095a01a73a
Similar to what we did for area lights previously, this should help preserve stratification when using multiple BSDFs in theory. Improvements are not easily noticeable in practice though, because the number of BSDFs is usually low. Still nice to eliminate one sampling dimension.
314 lines
12 KiB
C
314 lines
12 KiB
C
/*
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* Copyright 2011-2017 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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ccl_device_inline void kernel_split_branched_path_subsurface_indirect_light_init(KernelGlobals *kg, int ray_index)
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{
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kernel_split_branched_path_indirect_loop_init(kg, ray_index);
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SplitBranchedState *branched_state = &kernel_split_state.branched_state[ray_index];
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branched_state->ss_next_closure = 0;
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branched_state->ss_next_sample = 0;
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branched_state->num_hits = 0;
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branched_state->next_hit = 0;
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ADD_RAY_FLAG(kernel_split_state.ray_state, ray_index, RAY_BRANCHED_SUBSURFACE_INDIRECT);
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}
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ccl_device_noinline bool kernel_split_branched_path_subsurface_indirect_light_iter(KernelGlobals *kg, int ray_index)
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{
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SplitBranchedState *branched_state = &kernel_split_state.branched_state[ray_index];
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ShaderData *sd = &branched_state->sd;
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PathRadiance *L = &kernel_split_state.path_radiance[ray_index];
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ShaderData *emission_sd = &kernel_split_state.sd_DL_shadow[ray_index];
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for(int i = branched_state->ss_next_closure; i < sd->num_closure; i++) {
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ShaderClosure *sc = &sd->closure[i];
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if(!CLOSURE_IS_BSSRDF(sc->type))
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continue;
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/* set up random number generator */
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if(branched_state->ss_next_sample == 0 && branched_state->next_hit == 0 &&
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branched_state->next_closure == 0 && branched_state->next_sample == 0)
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{
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branched_state->lcg_state = lcg_state_init_addrspace(&branched_state->path_state,
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0x68bc21eb);
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}
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int num_samples = kernel_data.integrator.subsurface_samples;
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float num_samples_inv = 1.0f/num_samples;
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uint bssrdf_rng_hash = cmj_hash(branched_state->path_state.rng_hash, i);
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/* do subsurface scatter step with copy of shader data, this will
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* replace the BSSRDF with a diffuse BSDF closure */
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for(int j = branched_state->ss_next_sample; j < num_samples; j++) {
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ccl_global SubsurfaceIntersection *ss_isect = &branched_state->ss_isect;
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float bssrdf_u, bssrdf_v;
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path_branched_rng_2D(kg,
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bssrdf_rng_hash,
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&branched_state->path_state,
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j,
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num_samples,
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PRNG_BSDF_U,
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&bssrdf_u,
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&bssrdf_v);
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/* intersection is expensive so avoid doing multiple times for the same input */
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if(branched_state->next_hit == 0 && branched_state->next_closure == 0 && branched_state->next_sample == 0) {
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uint lcg_state = branched_state->lcg_state;
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SubsurfaceIntersection ss_isect_private;
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branched_state->num_hits = subsurface_scatter_multi_intersect(kg,
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&ss_isect_private,
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sd,
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sc,
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&lcg_state,
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bssrdf_u, bssrdf_v,
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true);
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branched_state->lcg_state = lcg_state;
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*ss_isect = ss_isect_private;
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}
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#ifdef __VOLUME__
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Ray volume_ray = branched_state->ray;
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bool need_update_volume_stack =
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kernel_data.integrator.use_volumes &&
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sd->object_flag & SD_OBJECT_INTERSECTS_VOLUME;
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#endif /* __VOLUME__ */
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/* compute lighting with the BSDF closure */
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for(int hit = branched_state->next_hit; hit < branched_state->num_hits; hit++) {
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ShaderData *bssrdf_sd = &kernel_split_state.sd[ray_index];
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*bssrdf_sd = *sd; /* note: copy happens each iteration of inner loop, this is
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* important as the indirect path will write into bssrdf_sd */
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SubsurfaceIntersection ss_isect_private = *ss_isect;
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subsurface_scatter_multi_setup(kg,
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&ss_isect_private,
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hit,
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bssrdf_sd,
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&branched_state->path_state,
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branched_state->path_state.flag,
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sc,
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true);
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*ss_isect = ss_isect_private;
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ccl_global PathState *hit_state = &kernel_split_state.path_state[ray_index];
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*hit_state = branched_state->path_state;
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path_state_branch(hit_state, j, num_samples);
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#ifdef __VOLUME__
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if(need_update_volume_stack) {
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/* Setup ray from previous surface point to the new one. */
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float3 P = ray_offset(bssrdf_sd->P, -bssrdf_sd->Ng);
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volume_ray.D = normalize_len(P - volume_ray.P, &volume_ray.t);
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/* this next part is expensive as it does scene intersection so only do once */
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if(branched_state->next_closure == 0 && branched_state->next_sample == 0) {
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for(int k = 0; k < VOLUME_STACK_SIZE; k++) {
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branched_state->volume_stack[k] = hit_state->volume_stack[k];
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}
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kernel_volume_stack_update_for_subsurface(kg,
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emission_sd,
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&volume_ray,
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branched_state->volume_stack);
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}
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for(int k = 0; k < VOLUME_STACK_SIZE; k++) {
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hit_state->volume_stack[k] = branched_state->volume_stack[k];
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}
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}
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#endif /* __VOLUME__ */
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#ifdef __EMISSION__
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if(branched_state->next_closure == 0 && branched_state->next_sample == 0) {
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/* direct light */
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if(kernel_data.integrator.use_direct_light) {
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int all = (kernel_data.integrator.sample_all_lights_direct) ||
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(branched_state->path_state.flag & PATH_RAY_SHADOW_CATCHER);
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kernel_branched_path_surface_connect_light(kg,
