953 lines
30 KiB
C++
953 lines
30 KiB
C++
/* SPDX-License-Identifier: Apache-2.0
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* Copyright 2011-2022 Blender Foundation */
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/* Functions to evaluate shaders and use the resulting shader closures. */
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#pragma once
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#include "kernel/closure/alloc.h"
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#include "kernel/closure/bsdf.h"
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#include "kernel/closure/bsdf_util.h"
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#include "kernel/closure/emissive.h"
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#include "kernel/film/accumulate.h"
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#include "kernel/svm/svm.h"
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#ifdef __OSL__
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# include "kernel/osl/shader.h"
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#endif
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CCL_NAMESPACE_BEGIN
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/* Merging */
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#if defined(__VOLUME__)
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ccl_device_inline void shader_merge_volume_closures(ccl_private ShaderData *sd)
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{
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/* Merge identical closures to save closure space with stacked volumes. */
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for (int i = 0; i < sd->num_closure; i++) {
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ccl_private ShaderClosure *sci = &sd->closure[i];
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if (sci->type != CLOSURE_VOLUME_HENYEY_GREENSTEIN_ID) {
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continue;
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}
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for (int j = i + 1; j < sd->num_closure; j++) {
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ccl_private ShaderClosure *scj = &sd->closure[j];
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if (sci->type != scj->type) {
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continue;
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}
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ccl_private const HenyeyGreensteinVolume *hgi = (ccl_private const HenyeyGreensteinVolume *)
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sci;
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ccl_private const HenyeyGreensteinVolume *hgj = (ccl_private const HenyeyGreensteinVolume *)
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scj;
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if (!(hgi->g == hgj->g)) {
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continue;
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}
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sci->weight += scj->weight;
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sci->sample_weight += scj->sample_weight;
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int size = sd->num_closure - (j + 1);
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if (size > 0) {
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for (int k = 0; k < size; k++) {
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scj[k] = scj[k + 1];
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}
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}
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sd->num_closure--;
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kernel_assert(sd->num_closure >= 0);
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j--;
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}
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}
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}
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ccl_device_inline void shader_copy_volume_phases(ccl_private ShaderVolumePhases *ccl_restrict
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phases,
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ccl_private const ShaderData *ccl_restrict sd)
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{
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phases->num_closure = 0;
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for (int i = 0; i < sd->num_closure; i++) {
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ccl_private const ShaderClosure *from_sc = &sd->closure[i];
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ccl_private const HenyeyGreensteinVolume *from_hg =
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(ccl_private const HenyeyGreensteinVolume *)from_sc;
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if (from_sc->type == CLOSURE_VOLUME_HENYEY_GREENSTEIN_ID) {
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ccl_private ShaderVolumeClosure *to_sc = &phases->closure[phases->num_closure];
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to_sc->weight = from_sc->weight;
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to_sc->sample_weight = from_sc->sample_weight;
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to_sc->g = from_hg->g;
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phases->num_closure++;
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if (phases->num_closure >= MAX_VOLUME_CLOSURE) {
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break;
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}
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}
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}
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}
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#endif /* __VOLUME__ */
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ccl_device_inline void shader_prepare_surface_closures(KernelGlobals kg,
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ConstIntegratorState state,
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ccl_private ShaderData *sd,
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const uint32_t path_flag)
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{
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/* Filter out closures. */
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if (kernel_data.integrator.filter_closures) {
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if (kernel_data.integrator.filter_closures & FILTER_CLOSURE_EMISSION) {
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sd->closure_emission_background = zero_float3();
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}
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if (kernel_data.integrator.filter_closures & FILTER_CLOSURE_DIRECT_LIGHT) {
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sd->flag &= ~SD_BSDF_HAS_EVAL;
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}
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if (path_flag & PATH_RAY_CAMERA) {
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for (int i = 0; i < sd->num_closure; i++) {
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ccl_private ShaderClosure *sc = &sd->closure[i];
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if ((CLOSURE_IS_BSDF_DIFFUSE(sc->type) &&
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(kernel_data.integrator.filter_closures & FILTER_CLOSURE_DIFFUSE)) ||
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(CLOSURE_IS_BSDF_GLOSSY(sc->type) &&
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(kernel_data.integrator.filter_closures & FILTER_CLOSURE_GLOSSY)) ||
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(CLOSURE_IS_BSDF_TRANSMISSION(sc->type) &&
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(kernel_data.integrator.filter_closures & FILTER_CLOSURE_TRANSMISSION))) {
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sc->type = CLOSURE_NONE_ID;
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sc->sample_weight = 0.0f;
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}
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else if ((CLOSURE_IS_BSDF_TRANSPARENT(sc->type) &&
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(kernel_data.integrator.filter_closures & FILTER_CLOSURE_TRANSPARENT))) {
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sc->type = CLOSURE_HOLDOUT_ID;
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sc->sample_weight = 0.0f;
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sd->flag |= SD_HOLDOUT;
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}
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}
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}
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}
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/* Defensive sampling.
