forked from bartvdbraak/blender
603 lines
19 KiB
C
603 lines
19 KiB
C
/*
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* Copyright 2011-2013 Blender Foundation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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CCL_NAMESPACE_BEGIN
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#ifdef __BRANCHED_PATH__
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ccl_device_inline void kernel_branched_path_ao(KernelGlobals *kg,
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ShaderData *sd,
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ShaderData *emission_sd,
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PathRadiance *L,
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ccl_addr_space PathState *state,
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float3 throughput)
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{
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int num_samples = kernel_data.integrator.ao_samples;
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float num_samples_inv = 1.0f/num_samples;
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float ao_factor = kernel_data.background.ao_factor;
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float3 ao_N;
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float3 ao_bsdf = shader_bsdf_ao(kg, sd, ao_factor, &ao_N);
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float3 ao_alpha = shader_bsdf_alpha(kg, sd);
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for(int j = 0; j < num_samples; j++) {
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float bsdf_u, bsdf_v;
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path_branched_rng_2D(kg, state->rng_hash, state, j, num_samples, PRNG_BSDF_U, &bsdf_u, &bsdf_v);
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float3 ao_D;
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float ao_pdf;
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sample_cos_hemisphere(ao_N, bsdf_u, bsdf_v, &ao_D, &ao_pdf);
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if(dot(sd->Ng, ao_D) > 0.0f && ao_pdf != 0.0f) {
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Ray light_ray;
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float3 ao_shadow;
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light_ray.P = ray_offset(sd->P, sd->Ng);
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light_ray.D = ao_D;
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light_ray.t = kernel_data.background.ao_distance;
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light_ray.time = sd->time;
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light_ray.dP = sd->dP;
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light_ray.dD = differential3_zero();
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if(!shadow_blocked(kg, sd, emission_sd, state, &light_ray, &ao_shadow)) {
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path_radiance_accum_ao(L, state, throughput*num_samples_inv, ao_alpha, ao_bsdf, ao_shadow);
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}
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else {
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path_radiance_accum_total_ao(L, state, throughput*num_samples_inv, ao_bsdf);
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}
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}
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}
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}
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#ifndef __SPLIT_KERNEL__
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#ifdef __VOLUME__
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ccl_device_forceinline void kernel_branched_path_volume(
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KernelGlobals *kg,
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ShaderData *sd,
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PathState *state,
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Ray *ray,
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float3 *throughput,
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ccl_addr_space Intersection *isect,
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bool hit,
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ShaderData *indirect_sd,
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ShaderData *emission_sd,
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PathRadiance *L)
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{
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/* Sanitize volume stack. */
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if(!hit) {
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kernel_volume_clean_stack(kg, state->volume_stack);
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}
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if(state->volume_stack[0].shader == SHADER_NONE) {
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return;
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}
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/* volume attenuation, emission, scatter */
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Ray volume_ray = *ray;
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volume_ray.t = (hit)? isect->t: FLT_MAX;
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bool heterogeneous = volume_stack_is_heterogeneous(kg, state->volume_stack);
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# ifdef __VOLUME_DECOUPLED__
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/* decoupled ray marching only supported on CPU */
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if(kernel_data.integrator.volume_decoupled) {
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/* cache steps along volume for repeated sampling */
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VolumeSegment volume_segment;
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shader_setup_from_volume(kg, sd, &volume_ray);
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kernel_volume_decoupled_record(kg, state,
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&volume_ray, sd, &volume_segment, heterogeneous);
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/* direct light sampling */
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if(volume_segment.closure_flag & SD_SCATTER) {
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volume_segment.sampling_method = volume_stack_sampling_method(kg, state->volume_stack);
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int all = kernel_data.integrator.sample_all_lights_direct;
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kernel_branched_path_volume_connect_light(kg, sd,
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emission_sd, *throughput, state, L, all,
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&volume_ray, &volume_segment);
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/* indirect light sampling */
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int num_samples = kernel_data.integrator.volume_samples;
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float num_samples_inv = 1.0f/num_samples;
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for(int j = 0; j < num_samples; j++) {
