about the silly topic, red face.

ambershee

IIRC, in that example 'Rho' is a constant that represents something like specular intensity, for which you probably could (and probably should) indeed use a texture