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*
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* We can likely also do defensive sampling at deeper bounces, particularly
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* for cases like a perfect mirror but possibly also others. This will need
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* a good heuristic. */
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if (INTEGRATOR_STATE(state, path, bounce) + INTEGRATOR_STATE(state, path, transparent_bounce) ==
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0 &&
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sd->num_closure > 1) {
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float sum = 0.0f;
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for (int i = 0; i < sd->num_closure; i++) {
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ccl_private ShaderClosure *sc = &sd->closure[i];
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if (CLOSURE_IS_BSDF_OR_BSSRDF(sc->type)) {
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sum += sc->sample_weight;
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}
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}
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for (int i = 0; i < sd->num_closure; i++) {
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ccl_private ShaderClosure *sc = &sd->closure[i];
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if (CLOSURE_IS_BSDF_OR_BSSRDF(sc->type)) {
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sc->sample_weight = max(sc->sample_weight, 0.125f * sum);
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}
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}
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}
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/* Filter glossy.
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*
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* Blurring of bsdf after bounces, for rays that have a small likelihood
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* of following this particular path (diffuse, rough glossy) */
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if (kernel_data.integrator.filter_glossy != FLT_MAX
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#ifdef __MNEE__
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&& !(INTEGRATOR_STATE(state, path, mnee) & PATH_MNEE_VALID)
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#endif
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) {
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float blur_pdf = kernel_data.integrator.filter_glossy *
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INTEGRATOR_STATE(state, path, min_ray_pdf);
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if (blur_pdf < 1.0f) {
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float blur_roughness = sqrtf(1.0f - blur_pdf) * 0.5f;
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for (int i = 0; i < sd->num_closure; i++) {
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ccl_private ShaderClosure *sc = &sd->closure[i];
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if (CLOSURE_IS_BSDF(sc->type)) {
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bsdf_blur(kg, sc, blur_roughness);
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}
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}
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}
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}
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}
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/* BSDF */
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ccl_device_inline bool shader_bsdf_is_transmission(ccl_private const ShaderData *sd,
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const float3 omega_in)
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{
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return dot(sd->N, omega_in) < 0.0f;
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}
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ccl_device_forceinline bool _shader_bsdf_exclude(ClosureType type, uint light_shader_flags)
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{
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if (!(light_shader_flags & SHADER_EXCLUDE_ANY)) {
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return false;
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}
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if (light_shader_flags & SHADER_EXCLUDE_DIFFUSE) {
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if (CLOSURE_IS_BSDF_DIFFUSE(type)) {
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return true;
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}
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}
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if (light_shader_flags & SHADER_EXCLUDE_GLOSSY) {
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if (CLOSURE_IS_BSDF_GLOSSY(type)) {
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return true;
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}
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}
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if (light_shader_flags & SHADER_EXCLUDE_TRANSMIT) {
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if (CLOSURE_IS_BSDF_TRANSMISSION(type)) {
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return true;
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}
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}
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return false;
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}
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ccl_device_inline float _shader_bsdf_multi_eval(KernelGlobals kg,