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PathState ps = *state;
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Ray pray = *ray;
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float3 tp = *throughput;
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/* branch RNG state */
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path_state_branch(&ps, j, num_samples);
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/* scatter sample. if we use distance sampling and take just one
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* sample for direct and indirect light, we could share this
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* computation, but makes code a bit complex */
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float rphase = path_state_rng_1D(kg, &ps, PRNG_PHASE_CHANNEL);
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float rscatter = path_state_rng_1D(kg, &ps, PRNG_SCATTER_DISTANCE);
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VolumeIntegrateResult result = kernel_volume_decoupled_scatter(kg,
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&ps, &pray, sd, &tp, rphase, rscatter, &volume_segment, NULL, false);
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if(result == VOLUME_PATH_SCATTERED &&
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kernel_path_volume_bounce(kg,
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sd,
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&tp,
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&ps,
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&L->state,
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&pray))
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{
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kernel_path_indirect(kg,
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indirect_sd,
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emission_sd,
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&pray,
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tp*num_samples_inv,
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&ps,
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L);
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/* for render passes, sum and reset indirect light pass variables
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* for the next samples */
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path_radiance_sum_indirect(L);
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path_radiance_reset_indirect(L);
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}
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}
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}
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/* emission and transmittance */
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if(volume_segment.closure_flag & SD_EMISSION)
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path_radiance_accum_emission(L, state, *throughput, volume_segment.accum_emission);
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*throughput *= volume_segment.accum_transmittance;
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/* free cached steps */
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kernel_volume_decoupled_free(kg, &volume_segment);
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}
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else
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# endif /* __VOLUME_DECOUPLED__ */
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{
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/* GPU: no decoupled ray marching, scatter probalistically */
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int num_samples = kernel_data.integrator.volume_samples;
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float num_samples_inv = 1.0f/num_samples;
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/* todo: we should cache the shader evaluations from stepping
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* through the volume, for now we redo them multiple times */
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for(int j = 0; j < num_samples; j++) {
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PathState ps = *state;
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Ray pray = *ray;
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float3 tp = (*throughput) * num_samples_inv;
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/* branch RNG state */
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path_state_branch(&ps, j, num_samples);
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VolumeIntegrateResult result = kernel_volume_integrate(
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kg, &ps, sd, &volume_ray, L, &tp, heterogeneous);
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# ifdef __VOLUME_SCATTER__
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if(result == VOLUME_PATH_SCATTERED) {
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/* todo: support equiangular, MIS and all light sampling.
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* alternatively get decoupled ray marching working on the GPU */
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kernel_path_volume_connect_light(kg, sd, emission_sd, tp, state, L);
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if(kernel_path_volume_bounce(kg,
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sd,
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&tp,
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&ps,
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&L->state,
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&pray))
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{
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kernel_path_indirect(kg,
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indirect_sd,
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emission_sd,
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&pray,
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tp,
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&ps,
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L);
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/* for render passes, sum and reset indirect light pass variables
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* for the next samples */
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path_radiance_sum_indirect(L);
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path_radiance_reset_indirect(L);
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}
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}
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# endif /* __VOLUME_SCATTER__ */
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}
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/* todo: avoid this calculation using decoupled ray marching */
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kernel_volume_shadow(kg, emission_sd, state, &volume_ray, throughput);
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}
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}
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#endif /* __VOLUME__ */
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/* bounce off surface and integrate indirect light */
