forked from bartvdbraak/blender
915766f42d
This implements branched path tracing for the split kernel. General approach is to store the ray state at a branch point, trace the branched ray as normal, then restore the state as necessary before iterating to the next part of the path. A state machine is used to advance the indirect loop state, which avoids the need to add any new kernels. Each iteration the state machine recreates as much state as possible from the stored ray to keep overall storage down. Its kind of hard to keep all the different integration loops in sync, so this needs lots of testing to make sure everything is working correctly. We should probably start trying to deduplicate the integration loops more now. Nonbranched BMW is ~2% slower, while classroom is ~2% faster, other scenes could use more testing still. Reviewers: sergey, nirved Reviewed By: nirved Subscribers: Blendify, bliblubli Differential Revision: https://developer.blender.org/D2611
827 lines
26 KiB
C
827 lines
26 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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#ifdef __OSL__
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# include "kernel/osl/osl_shader.h"
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#endif
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#include "kernel/kernel_random.h"
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#include "kernel/kernel_projection.h"
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#include "kernel/kernel_montecarlo.h"
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#include "kernel/kernel_differential.h"
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#include "kernel/kernel_camera.h"
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#include "kernel/geom/geom.h"
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#include "kernel/bvh/bvh.h"
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#include "kernel/kernel_accumulate.h"
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#include "kernel/kernel_shader.h"
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#include "kernel/kernel_light.h"
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#include "kernel/kernel_passes.h"
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#ifdef __SUBSURFACE__
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# include "kernel/kernel_subsurface.h"
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#endif
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#ifdef __VOLUME__
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# include "kernel/kernel_volume.h"
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#endif
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#include "kernel/kernel_path_state.h"
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#include "kernel/kernel_shadow.h"
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#include "kernel/kernel_emission.h"
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#include "kernel/kernel_path_common.h"
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#include "kernel/kernel_path_surface.h"
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#include "kernel/kernel_path_volume.h"
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#include "kernel/kernel_path_subsurface.h"
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#ifdef __KERNEL_DEBUG__
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# include "kernel/kernel_debug.h"
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#endif
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CCL_NAMESPACE_BEGIN
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ccl_device_noinline void kernel_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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RNG *rng,
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float3 throughput,
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float3 ao_alpha)
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{
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/* todo: solve correlation */
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float bsdf_u, bsdf_v;
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path_state_rng_2D(kg, rng, state, PRNG_BSDF_U, &bsdf_u, &bsdf_v);
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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_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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#ifdef __OBJECT_MOTION__
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light_ray.time = sd->time;
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#endif /* __OBJECT_MOTION__ */
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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, emission_sd, state, &light_ray, &ao_shadow)) {
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path_radiance_accum_ao(L, throughput, ao_alpha, ao_bsdf, ao_shadow, state->bounce);
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}
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else {
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path_radiance_accum_total_ao(L, throughput, ao_bsdf);
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}
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}
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}
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#ifndef __SPLIT_KERNEL__
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ccl_device void kernel_path_indirect(KernelGlobals *kg,
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ShaderData *sd,
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ShaderData *emission_sd,
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RNG *rng,
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Ray *ray,
