forked from bartvdbraak/blender
6238214159
Unlike regular path tracing, branched path tracing is usually used with lower sample counts, at least for primary rays. This means that are less samples for the GPU to work on in parallel and rendering is slower. As there is less work overall there is also more inactive threads during rendering with BPT. This patch makes use of those inactive rays to render branched samples in parallel with other samples. Each thread that is preparing for a branched sample will attempt to find an inactive thread and if one is found the state for the sample is copied to that thread. Potentially, if there are enough inactive threads, 100s of branched samples could be generated from the same originating thread and ran in parallel giving large speed ups. Gives 70% faster render for pavillion midday scene. 20-60% faster on BMW with car paint replaced with SSS/volumes.
247 lines
9.3 KiB
C
247 lines
9.3 KiB
C
/*
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* Copyright 2011-2015 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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/*This kernel takes care of setting up ray for the next iteration of
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* path-iteration and accumulating radiance corresponding to AO and
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* direct-lighting
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*
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* Ray state of rays that are terminated in this kernel are changed
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* to RAY_UPDATE_BUFFER.
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*
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* Note on queues:
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* This kernel fetches rays from the queue QUEUE_ACTIVE_AND_REGENERATED_RAYS
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* and processes only the rays of state RAY_ACTIVE.
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* There are different points in this kernel where a ray may terminate and
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* reach RAY_UPDATE_BUFF state. These rays are enqueued into
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* QUEUE_HITBG_BUFF_UPDATE_TOREGEN_RAYS queue. These rays will still be present
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* in QUEUE_ACTIVE_AND_REGENERATED_RAYS queue, but since their ray-state has
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* been changed to RAY_UPDATE_BUFF, there is no problem.
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*
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* State of queues when this kernel is called:
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* At entry,
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* - QUEUE_ACTIVE_AND_REGENERATED_RAYS will be filled with RAY_ACTIVE,
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* RAY_REGENERATED, RAY_UPDATE_BUFFER rays.
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* - QUEUE_HITBG_BUFF_UPDATE_TOREGEN_RAYS will be filled with
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* RAY_TO_REGENERATE and RAY_UPDATE_BUFFER rays.
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* At exit,
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* - QUEUE_ACTIVE_AND_REGENERATED_RAYS will be filled with RAY_ACTIVE,
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* RAY_REGENERATED and more RAY_UPDATE_BUFFER rays.
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* - QUEUE_HITBG_BUFF_UPDATE_TOREGEN_RAYS will be filled with
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* RAY_TO_REGENERATE and more RAY_UPDATE_BUFFER rays.
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*/
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#ifdef __BRANCHED_PATH__
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ccl_device_inline void kernel_split_branched_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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ADD_RAY_FLAG(kernel_split_state.ray_state, ray_index, RAY_BRANCHED_LIGHT_INDIRECT);
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}
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ccl_device void kernel_split_branched_indirect_light_end(KernelGlobals *kg, int ray_index)
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{
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kernel_split_branched_path_indirect_loop_end(kg, ray_index);
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ccl_global float3 *throughput = &kernel_split_state.throughput[ray_index];
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ShaderData *sd = &kernel_split_state.sd[ray_index];
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ccl_global PathState *state = &kernel_split_state.path_state[ray_index];
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ccl_global Ray *ray = &kernel_split_state.ray[ray_index];
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/* continue in case of transparency */
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*throughput *= shader_bsdf_transparency(kg, sd);
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if(is_zero(*throughput)) {
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kernel_split_path_end(kg, ray_index);
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}
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else {
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/* Update Path State */
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state->flag |= PATH_RAY_TRANSPARENT;
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state->transparent_bounce++;
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ray->P = ray_offset(sd->P, -sd->Ng);
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ray->t -= sd->ray_length; /* clipping works through transparent */
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# ifdef __RAY_DIFFERENTIALS__
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ray->dP = sd->dP;
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ray->dD.dx = -sd->dI.dx;
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ray->dD.dy = -sd->dI.dy;
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# endif /* __RAY_DIFFERENTIALS__ */
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# ifdef __VOLUME__
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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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# endif /* __VOLUME__ */
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}
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}
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#endif /* __BRANCHED_PATH__ */
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ccl_device void kernel_next_iteration_setup(KernelGlobals *kg,
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ccl_local_param unsigned int *local_queue_atomics)
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{
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if(ccl_local_id(0) == 0 && ccl_local_id(1) == 0) {
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*local_queue_atomics = 0;
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}
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ccl_barrier(CCL_LOCAL_MEM_FENCE);
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if(ccl_global_id(0) == 0 && ccl_global_id(1) == 0) {
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/* If we are here, then it means that scene-intersect kernel
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* has already been executed atleast once. From the next time,
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* scene-intersect kernel may operate on queues to fetch ray index
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*/
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*kernel_split_params.use_queues_flag = 1;
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/* Mark queue indices of QUEUE_SHADOW_RAY_CAST_AO_RAYS and
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* QUEUE_SHADOW_RAY_CAST_DL_RAYS queues that were made empty during the
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* previous kernel.
