blender/intern/cycles/kernel/kernel_path_volume.h
Brecht Van Lommel 400e6f37b8 Cycles: reduce subsurface stack memory usage.
This is done by storing only a subset of PathRadiance, and by storing
direct light immediately in the main PathRadiance. Saves about 10% of
CUDA stack memory, and simplifies subsurface indirect ray code.
2017-09-28 15:18:43 +02:00

271 lines
8.5 KiB
C

/*
* Copyright 2011-2013 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 __VOLUME_SCATTER__
ccl_device_inline void kernel_path_volume_connect_light(
KernelGlobals *kg,
ShaderData *sd,
ShaderData *emission_sd,
float3 throughput,
ccl_addr_space PathState *state,
PathRadiance *L)
{
#ifdef __EMISSION__
if(!kernel_data.integrator.use_direct_light)
return;
/* 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);
Ray light_ray;
BsdfEval L_light;
LightSample ls;
bool is_lamp;
/* connect to light from given point where shader has been evaluated */
light_ray.time = sd->time;
if(light_sample(kg, light_u, light_v, sd->time, sd->P, state->bounce, &ls))
{
float terminate = path_state_rng_light_termination(kg, state);
if(direct_emission(kg, sd, emission_sd, &ls, state, &light_ray, &L_light, &is_lamp, terminate)) {
/* trace shadow ray */
float3 shadow;
if(!shadow_blocked(kg, sd, emission_sd, state, &light_ray, &shadow)) {
/* accumulate */
path_radiance_accum_light(L, state, throughput, &L_light, shadow, 1.0f, is_lamp);
}
}
}
#endif /* __EMISSION__ */
}
#ifdef __KERNEL_GPU__
ccl_device_noinline
#else
ccl_device
#endif
bool kernel_path_volume_bounce(
KernelGlobals *kg,
ShaderData *sd,
ccl_addr_space float3 *throughput,
ccl_addr_space PathState *state,
PathRadianceState *L_state,
ccl_addr_space Ray *ray)
{
/* sample phase function */
float phase_pdf;
BsdfEval phase_eval;
float3 phase_omega_in;
differential3 phase_domega_in;
float phase_u, phase_v;
path_state_rng_2D(kg, state, PRNG_BSDF_U, &phase_u, &phase_v);
int label;
label = shader_volume_phase_sample(kg, sd, phase_u, phase_v, &phase_eval,
&phase_omega_in, &phase_domega_in, &phase_pdf);
if(phase_pdf == 0.0f || bsdf_eval_is_zero(&phase_eval))
return false;
/* modify throughput */
path_radiance_bsdf_bounce(kg, L_state, throughput, &phase_eval, phase_pdf, state->bounce, label);
/* set labels */
state->ray_pdf = phase_pdf;
#ifdef __LAMP_MIS__
state->ray_t = 0.0f;
#endif
state->min_ray_pdf = fminf(phase_pdf, state->min_ray_pdf);
/* update path state */
path_state_next(kg, state, label);
/* setup ray */
ray->P = sd->P;
ray->D = phase_omega_in;
ray->t = FLT_MAX;
#ifdef __RAY_DIFFERENTIALS__
ray->dP = sd->dP;
ray->dD = phase_domega_in;
#endif
return true;
}
#ifndef __SPLIT_KERNEL__
ccl_device void kernel_branched_path_volume_connect_light(
KernelGlobals *kg,
ShaderData *sd,
ShaderData *emission_sd,
float3 throughput,
ccl_addr_space PathState *state,
PathRadiance *L,
bool sample_all_lights,
Ray *ray,
const VolumeSegment *segment)
{
#ifdef __EMISSION__
if(!kernel_data.integrator.use_direct_light)
return;
Ray light_ray;
BsdfEval L_light;
bool is_lamp;
light_ray.time = sd->time;
if(sample_all_lights) {
/* lamp sampling */
for(int i = 0; i < kernel_data.integrator.num_all_lights; i++) {
if(UNLIKELY(light_select_reached_max_bounces(kg, i, state->bounce)))
continue;
int num_samples = light_select_num_samples(kg, i);
float num_samples_inv = 1.0f/(num_samples*kernel_data.integrator.num_all_lights);
uint lamp_rng_hash = cmj_hash(state->rng_hash, i);
for(int j = 0; j < num_samples; j++) {
/* sample random position on given light */
float light_u, light_v;