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float3 throughput,
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int num_samples,
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PathState *state,
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PathRadiance *L)
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{
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/* path iteration */
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for(;;) {
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/* intersect scene */
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Intersection isect;
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uint visibility = path_state_ray_visibility(kg, state);
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if(state->bounce > kernel_data.integrator.ao_bounces) {
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visibility = PATH_RAY_SHADOW;
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ray->t = kernel_data.background.ao_distance;
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}
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bool hit = scene_intersect(kg,
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*ray,
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visibility,
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&isect,
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NULL,
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0.0f, 0.0f);
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#ifdef __LAMP_MIS__
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if(kernel_data.integrator.use_lamp_mis && !(state->flag & PATH_RAY_CAMERA)) {
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/* ray starting from previous non-transparent bounce */
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Ray light_ray;
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light_ray.P = ray->P - state->ray_t*ray->D;
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state->ray_t += isect.t;
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light_ray.D = ray->D;
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light_ray.t = state->ray_t;
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light_ray.time = ray->time;
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light_ray.dD = ray->dD;
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light_ray.dP = ray->dP;
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/* intersect with lamp */
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float3 emission;
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if(indirect_lamp_emission(kg, emission_sd, state, &light_ray, &emission)) {
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path_radiance_accum_emission(L,
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throughput,
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emission,
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state->bounce);
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}
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}
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#endif /* __LAMP_MIS__ */
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#ifdef __VOLUME__
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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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/* volume attenuation, emission, scatter */
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if(state->volume_stack[0].shader != SHADER_NONE) {
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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 =
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volume_stack_is_heterogeneous(kg,
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state->volume_stack);
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# ifdef __VOLUME_DECOUPLED__
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int sampling_method =
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volume_stack_sampling_method(kg,
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state->volume_stack);
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bool decoupled = kernel_volume_use_decoupled(kg, heterogeneous, false, sampling_method);
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if(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,
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sd,
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&volume_ray);
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kernel_volume_decoupled_record(kg,
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state,
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&volume_ray,
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sd,
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&volume_segment,
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heterogeneous);
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volume_segment.sampling_method = sampling_method;
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/* emission */
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if(volume_segment.closure_flag & SD_EMISSION) {
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path_radiance_accum_emission(L,
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throughput,
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volume_segment.accum_emission,
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state->bounce);
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}
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/* scattering */
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VolumeIntegrateResult result = VOLUME_PATH_ATTENUATED;
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if(volume_segment.closure_flag & SD_SCATTER) {
