Switching from lambert diffuse to oren nayar diffuse !

Development Rendering
1

[FONT=&amp]Hey so i’m doing a game mostly made in sand and concrete so oren nayar is way better then the default lambert, in 4.17 i was able to switch from lambert to oren nayar with this fonction in the shadingmodels.ush : [FONT=&amp]

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[FONT=&amp]But this fonction isn’t here anymore in 4.22 how do i switch to oren nayar now ? thanks in advance :slight_smile: !

(Oren nayar is still in the BRDF library)

2

Bump.

I would like to know this as well.

3

Would like to know this too, since it seems to have changed in recent versions.

4

Well, it seems that they split it up between ShadingModels.ush and BRDF.ush.

On BRDF you’ll find the three methods defined as functions. I havne’t tried yet but ShadingModels inherit from BRDF so you probably should change the six calls to this function.


float3 Diffuse_OrenNayar( float3 DiffuseColor, float Roughness, float NoV, float NoL, float VoH )
{
    float a = Roughness * Roughness;
    float s = a;// / ( 1.29 + 0.5 * a );
    float s2 = s * s;
    float VoL = 2 * VoH * VoH - 1;        // double angle identity
    float Cosri = VoL - NoV * NoL;
    float C1 = 1 - 0.5 * s2 / (s2 + 0.33);
    float C2 = 0.45 * s2 / (s2 + 0.09) * Cosri * ( Cosri >= 0 ? rcp( max( NoL, NoV ) ) : 1 );
    return DiffuseColor / PI * ( C1 + C2 ) * ( 1 + Roughness * 0.5 );
}
5

You need to change the DefaultLitBxDF function in ShadingModels to use the Diffuse_OrenNayar diffuse model. You’ll need to add in the missing variables that Oren-Nayar needs to call it correctly.