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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.
*/
#include "kernel_split_common.h"
/* Note on kernel_direct_lighting kernel.
* This is the eighth kernel in the ray tracing logic. This is the seventh
* of the path iteration kernels. 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
*
* The input and output are as follows,
*
* rng_coop -----------------------------------------|--- kernel_direct_lighting --|--- BSDFEval_coop
* PathState_coop -----------------------------------| |--- ISLamp_coop
* sd -----------------------------------------------| |--- LightRay_coop
* ray_state ----------------------------------------| |--- ray_state
* Queue_data (QUEUE_ACTIVE_AND_REGENERATED_RAYS) ---| |
* kg (globals) -------------------------------------| |
* queuesize ----------------------------------------| |
*
* 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 char kernel_direct_lighting(
KernelGlobals *kg,
ShaderData *sd, /* Required for direct lighting */
ccl_global uint *rng_coop, /* Required for direct lighting */
ccl_global PathState *PathState_coop, /* Required for direct lighting */
ccl_global int *ISLamp_coop, /* Required for direct lighting */
ccl_global Ray *LightRay_coop, /* Required for direct lighting */
ccl_global BsdfEval *BSDFEval_coop, /* Required for direct lighting */
ccl_global char *ray_state, /* Denotes the state of each ray */
int ray_index)
{
char enqueue_flag = 0;
if(IS_STATE(ray_state, ray_index, RAY_ACTIVE)) {
ccl_global PathState *state = &PathState_coop[ray_index];
/* direct lighting */
#ifdef __EMISSION__
if((kernel_data.integrator.use_direct_light &&
(ccl_fetch(sd, flag) & SD_BSDF_HAS_EVAL)))
{
/* Sample illumination from lights to find path contribution. */
ccl_global RNG* rng = &rng_coop[ray_index];
float light_t = path_state_rng_1D(kg, rng, state, PRNG_LIGHT);
float light_u, light_v;
path_state_rng_2D(kg, rng, state, PRNG_LIGHT_U, &light_u, &light_v);
float terminate = path_state_rng_light_termination(kg, rng, state);
LightSample ls;
if(light_sample(kg,
light_t, light_u, light_v,
ccl_fetch(sd, time),
ccl_fetch(sd, P),
state->bounce,
&ls)) {
Ray light_ray;
#ifdef __OBJECT_MOTION__
light_ray.time = ccl_fetch(sd, time);
#endif
BsdfEval L_light;
bool is_lamp;
if(direct_emission(kg, sd, kg->sd_input, &ls, state, &light_ray, &L_light, &is_lamp, terminate)) {
/* Write intermediate data to global memory to access from
* the next kernel.
*/
LightRay_coop[ray_index] = light_ray;
BSDFEval_coop[ray_index] = L_light;
ISLamp_coop[ray_index] = is_lamp;
/* Mark ray state for next shadow kernel. */
ADD_RAY_FLAG(ray_state, ray_index, RAY_SHADOW_RAY_CAST_DL);
enqueue_flag = 1;
}
}
}
#endif /* __EMISSION__ */
}
return enqueue_flag;
}
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