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ccl_private ShaderData *sd,
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const float3 omega_in,
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const bool is_transmission,
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ccl_private const ShaderClosure *skip_sc,
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ccl_private BsdfEval *result_eval,
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float sum_pdf,
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float sum_sample_weight,
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const uint light_shader_flags)
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{
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/* This is the veach one-sample model with balance heuristic,
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* some PDF factors drop out when using balance heuristic weighting. */
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for (int i = 0; i < sd->num_closure; i++) {
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ccl_private const ShaderClosure *sc = &sd->closure[i];
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if (sc == skip_sc) {
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continue;
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}
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if (CLOSURE_IS_BSDF_OR_BSSRDF(sc->type)) {
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if (CLOSURE_IS_BSDF(sc->type) && !_shader_bsdf_exclude(sc->type, light_shader_flags)) {
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float bsdf_pdf = 0.0f;
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float3 eval = bsdf_eval(kg, sd, sc, omega_in, is_transmission, &bsdf_pdf);
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if (bsdf_pdf != 0.0f) {
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bsdf_eval_accum(result_eval, sc->type, eval * sc->weight);
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sum_pdf += bsdf_pdf * sc->sample_weight;
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}
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}
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sum_sample_weight += sc->sample_weight;
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}
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}
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return (sum_sample_weight > 0.0f) ? sum_pdf / sum_sample_weight : 0.0f;
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}
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#ifndef __KERNEL_CUDA__
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ccl_device
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#else
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ccl_device_inline
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#endif
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float
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shader_bsdf_eval(KernelGlobals kg,
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ccl_private ShaderData *sd,
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const float3 omega_in,
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const bool is_transmission,
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ccl_private BsdfEval *bsdf_eval,
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const uint light_shader_flags)
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{
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bsdf_eval_init(bsdf_eval, CLOSURE_NONE_ID, zero_float3());
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return _shader_bsdf_multi_eval(
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kg, sd, omega_in, is_transmission, NULL, bsdf_eval, 0.0f, 0.0f, light_shader_flags);
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}
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/* Randomly sample a BSSRDF or BSDF proportional to ShaderClosure.sample_weight. */
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ccl_device_inline ccl_private const ShaderClosure *shader_bsdf_bssrdf_pick(
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ccl_private const ShaderData *ccl_restrict sd, ccl_private float *randu)
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{
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int sampled = 0;
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if (sd->num_closure > 1) {
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/* Pick a BSDF or based on sample weights. */
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float sum = 0.0f;
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for (int i = 0; i < sd->num_closure; i++) {
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ccl_private const ShaderClosure *sc = &sd->closure[i];
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if (CLOSURE_IS_BSDF_OR_BSSRDF(sc->type)) {
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sum += sc->sample_weight;
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}
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}
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float r = (*randu) * sum;
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float partial_sum = 0.0f;
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for (int i = 0; i < sd->num_closure; i++) {
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ccl_private const ShaderClosure *sc = &sd->closure[i];
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if (CLOSURE_IS_BSDF_OR_BSSRDF(sc->type)) {
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float next_sum = partial_sum + sc->sample_weight;
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if (r < next_sum) {
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sampled = i;