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bssrdf_sd,
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emission_sd,
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hit_state,
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branched_state->throughput,
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num_samples_inv,
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L,
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all);
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}
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}
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#endif /* __EMISSION__ */
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/* indirect light */
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if(kernel_split_branched_path_surface_indirect_light_iter(kg,
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ray_index,
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num_samples_inv,
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bssrdf_sd,
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false,
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false))
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{
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branched_state->ss_next_closure = i;
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branched_state->ss_next_sample = j;
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branched_state->next_hit = hit;
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return true;
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}
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branched_state->next_closure = 0;
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}
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branched_state->next_hit = 0;
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}
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branched_state->ss_next_sample = 0;
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}
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branched_state->ss_next_closure = sd->num_closure;
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branched_state->waiting_on_shared_samples = (branched_state->shared_sample_count > 0);
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if(branched_state->waiting_on_shared_samples) {
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return true;
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}
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kernel_split_branched_path_indirect_loop_end(kg, ray_index);
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return false;
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}
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#endif /* __BRANCHED_PATH__ && __SUBSURFACE__ */
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ccl_device void kernel_subsurface_scatter(KernelGlobals *kg)
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{
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int thread_index = ccl_global_id(1) * ccl_global_size(0) + ccl_global_id(0);
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if(thread_index == 0) {
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/* We will empty both queues in this kernel. */
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kernel_split_params.queue_index[QUEUE_ACTIVE_AND_REGENERATED_RAYS] = 0;
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kernel_split_params.queue_index[QUEUE_HITBG_BUFF_UPDATE_TOREGEN_RAYS] = 0;
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}
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int ray_index = ccl_global_id(1) * ccl_global_size(0) + ccl_global_id(0);
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ray_index = get_ray_index(kg, ray_index,
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QUEUE_ACTIVE_AND_REGENERATED_RAYS,
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kernel_split_state.queue_data,
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kernel_split_params.queue_size,
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1);
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get_ray_index(kg, thread_index,
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QUEUE_HITBG_BUFF_UPDATE_TOREGEN_RAYS,
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kernel_split_state.queue_data,
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kernel_split_params.queue_size,
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1);
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#ifdef __SUBSURFACE__
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ccl_global char *ray_state = kernel_split_state.ray_state;
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if(IS_STATE(ray_state, ray_index, RAY_ACTIVE)) {
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ccl_global PathState *state = &kernel_split_state.path_state[ray_index];
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PathRadiance *L = &kernel_split_state.path_radiance[ray_index];
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ccl_global Ray *ray = &kernel_split_state.ray[ray_index];
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ccl_global float3 *throughput = &kernel_split_state.throughput[ray_index];
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ccl_global SubsurfaceIndirectRays *ss_indirect = &kernel_split_state.ss_rays[ray_index];
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ShaderData *sd = &kernel_split_state.sd[ray_index];
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ShaderData *emission_sd = &kernel_split_state.sd_DL_shadow[ray_index];
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if(sd->flag & SD_BSSRDF) {
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#ifdef __BRANCHED_PATH__
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if(!kernel_data.integrator.branched) {
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#endif
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if(kernel_path_subsurface_scatter(kg,
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sd,
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emission_sd,
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L,
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state,
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ray,
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throughput,
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ss_indirect))
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{
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kernel_split_path_end(kg, ray_index);
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}
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#ifdef __BRANCHED_PATH__
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}
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else if(IS_FLAG(ray_state, ray_index, RAY_BRANCHED_INDIRECT)) {
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float bssrdf_u, bssrdf_v;
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path_state_rng_2D(kg,
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state,
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PRNG_BSDF_U,
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&bssrdf_u, &bssrdf_v);
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const ShaderClosure *sc = shader_bssrdf_pick(sd, throughput, &bssrdf_u);
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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_addrspace(state, 0x68bc21eb);
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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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else {
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kernel_split_branched_path_subsurface_indirect_light_init(kg, ray_index);
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if(kernel_split_branched_path_subsurface_indirect_light_iter(kg, ray_index)) {
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ASSIGN_RAY_STATE(ray_state, ray_index, RAY_REGENERATED);
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}
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}
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#endif
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}
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}
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# ifdef __BRANCHED_PATH__
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if(ccl_global_id(0) == 0 && ccl_global_id(1) == 0) {
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kernel_split_params.queue_index[QUEUE_SUBSURFACE_INDIRECT_ITER] = 0;
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}
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/* iter loop */
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ray_index = get_ray_index(kg, ccl_global_id(1) * ccl_global_size(0) + ccl_global_id(0),
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QUEUE_SUBSURFACE_INDIRECT_ITER,
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kernel_split_state.queue_data,
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kernel_split_params.queue_size,
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1);
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if(IS_STATE(ray_state, ray_index, RAY_SUBSURFACE_INDIRECT_NEXT_ITER)) {
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/* for render passes, sum and reset indirect light pass variables
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* for the next samples */
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path_radiance_sum_indirect(&kernel_split_state.path_radiance[ray_index]);
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path_radiance_reset_indirect(&kernel_split_state.path_radiance[ray_index]);
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if(kernel_split_branched_path_subsurface_indirect_light_iter(kg, ray_index)) {
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ASSIGN_RAY_STATE(ray_state, ray_index, RAY_REGENERATED);
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}
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}
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# endif /* __BRANCHED_PATH__ */
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#endif /* __SUBSURFACE__ */
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}
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CCL_NAMESPACE_END
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