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*/
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kernel_split_params.queue_index[QUEUE_SHADOW_RAY_CAST_AO_RAYS] = 0;
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kernel_split_params.queue_index[QUEUE_SHADOW_RAY_CAST_DL_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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0);
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ccl_global char *ray_state = kernel_split_state.ray_state;
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bool active = IS_STATE(ray_state, ray_index, RAY_ACTIVE);
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if(active) {
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ccl_global float3 *throughput = &kernel_split_state.throughput[ray_index];
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ccl_global Ray *ray = &kernel_split_state.ray[ray_index];
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RNG rng = kernel_split_state.rng[ray_index];
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ShaderData *sd = &kernel_split_state.sd[ray_index];
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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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#ifdef __BRANCHED_PATH__
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if(!kernel_data.integrator.branched || IS_FLAG(ray_state, ray_index, RAY_BRANCHED_INDIRECT)) {
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#endif
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/* Compute direct lighting and next bounce. */
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if(!kernel_path_surface_bounce(kg, &rng, sd, throughput, state, L, ray)) {
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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 {
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kernel_split_branched_indirect_light_init(kg, ray_index);
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if(kernel_split_branched_path_surface_indirect_light_iter(kg,
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ray_index,
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1.0f,
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&kernel_split_state.branched_state[ray_index].sd,
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true,
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true))
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{
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ASSIGN_RAY_STATE(ray_state, ray_index, RAY_REGENERATED);
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}
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else {
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kernel_split_branched_indirect_light_end(kg, ray_index);
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}
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}
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#endif /* __BRANCHED_PATH__ */
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kernel_split_state.rng[ray_index] = rng;
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}
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/* Enqueue RAY_UPDATE_BUFFER rays. */
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enqueue_ray_index_local(ray_index,
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QUEUE_HITBG_BUFF_UPDATE_TOREGEN_RAYS,
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IS_STATE(ray_state, ray_index, RAY_UPDATE_BUFFER) && active,
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kernel_split_params.queue_size,
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local_queue_atomics,
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kernel_split_state.queue_data,
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kernel_split_params.queue_index);
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#ifdef __BRANCHED_PATH__
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/* iter loop */
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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_LIGHT_INDIRECT_ITER] = 0;
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}
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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_LIGHT_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_LIGHT_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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PathRadiance *L = &kernel_split_state.path_radiance[ray_index];
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path_radiance_sum_indirect(L);
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path_radiance_reset_indirect(L);
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if(kernel_split_branched_path_surface_indirect_light_iter(kg,
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ray_index,
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1.0f,
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&kernel_split_state.branched_state[ray_index].sd,
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true,
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true))
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{
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ASSIGN_RAY_STATE(ray_state, ray_index, RAY_REGENERATED);
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}
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else {
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kernel_split_branched_indirect_light_end(kg, ray_index);
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}
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}
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# ifdef __VOLUME__
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/* Enqueue RAY_VOLUME_INDIRECT_NEXT_ITER rays */
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ccl_barrier(CCL_LOCAL_MEM_FENCE);
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if(ccl_local_id(0) == 0 && ccl_local_id(1) == 0) {
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*local_queue_atomics = 0;
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}
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ccl_barrier(CCL_LOCAL_MEM_FENCE);
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ray_index = ccl_global_id(1) * ccl_global_size(0) + ccl_global_id(0);
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enqueue_ray_index_local(ray_index,
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QUEUE_VOLUME_INDIRECT_ITER,
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IS_STATE(kernel_split_state.ray_state, ray_index, RAY_VOLUME_INDIRECT_NEXT_ITER),
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kernel_split_params.queue_size,
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local_queue_atomics,
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kernel_split_state.queue_data,
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kernel_split_params.queue_index);
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# endif /* __VOLUME__ */
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# ifdef __SUBSURFACE__
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/* Enqueue RAY_SUBSURFACE_INDIRECT_NEXT_ITER rays */
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ccl_barrier(CCL_LOCAL_MEM_FENCE);
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if(ccl_local_id(0) == 0 && ccl_local_id(1) == 0) {
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*local_queue_atomics = 0;
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}
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ccl_barrier(CCL_LOCAL_MEM_FENCE);
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ray_index = ccl_global_id(1) * ccl_global_size(0) + ccl_global_id(0);
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enqueue_ray_index_local(ray_index,
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QUEUE_SUBSURFACE_INDIRECT_ITER,
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IS_STATE(kernel_split_state.ray_state, ray_index, RAY_SUBSURFACE_INDIRECT_NEXT_ITER),
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kernel_split_params.queue_size,
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local_queue_atomics,
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kernel_split_state.queue_data,
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kernel_split_params.queue_index);
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# endif /* __SUBSURFACE__ */
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#endif /* __BRANCHED_PATH__ */
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}
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CCL_NAMESPACE_END
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