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/* Rescale to reuse for direction sample, to better preserve stratification. */
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*randu = (r - partial_sum) / sc->sample_weight;
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break;
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}
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partial_sum = next_sum;
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}
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}
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}
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return &sd->closure[sampled];
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}
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/* Return weight for picked BSSRDF. */
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ccl_device_inline float3
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shader_bssrdf_sample_weight(ccl_private const ShaderData *ccl_restrict sd,
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ccl_private const ShaderClosure *ccl_restrict bssrdf_sc)
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{
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float3 weight = bssrdf_sc->weight;
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if (sd->num_closure > 1) {
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float sum = 0.0f;
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for (int i = 0; i < sd->num_closure; i++) {
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ccl_private const ShaderClosure *sc = &sd->closure[i];
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if (CLOSURE_IS_BSDF_OR_BSSRDF(sc->type)) {
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sum += sc->sample_weight;
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}
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}
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weight *= sum / bssrdf_sc->sample_weight;
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}
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return weight;
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}
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/* Sample direction for picked BSDF, and return evaluation and pdf for all
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* BSDFs combined using MIS. */
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ccl_device int shader_bsdf_sample_closure(KernelGlobals kg,
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ccl_private ShaderData *sd,
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ccl_private const ShaderClosure *sc,
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float randu,
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float randv,
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ccl_private BsdfEval *bsdf_eval,
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ccl_private float3 *omega_in,
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ccl_private differential3 *domega_in,
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ccl_private float *pdf)
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{
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/* BSSRDF should already have been handled elsewhere. */
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kernel_assert(CLOSURE_IS_BSDF(sc->type));
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int label;
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float3 eval = zero_float3();
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*pdf = 0.0f;
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label = bsdf_sample(kg, sd, sc, randu, randv, &eval, omega_in, domega_in, pdf);
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if (*pdf != 0.0f) {
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bsdf_eval_init(bsdf_eval, sc->type, eval * sc->weight);
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if (sd->num_closure > 1) {
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const bool is_transmission = shader_bsdf_is_transmission(sd, *omega_in);
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float sweight = sc->sample_weight;
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*pdf = _shader_bsdf_multi_eval(
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kg, sd, *omega_in, is_transmission, sc, bsdf_eval, *pdf * sweight, sweight, 0);
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}
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}
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return label;
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}
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ccl_device float shader_bsdf_average_roughness(ccl_private const ShaderData *sd)
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{
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float roughness = 0.0f;
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float sum_weight = 0.0f;
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for (int i = 0; i < sd->num_closure; i++) {
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ccl_private const ShaderClosure *sc = &sd->closure[i];
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if (CLOSURE_IS_BSDF(sc->type)) {
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/* sqrt once to undo the squaring from multiplying roughness on the
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* two axes, and once for the squared roughness convention. */
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float weight = fabsf(average(sc->weight));
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roughness += weight * sqrtf(safe_sqrtf(bsdf_get_roughness_squared(sc)));
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sum_weight += weight;
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}
