diff options
Diffstat (limited to 'intern/cycles/kernel/integrator/surface_shader.h')
| -rw-r--r-- | intern/cycles/kernel/integrator/surface_shader.h | 588 |
1 files changed, 588 insertions, 0 deletions
diff --git a/intern/cycles/kernel/integrator/surface_shader.h b/intern/cycles/kernel/integrator/surface_shader.h new file mode 100644 index 00000000000..64b5556f7e9 --- /dev/null +++ b/intern/cycles/kernel/integrator/surface_shader.h @@ -0,0 +1,588 @@ +/* SPDX-License-Identifier: Apache-2.0 + * Copyright 2011-2022 Blender Foundation */ + +/* Functions to evaluate shaders. */ + +#pragma once + +#include "kernel/closure/alloc.h" +#include "kernel/closure/bsdf.h" +#include "kernel/closure/bsdf_util.h" +#include "kernel/closure/emissive.h" + +#ifdef __SVM__ +# include "kernel/svm/svm.h" +#endif +#ifdef __OSL__ +# include "kernel/osl/osl.h" +#endif + +CCL_NAMESPACE_BEGIN + +ccl_device_inline void surface_shader_prepare_closures(KernelGlobals kg, + ConstIntegratorState state, + ccl_private ShaderData *sd, + const uint32_t path_flag) +{ + /* Filter out closures. */ + if (kernel_data.integrator.filter_closures) { + if (kernel_data.integrator.filter_closures & FILTER_CLOSURE_EMISSION) { + sd->closure_emission_background = zero_spectrum(); + } + + if (kernel_data.integrator.filter_closures & FILTER_CLOSURE_DIRECT_LIGHT) { + sd->flag &= ~SD_BSDF_HAS_EVAL; + } + + if (path_flag & PATH_RAY_CAMERA) { + for (int i = 0; i < sd->num_closure; i++) { + ccl_private ShaderClosure *sc = &sd->closure[i]; + + if ((CLOSURE_IS_BSDF_DIFFUSE(sc->type) && + (kernel_data.integrator.filter_closures & FILTER_CLOSURE_DIFFUSE)) || + (CLOSURE_IS_BSDF_GLOSSY(sc->type) && + (kernel_data.integrator.filter_closures & FILTER_CLOSURE_GLOSSY)) || + (CLOSURE_IS_BSDF_TRANSMISSION(sc->type) && + (kernel_data.integrator.filter_closures & FILTER_CLOSURE_TRANSMISSION))) { + sc->type = CLOSURE_NONE_ID; + sc->sample_weight = 0.0f; + } + else if ((CLOSURE_IS_BSDF_TRANSPARENT(sc->type) && + (kernel_data.integrator.filter_closures & FILTER_CLOSURE_TRANSPARENT))) { + sc->type = CLOSURE_HOLDOUT_ID; + sc->sample_weight = 0.0f; + sd->flag |= SD_HOLDOUT; + } + } + } + } + + /* Defensive sampling. + * + * We can likely also do defensive sampling at deeper bounces, particularly + * for cases like a perfect mirror but possibly also others. This will need + * a good heuristic. */ + if (INTEGRATOR_STATE(state, path, bounce) + INTEGRATOR_STATE(state, path, transparent_bounce) == + 0 && + sd->num_closure > 1) { + float sum = 0.0f; + + for (int i = 0; i < sd->num_closure; i++) { + ccl_private ShaderClosure *sc = &sd->closure[i]; + if (CLOSURE_IS_BSDF_OR_BSSRDF(sc->type)) { + sum += sc->sample_weight; + } + } + + for (int i = 0; i < sd->num_closure; i++) { + ccl_private ShaderClosure *sc = &sd->closure[i]; + if (CLOSURE_IS_BSDF_OR_BSSRDF(sc->type)) { + sc->sample_weight = max(sc->sample_weight, 0.125f * sum); + } + } + } + + /* Filter glossy. + * + * Blurring of bsdf after bounces, for rays that have a small likelihood + * of following this particular path (diffuse, rough glossy) */ + if (kernel_data.integrator.filter_glossy != FLT_MAX +#ifdef __MNEE__ + && !