intern/cycles/kernel/split/kernel_shadow_blocked.h

   1 /*
   2  * Copyright 2011-2015 Blender Foundation
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  * http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #include "kernel_split_common.h"
  18
  19 /* Note on kernel_shadow_blocked kernel.
  20  * This is the ninth kernel in the ray tracing logic. This is the eighth
  21  * of the path iteration kernels. This kernel takes care of "shadow ray cast"
  22  * logic of the direct lighting and AO  part of ray tracing.
  23  *
  24  * The input and output are as follows,
  25  *
  26  * PathState_coop ----------------------------------|--- kernel_shadow_blocked --|
  27  * LightRay_dl_coop --------------------------------|                            |--- LightRay_dl_coop
  28  * LightRay_ao_coop --------------------------------|                            |--- LightRay_ao_coop
  29  * ray_state ---------------------------------------|                            |--- ray_state
  30  * Queue_data(QUEUE_SHADOW_RAY_CAST_AO_RAYS &       |                            |--- Queue_data (QUEUE_SHADOW_RAY_CAST_AO_RAYS & QUEUE_SHADOW_RAY_CAST_AO_RAYS)
  31               QUEUE_SHADOW_RAY_CAST_DL_RAYS) -------|                            |
  32  * Queue_index(QUEUE_SHADOW_RAY_CAST_AO_RAYS&
  33               QUEUE_SHADOW_RAY_CAST_DL_RAYS) -------|                            |
  34  * kg (globals) ------------------------------------|                            |
  35  * queuesize ---------------------------------------|                            |
  36  *
  37  * Note on sd_shadow : sd_shadow is neither input nor output to this kernel. sd_shadow is filled and consumed in this kernel itself.
  38  * Note on queues :
  39  * The kernel fetches from QUEUE_SHADOW_RAY_CAST_AO_RAYS and QUEUE_SHADOW_RAY_CAST_DL_RAYS queues. We will empty
  40  * these queues this kernel.
  41  * State of queues when this kernel is called :
  42  * state of queues QUEUE_ACTIVE_AND_REGENERATED_RAYS and QUEUE_HITBG_BUFF_UPDATE_TOREGEN_RAYS will be same
  43  * before and after this kernel call.
  44  * QUEUE_SHADOW_RAY_CAST_AO_RAYS & QUEUE_SHADOW_RAY_CAST_DL_RAYS will be filled with rays marked with flags RAY_SHADOW_RAY_CAST_AO
  45  * and RAY_SHADOW_RAY_CAST_DL respectively, during kernel entry.
  46  * QUEUE_SHADOW_RAY_CAST_AO_RAYS and QUEUE_SHADOW_RAY_CAST_DL_RAYS will be empty at kernel exit.
  47  */
  48 ccl_device void kernel_shadow_blocked(
  49         KernelGlobals *kg,
  50         ShaderData *sd_shadow,                 /* Required for shadow blocked */
  51         ccl_global PathState *PathState_coop,  /* Required for shadow blocked */
  52         ccl_global Ray *LightRay_dl_coop,      /* Required for direct lighting's shadow blocked */
  53         ccl_global Ray *LightRay_ao_coop,      /* Required for AO's shadow blocked */
  54         ccl_global char *ray_state,
  55         int total_num_rays,
  56         char shadow_blocked_type,
  57         int ray_index)
  58 {
  59         /* Flag determining if we need to update L. */
  60         char update_path_radiance = 0;
  61
  62         if(IS_FLAG(ray_state, ray_index, RAY_SHADOW_RAY_CAST_DL) ||
  63            IS_FLAG(ray_state, ray_index, RAY_SHADOW_RAY_CAST_AO))
  64         {
  65                 ccl_global PathState *state = &PathState_coop[ray_index];
  66                 ccl_global Ray *light_ray_dl_global = &LightRay_dl_coop[ray_index];
  67                 ccl_global Ray *light_ray_ao_global = &LightRay_ao_coop[ray_index];
  68
  69                 ccl_global Ray *light_ray_global =
  70                         shadow_blocked_type == RAY_SHADOW_RAY_CAST_AO
  71                                 ? light_ray_ao_global
  72                                 : light_ray_dl_global;
  73
  74                 float3 shadow;
  75                 update_path_radiance = !(shadow_blocked(kg,
  76                                                         state,
  77                                                         light_ray_global,
  78                                                         &shadow));
  79
  80                 /* We use light_ray_global's P and t to store shadow and
  81                  * update_path_radiance.
  82                  */
  83                 light_ray_global->P = shadow;
  84                 light_ray_global->t = update_path_radiance;
  85         }
  86 }