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int all = kernel_data.integrator.sample_all_lights_indirect;
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/* direct light sampling */
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kernel_branched_path_volume_connect_light(kg,
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rng,
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sd,
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emission_sd,
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throughput,
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state,
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L,
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all,
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&volume_ray,
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&volume_segment);
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/* indirect sample. if we use distance sampling and take just
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* one sample for direct and indirect light, we could share
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* this computation, but makes code a bit complex */
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float rphase = path_state_rng_1D_for_decision(kg, rng, state, PRNG_PHASE);
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float rscatter = path_state_rng_1D_for_decision(kg, rng, state, PRNG_SCATTER_DISTANCE);
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result = kernel_volume_decoupled_scatter(kg,
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state,
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&volume_ray,
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sd,
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&throughput,
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rphase,
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rscatter,
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&volume_segment,
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NULL,
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true);
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}
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/* free cached steps */
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kernel_volume_decoupled_free(kg, &volume_segment);
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if(result == VOLUME_PATH_SCATTERED) {
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if(kernel_path_volume_bounce(kg,
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rng,
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sd,
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&throughput,
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state,
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L,
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ray))
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{
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continue;
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}
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else {
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break;
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}
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}
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else {
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throughput *= volume_segment.accum_transmittance;
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}
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}
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else
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# endif /* __VOLUME_DECOUPLED__ */
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{
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/* integrate along volume segment with distance sampling */
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VolumeIntegrateResult result = kernel_volume_integrate(
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kg, state, sd, &volume_ray, L, &throughput, rng, heterogeneous);
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# ifdef __VOLUME_SCATTER__
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if(result == VOLUME_PATH_SCATTERED) {
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/* direct lighting */
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kernel_path_volume_connect_light(kg,
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rng,
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sd,
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emission_sd,
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throughput,
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state,
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L);
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/* indirect light bounce */
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if(kernel_path_volume_bounce(kg,
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rng,
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sd,
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&throughput,
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state,
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L,
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ray))
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{
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continue;
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}
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else {
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break;
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}
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}
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# endif /* __VOLUME_SCATTER__ */
