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/*
* Copyright 2017 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
#ifdef __SUBSURFACE__
# ifndef __KERNEL_CUDA__
ccl_device
# else
ccl_device_inline
# endif
bool kernel_path_subsurface_scatter(
KernelGlobals *kg,
ShaderData *sd,
ShaderData *emission_sd,
PathRadiance *L,
ccl_addr_space PathState *state,
ccl_addr_space Ray *ray,
ccl_addr_space float3 *throughput,
ccl_addr_space SubsurfaceIndirectRays *ss_indirect)
{
float bssrdf_u, bssrdf_v;
path_state_rng_2D(kg, state, PRNG_BSDF_U, &bssrdf_u, &bssrdf_v);
const ShaderClosure *sc = shader_bssrdf_pick(sd, throughput, &bssrdf_u);
/* do bssrdf scatter step if we picked a bssrdf closure */
if(sc) {
/* We should never have two consecutive BSSRDF bounces,
* the second one should be converted to a diffuse BSDF to
* avoid this.
*/
kernel_assert(!(state->flag & PATH_RAY_DIFFUSE_ANCESTOR));
uint lcg_state = lcg_state_init_addrspace(state, 0x68bc21eb);
SubsurfaceIntersection ss_isect;
int num_hits = subsurface_scatter_multi_intersect(kg,
&ss_isect,
sd,
sc,
&lcg_state,
bssrdf_u, bssrdf_v,
false);
# ifdef __VOLUME__
bool need_update_volume_stack =
kernel_data.integrator.use_volumes &&
sd->object_flag & SD_OBJECT_INTERSECTS_VOLUME;
# endif /* __VOLUME__ */
/* compute lighting with the BSDF closure */
for(int hit = 0; hit < num_hits; hit++) {
/* NOTE: We reuse the existing ShaderData, we assume the path
* integration loop stops when this function returns true.
*/
subsurface_scatter_multi_setup(kg,
&ss_isect,
hit,
sd,
state,
state->flag,
sc,
false);
kernel_path_surface_connect_light(kg, sd, emission_sd, *throughput, state, L);
ccl_addr_space PathState *hit_state = &ss_indirect->state[ss_indirect->num_rays];
ccl_addr_space Ray *hit_ray = &ss_indirect->rays[ss_indirect->num_rays];
ccl_addr_space float3 *hit_tp = &ss_indirect->throughputs[ss_indirect->num_rays];
PathRadianceState *hit_L_state = &ss_indirect->L_state[ss_indirect->num_rays];
*hit_state = *state;
*hit_ray = *ray;
*hit_tp = *throughput;
*hit_L_state = L->state;
hit_state->rng_offset += PRNG_BOUNCE_NUM;
if(kernel_path_surface_bounce(kg,
sd,
hit_tp,
hit_state,
hit_L_state,
hit_ray))
{
# ifdef __LAMP_MIS__
hit_state->ray_t = 0.0f;
# endif /* __LAMP_MIS__ */
# ifdef __VOLUME__
if(need_update_volume_stack) {
Ray volume_ray = *ray;
/* Setup ray from previous surface point to the new one. */
volume_ray.D = normalize_len(hit_ray->P - volume_ray.P,
&volume_ray.t);
kernel_volume_stack_update_for_subsurface(
kg,
emission_sd,
&volume_ray,
hit_state->volume_stack);
}
# endif /* __VOLUME__ */
ss_indirect->num_rays++;
}
}
return true;
}
return false;
}
ccl_device_inline void kernel_path_subsurface_init_indirect(
ccl_addr_space SubsurfaceIndirectRays *ss_indirect)
{
ss_indirect->num_rays = 0;
}
ccl_device void kernel_path_subsurface_setup_indirect(
KernelGlobals *kg,
ccl_addr_space SubsurfaceIndirectRays *ss_indirect,
ccl_addr_space PathState *state,
ccl_addr_space Ray *ray,
PathRadiance *L,
ccl_addr_space float3 *throughput)
{
/* Setup state, ray and throughput for indirect SSS rays. */
ss_indirect->num_rays--;
path_radiance_sum_indirect(L);
path_radiance_reset_indirect(L);
*state = ss_indirect->state[ss_indirect->num_rays];
*ray = ss_indirect->rays[ss_indirect->num_rays];
L->state = ss_indirect->L_state[ss_indirect->num_rays];
*throughput = ss_indirect->throughputs[ss_indirect->num_rays];
state->rng_offset += ss_indirect->num_rays * PRNG_BOUNCE_NUM;
}
#endif /* __SUBSURFACE__ */
CCL_NAMESPACE_END
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