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ccl_device_noinline void kernel_branched_path_surface_indirect_light(KernelGlobals *kg,
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ShaderData *sd, ShaderData *indirect_sd, ShaderData *emission_sd,
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float3 throughput, float num_samples_adjust, PathState *state, PathRadiance *L)
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{
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float sum_sample_weight = 0.0f;
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#ifdef __DENOISING_FEATURES__
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if(state->denoising_feature_weight > 0.0f) {
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for(int i = 0; i < sd->num_closure; i++) {
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const ShaderClosure *sc = &sd->closure[i];
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/* transparency is not handled here, but in outer loop */
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if(!CLOSURE_IS_BSDF(sc->type) || CLOSURE_IS_BSDF_TRANSPARENT(sc->type)) {
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continue;
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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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else {
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sum_sample_weight = 1.0f;
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}
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#endif /* __DENOISING_FEATURES__ */
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for(int i = 0; i < sd->num_closure; i++) {
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const ShaderClosure *sc = &sd->closure[i];
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/* transparency is not handled here, but in outer loop */
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if(!CLOSURE_IS_BSDF(sc->type) || CLOSURE_IS_BSDF_TRANSPARENT(sc->type)) {
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continue;
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}
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int num_samples;
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if(CLOSURE_IS_BSDF_DIFFUSE(sc->type))
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num_samples = kernel_data.integrator.diffuse_samples;
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else if(CLOSURE_IS_BSDF_BSSRDF(sc->type))
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num_samples = 1;
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else if(CLOSURE_IS_BSDF_GLOSSY(sc->type))
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num_samples = kernel_data.integrator.glossy_samples;
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else
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num_samples = kernel_data.integrator.transmission_samples;
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num_samples = ceil_to_int(num_samples_adjust*num_samples);
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float num_samples_inv = num_samples_adjust/num_samples;
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for(int j = 0; j < num_samples; j++) {
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PathState ps = *state;
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float3 tp = throughput;
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Ray bsdf_ray;
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#ifdef __SHADOW_TRICKS__
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float shadow_transparency = L->shadow_transparency;
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#endif
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ps.rng_hash = cmj_hash(state->rng_hash, i);
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if(!kernel_branched_path_surface_bounce(kg,
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sd,
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sc,
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j,
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num_samples,
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&tp,
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&ps,
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&L->state,
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&bsdf_ray,
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sum_sample_weight))
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{
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continue;
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}
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ps.rng_hash = state->rng_hash;
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kernel_path_indirect(kg,
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indirect_sd,
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emission_sd,
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&bsdf_ray,
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tp*num_samples_inv,
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&ps,
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L);
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/* for render passes, sum and reset indirect light pass variables
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* for the next samples */
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path_radiance_sum_indirect(L);
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path_radiance_reset_indirect(L);
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#ifdef __SHADOW_TRICKS__
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L->shadow_transparency = shadow_transparency;
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#endif
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}
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}
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}
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#ifdef __SUBSURFACE__
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ccl_device void kernel_branched_path_subsurface_scatter(KernelGlobals *kg,
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ShaderData *sd,
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ShaderData *indirect_sd,
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ShaderData *emission_sd,
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PathRadiance *L,
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PathState *state,
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Ray *ray,
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float3 throughput)
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{
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for(int i = 0; i < sd->num_closure; i++) {
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ShaderClosure *sc = &sd->closure[i];
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if(!CLOSURE_IS_BSSRDF(sc->type))
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continue;
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/* set up random number generator */
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uint lcg_state = lcg_state_init(state, 0x68bc21eb);
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int num_samples = kernel_data.integrator.subsurface_samples;
