#### Standard Pipeline: Reducing specular halo in UnityStandardBRDF.cginc ####

Hi everyone,

I like to reduce the specular halo in the standard render pipeline. I tried to search in the CGIncludes\UnityStandardBRDF.cginc but was not found any value in

~ SmithJointGGXVisibilityTerm (nl, nv, roughness);
~ GGXTerm (nh, roughness);

to reduce the smooth halo. I tried also to change the previous values NL NV, but no chance.


Here is an example what I like to archive.
Currently:



I think the specular light would be calculated in real-time based on roughness and is not ploted through any cube or texture. Does anyone know where this specular light is calculated ?

Thanks a lot...

 

That "specular halo" is the GGX specular lobe shape. If you don't want it, and you're manually modifying the built in shader files already, find the

#define UNITY_BRDF_GGX 1

in UnityStandardConfig.cginc and set that to 0. Or if you have a custom shader, add this to your shader:

Code (csharp):

1. #ifdef UNITY_BRDF_GGX
2. #undef UNITY_BRDF_GGX
3. #endif
4. #define UNITY_BRDF_GGX 0

That should make that shader use the original blinn-phong lobe, which is much sharper.

 

Thanks a lot.

I currently use the ggxTern and ndfBlin like this: (and some other small changes)

Code (CSharp):

1. #if UNITY_BRDF_GGX
2.     // GGX with roughtness to 0 would mean no specular at all, using max(roughness, 0.002) here to match HDrenderloop roughtness remapping.
3.     roughness = max(roughness, 0.002);
4.     float V = SmithJointGGXVisibilityTerm(nl, nv, roughness);
5.     float D;
6.     if(smoothness > 0.95) {
7.         D = NDFBlinnPhongNormalizedTerm(nh, PerceptualRoughnessToSpecPower(perceptualRoughness)) * 0.01;
8.     } else {
9.         D = GGXTerm(nh, roughness);
10.     }
11. #else
12. ....
13.  

Gives me in my opinion better more overall shiny results. (left side shpere reflections)


+ Is there any possibility to optimize the content of the if statement
+ or the GGXTerm.

I thought about to lerping the result of D:

Code (CSharp):

1.    float D = GGXTerm(nh, roughness);
2.     if(smoothness > 0.95) {
3.       D = lerp (-2,1,D);
4.      }

But the result does not looks well.

 

Not really, no. Those two functions are quite different, so most likely you're always going to be calculating both going that route.