forked from bartvdbraak/blender
Brecht Van Lommel
01df756bd1
This is done by adding a Volume Scatter node. In many cases you will want to add together a Volume Absorption and Volume Scatter node with the same color and density to get the expected results. This should work with branched path tracing, mixing closures, overlapping volumes, etc. However there's still various optimizations needed for sampling. The main missing thing from the volume branch is the equiangular sampling for homogeneous volumes. The heterogeneous scattering code was arranged such that we can use a single stratified random number for distance sampling, which gives less noise than pseudo random numbers for each step. For volumes where the color is textured there still seems to be something off, needs to be investigated.
1431 lines
40 KiB
C
1431 lines
40 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 "osl_shader.h"
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#endif
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#include "kernel_differential.h"
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#include "kernel_montecarlo.h"
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#include "kernel_projection.h"
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#include "kernel_object.h"
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#include "kernel_triangle.h"
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#include "kernel_curve.h"
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#include "kernel_primitive.h"
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#include "kernel_projection.h"
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#include "kernel_random.h"
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#include "kernel_bvh.h"
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#include "kernel_accumulate.h"
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#include "kernel_camera.h"
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#include "kernel_shader.h"
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#include "kernel_light.h"
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#include "kernel_emission.h"
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#include "kernel_passes.h"
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#ifdef __SUBSURFACE__
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#include "kernel_subsurface.h"
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#endif
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#ifdef __VOLUME__
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#include "kernel_volume.h"
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#endif
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#include "kernel_path_state.h"
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#include "kernel_shadow.h"
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CCL_NAMESPACE_BEGIN
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#ifdef __VOLUME__
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ccl_device_inline bool kernel_path_integrate_scatter_lighting(KernelGlobals *kg, RNG *rng,
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ShaderData *sd, float3 *throughput, PathState *state, PathRadiance *L, Ray *ray,
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float num_samples_adjust)
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{
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#ifdef __EMISSION__
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if(kernel_data.integrator.use_direct_light) {
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/* sample illumination from lights to find path contribution */
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if(sd->flag & SD_BSDF_HAS_EVAL) {
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float light_t = path_state_rng_1D(kg, rng, state, PRNG_LIGHT);
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#ifdef __MULTI_CLOSURE__
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float light_o = 0.0f;
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#else
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float light_o = path_state_rng_1D(kg, rng, state, PRNG_LIGHT_F);
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#endif
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float light_u, light_v;
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path_state_rng_2D(kg, rng, state, PRNG_LIGHT_U, &light_u, &light_v);
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Ray light_ray;
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BsdfEval L_light;
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bool is_lamp;
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#ifdef __OBJECT_MOTION__
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light_ray.time = sd->time;
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#endif
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if(direct_emission(kg, sd, -1, light_t, light_o, light_u, light_v, &light_ray, &L_light, &is_lamp, state->bounce)) {
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/* trace shadow ray */
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float3 shadow;
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if(!shadow_blocked(kg, state, &light_ray, &shadow)) {
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/* accumulate */
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path_radiance_accum_light(L, *throughput * num_samples_adjust, &L_light, shadow, 1.0f, state->bounce, is_lamp);
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}
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}
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}
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}
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#endif
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/* sample phase function */
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float phase_pdf;
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BsdfEval phase_eval;
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float3 phase_omega_in;
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differential3 phase_domega_in;
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float phase_u, phase_v;