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}
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return (sum_weight > 0.0f) ? roughness / sum_weight : 0.0f;
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}
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ccl_device float3 shader_bsdf_transparency(KernelGlobals kg, ccl_private const ShaderData *sd)
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{
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if (sd->flag & SD_HAS_ONLY_VOLUME) {
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return one_float3();
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}
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else if (sd->flag & SD_TRANSPARENT) {
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return sd->closure_transparent_extinction;
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}
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else {
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return zero_float3();
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}
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}
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ccl_device void shader_bsdf_disable_transparency(KernelGlobals kg, ccl_private ShaderData *sd)
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{
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if (sd->flag & SD_TRANSPARENT) {
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for (int i = 0; i < sd->num_closure; i++) {
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ccl_private ShaderClosure *sc = &sd->closure[i];
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if (sc->type == CLOSURE_BSDF_TRANSPARENT_ID) {
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sc->sample_weight = 0.0f;
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sc->weight = zero_float3();
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}
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}
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sd->flag &= ~SD_TRANSPARENT;
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}
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}
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ccl_device float3 shader_bsdf_alpha(KernelGlobals kg, ccl_private const ShaderData *sd)
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{
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float3 alpha = one_float3() - shader_bsdf_transparency(kg, sd);
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alpha = max(alpha, zero_float3());
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alpha = min(alpha, one_float3());
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return alpha;
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}
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ccl_device float3 shader_bsdf_diffuse(KernelGlobals kg, ccl_private const ShaderData *sd)
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{
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float3 eval = zero_float3();
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for (int i = 0; i < sd->num_closure; i++) {
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ccl_private const ShaderClosure *sc = &sd->closure[i];
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if (CLOSURE_IS_BSDF_DIFFUSE(sc->type) || CLOSURE_IS_BSSRDF(sc->type))
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eval += sc->weight;
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}
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return eval;
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}
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ccl_device float3 shader_bsdf_glossy(KernelGlobals kg, ccl_private const ShaderData *sd)
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{
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float3 eval = zero_float3();
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for (int i = 0; i < sd->num_closure; i++) {
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ccl_private const ShaderClosure *sc = &sd->closure[i];
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if (CLOSURE_IS_BSDF_GLOSSY(sc->type))
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eval += sc->weight;
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}
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return eval;
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}
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ccl_device float3 shader_bsdf_transmission(KernelGlobals kg, ccl_private const ShaderData *sd)
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{
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float3 eval = zero_float3();
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for (int i = 0; i < sd->num_closure; i++) {
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ccl_private const ShaderClosure *sc = &sd->closure[i];
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if (CLOSURE_IS_BSDF_TRANSMISSION(sc->type))
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eval += sc->weight;
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}
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return eval;
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}
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ccl_device float3 shader_bsdf_average_normal(KernelGlobals kg, ccl_private const ShaderData *sd)
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{
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float3 N = zero_float3();
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for (int i = 0; i < sd->num_closure; i++) {
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ccl_private const ShaderClosure *sc = &sd->closure[i];
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if (CLOSURE_IS_BSDF_OR_BSSRDF(sc->type))
