c6d7bee181
Add Burley diffuse to OSL for MaterialX compatibility. It is OSL only and isn't a closure that will be looked for in SVM. Pull Request: https://projects.blender.org/blender/blender/pulls/133845
91 lines
2.7 KiB
C
91 lines
2.7 KiB
C
/* SPDX-FileCopyrightText: 2009-2025 Sony Pictures Imageworks Inc., et al. All Rights Reserved.
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* SPDX-FileCopyrightText: 2011-2025 Blender Foundation
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*
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* SPDX-License-Identifier: BSD-3-Clause
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*
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* Adapted code from Open Shading Language. */
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#pragma once
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#include "kernel/closure/bsdf_util.h"
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#include "kernel/sample/mapping.h"
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CCL_NAMESPACE_BEGIN
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#ifdef __OSL__
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typedef struct BurleyBsdf {
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SHADER_CLOSURE_BASE;
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float roughness;
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} BurleyBsdf;
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static_assert(sizeof(ShaderClosure) >= sizeof(BurleyBsdf), "BurleyBsdf is too large!");
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ccl_device Spectrum bsdf_burley_get_intensity(const float roughness,
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const float3 n,
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const float3 v,
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const float3 l)
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{
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const float NdotL = dot(n, l);
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const float NdotV = dot(n, v);
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const float fl = schlick_fresnel(NdotL);
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const float fv = schlick_fresnel(NdotV);
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const float LdotH = dot(l, normalize(l + v));
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const float F90 = 0.5f + (2.0f * roughness * LdotH * LdotH);
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return make_spectrum(M_1_PI_F * NdotL * mix(1.0f, F90, fl) * mix(1.0f, F90, fv));
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}
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ccl_device int bsdf_burley_setup(ccl_private BurleyBsdf *bsdf, const float roughness)
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{
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bsdf->type = CLOSURE_BSDF_BURLEY_ID;
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bsdf->roughness = saturatef(roughness);
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return SD_BSDF | SD_BSDF_HAS_EVAL;
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}
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ccl_device Spectrum bsdf_burley_eval(ccl_private const ShaderClosure *sc,
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const float3 wi,
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const float3 wo,
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ccl_private float *pdf)
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{
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ccl_private const BurleyBsdf *bsdf = (ccl_private const BurleyBsdf *)sc;
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const float cosNO = dot(bsdf->N, wo);
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if (cosNO > 0.0f) {
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*pdf = cosNO * M_1_PI_F;
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return bsdf_burley_get_intensity(bsdf->roughness, bsdf->N, wi, wo);
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}
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else {
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*pdf = 0.0f;
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return zero_spectrum();
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}
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}
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ccl_device int bsdf_burley_sample(ccl_private const ShaderClosure *sc,
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float3 Ng,
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float3 wi,
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float2 rand,
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ccl_private Spectrum *eval,
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ccl_private float3 *wo,
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ccl_private float *pdf)
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{
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ccl_private const BurleyBsdf *bsdf = (ccl_private const BurleyBsdf *)sc;
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float3 N = bsdf->N;
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// distribution over the hemisphere
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sample_cos_hemisphere(N, rand, wo, pdf);
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if (dot(Ng, *wo) > 0.0f) {
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*eval = bsdf_burley_get_intensity(bsdf->roughness, bsdf->N, wi, *wo);
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}
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else {
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*pdf = 0.0f;
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*eval = zero_spectrum();
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}
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return LABEL_REFLECT | LABEL_DIFFUSE;
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}
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#endif /* __OSL__ */
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CCL_NAMESPACE_END
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