113 lines
3.4 KiB
C
113 lines
3.4 KiB
C
/* SPDX-FileCopyrightText: 2009-2010 Sony Pictures Imageworks Inc., et al. All Rights Reserved.
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* SPDX-FileCopyrightText: 2011-2022 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/types.h"
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#include "kernel/sample/mapping.h"
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CCL_NAMESPACE_BEGIN
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struct DiffuseBsdf {
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SHADER_CLOSURE_BASE;
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};
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static_assert(sizeof(ShaderClosure) >= sizeof(DiffuseBsdf), "DiffuseBsdf is too large!");
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/* DIFFUSE */
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ccl_device int bsdf_diffuse_setup(ccl_private DiffuseBsdf *bsdf)
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{
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bsdf->type = CLOSURE_BSDF_DIFFUSE_ID;
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return SD_BSDF | SD_BSDF_HAS_EVAL;
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}
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ccl_device Spectrum bsdf_diffuse_eval(const ccl_private 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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const ccl_private DiffuseBsdf *bsdf = (const ccl_private DiffuseBsdf *)sc;
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const float3 N = bsdf->N;
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const float cosNO = fmaxf(dot(N, wo), 0.0f) * M_1_PI_F;
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*pdf = cosNO;
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return make_spectrum(cosNO);
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}
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ccl_device int bsdf_diffuse_sample(const ccl_private ShaderClosure *sc,
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const float3 Ng,
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const float3 wi,
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const 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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const ccl_private DiffuseBsdf *bsdf = (const ccl_private DiffuseBsdf *)sc;
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const 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 = make_spectrum(*pdf);
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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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/* TRANSLUCENT */
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ccl_device int bsdf_translucent_setup(ccl_private DiffuseBsdf *bsdf)
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{
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bsdf->type = CLOSURE_BSDF_TRANSLUCENT_ID;
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return SD_BSDF | SD_BSDF_HAS_EVAL | SD_BSDF_HAS_TRANSMISSION;
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}
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ccl_device Spectrum bsdf_translucent_eval(const ccl_private 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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const ccl_private DiffuseBsdf *bsdf = (const ccl_private DiffuseBsdf *)sc;
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const float3 N = bsdf->N;
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const float cosNO = fmaxf(-dot(N, wo), 0.0f) * M_1_PI_F;
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*pdf = cosNO;
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return make_spectrum(cosNO);
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}
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ccl_device int bsdf_translucent_sample(const ccl_private ShaderClosure *sc,
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const float3 Ng,
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const float3 wi,
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const 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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const ccl_private DiffuseBsdf *bsdf = (const ccl_private DiffuseBsdf *)sc;
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const float3 N = bsdf->N;
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// we are viewing the surface from the right side - send a ray out with cosine
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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) {
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*eval = make_spectrum(*pdf);
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}
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else {
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*pdf = 0;
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*eval = zero_spectrum();
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}
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return LABEL_TRANSMIT | LABEL_DIFFUSE;
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}
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CCL_NAMESPACE_END
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