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path_state_rng_2D(kg, rng, state, PRNG_PHASE_U, &phase_u, &phase_v);
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int label;
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label = shader_volume_phase_sample(kg, sd, phase_u, phase_v, &phase_eval,
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&phase_omega_in, &phase_domega_in, &phase_pdf);
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if(phase_pdf == 0.0f || bsdf_eval_is_zero(&phase_eval))
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return false;
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/* modify throughput */
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path_radiance_bsdf_bounce(L, throughput, &phase_eval, phase_pdf, state->bounce, label);
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/* set labels */
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state->ray_pdf = phase_pdf;
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#ifdef __LAMP_MIS__
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state->ray_t = 0.0f;
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#endif
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state->min_ray_pdf = fminf(phase_pdf, state->min_ray_pdf);
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/* update path state */
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path_state_next(kg, state, label);
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/* setup ray */
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ray->P = sd->P;
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ray->D = phase_omega_in;
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ray->t = FLT_MAX;
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#ifdef __RAY_DIFFERENTIALS__
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ray->dP = sd->dP;
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ray->dD = phase_domega_in;
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#endif
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return true;
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}
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#endif
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#if defined(__BRANCHED_PATH__) || defined(__SUBSURFACE__)
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ccl_device void kernel_path_indirect(KernelGlobals *kg, RNG *rng, Ray ray, ccl_global float *buffer,
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float3 throughput, int num_samples, PathState state, 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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#ifdef __HAIR__
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bool hit = scene_intersect(kg, &ray, visibility, &isect, NULL, 0.0f, 0.0f);
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#else
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bool hit = scene_intersect(kg, &ray, visibility, &isect);
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#endif
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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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float light_t = path_state_rng_1D(kg, rng, &state, PRNG_LIGHT);
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float3 emission;
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if(indirect_lamp_emission(kg, &light_ray, state.flag, state.ray_pdf, light_t, &emission, state.bounce))
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path_radiance_accum_emission(L, throughput, emission, state.bounce);
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}
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#endif
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#ifdef __VOLUME__
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/* volume attenuation, emission, scatter */
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if(state.volume_stack[0].shader != SHADER_NO_ID) {
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Ray volume_ray = ray;
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volume_ray.t = (hit)? isect.t: FLT_MAX;
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ShaderData volume_sd;
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VolumeIntegrateResult result = kernel_volume_integrate(kg, &state,
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&volume_sd, &volume_ray, L, &throughput, rng);
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if(result == VOLUME_PATH_SCATTERED) {
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if(kernel_path_integrate_scatter_lighting(kg, rng, &volume_sd, &throughput, &state, L, &ray, 1.0f))
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continue;
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else
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break;
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}
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}
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#endif
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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, &ray, state.flag, state.ray_pdf, state.bounce);
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path_radiance_accum_background(L, throughput, L_background, state.bounce);
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#endif
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break;
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}
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/* setup shading */
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ShaderData sd;
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shader_setup_from_ray(kg, &sd, &isect, &ray, state.bounce);
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float rbsdf = path_state_rng_1D(kg, rng, &state, PRNG_BSDF);
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shader_eval_surface(kg, &sd, 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
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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, &sd, isect.t, state.flag, 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
