fbc884d2a8
Currently, the `eval` and `pdf` are not explicitly set to zero when a BSDF sample is invalid (e.g., below the upper hemisphere), when calling `bsdf_sample` or `bsdf_eval`. It is assumed that `eval` and `pdf` are set to zero before these functions are called, which can cause problems if not. This patch fixes this potential problem by explicitly setting `eval` and `pdf` to zero when the sampled direction is invalid. I also added a sanity check if `eval` and `pdf` are valid (i.e., >= 0.f). The check is activated when build in debug mode and with the `WITH_CYCLES_DEBUG` set to `ON`. Reviewed By: brecht, sergey Differential Revision: https://developer.blender.org/D14776
150 lines
5.1 KiB
C
150 lines
5.1 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 float3 bsdf_diffuse_eval_reflect(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_float3(cos_pi, cos_pi, cos_pi);
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}
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ccl_device float3 bsdf_diffuse_eval_transmit(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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*pdf = 0.0f;
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return make_float3(0.0f, 0.0f, 0.0f);
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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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float3 dIdx,
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float3 dIdy,
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float randu,
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float randv,
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ccl_private float3 *eval,
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ccl_private float3 *omega_in,
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ccl_private float3 *domega_in_dx,
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ccl_private float3 *domega_in_dy,
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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_float3(*pdf, *pdf, *pdf);
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#ifdef __RAY_DIFFERENTIALS__
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// TODO: find a better approximation for the diffuse bounce
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*domega_in_dx = (2 * dot(N, dIdx)) * N - dIdx;
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*domega_in_dy = (2 * dot(N, dIdy)) * N - dIdy;
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#endif
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}
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else {
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*pdf = 0.0f;
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*eval = make_float3(0.0f, 0.0f, 0.0f);
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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;
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}
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ccl_device float3 bsdf_translucent_eval_reflect(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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*pdf = 0.0f;
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return make_float3(0.0f, 0.0f, 0.0f);
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}
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ccl_device float3 bsdf_translucent_eval_transmit(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_float3(cos_pi, cos_pi, 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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float3 dIdx,
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float3 dIdy,
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float randu,
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float randv,
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ccl_private float3 *eval,
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ccl_private float3 *omega_in,
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ccl_private float3 *domega_in_dx,
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ccl_private float3 *domega_in_dy,
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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_float3(*pdf, *pdf, *pdf);
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#ifdef __RAY_DIFFERENTIALS__
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// TODO: find a better approximation for the diffuse bounce
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*domega_in_dx = -((2 * dot(N, dIdx)) * N - dIdx);
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*domega_in_dy = -((2 * dot(N, dIdy)) * N - dIdy);
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#endif
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}
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else {
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*pdf = 0;
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*eval = make_float3(0.0f, 0.0f, 0.0f);
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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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