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N += sc->N * fabsf(average(sc->weight));
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}
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return (is_zero(N)) ? sd->N : normalize(N);
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}
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ccl_device float3 shader_bsdf_ao(KernelGlobals kg,
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ccl_private const ShaderData *sd,
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const float ao_factor,
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ccl_private float3 *N_)
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{
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float3 eval = zero_float3();
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float3 N = zero_float3();
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for (int i = 0; i < sd->num_closure; i++) {
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ccl_private const ShaderClosure *sc = &sd->closure[i];
|
|
|
|
if (CLOSURE_IS_BSDF_DIFFUSE(sc->type)) {
|
|
ccl_private const DiffuseBsdf *bsdf = (ccl_private const DiffuseBsdf *)sc;
|
|
eval += sc->weight * ao_factor;
|
|
N += bsdf->N * fabsf(average(sc->weight));
|
|
}
|
|
}
|
|
|
|
*N_ = (is_zero(N)) ? sd->N : normalize(N);
|
|
return eval;
|
|
}
|
|
|
|
#ifdef __SUBSURFACE__
|
|
ccl_device float3 shader_bssrdf_normal(ccl_private const ShaderData *sd)
|
|
{
|
|
float3 N = zero_float3();
|
|
|
|
for (int i = 0; i < sd->num_closure; i++) {
|
|
ccl_private const ShaderClosure *sc = &sd->closure[i];
|
|
|
|
if (CLOSURE_IS_BSSRDF(sc->type)) {
|
|
ccl_private const Bssrdf *bssrdf = (ccl_private const Bssrdf *)sc;
|
|
float avg_weight = fabsf(average(sc->weight));
|
|
|
|
N += bssrdf->N * avg_weight;
|
|
}
|
|
}
|
|
|
|
return (is_zero(N)) ? sd->N : normalize(N);
|
|
}
|
|
#endif /* __SUBSURFACE__ */
|
|
|
|
/* Constant emission optimization */
|
|
|
|
ccl_device bool shader_constant_emission_eval(KernelGlobals kg,
|
|
int shader,
|
|
ccl_private float3 *eval)
|
|
{
|
|
int shader_index = shader & SHADER_MASK;
|
|
int shader_flag = kernel_tex_fetch(__shaders, shader_index).flags;
|
|
|
|
if (shader_flag & SD_HAS_CONSTANT_EMISSION) {
|
|
*eval = make_float3(kernel_tex_fetch(__shaders, shader_index).constant_emission[0],
|
|
kernel_tex_fetch(__shaders, shader_index).constant_emission[1],
|
|
kernel_tex_fetch(__shaders, shader_index).constant_emission[2]);
|
|
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
/* Background */
|
|
|
|
ccl_device float3 shader_background_eval(ccl_private const ShaderData *sd)
|
|
{
|
|
if (sd->flag & SD_EMISSION) {
|
|
return sd->closure_emission_background;
|
|
}
|
|
else {
|
|
return zero_float3();
|
|
}
|
|
}
|
|
|
|
/* Emission */
|
|
|
|
ccl_device float3 shader_emissive_eval(ccl_private const ShaderData *sd)
|
|
{
|
|
if (sd->flag & SD_EMISSION) {
|
|
return emissive_simple_eval(sd->Ng, sd->I) * sd->closure_emission_background;
|
|
}
|
|
else {
|
|
return zero_float3();
|
|
}
|
|
}
|
|
|
|
/* Holdout */
|
|
|
|
ccl_device float3 shader_holdout_apply(KernelGlobals kg, ccl_private ShaderData *sd)
|
|
{
|
|
float3 weight = zero_float3();
|
|
|
|
/* For objects marked as holdout, preserve transparency and remove all other
|
|
* closures, replacing them with a holdout weight. */
|
|
if (sd->object_flag & SD_OBJECT_HOLDOUT_MASK) {
|
|
if ((sd->flag & SD_TRANSPARENT) && !(sd->flag & SD_HAS_ONLY_VOLUME)) {
|
|
weight = one_float3() - sd->closure_transparent_extinction;
|
|
|
|
for (int i = 0; i < sd->num_closure; i++) {
|
|
ccl_private ShaderClosure *sc = &sd->closure[i];
|
|
if (!CLOSURE_IS_BSDF_TRANSPARENT(sc->type)) {
|
|
sc->type = NBUILTIN_CLOSURES;
|
|
}
|
|
}
|
|
|
|
sd->flag &= ~(SD_CLOSURE_FLAGS - (SD_TRANSPARENT | SD_BSDF));
|
|
}
|
|
else {
|
|
weight = one_float3();
|
|
}
|
|
}
|
|
else {
|
|
for (int i = 0; i < sd->num_closure; i++) {
|
|
ccl_private const ShaderClosure *sc = &sd->closure[i];
|
|
if (CLOSURE_IS_HOLDOUT(sc->type)) {
|
|
weight += sc->weight;
|
|
}
|
|
}
|
|
}
|
|
|
|
return weight;
|
|
}
|
|
|
|
/* Surface Evaluation */
|
|
|
|
template<uint node_feature_mask, typename ConstIntegratorGenericState>
|
|
ccl_device void shader_eval_surface(KernelGlobals kg,
|
|
ConstIntegratorGenericState state,
|
|
ccl_private ShaderData *ccl_restrict sd,
|
|
ccl_global float *ccl_restrict buffer,
|
|
uint32_t path_flag,
|
|
bool use_caustics_storage = false)
|
|
{
|
|
/* If path is being terminated, we are tracing a shadow ray or evaluating
|
|
* emission, then we don't need to store closures. The emission and shadow
|
|
* shader data also do not have a closure array to save GPU memory. */
|
|
int max_closures;
|
|
if (path_flag & (PATH_RAY_TERMINATE | PATH_RAY_SHADOW | PATH_RAY_EMISSION)) {
|
|
max_closures = 0;
|
|
}
|
|
else {
|
|
max_closures = use_caustics_storage ? CAUSTICS_MAX_CLOSURE : kernel_data.max_closures;
|
|
}
|
|
|
|
sd->num_closure = 0;
|
|
sd->num_closure_left = max_closures;
|
|
|
|
#ifdef __OSL__
|
|
if (kg->osl) {
|
|
if (sd->object == OBJECT_NONE && sd->lamp == LAMP_NONE) {
|
|
OSLShader::eval_background(kg, state, sd, path_flag);
|
|
}
|
|
else {
|
|
OSLShader::eval_surface(kg, state, sd, path_flag);
|
|
}
|
|
}
|
|
else
|
|
#endif
|
|
{
|
|
#ifdef __SVM__
|
|
svm_eval_nodes<node_feature_mask, SHADER_TYPE_SURFACE>(kg, state, sd, buffer, path_flag);
|
|
#else
|
|
if (sd->object == OBJECT_NONE) {
|
|
sd->closure_emission_background = make_float3(0.8f, 0.8f, 0.8f);
|
|
sd->flag |= SD_EMISSION;
|
|
}
|
|
else {
|
|
ccl_private DiffuseBsdf *bsdf = (ccl_private DiffuseBsdf *)bsdf_alloc(
|
|
sd, sizeof(DiffuseBsdf), make_float3(0.8f, 0.8f, 0.8f));
|
|
if (bsdf != NULL) {
|
|
bsdf->N = sd->N;
|
|
sd->flag |= bsdf_diffuse_setup(bsdf);
|
|
}
|
|
}
|
|
#endif
|
|
}
|
|
}
|
|
|
|
/* Volume */
|
|
|
|
#ifdef __VOLUME__
|
|
|
|