(INTEGRATOR_STATE(state, path, mnee) & PATH_MNEE_VALID) +#endif + ) { + float blur_pdf = kernel_data.integrator.filter_glossy * + INTEGRATOR_STATE(state, path, min_ray_pdf); + + if (blur_pdf < 1.0f) { + float blur_roughness = sqrtf(1.0f - blur_pdf) * 0.5f; + + for (int i = 0; i < sd->num_closure; i++) { + ccl_private ShaderClosure *sc = &sd->closure[i]; + if (CLOSURE_IS_BSDF(sc->type)) { + bsdf_blur(kg, sc, blur_roughness); + } + } + } + } +} + +/* BSDF */ + +ccl_device_inline bool surface_shader_is_transmission(ccl_private const ShaderData *sd, + const float3 omega_in) +{ + return dot(sd->N, omega_in) < 0.0f; +} + +ccl_device_forceinline bool _surface_shader_exclude(ClosureType type, uint light_shader_flags) +{ + if (!(light_shader_flags & SHADER_EXCLUDE_ANY)) { + return false; + } + if (light_shader_flags & SHADER_EXCLUDE_DIFFUSE) { + if (CLOSURE_IS_BSDF_DIFFUSE(type)) { + return true; + } + } + if (light_shader_flags & SHADER_EXCLUDE_GLOSSY) { + if (CLOSURE_IS_BSDF_GLOSSY(type)) { + return true; + } + } + if (light_shader_flags & SHADER_EXCLUDE_TRANSMIT) { + if (CLOSURE_IS_BSDF_TRANSMISSION(type)) { + return true; + } + } + return false; +} + +ccl_device_inline float _surface_shader_bsdf_eval_mis(KernelGlobals kg, + ccl_private ShaderData *sd, + const float3 omega_in, + const bool is_transmission, + ccl_private const ShaderClosure *skip_sc, + ccl_private BsdfEval *result_eval, + float sum_pdf, + float sum_sample_weight, + const uint light_shader_flags) +{ + /* This is the veach one-sample model with balance heuristic, + * some PDF factors drop out when using balance heuristic weighting. */ + for (int i = 0; i < sd->num_closure; i++) { + ccl_private const ShaderClosure *sc = &sd->closure[i]; + + if (sc == skip_sc) { + continue; + } + + if (CLOSURE_IS_BSDF_OR_BSSRDF(sc->type)) { + if (CLOSURE_IS_BSDF(sc->type) && !_surface_shader_exclude(sc->type, light_shader_flags)) { + float bsdf_pdf = 0.0f; + Spectrum eval = bsdf_eval(kg, sd, sc, omega_in, is_transmission, &bsdf_pdf); + + if (bsdf_pdf != 0.0f) { + bsdf_eval_accum(result_eval, sc->type, eval * sc->weight); + sum_pdf += bsdf_pdf * sc->sample_weight; + } + } + + sum_sample_weight += sc->sample_weight; + } + } + + return (sum_sample_weight > 0.0f) ? sum_pdf / sum_sample_weight : 0.0f; +} + +#ifndef __KERNEL_CUDA__ +ccl_device +#else +ccl_device_inline +#endif + float + surface_shader_bsdf_eval(KernelGlobals kg, + ccl_private ShaderData *sd, + const float3 omega_in, + const bool is_transmission, + ccl_private BsdfEval *bsdf_eval, + const uint light_shader_flags) +{ + bsdf_eval_init(bsdf_eval, CLOSURE_NONE_ID, zero_spectrum()); + + return _surface_shader_bsdf_eval_mis( + kg, sd, omega_in, is_transmission, NULL, bsdf_eval, 0.0f, 0.0f, light_shader_flags); +} + +/* Randomly sample a BSSRDF or BSDF proportional to ShaderClosure.sample_weight. */ +ccl_device_inline ccl_private const ShaderClosure *surface_shader_bsdf_bssrdf_pick( + ccl_private const ShaderData *ccl_restrict sd, ccl_private float2 *rand_bsdf) +{ + int sampled = 0; + + if (sd->num_closure > 1) { + /* Pick a BSDF or based on sample weights. */ + float sum = 0.0f; + + for (int i = 0; i < sd->num_closure; i++) { + ccl_private const ShaderClosure *sc = &sd->closure[i]; + + if (CLOSURE_IS_BSDF_OR_BSSRDF(sc->type)) { + sum += sc->sample_weight; + } + } + + float r = (*rand_bsdf).x * sum; + float partial_sum = 0.0f; + + for (int i = 0; i < sd->num_closure; i++) { + ccl_private const ShaderClosure *sc = &sd->closure[i]; + + if (CLOSURE_IS_BSDF_OR_BSSRDF(sc->type)) { + float next_sum = partial_sum + sc->sample_weight; + + if (r < next_sum) { + sampled = i; + + /* Rescale to reuse for direction sample, to better preserve stratification. */ + (*rand_bsdf).x = (r - partial_sum) / sc->sample_weight; + break; + } + + partial_sum = next_sum; + } + } + } + + return &sd->closure[sampled]; +} + +/* Return weight for picked BSSRDF. */ +ccl_device_inline Spectrum +surface_shader_bssrdf_sample_weight(ccl_private const ShaderData *ccl_restrict sd, + ccl_private const ShaderClosure *ccl_restrict bssrdf_sc) +{ + Spectrum weight = bssrdf_sc->weight; + + if (sd->num_closure > 1) { + float sum = 0.0f; + for (int i = 0; i < sd->num_closure; i++) { + ccl_private const ShaderClosure *sc = &sd->closure[i]; + + if (CLOSURE_IS_BSDF_OR_BSSRDF(sc->type)) { + sum += sc->sample_weight; + } + } + weight *= sum / bssrdf_sc->sample_weight; + } + + return weight; +} + +/* Sample direction for picked BSDF, and return evaluation and pdf for all + * BSDFs combined using MIS. */ +ccl_device int surface_shader_bsdf_sample_closure(KernelGlobals kg, + ccl_private ShaderData *sd, + ccl_private const ShaderClosure *sc, + const float2 rand_bsdf, + ccl_private BsdfEval *bsdf_eval, + ccl_private float3 *omega_in, + ccl_private float *pdf) +{ + /* BSSRDF should already have been handled elsewhere. */ + kernel_assert(CLOSURE_IS_BSDF(sc->type)); + + int label; + Spectrum eval = zero_spectrum(); + + *pdf = 0.0f; + label = bsdf_sample(kg, sd, sc, rand_bsdf.x, rand_bsdf.y, &eval, omega_in, pdf); + + if (*pdf != 0.0f) { + bsdf_eval_init(bsdf_eval, sc->type, eval * sc->weight); + + if (sd->num_closure > 1) { + const bool is_transmission = surface_shader_is_transmission(sd, *omega_in); + float sweight = sc->sample_weight; + *pdf = _surface_shader_bsdf_eval_mis( + kg, sd, *omega_in, is_transmission, sc, bsdf_eval, *pdf * sweight, sweight, 0); + } + } + + return label; +} + +ccl_device float surface_shader_average_roughness(ccl_private const ShaderData *sd) +{ + float roughness = 0.0f; + float sum_weight = 0.0f; + + for (int i = 0; i < sd->num_closure; i++) { + ccl_private const ShaderClosure *sc = &sd->closure[i]; + + if (CLOSURE_IS_BSDF(sc->type)) { + /* sqrt once to undo the squaring from multiplying roughness on the + * two axes, and once for the squared roughness convention. */ + float weight = fabsf(average(sc->weight)); + roughness += weight * sqrtf(safe_sqrtf(bsdf_get_roughness_squared(sc))); + sum_weight += weight; + } + } + + return (sum_weight > 0.0f) ? roughness / sum_weight : 0.0f; +} + +ccl_device Spectrum surface_shader_transparency(KernelGlobals kg, ccl_private const ShaderData *sd) +{ + if (sd->flag & SD_HAS_ONLY_VOLUME) { + return one_spectrum(); + } + else if (sd->flag & SD_TRANSPARENT) { + return sd->closure_transparent_extinction; + } + else { + return zero_spectrum(); + } +} + +ccl_device void surface_shader_disable_transparency(KernelGlobals kg, ccl_private ShaderData *sd) +{ + if (sd->flag & SD_TRANSPARENT) { + for (int i = 0; i < sd->num_closure; i++) { + ccl_private ShaderClosure *sc = &sd->closure[i]; + + if (sc->type == CLOSURE_BSDF_TRANSPARENT_ID) { + sc->sample_weight = 0.0f; + sc->weight = zero_spectrum(); + } + } + + sd->flag &= ~SD_TRANSPARENT; + } +} + +ccl_device Spectrum surface_shader_alpha(KernelGlobals kg, ccl_private const ShaderData *sd) +{ + Spectrum alpha = one_spectrum() - surface_shader_transparency(kg, sd); + + alpha = saturate(alpha); + + return alpha; +} + +ccl_device Spectrum surface_shader_diffuse(KernelGlobals kg, ccl_private const ShaderData *sd) +{ + Spectrum eval = zero_spectrum(); + + for (int i = 0; i < sd->num_closure; i++) { + ccl_private const ShaderClosure *sc = &sd->closure[i]; + + if (CLOSURE_IS_BSDF_DIFFUSE(sc->type) || CLOSURE_IS_BSSRDF(sc->type)) + eval += sc->weight; + } + + return eval; +} + +ccl_device Spectrum surface_shader_glossy(KernelGlobals kg, ccl_private const ShaderData *sd) +{ + Spectrum eval = zero_spectrum(); + + for (int i = 0; i < sd->num_closure; i++) { + ccl_private const ShaderClosure *sc = &sd->closure[i]; + + if (CLOSURE_IS_BSDF_GLOSSY(sc->type)) + eval += sc->weight; + } + + return eval; +} + +ccl_device Spectrum surface_shader_transmission(KernelGlobals kg, ccl_private const ShaderData *sd) +{ + Spectrum eval = zero_spectrum(); + + for (int i = 0; i < sd->num_closure; i++) { + ccl_private const ShaderClosure *sc = &sd->closure[i]; + + if (CLOSURE_IS_BSDF_TRANSMISSION(sc->type)) + eval += sc->weight; + } + + return eval; +} + +ccl_device float3 surface_shader_average_normal(KernelGlobals kg, 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_BSDF_OR_BSSRDF(sc->type)) + N += sc->N * fabsf(average(sc->weight)); + } + + return (is_zero(N)) ? sd->N : normalize(N); +} + +ccl_device Spectrum surface_shader_ao(KernelGlobals kg, + ccl_private const ShaderData *sd, + const float ao_factor, + ccl_private float3 *N_) +{ + Spectrum eval = zero_spectrum(); + float3 N = zero_float3(); + + for (int i = 0; i < sd->num_closure; i++) { + 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 surface_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 surface_shader_constant_emission(KernelGlobals kg, + int shader, + ccl_private Spectrum *eval) +{ + int shader_index = shader & SHADER_MASK; + int shader_flag = kernel_data_fetch(shaders, shader_index).flags; + + if (shader_flag & SD_HAS_CONSTANT_EMISSION) { + const float3 emission_rgb = make_float3( + kernel_data_fetch(shaders, shader_index).constant_emission[0], + kernel_data_fetch(shaders, shader_index).constant_emission[1], + kernel_data_fetch(shaders, shader_index).constant_emission[2]); + *eval = rgb_to_spectrum(emission_rgb); + + return true; + } + + return false; +} + +/* Background */ + +ccl_device Spectrum surface_shader_background(ccl_private const ShaderData *sd) +{ + if (sd->flag & SD_EMISSION) { + return sd->closure_emission_background; + } + else { + return zero_spectrum(); + } +} + +/* Emission */ + +ccl_device Spectrum surface_shader_emission(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_spectrum(); + } +} + +/* Holdout */ + +ccl_device Spectrum surface_shader_apply_holdout(KernelGlobals kg, ccl_private ShaderData *sd) +{ + Spectrum weight = zero_spectrum(); + + /* 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_spectrum() - 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_spectrum(); + } + } + 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 surface_shader_eval(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_spectrum(0.8f); + sd->flag |= SD_EMISSION; + } + else { + ccl_private DiffuseBsdf *bsdf = (ccl_private DiffuseBsdf *)bsdf_alloc( + sd, sizeof(DiffuseBsdf), make_spectrum(0.8f)); + if (bsdf != NULL) { + bsdf->N = sd->N; + sd->flag |= bsdf_diffuse_setup(bsdf); + } + } +#endif + } +} + +CCL_NAMESPACE_END |