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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_terminate_probability(kg, &state, 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(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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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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float3 ao_alpha = make_float3(0.0f, 0.0f, 0.0f);
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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
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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, &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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}
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#endif
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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, 0x68bc21eb);
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float bssrdf_u, bssrdf_v;
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path_state_rng_2D(kg, rng, &state, PRNG_BSDF_U, &bssrdf_u, &bssrdf_v);
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subsurface_scatter_step(kg, &sd, state.flag, sc, &lcg_state, bssrdf_u, bssrdf_v, false);
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state.flag |= PATH_RAY_BSSRDF_ANCESTOR;
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}
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}
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#endif
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#ifdef __EMISSION__
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if(kernel_data.integrator.use_direct_light) {
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/* sample illumination from lights to find path contribution */
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if(sd.flag & SD_BSDF_HAS_EVAL) {
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float light_t = path_state_rng_1D(kg, rng, &state, PRNG_LIGHT);
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#ifdef __MULTI_CLOSURE__
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float light_o = 0.0f;
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#else
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float light_o = path_state_rng_1D(kg, rng, &state, PRNG_LIGHT_F);
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#endif
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float light_u, light_v;
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path_state_rng_2D(kg, rng, &state, PRNG_LIGHT_U, &light_u, &light_v);
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Ray light_ray;
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BsdfEval L_light;
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bool is_lamp;
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#ifdef __OBJECT_MOTION__
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light_ray.time = sd.time;
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#endif
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/* sample random light */
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if(direct_emission(kg, &sd, -1, light_t, light_o, light_u, light_v, &light_ray, &L_light, &is_lamp, state.bounce)) {
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/* trace shadow ray */
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float3 shadow;
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if(!shadow_blocked(kg, &state, &light_ray, &shadow)) {
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/* accumulate */
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path_radiance_accum_light(L, throughput, &L_light, shadow, 1.0f, state.bounce, is_lamp);
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}
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}
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}
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}
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#endif
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/* no BSDF? we can stop here */
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if(sd.flag & SD_BSDF) {
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/* sample BSDF */
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float bsdf_pdf;
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BsdfEval bsdf_eval;
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float3 bsdf_omega_in;
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differential3 bsdf_domega_in;
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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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int label;
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label = shader_bsdf_sample(kg, &sd, bsdf_u, bsdf_v, &bsdf_eval,
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&bsdf_omega_in, &bsdf_domega_in, &bsdf_pdf);
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if(bsdf_pdf == 0.0f || bsdf_eval_is_zero(&bsdf_eval))
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break;
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/* modify throughput */
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path_radiance_bsdf_bounce(L, &throughput, &bsdf_eval, bsdf_pdf, state.bounce, label);
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/* set labels */
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if(!(label & LABEL_TRANSPARENT)) {
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state.ray_pdf = bsdf_pdf;
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#ifdef __LAMP_MIS__
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state.ray_t = 0.0f;
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#endif
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state.min_ray_pdf = fminf(bsdf_pdf, state.min_ray_pdf);
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}
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/* update path state */
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path_state_next(kg, &state, label);
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/* setup ray */
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ray.P = ray_offset(sd.P, (label & LABEL_TRANSMIT)? -sd.Ng: sd.Ng);
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ray.D = bsdf_omega_in;