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}
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}
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#endif /* __VOLUME__ */
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if(!hit) {
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#ifdef __BACKGROUND__
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/* sample background shader */
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float3 L_background = indirect_background(kg, emission_sd, state, ray);
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path_radiance_accum_background(L,
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state,
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throughput,
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L_background);
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#endif /* __BACKGROUND__ */
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break;
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}
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else if(state->bounce > kernel_data.integrator.ao_bounces) {
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break;
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}
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/* setup shading */
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shader_setup_from_ray(kg,
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sd,
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&isect,
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ray);
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float rbsdf = path_state_rng_1D_for_decision(kg, rng, state, PRNG_BSDF);
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shader_eval_surface(kg, sd, rng, state, rbsdf, state->flag, SHADER_CONTEXT_INDIRECT);
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#ifdef __BRANCHED_PATH__
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shader_merge_closures(sd);
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#endif /* __BRANCHED_PATH__ */
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#ifdef __SHADOW_TRICKS__
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if(!(sd->object_flag & SD_OBJECT_SHADOW_CATCHER)) {
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state->flag &= ~PATH_RAY_SHADOW_CATCHER_ONLY;
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}
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#endif /* __SHADOW_TRICKS__ */
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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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float blur_pdf = kernel_data.integrator.filter_glossy*state->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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shader_bsdf_blur(kg, sd, blur_roughness);
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}
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}
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#ifdef __EMISSION__
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/* emission */
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if(sd->flag & SD_EMISSION) {
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float3 emission = indirect_primitive_emission(kg,
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sd,
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isect.t,
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state->flag,
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state->ray_pdf);
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path_radiance_accum_emission(L, throughput, emission, state->bounce);
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}
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#endif /* __EMISSION__ */
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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 =
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path_state_terminate_probability(kg,
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state,
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throughput*num_samples);
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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_for_decision(kg, rng, 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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#ifdef __AO__
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/* ambient occlusion */
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if(kernel_data.integrator.use_ambient_occlusion || (sd->flag & SD_AO)) {
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kernel_path_ao(kg, sd, emission_sd, L, state, rng, throughput, make_float3(0.0f, 0.0f, 0.0f));
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}
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#endif /* __AO__ */
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#ifdef __SUBSURFACE__
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/* bssrdf scatter to a different location on the same object, replacing
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* the closures with a diffuse BSDF */
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if(sd->flag & SD_BSSRDF) {
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float bssrdf_probability;
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ShaderClosure *sc = subsurface_scatter_pick_closure(kg, sd, &bssrdf_probability);
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/* modify throughput for picking bssrdf or bsdf */
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throughput *= bssrdf_probability;
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/* do bssrdf scatter step if we picked a bssrdf closure */
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if(sc) {