ccl_device_inline float _shader_volume_phase_multi_eval(
|
|
ccl_private const ShaderData *sd,
|
|
ccl_private const ShaderVolumePhases *phases,
|
|
const float3 omega_in,
|
|
int skip_phase,
|
|
ccl_private BsdfEval *result_eval,
|
|
float sum_pdf,
|
|
float sum_sample_weight)
|
|
{
|
|
for (int i = 0; i < phases->num_closure; i++) {
|
|
if (i == skip_phase)
|
|
continue;
|
|
|
|
ccl_private const ShaderVolumeClosure *svc = &phases->closure[i];
|
|
float phase_pdf = 0.0f;
|
|
float3 eval = volume_phase_eval(sd, svc, omega_in, &phase_pdf);
|
|
|
|
if (phase_pdf != 0.0f) {
|
|
bsdf_eval_accum(result_eval, CLOSURE_VOLUME_HENYEY_GREENSTEIN_ID, eval);
|
|
sum_pdf += phase_pdf * svc->sample_weight;
|
|
}
|
|
|
|
sum_sample_weight += svc->sample_weight;
|
|
}
|
|
|
|
return (sum_sample_weight > 0.0f) ? sum_pdf / sum_sample_weight : 0.0f;
|
|
}
|
|
|
|
ccl_device float shader_volume_phase_eval(KernelGlobals kg,
|
|
ccl_private const ShaderData *sd,
|
|
ccl_private const ShaderVolumePhases *phases,
|
|
const float3 omega_in,
|
|
ccl_private BsdfEval *phase_eval)
|
|
{
|
|
bsdf_eval_init(phase_eval, CLOSURE_VOLUME_HENYEY_GREENSTEIN_ID, zero_float3());
|
|
|
|
return _shader_volume_phase_multi_eval(sd, phases, omega_in, -1, phase_eval, 0.0f, 0.0f);
|
|
}
|
|
|
|
ccl_device int shader_volume_phase_sample(KernelGlobals kg,
|
|
ccl_private const ShaderData *sd,
|
|
ccl_private const ShaderVolumePhases *phases,
|
|
float randu,
|
|
float randv,
|
|
ccl_private BsdfEval *phase_eval,
|
|
ccl_private float3 *omega_in,
|
|
ccl_private differential3 *domega_in,
|
|
ccl_private float *pdf)
|
|
{
|
|
int sampled = 0;
|
|
|
|
if (phases->num_closure > 1) {
|
|
/* pick a phase closure based on sample weights */
|
|
float sum = 0.0f;
|
|
|
|
for (sampled = 0; sampled < phases->num_closure; sampled++) {
|
|
ccl_private const ShaderVolumeClosure *svc = &phases->closure[sampled];
|
|
sum += svc->sample_weight;
|
|
}
|
|
|
|
float r = randu * sum;
|
|
float partial_sum = 0.0f;
|
|
|
|
for (sampled = 0; sampled < phases->num_closure; sampled++) {
|
|
ccl_private const ShaderVolumeClosure *svc = &phases->closure[sampled];
|
|
float next_sum = partial_sum + svc->sample_weight;
|
|
|
|
if (r <= next_sum) {
|
|
/* Rescale to reuse for BSDF direction sample. */
|
|
randu = (r - partial_sum) / svc->sample_weight;
|
|
break;
|
|
}
|
|
|
|
partial_sum = next_sum;
|
|
}
|
|
|
|
if (sampled == phases->num_closure) {
|
|
*pdf = 0.0f;
|
|
return LABEL_NONE;
|
|
}
|
|
}
|
|
|
|
/* todo: this isn't quite correct, we don't weight anisotropy properly
|
|
* depending on color channels, even if this is perhaps not a common case */
|
|
ccl_private const ShaderVolumeClosure *svc = &phases->closure[sampled];
|
|
int label;
|
|
float3 eval = zero_float3();
|
|
|
|
*pdf = 0.0f;
|
|
label = volume_phase_sample(sd, svc, randu, randv, &eval, omega_in, domega_in, pdf);
|
|
|
|
if (*pdf != 0.0f) {
|
|
bsdf_eval_init(phase_eval, CLOSURE_VOLUME_HENYEY_GREENSTEIN_ID, eval);
|
|
}
|
|
|
|
return label;
|
|
}
|
|
|
|
ccl_device int shader_phase_sample_closure(KernelGlobals kg,
|
|
ccl_private const ShaderData *sd,
|
|
ccl_private const ShaderVolumeClosure *sc,
|
|
float randu,
|
|
float randv,
|
|
ccl_private BsdfEval *phase_eval,
|
|
ccl_private float3 *omega_in,
|
|
ccl_private differential3 *domega_in,
|
|
ccl_private float *pdf)
|
|
{
|
|
int label;
|
|
float3 eval = zero_float3();
|
|
|
|
*pdf = 0.0f;
|
|
label = volume_phase_sample(sd, sc, randu, randv, &eval, omega_in, domega_in, pdf);
|
|
|
|
if (*pdf != 0.0f)
|
|
bsdf_eval_init(phase_eval, CLOSURE_VOLUME_HENYEY_GREENSTEIN_ID, eval);
|
|
|
|
return label;
|
|
}
|
|
|
|
/* Volume Evaluation */
|
|
|
|
template<const bool shadow, typename StackReadOp, typename ConstIntegratorGenericState>
|
|
ccl_device_inline void shader_eval_volume(KernelGlobals kg,
|
|
ConstIntegratorGenericState state,
|
|
ccl_private ShaderData *ccl_restrict sd,
|
|
const uint32_t path_flag,
|
|
StackReadOp stack_read)
|
|
{
|
|
/* If path is being terminated, we are tracing a shadow ray or evaluating
|
|
* emission, then we don't need to store closures. The emission and shadow
|
|
* shader data also do not have a closure array to save GPU memory. */
|
|
int max_closures;
|
|
if (path_flag & (PATH_RAY_TERMINATE | PATH_RAY_SHADOW | PATH_RAY_EMISSION)) {
|
|
max_closures = 0;
|
|
}
|
|
else {
|
|
max_closures = kernel_data.max_closures;
|
|
}
|
|
|
|
/* reset closures once at the start, we will be accumulating the closures
|
|
* for all volumes in the stack into a single array of closures */
|
|
sd->num_closure = 0;
|
|
sd->num_closure_left = max_closures;
|
|
sd->flag = 0;
|
|
sd->object_flag = 0;
|
|
|
|
for (int i = 0;; i++) {
|
|
const VolumeStack entry = stack_read(i);
|
|
if (entry.shader == SHADER_NONE) {
|
|
break;
|
|
}
|
|
|
|
/* Setup shader-data from stack. it's mostly setup already in
|
|
* shader_setup_from_volume, this switching should be quick. */
|
|
sd->object = entry.object;
|
|
sd->lamp = LAMP_NONE;
|
|
sd->shader = entry.shader;
|
|
|
|
sd->flag &= ~SD_SHADER_FLAGS;
|
|
sd->flag |= kernel_tex_fetch(__shaders, (sd->shader & SHADER_MASK)).flags;
|
|
sd->object_flag &= ~SD_OBJECT_FLAGS;
|
|
|
|
if (sd->object != OBJECT_NONE) {
|
|
sd->object_flag |= kernel_tex_fetch(__object_flag, sd->object);
|
|
|
|
# ifdef __OBJECT_MOTION__
|
|
/* todo: this is inefficient for motion blur, we should be
|
|
* caching matrices instead of recomputing them each step */
|
|
shader_setup_object_transforms(kg, sd, sd->time);
|
|
|
|
if ((sd->object_flag & SD_OBJECT_HAS_VOLUME_MOTION) != 0) {
|
|
AttributeDescriptor v_desc = find_attribute(kg, sd, ATTR_STD_VOLUME_VELOCITY);
|
|
kernel_assert(v_desc.offset != ATTR_STD_NOT_FOUND);
|
|
|
|
const float3 P = sd->P;
|
|
const float velocity_scale = kernel_tex_fetch(__objects, sd->object).velocity_scale;
|
|
const float time_offset = kernel_data.cam.motion_position == MOTION_POSITION_CENTER ?
