forked from bartvdbraak/blender
Brecht Van Lommel
a29807cd63
* Volume multiple importace sampling support to combine equiangular and distance sampling, for both homogeneous and heterogeneous volumes. * Branched path "Sample All Direct Lights" and "Sample All Indirect Lights" now apply to volumes as well as surfaces. Implementation note: For simplicity this is all done with decoupled ray marching, the only case we do not use decoupled is for distance only sampling with one light sample. The homogeneous case should still compile on the GPU because it only requires fixed size storage, but the heterogeneous case will be trickier to get working.
300 lines
8.8 KiB
C
300 lines
8.8 KiB
C
/*
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* Copyright 2011-2013 Blender Foundation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License
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*/
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CCL_NAMESPACE_BEGIN
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#if defined(__BRANCHED_PATH__) || defined(__SUBSURFACE__)
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/* branched path tracing: connect path directly to position on one or more lights and add it to L */
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ccl_device void kernel_branched_path_surface_connect_light(KernelGlobals *kg, RNG *rng,
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ShaderData *sd, PathState *state, float3 throughput, float num_samples_adjust, PathRadiance *L, bool sample_all_lights)
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{
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#ifdef __EMISSION__
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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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return;
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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(sample_all_lights) {
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/* lamp sampling */
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for(int i = 0; i < kernel_data.integrator.num_all_lights; i++) {
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int num_samples = ceil_to_int(num_samples_adjust*light_select_num_samples(kg, i));
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float num_samples_inv = num_samples_adjust/(num_samples*kernel_data.integrator.num_all_lights);
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RNG lamp_rng = cmj_hash(*rng, i);
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if(kernel_data.integrator.pdf_triangles != 0.0f)
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num_samples_inv *= 0.5f;
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for(int j = 0; j < num_samples; j++) {
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float light_u, light_v;
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path_branched_rng_2D(kg, &lamp_rng, state, j, num_samples, PRNG_LIGHT_U, &light_u, &light_v);
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LightSample ls;
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light_select(kg, i, light_u, light_v, sd->P, &ls, false);
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if(direct_emission(kg, sd, &ls, &light_ray, &L_light, &is_lamp, state->bounce, state->transparent_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_inv, &L_light, shadow, num_samples_inv, state->bounce, is_lamp);
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}
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}
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}
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}
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/* mesh light sampling */
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if(kernel_data.integrator.pdf_triangles != 0.0f) {
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int num_samples = ceil_to_int(num_samples_adjust*kernel_data.integrator.mesh_light_samples);
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float num_samples_inv = num_samples_adjust/num_samples;
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if(kernel_data.integrator.num_all_lights)
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num_samples_inv *= 0.5f;
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for(int j = 0; j < num_samples; j++) {
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float light_t = path_branched_rng_1D(kg, rng, state, j, num_samples, PRNG_LIGHT);
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float light_u, light_v;
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path_branched_rng_2D(kg, rng, state, j, num_samples, PRNG_LIGHT_U, &light_u, &light_v);
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/* only sample triangle lights */
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if(kernel_data.integrator.num_all_lights)
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light_t = 0.5f*light_t;
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LightSample ls;
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light_sample(kg, light_t, light_u, light_v, sd->time, sd->P, &ls, false);
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if(direct_emission(kg, sd, &ls, &light_ray, &L_light, &is_lamp, state->bounce, state->transparent_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_inv, &L_light, shadow, num_samples_inv, state->bounce, is_lamp);
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}
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}
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}
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}
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}
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else {
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/* sample one light at random */
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float light_t = path_state_rng_1D(kg, rng, state, PRNG_LIGHT);
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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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LightSample ls;
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light_sample(kg, light_t, light_u, light_v, sd->time, sd->P, &ls, false);
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/* sample random light */
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if(direct_emission(kg, sd, &ls, &light_ray, &L_light, &is_lamp, state->bounce, state->transparent_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, num_samples_adjust, state->bounce, is_lamp);
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}
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}
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}
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#endif
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}
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/* branched path tracing: bounce off or through surface to with new direction stored in ray */
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ccl_device bool kernel_branched_path_surface_bounce(KernelGlobals *kg, RNG *rng,
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ShaderData *sd, const ShaderClosure *sc, int sample, int num_samples,
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float3 *throughput, PathState *state, PathRadiance *L, Ray *ray)
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{
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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_branched_rng_2D(kg, rng, state, sample, num_samples, PRNG_BSDF_U, &bsdf_u, &bsdf_v);
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int label;
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label = shader_bsdf_sample_closure(kg, sd, sc, 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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return false;
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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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/* modify 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 __OBJECT_MOTION__
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ray->time = sd->time;
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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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/* branch RNG state */
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path_state_branch(state, sample, num_samples);
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/* set MIS state */
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state->min_ray_pdf = fminf(bsdf_pdf, FLT_MAX);
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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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return true;
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}
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#endif
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/* path tracing: connect path directly to position on a light and add it to L */
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ccl_device_inline void kernel_path_surface_connect_light(KernelGlobals *kg, RNG *rng,
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ShaderData *sd, float3 throughput, PathState *state, PathRadiance *L)
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{
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#ifdef __EMISSION__
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if(!(kernel_data.integrator.use_direct_light && (sd->flag & SD_BSDF_HAS_EVAL)))
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return;
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/* sample illumination from lights to find path contribution */
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float light_t = path_state_rng_1D(kg, rng, state, PRNG_LIGHT);
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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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LightSample ls;
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light_sample(kg, light_t, light_u, light_v, sd->time, sd->P, &ls, false);
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if(direct_emission(kg, sd, &ls, &light_ray, &L_light, &is_lamp, state->bounce, state->transparent_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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#endif
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}
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/* path tracing: bounce off or through surface to with new direction stored in ray */
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ccl_device_inline bool kernel_path_surface_bounce(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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/* 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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return false;
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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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if(state->bounce == 0)
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ray->t -= sd->ray_length; /* clipping works through transparent */
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else
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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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return true;
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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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return true;
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}
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#endif
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else {
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/* no bsdf or volume? */
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return false;
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}
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}
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CCL_NAMESPACE_END
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