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float num_samples_inv = 1.0f/num_samples;
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uint bssrdf_rng_hash = cmj_hash(state->rng_hash, i);
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/* do subsurface scatter step with copy of shader data, this will
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* replace the BSSRDF with a diffuse BSDF closure */
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for(int j = 0; j < num_samples; j++) {
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SubsurfaceIntersection ss_isect;
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float bssrdf_u, bssrdf_v;
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path_branched_rng_2D(kg, bssrdf_rng_hash, state, j, num_samples, PRNG_BSDF_U, &bssrdf_u, &bssrdf_v);
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int num_hits = subsurface_scatter_multi_intersect(kg,
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&ss_isect,
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sd,
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sc,
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&lcg_state,
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bssrdf_u, bssrdf_v,
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true);
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#ifdef __VOLUME__
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Ray volume_ray = *ray;
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bool need_update_volume_stack =
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kernel_data.integrator.use_volumes &&
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sd->object_flag & SD_OBJECT_INTERSECTS_VOLUME;
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#endif /* __VOLUME__ */
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/* compute lighting with the BSDF closure */
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for(int hit = 0; hit < num_hits; hit++) {
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ShaderData bssrdf_sd = *sd;
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subsurface_scatter_multi_setup(kg,
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&ss_isect,
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hit,
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&bssrdf_sd,
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state,
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state->flag,
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sc,
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true);
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PathState hit_state = *state;
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path_state_branch(&hit_state, j, num_samples);
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#ifdef __VOLUME__
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if(need_update_volume_stack) {
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/* Setup ray from previous surface point to the new one. */
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float3 P = ray_offset(bssrdf_sd.P, -bssrdf_sd.Ng);
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volume_ray.D = normalize_len(P - volume_ray.P,
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&volume_ray.t);
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kernel_volume_stack_update_for_subsurface(
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kg,
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emission_sd,
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&volume_ray,
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hit_state.volume_stack);
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}
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#endif /* __VOLUME__ */
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#ifdef __EMISSION__
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/* direct light */
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if(kernel_data.integrator.use_direct_light) {
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int all = (kernel_data.integrator.sample_all_lights_direct) ||
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(state->flag & PATH_RAY_SHADOW_CATCHER);
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kernel_branched_path_surface_connect_light(
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kg,
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&bssrdf_sd,
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emission_sd,
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&hit_state,
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throughput,
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num_samples_inv,
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L,
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all);
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}
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#endif /* __EMISSION__ */
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/* indirect light */
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kernel_branched_path_surface_indirect_light(
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kg,
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&bssrdf_sd,
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indirect_sd,
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emission_sd,
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throughput,
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num_samples_inv,
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&hit_state,
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L);
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}
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}
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}
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}
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#endif /* __SUBSURFACE__ */
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ccl_device void kernel_branched_path_integrate(KernelGlobals *kg,
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uint rng_hash,
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int sample,
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Ray ray,
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ccl_global float *buffer,
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PathRadiance *L)
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{
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/* initialize */
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float3 throughput = make_float3(1.0f, 1.0f, 1.0f);
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path_radiance_init(L, kernel_data.film.use_light_pass);
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/* shader data memory used for both volumes and surfaces, saves stack space */
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ShaderData sd;
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/* shader data used by emission, shadows, volume stacks, indirect path */
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ShaderData emission_sd, indirect_sd;
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PathState state;
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path_state_init(kg, &emission_sd, &state, rng_hash, sample, &ray);
