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SL-17766: PBR: Add V_GGX references

meow-7.2.2
Ptolemy 2022-08-23 04:17:12 -07:00
parent 459faa8f7f
commit 0079dcd6a4
1 changed files with 18 additions and 0 deletions
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18
indra/newview/app_settings/shaders/class1/deferred/deferredUtil.glsl
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@ -392,17 +392,35 @@ float D_GGX( float nh, float alphaRough )
}
// NOTE: This is different from the GGX texture
// See:
// Real Time Rendering, 4th Edition
// Page 341
// Equation 9.43
// Also see:
// https://google.github.io/filament/Filament.md.html#materialsystem/specularbrdf/geometricshadowing(specularg)
// 4.4.2 Geometric Shadowing (specular G)
float V_GGX( float nl, float nv, float alphaRough )
{
#if 1
// Note: When roughness is zero, has discontuinity in the bottom hemisphere
float rough2 = alphaRough * alphaRough;
float ggxv = nl * sqrt(nv * nv * (1.0 - rough2) + rough2);
float ggxl = nv * sqrt(nl * nl * (1.0 - rough2) + rough2);
float ggx = ggxv + ggxl;
if (ggx > 0.0)
{
return 0.5 / ggx;
}
return 0.0;
#else
// See: smithVisibility_GGXCorrelated, V_SmithCorrelated, etc.
float rough2 = alphaRough * alphaRough;
float ggxv = nl * sqrt(nv * (nv - rough2 * nv) + rough2);
float ggxl = nv * sqrt(nl * (nl - rough2 * nl) + rough2);
return 0.5 / (ggxv + ggxl);
#endif
}
// NOTE: Assumes a hard-coded IOR = 1.5