Add color82 to generalized_schlick_bsdf #1727
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Generalized Schlick BSDF with white color82: Generalized Schlick BSDF with gold color82: Generalized Schlick BSDF with blue color82: |
| vec3 mx_fresnel_hoffman_schlick(float cosTheta, vec3 F0, vec3 F82, vec3 F90, float exponent) | ||
| { | ||
| const float COS_THETA_MAX = 1.0 / 7.0; | ||
| const float COS_THETA_FACTOR = 1.0 / (COS_THETA_MAX * pow(1.0 - COS_THETA_MAX, 6.0)); |
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For consistency you could use the added mx_pow6 function here as well.
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That's a good note, @niklasharrysson, and I had wanted to use the approach you describe, but some GLSL compilers require that a const value be defined entirely in terms of constant expressions.
So I actually see a compile-time error in my GLSL environment if I use the non-const mx_pow6 as a sub-expression of COS_THETA_FACTOR.
For simplicity, I went back to using the built-in pow function, but there may be a more clever way of notating mx_pow6 so that it can also be used in this way.
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Ah, that's fine, this was just a tiny thing I noticed.
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This looks good to me @jstone-lucasfilm, and I only had a nitpick comment above. |
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This changelist adds a color82 input to the generalized_schlick_bsdf node in MaterialX, with a full implementation in hardware shading languages (GLSL/MSL/ESSL) and simple fallback behavior in closure-based shading languages (OSL/MDL). The real-time implementation is based on Naty Hoffman's generalization of Adobe Fresnel (https://renderwonk.com/publications/wp-generalization-adobe/gen-adobe.pdf), which is visually consistent with previous versions of generalized_schlick_bsdf when color82 is left at its default setting.
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AcademySoftwareFoundation:dev_1.39
This changelist adds a color82 input to the generalized_schlick_bsdf node in MaterialX, with a full implementation in hardware shading languages (GLSL/MSL/ESSL) and simple fallback behavior in closure-based shading languages (OSL/MDL).
The real-time implementation is based on Naty Hoffman's generalization of Adobe Fresnel (https://renderwonk.com/publications/wp-generalization-adobe/gen-adobe.pdf), which is visually consistent with previous versions of generalized_schlick_bsdf when color82 is left at its default setting.