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ray.t = FLT_MAX;
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#ifdef __RAY_DIFFERENTIALS__
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ray.dP = sd.dP;
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ray.dD = bsdf_domega_in;
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#endif
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#ifdef __VOLUME__
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/* enter/exit volume */
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if(label & LABEL_TRANSMIT)
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kernel_volume_stack_enter_exit(kg, &sd, state.volume_stack);
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#endif
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}
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#ifdef __VOLUME__
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else if(sd.flag & SD_HAS_ONLY_VOLUME) {
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/* no surface shader but have a volume shader? act transparent */
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/* update path state, count as transparent */
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path_state_next(kg, &state, LABEL_TRANSPARENT);
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/* setup ray position, direction stays unchanged */
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ray.P = ray_offset(sd.P, -sd.Ng);
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#ifdef __RAY_DIFFERENTIALS__
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ray.dP = sd.dP;
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#endif
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/* enter/exit volume */
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kernel_volume_stack_enter_exit(kg, &sd, state.volume_stack);
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}
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#endif
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else {
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/* no bsdf or volume? we're done */
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break;
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}
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}
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}
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#endif
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#ifdef __SUBSURFACE__
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ccl_device_inline bool kernel_path_integrate_lighting(KernelGlobals *kg, RNG *rng,
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ShaderData *sd, float3 *throughput, PathState *state, PathRadiance *L, Ray *ray)
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{
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|
#ifdef __EMISSION__
|
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if(kernel_data.integrator.use_direct_light) {
|
|
/* sample illumination from lights to find path contribution */
|
|
if(sd->flag & SD_BSDF_HAS_EVAL) {
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float light_t = path_state_rng_1D(kg, rng, state, PRNG_LIGHT);
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#ifdef __MULTI_CLOSURE__
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float light_o = 0.0f;
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#else
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float light_o = path_state_rng_1D(kg, rng, state, PRNG_LIGHT_F);
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#endif
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float light_u, light_v;
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path_state_rng_2D(kg, rng, state, PRNG_LIGHT_U, &light_u, &light_v);
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Ray light_ray;
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BsdfEval L_light;
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bool is_lamp;
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#ifdef __OBJECT_MOTION__
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light_ray.time = sd->time;
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#endif
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if(direct_emission(kg, sd, -1, light_t, light_o, light_u, light_v, &light_ray, &L_light, &is_lamp, state->bounce)) {
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/* trace shadow ray */
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float3 shadow;
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if(!shadow_blocked(kg, state, &light_ray, &shadow)) {
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/* accumulate */
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path_radiance_accum_light(L, *throughput, &L_light, shadow, 1.0f, state->bounce, is_lamp);
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}
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}
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}
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}
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#endif
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/* no BSDF? we can stop here */
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if(sd->flag & SD_BSDF) {
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/* sample BSDF */
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float bsdf_pdf;
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BsdfEval bsdf_eval;
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float3 bsdf_omega_in;
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differential3 bsdf_domega_in;
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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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int label;
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label = shader_bsdf_sample(kg, sd, bsdf_u, bsdf_v, &bsdf_eval,
|
|
&bsdf_omega_in, &bsdf_domega_in, &bsdf_pdf);
|
|
|
|
if(bsdf_pdf == 0.0f || bsdf_eval_is_zero(&bsdf_eval))
|
|
return false;
|
|
|
|
/* modify throughput */
|
|
path_radiance_bsdf_bounce(L, throughput, &bsdf_eval, bsdf_pdf, state->bounce, label);
|
|
|
|
/* set labels */
|
|
if(!(label & LABEL_TRANSPARENT)) {
|
|