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uint lcg_state = lcg_state_init(rng, state->rng_offset, state->sample, 0x68bc21eb);
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float bssrdf_u, bssrdf_v;
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path_state_rng_2D(kg,
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rng,
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state,
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PRNG_BSDF_U,
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&bssrdf_u, &bssrdf_v);
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subsurface_scatter_step(kg,
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sd,
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state,
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state->flag,
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sc,
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&lcg_state,
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bssrdf_u, bssrdf_v,
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false);
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}
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}
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#endif /* __SUBSURFACE__ */
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#if defined(__EMISSION__) && defined(__BRANCHED_PATH__)
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if(kernel_data.integrator.use_direct_light) {
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int all = (kernel_data.integrator.sample_all_lights_indirect) ||
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(state->flag & PATH_RAY_SHADOW_CATCHER);
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kernel_branched_path_surface_connect_light(kg,
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rng,
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sd,
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emission_sd,
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state,
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throughput,
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1.0f,
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L,
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all);
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}
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#endif /* defined(__EMISSION__) && defined(__BRANCHED_PATH__) */
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if(!kernel_path_surface_bounce(kg, rng, sd, &throughput, state, L, ray))
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break;
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}
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}
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ccl_device_inline float4 kernel_path_integrate(KernelGlobals *kg,
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RNG *rng,
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int sample,
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Ray ray,
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ccl_global float *buffer)
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{
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/* initialize */
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PathRadiance L;
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float3 throughput = make_float3(1.0f, 1.0f, 1.0f);
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float L_transparent = 0.0f;
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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 */
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ShaderData emission_sd;
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PathState state;
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path_state_init(kg, &emission_sd, &state, rng, sample, &ray);
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#ifdef __KERNEL_DEBUG__
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DebugData debug_data;
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debug_data_init(&debug_data);
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#endif /* __KERNEL_DEBUG__ */
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#ifdef __SUBSURFACE__
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SubsurfaceIndirectRays ss_indirect;
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kernel_path_subsurface_init_indirect(&ss_indirect);
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for(;;) {
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#endif /* __SUBSURFACE__ */
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/* path iteration */
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for(;;) {
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/* intersect scene */
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Intersection isect;
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uint visibility = path_state_ray_visibility(kg, &state);
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#ifdef __HAIR__
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float difl = 0.0f, extmax = 0.0f;
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uint lcg_state = 0;
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if(kernel_data.bvh.have_curves) {
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if((kernel_data.cam.resolution == 1) && (state.flag & PATH_RAY_CAMERA)) {
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float3 pixdiff = ray.dD.dx + ray.dD.dy;
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/*pixdiff = pixdiff - dot(pixdiff, ray.D)*ray.D;*/
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difl = kernel_data.curve.minimum_width * len(pixdiff) * 0.5f;
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}
