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
136 lines
4.4 KiB
C
136 lines
4.4 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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CCL_NAMESPACE_BEGIN
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#ifdef __OSL__
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typedef struct PhongRampBsdf {
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SHADER_CLOSURE_BASE;
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float exponent;
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ccl_private float3 *colors;
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} PhongRampBsdf;
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static_assert(sizeof(ShaderClosure) >= sizeof(PhongRampBsdf), "PhongRampBsdf is too large!");
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ccl_device float3 bsdf_phong_ramp_get_color(const float3 colors[8], float pos)
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{
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int MAXCOLORS = 8;
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float npos = pos * (float)(MAXCOLORS - 1);
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int ipos = float_to_int(npos);
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if (ipos < 0)
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return colors[0];
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if (ipos >= (MAXCOLORS - 1))
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return colors[MAXCOLORS - 1];
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float offset = npos - (float)ipos;
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return colors[ipos] * (1.0f - offset) + colors[ipos + 1] * offset;
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}
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ccl_device int bsdf_phong_ramp_setup(ccl_private PhongRampBsdf *bsdf)
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{
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bsdf->type = CLOSURE_BSDF_PHONG_RAMP_ID;
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bsdf->exponent = max(bsdf->exponent, 0.0f);
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return SD_BSDF | SD_BSDF_HAS_EVAL;
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}
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ccl_device float3 bsdf_phong_ramp_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 PhongRampBsdf *bsdf = (ccl_private const PhongRampBsdf *)sc;
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float m_exponent = bsdf->exponent;
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float cosNI = dot(bsdf->N, omega_in);
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float cosNO = dot(bsdf->N, I);
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if (cosNI > 0 && cosNO > 0) {
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// reflect the view vector
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float3 R = (2 * cosNO) * bsdf->N - I;
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float cosRI = dot(R, omega_in);
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if (cosRI > 0) {
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float cosp = powf(cosRI, m_exponent);
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float common = 0.5f * M_1_PI_F * cosp;
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float out = cosNI * (m_exponent + 2) * common;
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*pdf = (m_exponent + 1) * common;
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return bsdf_phong_ramp_get_color(bsdf->colors, cosp) * out;
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}
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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_phong_ramp_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_phong_ramp_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 PhongRampBsdf *bsdf = (ccl_private const PhongRampBsdf *)sc;
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float cosNO = dot(bsdf->N, I);
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float m_exponent = bsdf->exponent;
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if (cosNO > 0) {
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// reflect the view vector
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float3 R = (2 * cosNO) * bsdf->N - I;
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# ifdef __RAY_DIFFERENTIALS__
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*domega_in_dx = (2 * dot(bsdf->N, dIdx)) * bsdf->N - dIdx;
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*domega_in_dy = (2 * dot(bsdf->N, dIdy)) * bsdf->N - dIdy;
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# endif
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float3 T, B;
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make_orthonormals(R, &T, &B);
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float phi = M_2PI_F * randu;
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float cosTheta = powf(randv, 1 / (m_exponent + 1));
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float sinTheta2 = 1 - cosTheta * cosTheta;
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float sinTheta = sinTheta2 > 0 ? sqrtf(sinTheta2) : 0;
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*omega_in = (cosf(phi) * sinTheta) * T + (sinf(phi) * sinTheta) * B + (cosTheta)*R;
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if (dot(Ng, *omega_in) > 0.0f) {
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// common terms for pdf and eval
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float cosNI = dot(bsdf->N, *omega_in);
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// make sure the direction we chose is still in the right hemisphere
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if (cosNI > 0) {
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float cosp = powf(cosTheta, m_exponent);
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float common = 0.5f * M_1_PI_F * cosp;
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*pdf = (m_exponent + 1) * common;
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float out = cosNI * (m_exponent + 2) * common;
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*eval = bsdf_phong_ramp_get_color(bsdf->colors, cosp) * out;
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}
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}
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}
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else {
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*eval = make_float3(0.0f, 0.0f, 0.0f);
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*pdf = 0.0f;
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}
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return LABEL_REFLECT | LABEL_GLOSSY;
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}
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#endif /* __OSL__ */
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CCL_NAMESPACE_END
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