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/*
* Copyright 2011-2015 Blender Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
CCL_NAMESPACE_BEGIN
/* This kernel takes care of the logic to process "material of type holdout",
* indirect primitive emission, bsdf blurring, probabilistic path termination
* and AO.
*
* This kernels determines the rays for which a shadow_blocked() function
* associated with AO should be executed. Those rays for which a
* shadow_blocked() function for AO must be executed are marked with flag
* RAY_SHADOW_RAY_CAST_ao and enqueued into the queue
* QUEUE_SHADOW_RAY_CAST_AO_RAYS
*
* Ray state of rays that are terminated in this kernel are changed to RAY_UPDATE_BUFFER
*
* Note on Queues:
* This kernel fetches rays from the queue QUEUE_ACTIVE_AND_REGENERATED_RAYS
* and processes only the rays of state RAY_ACTIVE.
* There are different points in this kernel where a ray may terminate and
* reach RAY_UPDATE_BUFFER state. These rays are enqueued into
* QUEUE_HITBG_BUFF_UPDATE_TOREGEN_RAYS queue. These rays will still be present
* in QUEUE_ACTIVE_AND_REGENERATED_RAYS queue, but since their ray-state has
* been changed to RAY_UPDATE_BUFFER, there is no problem.
*
* State of queues when this kernel is called:
* At entry,
* - QUEUE_ACTIVE_AND_REGENERATED_RAYS will be filled with RAY_ACTIVE and
* RAY_REGENERATED rays
* - QUEUE_HITBG_BUFF_UPDATE_TOREGEN_RAYS will be filled with
* RAY_TO_REGENERATE rays.
* - QUEUE_SHADOW_RAY_CAST_AO_RAYS will be empty.
* At exit,
* - QUEUE_ACTIVE_AND_REGENERATED_RAYS will be filled with RAY_ACTIVE,
* RAY_REGENERATED and RAY_UPDATE_BUFFER rays.
* - QUEUE_HITBG_BUFF_UPDATE_TOREGEN_RAYS will be filled with
* RAY_TO_REGENERATE and RAY_UPDATE_BUFFER rays.
* - QUEUE_SHADOW_RAY_CAST_AO_RAYS will be filled with rays marked with
* flag RAY_SHADOW_RAY_CAST_AO
*/
ccl_device void kernel_holdout_emission_blurring_pathtermination_ao(
KernelGlobals *kg,
ccl_local_param BackgroundAOLocals *locals)
{
if(ccl_local_id(0) == 0 && ccl_local_id(1) == 0) {
locals->queue_atomics_bg = 0;
locals->queue_atomics_ao = 0;
}
ccl_barrier(CCL_LOCAL_MEM_FENCE);
#ifdef __AO__
char enqueue_flag = 0;
#endif
int ray_index = ccl_global_id(1) * ccl_global_size(0) + ccl_global_id(0);
ray_index = get_ray_index(kg, ray_index,
QUEUE_ACTIVE_AND_REGENERATED_RAYS,
kernel_split_state.queue_data,
kernel_split_params.queue_size,
0);
#ifdef __COMPUTE_DEVICE_GPU__
/* If we are executing on a GPU device, we exit all threads that are not
* required.
*
* If we are executing on a CPU device, then we need to keep all threads
* active since we have barrier() calls later in the kernel. CPU devices,
* expect all threads to execute barrier statement.
*/
if(ray_index == QUEUE_EMPTY_SLOT) {
return;
}
#endif /* __COMPUTE_DEVICE_GPU__ */
#ifndef __COMPUTE_DEVICE_GPU__
if(ray_index != QUEUE_EMPTY_SLOT) {
#endif
ccl_global PathState *state = 0x0;
float3 throughput;
ccl_global char *ray_state = kernel_split_state.ray_state;
ShaderData *sd = &kernel_split_state.sd[ray_index];
if(IS_STATE(ray_state, ray_index, RAY_ACTIVE)) {
uint buffer_offset = kernel_split_state.buffer_offset[ray_index];
ccl_global float *buffer = kernel_split_params.tile.buffer + buffer_offset;
ccl_global Ray *ray = &kernel_split_state.ray[ray_index];
ShaderData *emission_sd = &kernel_split_state.sd_DL_shadow[ray_index];
PathRadiance *L = &kernel_split_state.path_radiance[ray_index];
throughput = kernel_split_state.throughput[ray_index];
state = &kernel_split_state.path_state[ray_index];
if(!kernel_path_shader_apply(kg,
sd,
state,
ray,
throughput,
emission_sd,
L,
buffer))
{
kernel_split_path_end(kg, ray_index);
}
}
if(IS_STATE(ray_state, ray_index, RAY_ACTIVE)) {
/* 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_continuation_probability(kg, state, throughput);
if(probability == 0.0f) {
kernel_split_path_end(kg, ray_index);
}
else if(probability < 1.0f) {
float terminate = path_state_rng_1D(kg, state, PRNG_TERMINATE);
if(terminate >= probability) {
kernel_split_path_end(kg, ray_index);
}
else {
kernel_split_state.throughput[ray_index] = throughput/probability;
}
}
if(IS_STATE(ray_state, ray_index, RAY_ACTIVE)) {
PathRadiance *L = &kernel_split_state.path_radiance[ray_index];
kernel_update_denoising_features(kg, sd, state, L);
}
}
#ifdef __AO__
if(IS_STATE(ray_state, ray_index, RAY_ACTIVE)) {
/* ambient occlusion */
if(kernel_data.integrator.use_ambient_occlusion || (sd->flag & SD_AO)) {
enqueue_flag = 1;
}
}
#endif /* __AO__ */
#ifndef __COMPUTE_DEVICE_GPU__
}
#endif
#ifdef __AO__
/* Enqueue to-shadow-ray-cast rays. */
enqueue_ray_index_local(ray_index,
QUEUE_SHADOW_RAY_CAST_AO_RAYS,
enqueue_flag,
kernel_split_params.queue_size,
&locals->queue_atomics_ao,
kernel_split_state.queue_data,
kernel_split_params.queue_index);
#endif
}
CCL_NAMESPACE_END
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