Brecht Van Lommel
396b407c7d
Materials now have an enum to set the emission sampling method, to be either None, Auto, Front, Back or Front & Back. This replace the previous "Multiple Importance Sample" option. Auto is the new default, and uses a heuristic to estimate the emitted light intensity to determine of the mesh should be considered as a light for sampling. Shaders sometimes have a bit of emission but treating them as a light source is not worth the memory/performance overhead. The Front/Back settings are not important yet, but will help when a light tree is added. In that case setting emission to Front only on closed meshes can help ignore emission from inside the mesh interior that does not contribute anything. Includes contributions by Brecht Van Lommel and Alaska. Ref T77889
114 lines
3.5 KiB
C++
114 lines
3.5 KiB
C++
/* SPDX-License-Identifier: BSD-3-Clause
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*
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* Adapted from Open Shading Language
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* Copyright (c) 2009-2010 Sony Pictures Imageworks Inc., et al.
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* All Rights Reserved.
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*
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* Modifications Copyright 2011-2022 Blender Foundation. */
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#pragma once
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#include "kernel/sample/mapping.h"
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CCL_NAMESPACE_BEGIN
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typedef struct DiffuseBsdf {
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SHADER_CLOSURE_BASE;
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} DiffuseBsdf;
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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(ccl_private const ShaderClosure *sc,
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const float3 I,
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const float3 omega_in,
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ccl_private float *pdf)
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{
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ccl_private const DiffuseBsdf *bsdf = (ccl_private const DiffuseBsdf *)sc;
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float3 N = bsdf->N;
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float cos_pi = fmaxf(dot(N, omega_in), 0.0f) * M_1_PI_F;
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*pdf = cos_pi;
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return make_spectrum(cos_pi);
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}
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ccl_device int bsdf_diffuse_sample(ccl_private const ShaderClosure *sc,
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float3 Ng,
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float3 I,
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float randu,
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float randv,
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ccl_private Spectrum *eval,
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ccl_private float3 *omega_in,
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ccl_private float *pdf)
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{
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ccl_private const DiffuseBsdf *bsdf = (ccl_private const DiffuseBsdf *)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, randu, randv, omega_in, pdf);
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if (dot(Ng, *omega_in) > 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(ccl_private const ShaderClosure *sc,
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const float3 I,
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const float3 omega_in,
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ccl_private float *pdf)
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{
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ccl_private const DiffuseBsdf *bsdf = (ccl_private const DiffuseBsdf *)sc;
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float3 N = bsdf->N;
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float cos_pi = fmaxf(-dot(N, omega_in), 0.0f) * M_1_PI_F;
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*pdf = cos_pi;
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return make_spectrum(cos_pi);
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}
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ccl_device int bsdf_translucent_sample(ccl_private const ShaderClosure *sc,
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float3 Ng,
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float3 I,
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float randu,
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float randv,
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ccl_private Spectrum *eval,
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ccl_private float3 *omega_in,
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ccl_private float *pdf)
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{
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ccl_private const DiffuseBsdf *bsdf = (ccl_private const DiffuseBsdf *)sc;
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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, randu, randv, omega_in, pdf);
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if (dot(Ng, *omega_in) < 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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