state->ray_pdf = bsdf_pdf;
|
|
#ifdef __LAMP_MIS__
|
|
state->ray_t = 0.0f;
|
|
#endif
|
|
state->min_ray_pdf = fminf(bsdf_pdf, state->min_ray_pdf);
|
|
}
|
|
|
|
/* update path state */
|
|
path_state_next(kg, state, label);
|
|
|
|
/* setup ray */
|
|
ray->P = ray_offset(sd->P, (label & LABEL_TRANSMIT)? -sd->Ng: sd->Ng);
|
|
ray->D = bsdf_omega_in;
|
|
|
|
if(state->bounce == 0)
|
|
ray->t -= sd->ray_length; /* clipping works through transparent */
|
|
else
|
|
ray->t = FLT_MAX;
|
|
|
|
#ifdef __RAY_DIFFERENTIALS__
|
|
ray->dP = sd->dP;
|
|
ray->dD = bsdf_domega_in;
|
|
#endif
|
|
|
|
#ifdef __VOLUME__
|
|
/* enter/exit volume */
|
|
if(label & LABEL_TRANSMIT)
|
|
kernel_volume_stack_enter_exit(kg, sd, state->volume_stack);
|
|
#endif
|
|
return true;
|
|
}
|
|
#ifdef __VOLUME__
|
|
else if(sd->flag & SD_HAS_ONLY_VOLUME) {
|
|
/* no surface shader but have a volume shader? act transparent */
|
|
|
|
/* update path state, count as transparent */
|
|
path_state_next(kg, state, LABEL_TRANSPARENT);
|
|
|
|
/* setup ray position, direction stays unchanged */
|
|
ray->P = ray_offset(sd->P, -sd->Ng);
|
|
#ifdef __RAY_DIFFERENTIALS__
|
|
ray->dP = sd->dP;
|
|
#endif
|
|
|
|
/* enter/exit volume */
|
|
kernel_volume_stack_enter_exit(kg, sd, state->volume_stack);
|
|
return true;
|
|
}
|
|
#endif
|
|
else {
|
|
/* no bsdf or volume? */
|
|
return false;
|
|
}
|
|
}
|
|
|
|
#endif
|
|
|
|
ccl_device float4 kernel_path_integrate(KernelGlobals *kg, RNG *rng, int sample, Ray ray, ccl_global float *buffer)
|
|
{
|
|
/* initialize */
|
|
PathRadiance L;
|
|
float3 throughput = make_float3(1.0f, 1.0f, 1.0f);
|
|
float L_transparent = 0.0f;
|
|
|
|
path_radiance_init(&L, kernel_data.film.use_light_pass);
|
|
|
|
PathState state;
|
|
path_state_init(kg, &state, rng, sample);
|
|
|
|
/* path iteration */
|
|
for(;;) {
|
|
/* intersect scene */
|
|
Intersection isect;
|
|
uint visibility = path_state_ray_visibility(kg, &state);
|
|
|
|
#ifdef __HAIR__
|
|
float difl = 0.0f, extmax = 0.0f;
|
|
uint lcg_state = 0;
|
|
|
|
if(kernel_data.bvh.have_curves) {
|
|
if((kernel_data.cam.resolution == 1) && (state.flag & PATH_RAY_CAMERA)) {
|
|
float3 pixdiff = ray.dD.dx + ray.dD.dy;
|
|
/*pixdiff = pixdiff - dot(pixdiff, ray.D)*ray.D;*/
|
|
difl = kernel_data.curve.minimum_width * len(pixdiff) * 0.5f;
|
|
}
|
|
|
|
extmax = kernel_data.curve.maximum_width;
|
|
lcg_state = lcg_state_init(rng, &state, 0x51633e2d);
|
|
}
|
|
|
|
bool hit = scene_intersect(kg, &ray, visibility, &isect, &lcg_state, difl, extmax);
|
|
#else
|
|
bool hit = scene_intersect(kg, &ray, visibility, &isect);
|
|
#endif
|
|
|
|
#ifdef __LAMP_MIS__
|
|
if(kernel_data.integrator.use_lamp_mis && !(state.flag & PATH_RAY_CAMERA)) {
|
|
/* ray starting from previous non-transparent bounce */
|
|
Ray light_ray;
|
|
|
|
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 */
|
|
float light_t = path_state_rng_1D(kg, rng, &state, PRNG_LIGHT);
|
|
float3 emission;
|
|
|
|
if(indirect_lamp_emission(kg, &light_ray, state.flag, state.ray_pdf, light_t, &emission, state.bounce))
|
|
path_radiance_accum_emission(&L, throughput, emission, state.bounce);
|
|
}
|
|
#endif
|
|
|
|
#ifdef __VOLUME__
|
|
/* volume attenuation, emission, scatter */
|
|
if(state.volume_stack[0].shader != SHADER_NO_ID) {
|
|
Ray volume_ray = ray;
|
|
volume_ray.t = (hit)? isect.t: FLT_MAX;
|
|
|
|
ShaderData volume_sd;
|
|
VolumeIntegrateResult result = kernel_volume_integrate(kg, &state,
|
|
&volume_sd, &volume_ray, &L, &throughput, rng);
|
|
|
|
if(result == VOLUME_PATH_SCATTERED) {
|
|
if(kernel_path_integrate_scatter_lighting(kg, rng, &volume_sd, &throughput, &state, &L, &ray, 1.0f))
|
|
continue;
|
|
else
|
|
break;
|
|
}
|
|
}
|
|
#endif
|
|
|
|
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
|
|
break;
|
|
}
|
|
|
|
#ifdef __BACKGROUND__
|
|
/* sample background shader */
|
|
float3 L_background = indirect_background(kg, &ray, state.flag, state.ray_pdf, state.bounce);
|
|
path_radiance_accum_background(&L, throughput, L_background, state.bounce);
|
|
#endif
|
|
|
|
break;
|
|
}
|
|
|
|
/* setup shading */
|
|
ShaderData sd;
|
|
shader_setup_from_ray(kg, &sd, &isect, &ray, state.bounce);
|
|
float rbsdf = path_state_rng_1D(kg, rng, &state, PRNG_BSDF);
|
|
shader_eval_surface(kg, &sd, rbsdf, state.flag, SHADER_CONTEXT_MAIN);
|
|
|
|
/* holdout */
|
|
#ifdef __HOLDOUT__
|
|
if((sd.flag & (SD_HOLDOUT|SD_HOLDOUT_MASK)) && (state.flag & PATH_RAY_CAMERA)) {
|
|
if(kernel_data.background.transparent) {
|
|
float3 holdout_weight;
|
|
|
|
if(sd.flag & SD_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.flag & SD_HOLDOUT_MASK)
|
|
break;
|
|
}
|
|
#endif
|
|
|
|
/* holdout mask objects do not write data passes */
|
|
kernel_write_data_passes(kg, buffer, &L, &sd, sample, state.flag, 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
|
|
|
|
/* 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(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)) {
|
|
/* todo: solve correlation */
|
|
float bsdf_u, bsdf_v;
|
|
path_state_rng_2D(kg, rng, &state, PRNG_BSDF_U, &bsdf_u, &bsdf_v);
|
|
|
|
float ao_factor = kernel_data.background.ao_factor;
|
|
float3 ao_N;
|
|
float3 ao_bsdf = shader_bsdf_ao(kg, &sd, ao_factor, &ao_N);
|
|
float3 ao_D;
|
|
float ao_pdf;
|
|
float3 ao_alpha = shader_bsdf_alpha(kg, &sd);
|
|
|
|
sample_cos_hemisphere(ao_N, bsdf_u, bsdf_v, &ao_D, &ao_pdf);
|
|
|
|
if(dot(sd.Ng, ao_D) > 0.0f && ao_pdf != 0.0f) {
|
|
Ray light_ray;
|
|
float3 ao_shadow;
|
|
|
|
light_ray.P = ray_offset(sd.P, sd.Ng);
|
|
light_ray.D = ao_D;
|
|
light_ray.t = kernel_data.background.ao_distance;
|
|
#ifdef __OBJECT_MOTION__
|
|
light_ray.time = sd.time;
|
|
#endif
|
|
light_ray.dP = sd.dP;
|
|
light_ray.dD = differential3_zero();
|
|
|
|
if(!shadow_blocked(kg, &state, &light_ray, &ao_shadow))
|
|
path_radiance_accum_ao(&L, throughput, ao_alpha, ao_bsdf, ao_shadow, state.bounce);
|
|
}
|
|
}
|
|
#endif
|
|
|
|
#ifdef __SUBSURFACE__
|
|
/* bssrdf scatter to a different location on the same object, replacing
|
|
* the closures with a diffuse BSDF */
|
|
if(sd.flag & SD_BSSRDF) {
|
|
float bssrdf_probability;
|
|
ShaderClosure *sc = subsurface_scatter_pick_closure(kg, &sd, &bssrdf_probability);
|
|
|
|
/* modify throughput for picking bssrdf or bsdf */
|
|
throughput *= bssrdf_probability;
|
|
|
|