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/* Main Loop
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* Here we only handle transparency intersections from the camera ray.
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* Indirect bounces are handled in kernel_branched_path_surface_indirect_light().
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*/
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for(;;) {
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/* Find intersection with objects in scene. */
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Intersection isect;
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bool hit = kernel_path_scene_intersect(kg, &state, &ray, &isect, L);
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#ifdef __VOLUME__
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/* Volume integration. */
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kernel_branched_path_volume(kg,
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&sd,
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&state,
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&ray,
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&throughput,
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&isect,
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hit,
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&indirect_sd,
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&emission_sd,
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L);
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#endif /* __VOLUME__ */
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/* Shade background. */
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if(!hit) {
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kernel_path_background(kg, &state, &ray, throughput, &emission_sd, L);
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break;
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}
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/* Setup and evaluate shader. */
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shader_setup_from_ray(kg, &sd, &isect, &ray);
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shader_eval_surface(kg, &sd, &state, state.flag);
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shader_merge_closures(&sd);
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/* Apply shadow catcher, holdout, emission. */
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if(!kernel_path_shader_apply(kg,
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&sd,
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&state,
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&ray,
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throughput,
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&emission_sd,
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L,
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buffer))
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{
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break;
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}
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/* transparency termination */
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if(state.flag & PATH_RAY_TRANSPARENT) {
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/* path termination. this is a strange place to put the termination, it's
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* mainly due to the mixed in MIS that we use. gives too many unneeded
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* shader evaluations, only need emission if we are going to terminate */
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float probability = path_state_continuation_probability(kg, &state, throughput);
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if(probability == 0.0f) {
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break;
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}
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else if(probability != 1.0f) {
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float terminate = path_state_rng_1D(kg, &state, PRNG_TERMINATE);
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if(terminate >= probability)
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break;
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throughput /= probability;
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}
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}
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kernel_update_denoising_features(kg, &sd, &state, L);
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#ifdef __AO__
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/* ambient occlusion */
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if(kernel_data.integrator.use_ambient_occlusion || (sd.flag & SD_AO)) {
|
|
kernel_branched_path_ao(kg, &sd, &emission_sd, L, &state, throughput);
|
|
}
|
|
#endif /* __AO__ */
|
|
|
|
#ifdef __SUBSURFACE__
|
|
/* bssrdf scatter to a different location on the same object */
|
|
if(sd.flag & SD_BSSRDF) {
|
|
kernel_branched_path_subsurface_scatter(kg, &sd, &indirect_sd, &emission_sd,
|
|
L, &state, &ray, throughput);
|
|
}
|
|
#endif /* __SUBSURFACE__ */
|
|
|
|
if(!(sd.flag & SD_HAS_ONLY_VOLUME)) {
|
|
PathState hit_state = state;
|
|
|
|
#ifdef __EMISSION__
|
|
/* direct light */
|
|
if(kernel_data.integrator.use_direct_light) {
|
|
int all = (kernel_data.integrator.sample_all_lights_direct) ||
|
|
(state.flag & PATH_RAY_SHADOW_CATCHER);
|
|
kernel_branched_path_surface_connect_light(kg,
|
|
&sd, &emission_sd, &hit_state, throughput, 1.0f, L, all);
|
|
}
|
|
#endif /* __EMISSION__ */
|
|
|
|
/* indirect light */
|
|
kernel_branched_path_surface_indirect_light(kg,
|
|
&sd, &indirect_sd, &emission_sd, throughput, 1.0f, &hit_state, L);
|
|
|
|
/* continue in case of transparency */
|
|
throughput *= shader_bsdf_transparency(kg, &sd);
|
|
|
|
if(is_zero(throughput))
|
|
break;
|
|
}
|
|
|
|
/* Update Path State */
|
|
state.flag |= PATH_RAY_TRANSPARENT;
|
|
state.transparent_bounce++;
|
|
|
|
ray.P = ray_offset(sd.P, -sd.Ng);
|
|
ray.t -= sd.ray_length; /* clipping works through transparent */
|
|
|
|
|
|
#ifdef __RAY_DIFFERENTIALS__
|
|
ray.dP = sd.dP;
|
|
ray.dD.dx = -sd.dI.dx;
|
|
ray.dD.dy = -sd.dI.dy;
|
|
#endif /* __RAY_DIFFERENTIALS__ */
|
|
|
|
#ifdef __VOLUME__
|
|
/* enter/exit volume */
|
|
kernel_volume_stack_enter_exit(kg, &sd, state.volume_stack);
|
|
#endif /* __VOLUME__ */
|
|
}
|
|
}
|
|
|
|
ccl_device void kernel_branched_path_trace(KernelGlobals *kg,
|
|
ccl_global float *buffer,
|
|
int sample, int x, int y, int offset, int stride)
|
|
{
|
|
/* buffer offset */
|
|
int index = offset + x + y*stride;
|
|
int pass_stride = kernel_data.film.pass_stride;
|
|
|
|
buffer += index*pass_stride;
|
|
|
|
/* initialize random numbers and ray */
|
|
uint rng_hash;
|
|
Ray ray;
|
|
|
|
kernel_path_trace_setup(kg, sample, x, y, &rng_hash, &ray);
|
|
|
|
/* integrate */
|
|
PathRadiance L;
|
|
|
|
if(ray.t != 0.0f) {
|
|
kernel_branched_path_integrate(kg, rng_hash, sample, ray, buffer, &L);
|
|
kernel_write_result(kg, buffer, sample, &L);
|
|
}
|
|
}
|
|
|
|
#endif /* __SPLIT_KERNEL__ */
|
|
|
|
#endif /* __BRANCHED_PATH__ */
|
|
|
|
CCL_NAMESPACE_END
|