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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 direct lighting logic.
* However, the "shadow ray cast" part of direct lighting is handled
* in the next kernel.
*
* This kernels determines the rays for which a shadow_blocked() function
* associated with direct lighting should be executed. Those rays for which
* a shadow_blocked() function for direct-lighting must be executed, are
* marked with flag RAY_SHADOW_RAY_CAST_DL and enqueued into the queue
* QUEUE_SHADOW_RAY_CAST_DL_RAYS
*
* Note on Queues:
* This kernel only reads from the QUEUE_ACTIVE_AND_REGENERATED_RAYS queue
* and processes only the rays of state RAY_ACTIVE; If a ray needs to execute
* the corresponding shadow_blocked part, after direct lighting, the ray is
* marked with RAY_SHADOW_RAY_CAST_DL flag.
*
* State of queues when this kernel is called:
* - State of queues QUEUE_ACTIVE_AND_REGENERATED_RAYS and
* QUEUE_HITBG_BUFF_UPDATE_TOREGEN_RAYS will be same before and after this
* kernel call.
* - QUEUE_SHADOW_RAY_CAST_DL_RAYS queue will be filled with rays for which a
* shadow_blocked function must be executed, after this kernel call
* Before this kernel call the QUEUE_SHADOW_RAY_CAST_DL_RAYS will be empty.
*/
ccl_device void kernel_direct_lighting(KernelGlobals *kg,
ccl_local_param 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);
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);
if(IS_STATE(kernel_split_state.ray_state, ray_index, RAY_ACTIVE)) {
ccl_global PathState *state = &kernel_split_state.path_state[ray_index];
ShaderData *sd = &kernel_split_state.sd[ray_index];
/* direct lighting */
#ifdef __EMISSION__
bool flag = (kernel_data.integrator.use_direct_light &&
(sd->flag & SD_BSDF_HAS_EVAL));
# ifdef __BRANCHED_PATH__
if(flag && kernel_data.integrator.branched) {
flag = false;
enqueue_flag = 1;
}
# endif /* __BRANCHED_PATH__ */
# ifdef __SHADOW_TRICKS__
if(flag && state->flag & PATH_RAY_SHADOW_CATCHER) {
flag = false;
enqueue_flag = 1;
}
# endif /* __SHADOW_TRICKS__ */
if(flag) {
/* Sample illumination from lights to find path contribution. */
float light_u, light_v;
path_state_rng_2D(kg, state, PRNG_LIGHT_U, &light_u, &light_v);
float terminate = path_state_rng_light_termination(kg, state);
LightSample ls;
if(light_sample(kg,
light_u, light_v,
sd->time,
sd->P,
state->bounce,
&ls)) {
Ray light_ray;
light_ray.time = sd->time;
BsdfEval L_light;
bool is_lamp;
if(direct_emission(kg, sd, &kernel_split_state.sd_DL_shadow[ray_index], &ls, state, &light_ray, &L_light, &is_lamp, terminate)) {
/* Write intermediate data to global memory to access from
* the next kernel.
*/
kernel_split_state.light_ray[ray_index] = light_ray;
kernel_split_state.bsdf_eval[ray_index] = L_light;
kernel_split_state.is_lamp[ray_index] = is_lamp;
/* Mark ray state for next shadow kernel. */
enqueue_flag = 1;
}
}
}
#endif /* __EMISSION__ */
}
#ifdef __EMISSION__
/* Enqueue RAY_SHADOW_RAY_CAST_DL rays. */
enqueue_ray_index_local(ray_index,
QUEUE_SHADOW_RAY_CAST_DL_RAYS,
enqueue_flag,
kernel_split_params.queue_size,
local_queue_atomics,
kernel_split_state.queue_data,
kernel_split_params.queue_index);
#endif
#ifdef __BRANCHED_PATH__
/* Enqueue RAY_LIGHT_INDIRECT_NEXT_ITER rays
* this is the last kernel before next_iteration_setup that uses local atomics so we do this here
*/
ccl_barrier(CCL_LOCAL_MEM_FENCE);
if(ccl_local_id(0) == 0 && ccl_local_id(1) == 0) {
*local_queue_atomics = 0;
}
ccl_barrier(CCL_LOCAL_MEM_FENCE);
ray_index = ccl_global_id(1) * ccl_global_size(0) + ccl_global_id(0);
enqueue_ray_index_local(ray_index,
QUEUE_LIGHT_INDIRECT_ITER,
IS_STATE(kernel_split_state.ray_state, ray_index, RAY_LIGHT_INDIRECT_NEXT_ITER),
kernel_split_params.queue_size,
local_queue_atomics,
kernel_split_state.queue_data,
kernel_split_params.queue_index);
#endif /* __BRANCHED_PATH__ */
}
CCL_NAMESPACE_END
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