/* do bssrdf scatter step if we picked a bssrdf closure */
|
|
if(sc) {
|
|
uint lcg_state = lcg_state_init(rng, &state, 0x68bc21eb);
|
|
|
|
ShaderData bssrdf_sd[BSSRDF_MAX_HITS];
|
|
float bssrdf_u, bssrdf_v;
|
|
path_state_rng_2D(kg, rng, &state, PRNG_BSDF_U, &bssrdf_u, &bssrdf_v);
|
|
int num_hits = subsurface_scatter_multi_step(kg, &sd, bssrdf_sd, state.flag, sc, &lcg_state, bssrdf_u, bssrdf_v, false);
|
|
|
|
/* compute lighting with the BSDF closure */
|
|
for(int hit = 0; hit < num_hits; hit++) {
|
|
float3 tp = throughput;
|
|
PathState hit_state = state;
|
|
Ray hit_ray = ray;
|
|
|
|
hit_state.flag |= PATH_RAY_BSSRDF_ANCESTOR;
|
|
hit_state.rng_offset += PRNG_BOUNCE_NUM;
|
|
|
|
if(kernel_path_integrate_lighting(kg, rng, &bssrdf_sd[hit], &tp, &hit_state, &L, &hit_ray)) {
|
|
#ifdef __LAMP_MIS__
|
|
hit_state.ray_t = 0.0f;
|
|
#endif
|
|
|
|
kernel_path_indirect(kg, rng, hit_ray, buffer, tp, state.num_samples, hit_state, &L);
|
|
|
|
/* for render passes, sum and reset indirect light pass variables
|
|
* for the next samples */
|
|
path_radiance_sum_indirect(&L);
|
|
path_radiance_reset_indirect(&L);
|
|
}
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
#endif
|
|
|
|
/* The following code is the same as in kernel_path_integrate_lighting(),
|
|
but for CUDA the function call is slower. */
|
|
#ifdef __EMISSION__
|
|
if(kernel_data.integrator.use_direct_light) {
|
|
/* sample illumination from lights to find path contribution */
|
|
if(sd.flag & SD_BSDF_HAS_EVAL) {
|
|
float light_t = path_state_rng_1D(kg, rng, &state, PRNG_LIGHT);
|
|
#ifdef __MULTI_CLOSURE__
|
|
float light_o = 0.0f;
|
|
#else
|
|
float light_o = path_state_rng_1D(kg, rng, &state, PRNG_LIGHT_F);
|
|
#endif
|
|
float light_u, light_v;
|
|
path_state_rng_2D(kg, rng, &state, PRNG_LIGHT_U, &light_u, &light_v);
|
|
|
|
Ray light_ray;
|
|
BsdfEval L_light;
|
|
bool is_lamp;
|
|
|
|
#ifdef __OBJECT_MOTION__
|
|
light_ray.time = sd.time;
|
|
#endif
|
|
|
|
if(direct_emission(kg, &sd, -1, light_t, light_o, light_u, light_v, &light_ray, &L_light, &is_lamp, state.bounce)) {
|
|
/* trace shadow ray */
|
|
float3 shadow;
|
|
|
|
if(!shadow_blocked(kg, &state, &light_ray, &shadow)) {
|
|
/* accumulate */
|
|
path_radiance_accum_light(&L, throughput, &L_light, shadow, 1.0f, state.bounce, is_lamp);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
#endif
|
|
|
|
if(sd.flag & SD_BSDF) {
|
|
/* sample BSDF */
|
|
float bsdf_pdf;
|
|
BsdfEval bsdf_eval;
|
|
float3 bsdf_omega_in;
|
|
differential3 bsdf_domega_in;
|
|
float bsdf_u, bsdf_v;
|
|
path_state_rng_2D(kg, rng, &state, PRNG_BSDF_U, &bsdf_u, &bsdf_v);
|
|
int label;
|
|
|
|
label = shader_bsdf_sample(kg, &sd, bsdf_u, bsdf_v, &bsdf_eval,
|
|
&bsdf_omega_in, &bsdf_domega_in, &bsdf_pdf);
|
|
|
|
if(bsdf_pdf == 0.0f || bsdf_eval_is_zero(&bsdf_eval))
|
|
break;
|
|
|
|
/* modify throughput */
|
|
path_radiance_bsdf_bounce(&L, &throughput, &bsdf_eval, bsdf_pdf, state.bounce, label);
|
|
|
|
/* set labels */
|
|
if(!(label & LABEL_TRANSPARENT)) {
|
|
state.ray_pdf = bsdf_pdf;
|
|
#ifdef __LAMP_MIS__
|
|
state.ray_t = 0.0f;
|
|
#endif
|
|
state.min_ray_pdf = fminf(bsdf_pdf, state.min_ray_pdf);
|
|
}
|
|
|
|
/* update path state */
|
|
path_state_next(kg, &state, label);
|
|
|
|
/* setup ray */
|
|
ray.P = ray_offset(sd.P, (label & LABEL_TRANSMIT)? -sd.Ng: sd.Ng);
|
|
ray.D = bsdf_omega_in;
|
|
|
|
#ifdef __RAY_DIFFERENTIALS__
|
|
ray.dP = sd.dP;
|
|
ray.dD = bsdf_domega_in;
|
|
#endif
|
|
|
|
#ifdef __VOLUME__
|
|
/* enter/exit volume */
|
|
if(label & LABEL_TRANSMIT)
|
|
kernel_volume_stack_enter_exit(kg, &sd, state.volume_stack);
|
|
#endif
|
|
|
|
}
|
|
#ifdef __VOLUME__
|
|
else if(sd.flag & SD_HAS_ONLY_VOLUME) {
|
|
/* no surface shader but have a volume shader? act transparent */
|
|
|
|
/* update path state, count as transparent */
|
|
path_state_next(kg, &state, LABEL_TRANSPARENT);
|
|
|
|
/* setup ray position, direction stays unchanged */
|
|
ray.P = ray_offset(sd.P, -sd.Ng);
|
|
#ifdef __RAY_DIFFERENTIALS__
|
|
ray.dP = sd.dP;
|
|
#endif
|
|
|
|
/* enter/exit volume */
|
|
kernel_volume_stack_enter_exit(kg, &sd, state.volume_stack);
|
|
}
|
|
#endif
|
|
else {
|
|
/* no bsdf or volume? we're done */
|
|
break;
|
|
}
|
|
|
|
/* adjust ray distance for clipping */
|
|
if(state.bounce == 0)
|
|
ray.t -= sd.ray_length; /* clipping works through transparent */
|
|
else
|
|
ray.t = FLT_MAX;
|
|
}
|
|
|
|
float3 L_sum = path_radiance_sum(kg, &L);
|
|
|
|
#ifdef __CLAMP_SAMPLE__
|
|
path_radiance_clamp(&L, &L_sum, kernel_data.integrator.sample_clamp);
|
|
#endif
|
|
|
|
kernel_write_light_passes(kg, buffer, &L, sample);
|
|
|
|
return make_float4(L_sum.x, L_sum.y, L_sum.z, 1.0f - L_transparent);
|
|
}
|
|
|
|
#ifdef __BRANCHED_PATH__
|
|
|
|
ccl_device_noinline void kernel_branched_path_integrate_lighting(KernelGlobals *kg,
|
|
RNG *rng, ShaderData *sd, float3 throughput, float num_samples_adjust,
|
|
PathState *state, PathRadiance *L, ccl_global float *buffer)
|
|
{
|
|
#ifdef __EMISSION__
|
|
/* sample illumination from lights to find path contribution */
|
|
if(sd->flag & SD_BSDF_HAS_EVAL) {
|
|
Ray light_ray;
|
|
BsdfEval L_light;
|
|
bool is_lamp;
|
|
|
|
#ifdef __OBJECT_MOTION__
|
|
light_ray.time = sd->time;
|
|
#endif
|
|
|
|
/* lamp sampling */
|
|
for(int i = 0; i < kernel_data.integrator.num_all_lights; i++) {
|
|
int num_samples = ceil_to_int(num_samples_adjust*light_select_num_samples(kg, i));
|
|
float num_samples_inv = num_samples_adjust/(num_samples*kernel_data.integrator.num_all_lights);
|
|
RNG lamp_rng = cmj_hash(*rng, i);
|
|
|
|
if(kernel_data.integrator.pdf_triangles != 0.0f)
|
|
num_samples_inv *= 0.5f;
|
|
|
|
for(int j = 0; j < num_samples; j++) {
|
|
float light_u, light_v;
|
|
path_branched_rng_2D(kg, &lamp_rng, state, j, num_samples, PRNG_LIGHT_U, &light_u, &light_v);
|
|
|
|
if(direct_emission(kg, sd, i, 0.0f, 0.0f, light_u, light_v, &light_ray, &L_light, &is_lamp, state->bounce)) {
|
|
/* trace shadow ray */
|
|
float3 shadow;
|
|
|
|
if(!shadow_blocked(kg, state, &light_ray, &shadow)) {
|
|
/* accumulate */
|
|
path_radiance_accum_light(L, throughput*num_samples_inv, &L_light, shadow, num_samples_inv, state->bounce, is_lamp);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/* mesh light sampling */
|
|
if(kernel_data.integrator.pdf_triangles != 0.0f) {