|
|
0.5f :
|
|
0.0f;
|
|
const float time = kernel_data.cam.motion_position == MOTION_POSITION_END ?
|
|
(1.0f - kernel_data.cam.shuttertime) + sd->time :
|
|
sd->time;
|
|
|
|
/* Use a 1st order semi-lagrangian advection scheme to estimate what volume quantity
|
|
* existed, or will exist, at the given time:
|
|
*
|
|
* `phi(x, T) = phi(x - (T - t) * u(x, T), t)`
|
|
*
|
|
* where
|
|
*
|
|
* x : position
|
|
* T : super-sampled time (or ray time)
|
|
* t : current time of the simulation (in rendering we assume this is center frame with
|
|
* relative time = 0)
|
|
* phi : the volume quantity
|
|
* u : the velocity field
|
|
*
|
|
* But first we need to determine the velocity field `u(x, T)`, which we can estimate also
|
|
* using semi-lagrangian advection.
|
|
*
|
|
* `u(x, T) = u(x - (T - t) * u(x, T), t)`
|
|
*
|
|
* This is the typical way to model self-advection in fluid dynamics, however, we do not
|
|
* account for other forces affecting the velocity during simulation (pressure, buoyancy,
|
|
* etc.): this gives a linear interpolation when fluid are mostly "curvy". For better
|
|
* results, a higher order interpolation scheme can be used (at the cost of more lookups),
|
|
* or an interpolation of the velocity fields for the previous and next frames could also
|
|
* be used to estimate `u(x, T)` (which will cost more memory and lookups).
|
|
*
|
|
* References:
|
|
* "Eulerian Motion Blur", Kim and Ko, 2007
|
|
* "Production Volume Rendering", Wreninge et al., 2012
|
|
*/
|
|
|
|
/* Find velocity. */
|
|
float3 velocity = primitive_volume_attribute_float3(kg, sd, v_desc);
|
|
object_dir_transform(kg, sd, &velocity);
|
|
|
|
/* Find advected P. */
|
|
sd->P = P - (time - time_offset) * velocity_scale * velocity;
|
|
|
|
/* Find advected velocity. */
|
|
velocity = primitive_volume_attribute_float3(kg, sd, v_desc);
|
|
object_dir_transform(kg, sd, &velocity);
|
|
|
|
/* Find advected P. */
|
|
sd->P = P - (time - time_offset) * velocity_scale * velocity;
|
|
}
|
|
# endif
|
|
}
|
|
|
|
/* evaluate shader */
|
|
# ifdef __SVM__
|
|
# ifdef __OSL__
|
|
if (kg->osl) {
|
|
OSLShader::eval_volume(kg, state, sd, path_flag);
|
|
}
|
|
else
|
|
# endif
|
|
{
|
|
svm_eval_nodes<KERNEL_FEATURE_NODE_MASK_VOLUME, SHADER_TYPE_VOLUME>(
|
|
kg, state, sd, NULL, path_flag);
|
|
}
|
|
# endif
|
|
|
|
/* Merge closures to avoid exceeding number of closures limit. */
|
|
if (!shadow) {
|
|
if (i > 0) {
|
|
shader_merge_volume_closures(sd);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
#endif /* __VOLUME__ */
|
|
|
|
/* Displacement Evaluation */
|
|
|
|
template<typename ConstIntegratorGenericState>
|
|
ccl_device void shader_eval_displacement(KernelGlobals kg,
|
|
ConstIntegratorGenericState state,
|
|
ccl_private ShaderData *sd)
|
|
{
|
|
sd->num_closure = 0;
|
|
sd->num_closure_left = 0;
|
|
|
|
/* this will modify sd->P */
|
|
#ifdef __SVM__
|
|
# ifdef __OSL__
|
|
if (kg->osl)
|
|
OSLShader::eval_displacement(kg, state, sd);
|
|
else
|
|
# endif
|
|
{
|
|
svm_eval_nodes<KERNEL_FEATURE_NODE_MASK_DISPLACEMENT, SHADER_TYPE_DISPLACEMENT>(
|
|
kg, state, sd, NULL, 0);
|
|
}
|
|
#endif
|
|
}
|
|
|
|
/* Cryptomatte */
|
|
|
|
ccl_device float shader_cryptomatte_id(KernelGlobals kg, int shader)
|
|
{
|
|
return kernel_tex_fetch(__shaders, (shader & SHADER_MASK)).cryptomatte_id;
|
|
}
|
|
|
|
CCL_NAMESPACE_END
|