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extmax = kernel_data.curve.maximum_width;
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lcg_state = lcg_state_init(rng, state.rng_offset, state.sample, 0x51633e2d);
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}
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if(state.bounce > kernel_data.integrator.ao_bounces) {
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visibility = PATH_RAY_SHADOW;
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ray.t = kernel_data.background.ao_distance;
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}
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bool hit = scene_intersect(kg, ray, visibility, &isect, &lcg_state, difl, extmax);
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#else
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bool hit = scene_intersect(kg, ray, visibility, &isect, NULL, 0.0f, 0.0f);
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#endif /* __HAIR__ */
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#ifdef __KERNEL_DEBUG__
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if(state.flag & PATH_RAY_CAMERA) {
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debug_data.num_bvh_traversed_nodes += isect.num_traversed_nodes;
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debug_data.num_bvh_traversed_instances += isect.num_traversed_instances;
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debug_data.num_bvh_intersections += isect.num_intersections;
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}
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debug_data.num_ray_bounces++;
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#endif /* __KERNEL_DEBUG__ */
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#ifdef __LAMP_MIS__
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if(kernel_data.integrator.use_lamp_mis && !(state.flag & PATH_RAY_CAMERA)) {
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/* ray starting from previous non-transparent bounce */
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Ray light_ray;
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|
|
light_ray.P = ray.P - state.ray_t*ray.D;
|
|
state.ray_t += isect.t;
|
|
light_ray.D = ray.D;
|
|
light_ray.t = state.ray_t;
|
|
light_ray.time = ray.time;
|
|
light_ray.dD = ray.dD;
|
|
light_ray.dP = ray.dP;
|
|
|
|
/* intersect with lamp */
|
|
float3 emission;
|
|
|
|
if(indirect_lamp_emission(kg, &emission_sd, &state, &light_ray, &emission))
|
|
path_radiance_accum_emission(&L, throughput, emission, state.bounce);
|
|
}
|
|
#endif /* __LAMP_MIS__ */
|
|
|
|
#ifdef __VOLUME__
|
|
/* Sanitize volume stack. */
|
|
if(!hit) {
|
|
kernel_volume_clean_stack(kg, state.volume_stack);
|
|
}
|
|
/* volume attenuation, emission, scatter */
|
|
if(state.volume_stack[0].shader != SHADER_NONE) {
|
|
Ray volume_ray = ray;
|
|
volume_ray.t = (hit)? isect.t: FLT_MAX;
|
|
|
|
bool heterogeneous = volume_stack_is_heterogeneous(kg, state.volume_stack);
|
|
|
|
# ifdef __VOLUME_DECOUPLED__
|
|
int sampling_method = volume_stack_sampling_method(kg, state.volume_stack);
|
|
bool decoupled = kernel_volume_use_decoupled(kg, heterogeneous, true, sampling_method);
|
|
|
|
if(decoupled) {
|
|
/* cache steps along volume for repeated sampling */
|
|
VolumeSegment volume_segment;
|
|
|
|
shader_setup_from_volume(kg, &sd, &volume_ray);
|
|
kernel_volume_decoupled_record(kg, &state,
|
|
&volume_ray, &sd, &volume_segment, heterogeneous);
|
|
|
|
volume_segment.sampling_method = sampling_method;
|
|
|
|
/* emission */
|
|
if(volume_segment.closure_flag & SD_EMISSION)
|
|
path_radiance_accum_emission(&L, throughput, volume_segment.accum_emission, state.bounce);
|
|
|
|
/* scattering */
|
|
VolumeIntegrateResult result = VOLUME_PATH_ATTENUATED;
|
|
|
|
if(volume_segment.closure_flag & SD_SCATTER) {
|
|
int all = false;
|
|
|
|
/* direct light sampling */
|
|
kernel_branched_path_volume_connect_light(kg, rng, &sd,
|
|
&emission_sd, throughput, &state, &L, all,
|
|
&volume_ray, &volume_segment);
|
|
|
|
/* indirect sample. if we use distance sampling and take just
|
|
* one sample for direct and indirect light, we could share
|
|
* this computation, but makes code a bit complex */
|
|
float rphase = path_state_rng_1D_for_decision(kg, rng, &state, PRNG_PHASE);
|
|
float rscatter = path_state_rng_1D_for_decision(kg, rng, &state, PRNG_SCATTER_DISTANCE);
|
|
|
|
result = kernel_volume_decoupled_scatter(kg,
|
|
&state, &volume_ray, &sd, &throughput,
|
|
rphase, rscatter, &volume_segment, NULL, true);
|
|
}
|
|
|
|
/* free cached steps */
|
|
kernel_volume_decoupled_free(kg, &volume_segment);
|
|
|
|
if(result == VOLUME_PATH_SCATTERED) {
|
|
if(kernel_path_volume_bounce(kg, rng, &sd, &throughput, &state, &L, &ray))
|
|
continue;
|
|
else
|
|
break;
|
|
}
|
|
else {
|
|
throughput *= volume_segment.accum_transmittance;
|
|
}
|
|
}
|
|
else
|
|
# endif /* __VOLUME_DECOUPLED__ */
|
|
{
|
|
/* integrate along volume segment with distance sampling */
|
|
VolumeIntegrateResult result = kernel_volume_integrate(
|
|
kg, &state, &sd, &volume_ray, &L, &throughput, rng, heterogeneous);
|
|
|
|
# ifdef __VOLUME_SCATTER__
|
|
if(result == VOLUME_PATH_SCATTERED) {
|
|
/* direct lighting */
|
|
kernel_path_volume_connect_light(kg, rng, &sd, &emission_sd, throughput, &state, &L);
|
|
|
|
/* indirect light bounce */
|
|
if(kernel_path_volume_bounce(kg, rng, &sd, &throughput, &state, &L, &ray))
|
|
continue;
|
|
else
|
|
break;
|
|
}
|
|
# endif /* __VOLUME_SCATTER__ */
|
|
}
|
|
}
|
|
#endif /* __VOLUME__ */
|
|
|
|
if(!hit) {
|
|
/* eval background shader if nothing hit */
|
|
if(kernel_data.background.transparent && (state.flag & PATH_RAY_CAMERA)) {
|
|
L_transparent += average(throughput);
|
|
|
|
#ifdef __PASSES__
|
|
if(!(kernel_data.film.pass_flag & PASS_BACKGROUND))