|
|
int num_samples = ceil_to_int(num_samples_adjust*kernel_data.integrator.mesh_light_samples);
|
|
float num_samples_inv = num_samples_adjust/num_samples;
|
|
|
|
if(kernel_data.integrator.num_all_lights)
|
|
num_samples_inv *= 0.5f;
|
|
|
|
for(int j = 0; j < num_samples; j++) {
|
|
float light_t = path_branched_rng_1D(kg, rng, state, j, num_samples, PRNG_LIGHT);
|
|
float light_u, light_v;
|
|
path_branched_rng_2D(kg, rng, state, j, num_samples, PRNG_LIGHT_U, &light_u, &light_v);
|
|
|
|
/* only sample triangle lights */
|
|
if(kernel_data.integrator.num_all_lights)
|
|
light_t = 0.5f*light_t;
|
|
|
|
if(direct_emission(kg, sd, -1, light_t, 0.0f, light_u, light_v, &light_ray, &L_light, &is_lamp, state->bounce)) {
|
|
/* trace shadow ray */
|
|
float3 shadow;
|
|
|
|
if(!shadow_blocked(kg, state, &light_ray, &shadow)) {
|
|
/* accumulate */
|
|
path_radiance_accum_light(L, throughput*num_samples_inv, &L_light, shadow, num_samples_inv, state->bounce, is_lamp);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
#endif
|
|
|
|
for(int i = 0; i< sd->num_closure; i++) {
|
|
const ShaderClosure *sc = &sd->closure[i];
|
|
|
|
if(!CLOSURE_IS_BSDF(sc->type))
|
|
continue;
|
|
/* transparency is not handled here, but in outer loop */
|
|
if(sc->type == CLOSURE_BSDF_TRANSPARENT_ID)
|
|
continue;
|
|
|
|
int num_samples;
|
|
|
|
if(CLOSURE_IS_BSDF_DIFFUSE(sc->type))
|
|
num_samples = kernel_data.integrator.diffuse_samples;
|
|
else if(CLOSURE_IS_BSDF_BSSRDF(sc->type))
|
|
num_samples = 1;
|
|
else if(CLOSURE_IS_BSDF_GLOSSY(sc->type))
|
|
num_samples = kernel_data.integrator.glossy_samples;
|
|
else
|
|
num_samples = kernel_data.integrator.transmission_samples;
|
|
|
|
num_samples = ceil_to_int(num_samples_adjust*num_samples);
|
|
|
|
float num_samples_inv = num_samples_adjust/num_samples;
|
|
RNG bsdf_rng = cmj_hash(*rng, i);
|
|
|
|
for(int j = 0; j < num_samples; j++) {
|
|
/* sample BSDF */
|
|
float bsdf_pdf;
|
|
BsdfEval bsdf_eval;
|
|
float3 bsdf_omega_in;
|
|
differential3 bsdf_domega_in;
|
|
float bsdf_u, bsdf_v;
|
|
path_branched_rng_2D(kg, &bsdf_rng, state, j, num_samples, PRNG_BSDF_U, &bsdf_u, &bsdf_v);
|
|
int label;
|
|
|
|
label = shader_bsdf_sample_closure(kg, sd, sc, bsdf_u, bsdf_v, &bsdf_eval,
|
|
&bsdf_omega_in, &bsdf_domega_in, &bsdf_pdf);
|
|
|
|
if(bsdf_pdf == 0.0f || bsdf_eval_is_zero(&bsdf_eval))
|
|
continue;
|
|
|
|
/* modify throughput */
|
|
float3 tp = throughput;
|
|
path_radiance_bsdf_bounce(L, &tp, &bsdf_eval, bsdf_pdf, state->bounce, label);
|
|
|
|
/* modify path state */
|
|
PathState ps = *state;
|
|
path_state_next(kg, &ps, label);
|
|
|
|
/* setup ray */
|
|
Ray bsdf_ray;
|
|
|
|
bsdf_ray.P = ray_offset(sd->P, (label & LABEL_TRANSMIT)? -sd->Ng: sd->Ng);
|
|
bsdf_ray.D = bsdf_omega_in;
|
|
bsdf_ray.t = FLT_MAX;
|
|
#ifdef __RAY_DIFFERENTIALS__
|
|
bsdf_ray.dP = sd->dP;
|
|
bsdf_ray.dD = bsdf_domega_in;
|
|
#endif
|
|
#ifdef __OBJECT_MOTION__
|
|
bsdf_ray.time = sd->time;
|
|
#endif
|
|
|
|
#ifdef __VOLUME__
|
|
/* enter/exit volume */
|
|
if(label & LABEL_TRANSMIT)
|
|
kernel_volume_stack_enter_exit(kg, sd, ps.volume_stack);
|
|
#endif
|
|
|
|
/* branch RNG state */
|
|
path_state_branch(&ps, j, num_samples);
|
|
|
|
/* set MIS state */
|
|
ps.min_ray_pdf = fminf(bsdf_pdf, FLT_MAX);
|
|
ps.ray_pdf = bsdf_pdf;
|
|
#ifdef __LAMP_MIS__
|
|
ps.ray_t = 0.0f;
|
|
#endif
|
|
|
|
kernel_path_indirect(kg, rng, bsdf_ray, buffer, tp*num_samples_inv, num_samples, ps, L);
|
|
|
|
/* for render passes, sum and reset indirect light pass variables
|
|
* for the next samples */
|
|
path_radiance_sum_indirect(L);
|
|
path_radiance_reset_indirect(L);
|
|
}
|
|
}
|
|
}
|
|
|
|
ccl_device float4 kernel_branched_path_integrate(KernelGlobals *kg, RNG *rng, int sample, Ray ray, ccl_global float *buffer)
|
|
{
|
|
/* initialize */
|
|
PathRadiance L;
|
|
float3 throughput = make_float3(1.0f, 1.0f, 1.0f);
|
|
float L_transparent = 0.0f;
|
|
|
|
path_radiance_init(&L, kernel_data.film.use_light_pass);
|
|
|
|
PathState state;
|
|
path_state_init(kg, &state, rng, sample);
|
|
|
|
for(;;) {
|
|
/* intersect scene */
|
|
Intersection isect;
|
|
uint visibility = path_state_ray_visibility(kg, &state);
|
|
|
|
#ifdef __HAIR__
|
|
float difl = 0.0f, extmax = 0.0f;
|
|
uint lcg_state = 0;
|
|
|
|
if(kernel_data.bvh.have_curves) {
|
|
if((kernel_data.cam.resolution == 1) && (state.flag & PATH_RAY_CAMERA)) {
|
|
float3 pixdiff = ray.dD.dx + ray.dD.dy;
|
|
/*pixdiff = pixdiff - dot(pixdiff, ray.D)*ray.D;*/
|
|
difl = kernel_data.curve.minimum_width * len(pixdiff) * 0.5f;
|
|
}
|
|
|
|
extmax = kernel_data.curve.maximum_width;
|
|
lcg_state = lcg_state_init(rng, &state, 0x51633e2d);
|
|
}
|
|
|
|
bool hit = scene_intersect(kg, &ray, visibility, &isect, &lcg_state, difl, extmax);
|
|
#else
|
|
bool hit = scene_intersect(kg, &ray, visibility, &isect);
|
|
#endif
|
|
|
|
#ifdef __VOLUME__
|
|
/* volume attenuation, emission, scatter */
|
|
if(state.volume_stack[0].shader != SHADER_NO_ID) {
|
|
Ray volume_ray = ray;
|
|
volume_ray.t = (hit)? isect.t: FLT_MAX;
|
|
|
|
int num_samples = kernel_data.integrator.volume_samples;
|
|
float num_samples_inv = 1.0f/num_samples;
|
|
float3 avg_tp = make_float3(0.0f, 0.0f, 0.0f);
|
|
|
|
/* todo: we should cache the shader evaluations from stepping
|
|
* through the volume, for now we redo them multiple times */
|
|
|
|
for(int j = 0; j < num_samples; j++) {
|
|
PathState ps = state;
|
|
Ray pray = ray;
|
|
ShaderData volume_sd;
|
|
float3 tp = throughput;
|
|
|
|
/* branch RNG state */
|
|
path_state_branch(&ps, j, num_samples);
|
|
|
|
VolumeIntegrateResult result = kernel_volume_integrate(kg, &ps,
|
|
&volume_sd, &volume_ray, &L, &tp, rng);
|
|
|
|
if(result == VOLUME_PATH_SCATTERED) {
|
|
/* todo: use all-light sampling */
|
|
if(kernel_path_integrate_scatter_lighting(kg, rng, &volume_sd, &tp, &ps, &L, &pray, num_samples_inv)) {
|
|
kernel_path_indirect(kg, rng, pray, buffer, tp*num_samples_inv, num_samples, ps, &L);
|
|
|
|
/* for render passes, sum and reset indirect light pass variables
|
|
* for the next samples */
|
|
path_radiance_sum_indirect(&L);
|
|
path_radiance_reset_indirect(&L);
|
|
}
|
|
}
|
|
else
|
|
avg_tp += tp;
|
|
}
|
|
|
|
throughput = avg_tp * num_samples_inv;
|
|
}
|
|
#endif
|
|
|
|
if(!hit) {
|
|
/* eval background shader if nothing hit */
