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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
/* Note on kernel_setup_next_iteration kernel.
* This is the tenth kernel in the ray tracing logic. This is the ninth
* of the path iteration kernels. This kernel takes care of setting up
* Ray for the next iteration of path-iteration and accumulating radiance
* corresponding to AO and direct-lighting
*
* Ray state of rays that are terminated in this kernel are changed to RAY_UPDATE_BUFFER
*
* The input and output are as follows,
*
* rng_coop ---------------------------------------------|--- kernel_next_iteration_setup -|--- Queue_index (QUEUE_HITBG_BUFF_UPDATE_TOREGEN_RAYS)
* throughput_coop --------------------------------------| |--- Queue_data (QUEUE_HITBF_BUFF_UPDATE_TOREGEN_RAYS)
* PathRadiance_coop ------------------------------------| |--- throughput_coop
* PathState_coop ---------------------------------------| |--- PathRadiance_coop
* sd ---------------------------------------------------| |--- PathState_coop
* ray_state --------------------------------------------| |--- ray_state
* Queue_data (QUEUE_ACTIVE_AND_REGENERATD_RAYS) --------| |--- Ray_coop
* Queue_index (QUEUE_HITBG_BUFF_UPDATE_TOREGEN_RAYS) ---| |--- use_queues_flag
* Ray_coop ---------------------------------------------| |
* kg (globals) -----------------------------------------| |
* LightRay_dl_coop -------------------------------------|
* ISLamp_coop ------------------------------------------|
* BSDFEval_coop ----------------------------------------|
* LightRay_ao_coop -------------------------------------|
* AOBSDF_coop ------------------------------------------|
* AOAlpha_coop -----------------------------------------|
*
* 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_BUFF
* 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_BUFF, 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, RAY_REGENERATED, RAY_UPDATE_BUFFER rays.
* QUEUE_HITBG_BUFF_UPDATE_TOREGEN_RAYS will be filled with RAY_TO_REGENERATE and RAY_UPDATE_BUFFER rays
* At exit,
* QUEUE_ACTIVE_AND_REGENERATED_RAYS will be filled with RAY_ACTIVE, RAY_REGENERATED and more RAY_UPDATE_BUFFER rays.
* QUEUE_HITBG_BUFF_UPDATE_TOREGEN_RAYS will be filled with RAY_TO_REGENERATE and more RAY_UPDATE_BUFFER rays
*/
ccl_device void kernel_next_iteration_setup(KernelGlobals *kg)
{
ccl_local unsigned int local_queue_atomics;
if(ccl_local_id(0) == 0 && ccl_local_id(1) == 0) {
local_queue_atomics = 0;
}
ccl_barrier(CCL_LOCAL_MEM_FENCE);
if(ccl_global_id(0) == 0 && ccl_global_id(1) == 0) {
/* If we are here, then it means that scene-intersect kernel
* has already been executed atleast once. From the next time,
* scene-intersect kernel may operate on queues to fetch ray index
*/
*kernel_split_params.use_queues_flag = 1;
/* Mark queue indices of QUEUE_SHADOW_RAY_CAST_AO_RAYS and
* QUEUE_SHADOW_RAY_CAST_DL_RAYS queues that were made empty during the
* previous kernel.
*/
kernel_split_params.queue_index[QUEUE_SHADOW_RAY_CAST_AO_RAYS] = 0;
kernel_split_params.queue_index[QUEUE_SHADOW_RAY_CAST_DL_RAYS] = 0;
}
char enqueue_flag = 0;
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
#ifndef __COMPUTE_DEVICE_GPU__
if(ray_index != QUEUE_EMPTY_SLOT) {
#endif
/* Load ShaderData structure. */
PathRadiance *L = NULL;
ccl_global PathState *state = NULL;
ccl_global char *ray_state = kernel_split_state.ray_state;
/* Path radiance update for AO/Direct_lighting's shadow blocked. */
if(IS_FLAG(ray_state, ray_index, RAY_SHADOW_RAY_CAST_DL) ||
IS_FLAG(ray_state, ray_index, RAY_SHADOW_RAY_CAST_AO))
{
state = &kernel_split_state.path_state[ray_index];
L = &kernel_split_state.path_radiance[ray_index];
float3 _throughput = kernel_split_state.throughput[ray_index];
if(IS_FLAG(ray_state, ray_index, RAY_SHADOW_RAY_CAST_AO)) {
float3 shadow = kernel_split_state.ao_light_ray[ray_index].P;
// TODO(mai): investigate correctness here
char update_path_radiance = (char)kernel_split_state.ao_light_ray[ray_index].t;
if(update_path_radiance) {
path_radiance_accum_ao(L,
_throughput,
kernel_split_state.ao_alpha[ray_index],
kernel_split_state.ao_bsdf[ray_index],
shadow,
state->bounce);
}
REMOVE_RAY_FLAG(ray_state, ray_index, RAY_SHADOW_RAY_CAST_AO);
}
if(IS_FLAG(ray_state, ray_index, RAY_SHADOW_RAY_CAST_DL)) {
float3 shadow = kernel_split_state.light_ray[ray_index].P;
// TODO(mai): investigate correctness here
char update_path_radiance = (char)kernel_split_state.light_ray[ray_index].t;
if(update_path_radiance) {
BsdfEval L_light = kernel_split_state.bsdf_eval[ray_index];
path_radiance_accum_light(L,
_throughput,
&L_light,
shadow,
1.0f,
state->bounce,
kernel_split_state.is_lamp[ray_index]);
}
REMOVE_RAY_FLAG(ray_state, ray_index, RAY_SHADOW_RAY_CAST_DL);
}
}
if(IS_STATE(ray_state, ray_index, RAY_ACTIVE)) {
ccl_global float3 *throughput = &kernel_split_state.throughput[ray_index];
ccl_global Ray *ray = &kernel_split_state.ray[ray_index];
ccl_global RNG *rng = &kernel_split_state.rng[ray_index];
state = &kernel_split_state.path_state[ray_index];
L = &kernel_split_state.path_radiance[ray_index];
/* Compute direct lighting and next bounce. */
if(!kernel_path_surface_bounce(kg, rng, kernel_split_state.sd, throughput, state, L, ray)) {
ASSIGN_RAY_STATE(ray_state, ray_index, RAY_UPDATE_BUFFER);
enqueue_flag = 1;
}
}
#ifndef __COMPUTE_DEVICE_GPU__
}
#endif
/* Enqueue RAY_UPDATE_BUFFER rays. */
enqueue_ray_index_local(ray_index,
QUEUE_HITBG_BUFF_UPDATE_TOREGEN_RAYS,
enqueue_flag,
kernel_split_params.queue_size,
&local_queue_atomics,
kernel_split_state.queue_data,
kernel_split_params.queue_index);
}
CCL_NAMESPACE_END
|