|
|
#endif /* __PASSES__ */
|
|
break;
|
|
}
|
|
|
|
#ifdef __BACKGROUND__
|
|
/* sample background shader */
|
|
float3 L_background = indirect_background(kg, &emission_sd, &state, &ray);
|
|
path_radiance_accum_background(&L, &state, throughput, L_background);
|
|
#endif /* __BACKGROUND__ */
|
|
|
|
break;
|
|
}
|
|
else if(state.bounce > kernel_data.integrator.ao_bounces) {
|
|
break;
|
|
}
|
|
|
|
/* setup shading */
|
|
shader_setup_from_ray(kg, &sd, &isect, &ray);
|
|
float rbsdf = path_state_rng_1D_for_decision(kg, rng, &state, PRNG_BSDF);
|
|
shader_eval_surface(kg, &sd, rng, &state, rbsdf, state.flag, SHADER_CONTEXT_MAIN);
|
|
|
|
#ifdef __SHADOW_TRICKS__
|
|
if((sd.object_flag & SD_OBJECT_SHADOW_CATCHER)) {
|
|
if(state.flag & PATH_RAY_CAMERA) {
|
|
state.flag |= (PATH_RAY_SHADOW_CATCHER | PATH_RAY_SHADOW_CATCHER_ONLY);
|
|
state.catcher_object = sd.object;
|
|
if(!kernel_data.background.transparent) {
|
|
L.shadow_color = indirect_background(kg, &emission_sd, &state, &ray);
|
|
}
|
|
}
|
|
}
|
|
else {
|
|
state.flag &= ~PATH_RAY_SHADOW_CATCHER_ONLY;
|
|
}
|
|
#endif /* __SHADOW_TRICKS__ */
|
|
|
|
/* holdout */
|
|
#ifdef __HOLDOUT__
|
|
if(((sd.flag & SD_HOLDOUT) ||
|
|
(sd.object_flag & SD_OBJECT_HOLDOUT_MASK)) &&
|
|
(state.flag & PATH_RAY_CAMERA))
|
|
{
|
|
if(kernel_data.background.transparent) {
|
|
float3 holdout_weight;
|
|
if(sd.object_flag & SD_OBJECT_HOLDOUT_MASK) {
|
|
holdout_weight = make_float3(1.0f, 1.0f, 1.0f);
|
|
}
|
|
else {
|
|
holdout_weight = shader_holdout_eval(kg, &sd);
|
|
}
|
|
/* any throughput is ok, should all be identical here */
|
|
L_transparent += average(holdout_weight*throughput);
|
|
}
|
|
|
|
if(sd.object_flag & SD_OBJECT_HOLDOUT_MASK) {
|
|
break;
|
|
}
|
|
}
|
|
#endif /* __HOLDOUT__ */
|
|
|
|
/* holdout mask objects do not write data passes */
|
|
kernel_write_data_passes(kg, buffer, &L, &sd, sample, &state, throughput);
|
|
|
|
/* 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) {
|
|
float blur_pdf = kernel_data.integrator.filter_glossy*state.min_ray_pdf;
|
|
|
|
if(blur_pdf < 1.0f) {
|
|
float blur_roughness = sqrtf(1.0f - blur_pdf)*0.5f;
|
|
shader_bsdf_blur(kg, &sd, blur_roughness);
|
|
}
|
|
}
|
|
|
|
#ifdef __EMISSION__
|
|
/* emission */
|
|
if(sd.flag & SD_EMISSION) {
|
|
/* todo: is isect.t wrong here for transparent surfaces? */
|
|
float3 emission = indirect_primitive_emission(kg, &sd, isect.t, state.flag, state.ray_pdf);
|
|
path_radiance_accum_emission(&L, throughput, emission, state.bounce);
|
|
}
|
|
#endif /* __EMISSION__ */
|
|
|
|
/* path termination. this is a strange place to put the termination, it's
|
|
* mainly due to the mixed in MIS that we use. gives too many unneeded
|
|
* shader evaluations, only need emission if we are going to terminate */
|
|
float probability = path_state_terminate_probability(kg, &state, throughput);
|
|
|
|
if(probability == 0.0f) {
|
|
break;
|
|
}
|
|
else if(probability != 1.0f) {
|
|
float terminate = path_state_rng_1D_for_decision(kg, rng, &state, PRNG_TERMINATE);
|
|
if(terminate >= probability)
|
|
break;
|
|
|
|
throughput /= probability;
|
|
}
|
|
|
|
#ifdef __AO__
|
|
/* ambient occlusion */
|
|
if(kernel_data.integrator.use_ambient_occlusion || (sd.flag & SD_AO)) {
|
|
kernel_path_ao(kg, &sd, &emission_sd, &L, &state, rng, throughput, shader_bsdf_alpha(kg, &sd));
|
|
}
|
|
#endif /* __AO__ */
|
|
|
|
#ifdef __SUBSURFACE__
|
|
/* bssrdf scatter to a different location on the same object, replacing
|
|
* the closures with a diffuse BSDF */
|
|
if(sd.flag & SD_BSSRDF) {
|
|
if(kernel_path_subsurface_scatter(kg,
|
|
&sd,
|
|
&emission_sd,
|
|
&L,
|
|
&state,
|
|
rng,
|
|
&ray,
|
|
&throughput,
|
|
&ss_indirect))
|
|
{
|
|
break;
|
|
}
|
|
}
|
|
#endif /* __SUBSURFACE__ */
|
|
|
|
/* direct lighting */
|
|
kernel_path_surface_connect_light(kg, rng, &sd, &emission_sd, throughput, &state, &L);
|
|
|
|
/* compute direct lighting and next bounce */
|
|
if(!kernel_path_surface_bounce(kg, rng, &sd, &throughput, &state, &L, &ray))
|
|
break;
|
|
}
|
|
|
|
#ifdef __SUBSURFACE__
|
|
kernel_path_subsurface_accum_indirect(&ss_indirect, &L);
|
|
|
|
/* Trace indirect subsurface rays by restarting the loop. this uses less
|
|
* stack memory than invoking kernel_path_indirect.
|
|
*/
|
|
if(ss_indirect.num_rays) {
|
|
kernel_path_subsurface_setup_indirect(kg,
|
|
&ss_indirect,
|
|
&state,
|
|
&ray,
|
|
&L,
|
|
&throughput);
|
|
}
|
|
else {
|
|
break;
|
|
}
|
|
}
|
|
#endif /* __SUBSURFACE__ */
|
|
|
|
float3 L_sum;
|
|
#ifdef __SHADOW_TRICKS__
|
|
if(state.flag & PATH_RAY_SHADOW_CATCHER) {
|
|
L_sum = path_radiance_sum_shadowcatcher(kg, &L, &L_transparent);
|
|
}
|
|
else
|
|
#endif /* __SHADOW_TRICKS__ */
|
|
{
|
|
L_sum = path_radiance_clamp_and_sum(kg, &L);
|
|
}
|
|
|
|
kernel_write_light_passes(kg, buffer, &L, sample);
|
|
|
|
#ifdef __KERNEL_DEBUG__
|
|
kernel_write_debug_passes(kg, buffer, &state, &debug_data, sample);
|
|
#endif /* __KERNEL_DEBUG__ */
|
|
|
|
return make_float4(L_sum.x, L_sum.y, L_sum.z, 1.0f - L_transparent);
|
|
}
|
|
|
|
ccl_device void kernel_path_trace(KernelGlobals *kg,
|
|
ccl_global float *buffer, ccl_global uint *rng_state,
|
|
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;
|
|
|
|
rng_state += index;
|
|
buffer += index*pass_stride;
|
|
|
|
/* initialize random numbers and ray */
|
|
RNG rng;
|
|
Ray ray;
|
|
|
|
kernel_path_trace_setup(kg, rng_state, sample, x, y, &rng, &ray);
|
|
|
|
/* integrate */
|
|
float4 L;
|
|
|
|
if(ray.t != 0.0f)
|
|
L = kernel_path_integrate(kg, &rng, sample, ray, buffer);
|
|
else
|
|
L = make_float4(0.0f, 0.0f, 0.0f, 0.0f);
|
|
|
|
/* accumulate result in output buffer */
|
|
kernel_write_pass_float4(buffer, sample, L);
|
|
|
|
path_rng_end(kg, rng_state, rng);
|
|
}
|
|
|
|
#endif /* __SPLIT_KERNEL__ */
|
|
|
|
CCL_NAMESPACE_END
|
|
|