|
|
if(kernel_data.background.transparent) {
|
|
L_transparent += average(throughput);
|
|
|
|
#ifdef __PASSES__
|
|
if(!(kernel_data.film.pass_flag & PASS_BACKGROUND))
|
|
#endif
|
|
break;
|
|
}
|
|
|
|
#ifdef __BACKGROUND__
|
|
/* sample background shader */
|
|
float3 L_background = indirect_background(kg, &ray, state.flag, state.ray_pdf, state.bounce);
|
|
path_radiance_accum_background(&L, throughput, L_background, state.bounce);
|
|
#endif
|
|
|
|
break;
|
|
}
|
|
|
|
/* setup shading */
|
|
ShaderData sd;
|
|
shader_setup_from_ray(kg, &sd, &isect, &ray, state.bounce);
|
|
shader_eval_surface(kg, &sd, 0.0f, state.flag, SHADER_CONTEXT_MAIN);
|
|
shader_merge_closures(&sd);
|
|
|
|
/* holdout */
|
|
#ifdef __HOLDOUT__
|
|
if((sd.flag & (SD_HOLDOUT|SD_HOLDOUT_MASK))) {
|
|
if(kernel_data.background.transparent) {
|
|
float3 holdout_weight;
|
|
|
|
if(sd.flag & SD_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.flag & SD_HOLDOUT_MASK)
|
|
break;
|
|
}
|
|
#endif
|
|
|
|
/* holdout mask objects do not write data passes */
|
|
kernel_write_data_passes(kg, buffer, &L, &sd, sample, state.flag, throughput);
|
|
|
|
#ifdef __EMISSION__
|
|
/* emission */
|
|
if(sd.flag & SD_EMISSION) {
|
|
float3 emission = indirect_primitive_emission(kg, &sd, isect.t, state.flag, state.ray_pdf);
|
|
path_radiance_accum_emission(&L, throughput, emission, state.bounce);
|
|
}
|
|
#endif
|
|
|
|
/* transparency termination */
|
|
if(state.flag & PATH_RAY_TRANSPARENT) {
|
|
/* 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(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)) {
|
|
int num_samples = kernel_data.integrator.ao_samples;
|
|
float num_samples_inv = 1.0f/num_samples;
|
|
float ao_factor = kernel_data.background.ao_factor;
|
|
float3 ao_N;
|
|
float3 ao_bsdf = shader_bsdf_ao(kg, &sd, ao_factor, &ao_N);
|
|
float3 ao_alpha = shader_bsdf_alpha(kg, &sd);
|
|
|
|
for(int j = 0; j < num_samples; j++) {
|
|
float bsdf_u, bsdf_v;
|
|
path_branched_rng_2D(kg, rng, &state, j, num_samples, PRNG_BSDF_U, &bsdf_u, &bsdf_v);
|
|
|
|
float3 ao_D;
|
|
float ao_pdf;
|
|
|
|
sample_cos_hemisphere(ao_N, bsdf_u, bsdf_v, &ao_D, &ao_pdf);
|
|
|
|
if(dot(sd.Ng, ao_D) > 0.0f && ao_pdf != 0.0f) {
|
|
Ray light_ray;
|
|
float3 ao_shadow;
|
|
|
|
light_ray.P = ray_offset(sd.P, sd.Ng);
|
|
light_ray.D = ao_D;
|
|
light_ray.t = kernel_data.background.ao_distance;
|
|
#ifdef __OBJECT_MOTION__
|
|
light_ray.time = sd.time;
|
|
#endif
|
|
light_ray.dP = sd.dP;
|
|
light_ray.dD = differential3_zero();
|
|
|
|
if(!shadow_blocked(kg, &state, &light_ray, &ao_shadow))
|
|
path_radiance_accum_ao(&L, throughput*num_samples_inv, ao_alpha, ao_bsdf, ao_shadow, state.bounce);
|
|
}
|
|
}
|
|
}
|
|
#endif
|
|
|
|
#ifdef __SUBSURFACE__
|
|
/* bssrdf scatter to a different location on the same object */
|
|
if(sd.flag & SD_BSSRDF) {
|
|
for(int i = 0; i< sd.num_closure; i++) {
|
|
ShaderClosure *sc = &sd.closure[i];
|
|
|
|
if(!CLOSURE_IS_BSSRDF(sc->type))
|
|
continue;
|
|
|
|
/* set up random number generator */
|
|
uint lcg_state = lcg_state_init(rng, &state, 0x68bc21eb);
|
|
int num_samples = kernel_data.integrator.subsurface_samples;
|
|
float num_samples_inv = 1.0f/num_samples;
|
|
RNG bssrdf_rng = cmj_hash(*rng, i);
|
|
|
|
state.flag |= PATH_RAY_BSSRDF_ANCESTOR;
|
|
|
|
/* do subsurface scatter step with copy of shader data, this will
|
|
* replace the BSSRDF with a diffuse BSDF closure */
|
|
for(int j = 0; j < num_samples; j++) {
|
|
ShaderData bssrdf_sd[BSSRDF_MAX_HITS];
|
|
float bssrdf_u, bssrdf_v;
|
|
path_branched_rng_2D(kg, &bssrdf_rng, &state, j, num_samples, PRNG_BSDF_U, &bssrdf_u, &bssrdf_v);
|
|
int num_hits = subsurface_scatter_multi_step(kg, &sd, bssrdf_sd, state.flag, sc, &lcg_state, bssrdf_u, bssrdf_v, true);
|
|
|
|
/* compute lighting with the BSDF closure */
|
|
for(int hit = 0; hit < num_hits; hit++) {
|
|
PathState hit_state = state;
|
|
|
|
path_state_branch(&hit_state, j, num_samples);
|
|
|
|
kernel_branched_path_integrate_lighting(kg, rng,
|
|
&bssrdf_sd[hit], throughput, num_samples_inv,
|
|
&hit_state, &L, buffer);
|
|
}
|
|
}
|
|
|
|
state.flag &= ~PATH_RAY_BSSRDF_ANCESTOR;
|
|
}
|
|
}
|
|
#endif
|
|
|
|
if(!(sd.flag & SD_HAS_ONLY_VOLUME)) {
|
|
PathState hit_state = state;
|
|
|
|
/* lighting */
|
|
kernel_branched_path_integrate_lighting(kg, rng,
|
|
&sd, throughput, 1.0f, &hit_state, &L, buffer);
|
|
|
|
/* continue in case of transparency */
|
|
throughput *= shader_bsdf_transparency(kg, &sd);
|
|
|
|
if(is_zero(throughput))
|
|
break;
|
|
}
|
|
|
|
path_state_next(kg, &state, LABEL_TRANSPARENT);
|
|
ray.P = ray_offset(sd.P, -sd.Ng);
|
|
ray.t -= sd.ray_length; /* clipping works through transparent */
|
|
|
|
#ifdef __VOLUME__
|
|
/* enter/exit volume */
|
|
kernel_volume_stack_enter_exit(kg, &sd, state.volume_stack);
|
|
#endif
|
|
}
|
|
|
|
float3 L_sum = path_radiance_sum(kg, &L);
|
|
|
|
#ifdef __CLAMP_SAMPLE__
|
|
path_radiance_clamp(&L, &L_sum, kernel_data.integrator.sample_clamp);
|
|
#endif
|
|
|
|
kernel_write_light_passes(kg, buffer, &L, sample);
|
|
|
|
return make_float4(L_sum.x, L_sum.y, L_sum.z, 1.0f - L_transparent);
|
|
}
|
|
|
|
#endif
|
|
|
|
ccl_device_inline void kernel_path_trace_setup(KernelGlobals *kg, ccl_global uint *rng_state, int sample, int x, int y, RNG *rng, Ray *ray)
|
|
{
|
|
float filter_u;
|
|
float filter_v;
|
|
#ifdef __CMJ__
|
|
int num_samples = kernel_data.integrator.aa_samples;
|
|
#else
|
|
int num_samples = 0;
|
|
#endif
|
|
|
|
path_rng_init(kg, rng_state, sample, num_samples, rng, x, y, &filter_u, &filter_v);
|
|
|
|
/* sample camera ray */
|
|
|
|
float lens_u = 0.0f, lens_v = 0.0f;
|
|
|
|
if(kernel_data.cam.aperturesize > 0.0f)
|
|
path_rng_2D(kg, rng, sample, num_samples, PRNG_LENS_U, &lens_u, &lens_v);
|
|
|
|
float time = 0.0f;
|
|
|
|
#ifdef __CAMERA_MOTION__
|
|
if(kernel_data.cam.shuttertime != -1.0f)
|
|
time = path_rng_1D(kg, rng, sample, num_samples, PRNG_TIME);
|
|
#endif
|
|
|
|
camera_sample(kg, x, y, filter_u, filter_v, lens_u, lens_v, time, ray);
|
|
}
|
|
|
|
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);
|
|
}
|
|
|
|
#ifdef __BRANCHED_PATH__
|
|
ccl_device void kernel_branched_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_branched_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
|
|
|
|
CCL_NAMESPACE_END
|
|
|