path_branched_rng_2D(kg, lamp_rng_hash, state, j, num_samples, PRNG_LIGHT_U, &light_u, &light_v);
LightSample ls;
lamp_light_sample(kg, i, light_u, light_v, ray->P, &ls);
float3 tp = throughput;
/* sample position on volume segment */
float rphase = path_branched_rng_1D(kg, state->rng_hash, state, j, num_samples, PRNG_PHASE_CHANNEL);
float rscatter = path_branched_rng_1D(kg, state->rng_hash, state, j, num_samples, PRNG_SCATTER_DISTANCE);
VolumeIntegrateResult result = kernel_volume_decoupled_scatter(kg,
state, ray, sd, &tp, rphase, rscatter, segment, (ls.t != FLT_MAX)? &ls.P: NULL, false);
/* todo: split up light_sample so we don't have to call it again with new position */
if(result == VOLUME_PATH_SCATTERED &&
lamp_light_sample(kg, i, light_u, light_v, sd->P, &ls)) {
if(kernel_data.integrator.pdf_triangles != 0.0f)
ls.pdf *= 2.0f;
float terminate = path_branched_rng_light_termination(kg, state->rng_hash, state, j, num_samples);
if(direct_emission(kg, sd, emission_sd, &ls, state, &light_ray, &L_light, &is_lamp, terminate)) {
/* trace shadow ray */
float3 shadow;
if(!shadow_blocked(kg, sd, emission_sd, state, &light_ray, &shadow)) {
/* accumulate */
path_radiance_accum_light(L, state, tp*num_samples_inv, &L_light, shadow, num_samples_inv, is_lamp);
}
}
}
}
}
/* mesh light sampling */
if(kernel_data.integrator.pdf_triangles != 0.0f) {
int num_samples = kernel_data.integrator.mesh_light_samples;
float num_samples_inv = 1.0f/num_samples;
for(int j = 0; j < num_samples; j++) {
/* sample random position on random triangle */
float light_u, light_v;
path_branched_rng_2D(kg, state->rng_hash, state, j, num_samples, PRNG_LIGHT_U, &light_u, &light_v);
/* only sample triangle lights */
if(kernel_data.integrator.num_all_lights)
light_u = 0.5f*light_u;
LightSample ls;
light_sample(kg, light_u, light_v, sd->time, ray->P, state->bounce, &ls);
float3 tp = throughput;
/* sample position on volume segment */
float rphase = path_branched_rng_1D(kg, state->rng_hash, state, j, num_samples, PRNG_PHASE_CHANNEL);
float rscatter = path_branched_rng_1D(kg, state->rng_hash, state, j, num_samples, PRNG_SCATTER_DISTANCE);
VolumeIntegrateResult result = kernel_volume_decoupled_scatter(kg,
state, ray, sd, &tp, rphase, rscatter, segment, (ls.t != FLT_MAX)? &ls.P: NULL, false);
/* todo: split up light_sample so we don't have to call it again with new position */
if(result == VOLUME_PATH_SCATTERED &&
light_sample(kg, light_u, light_v, sd->time, sd->P, state->bounce, &ls)) {
if(kernel_data.integrator.num_all_lights)
ls.pdf *= 2.0f;
float terminate = path_branched_rng_light_termination(kg, state->rng_hash, state, j, num_samples);
if(direct_emission(kg, sd, emission_sd, &ls, state, &light_ray, &L_light, &is_lamp, terminate)) {
/* trace shadow ray */
float3 shadow;
if(!shadow_blocked(kg, sd, emission_sd, state, &light_ray, &shadow)) {
/* accumulate */
path_radiance_accum_light(L, state, tp*num_samples_inv, &L_light, shadow, num_samples_inv, is_lamp);
}
}
}
}
}
}
else {
/* sample random position on random light */
float light_u, light_v;
path_state_rng_2D(kg, state, PRNG_LIGHT_U, &light_u, &light_v);
LightSample ls;
light_sample(kg, light_u, light_v, sd->time, ray->P, state->bounce, &ls);
float3 tp = throughput;
/* sample position on volume segment */
float rphase = path_state_rng_1D(kg, state, PRNG_PHASE_CHANNEL);
float rscatter = path_state_rng_1D(kg, state, PRNG_SCATTER_DISTANCE);
VolumeIntegrateResult result = kernel_volume_decoupled_scatter(kg,
state, ray, sd, &tp, rphase, rscatter, segment, (ls.t != FLT_MAX)? &ls.P: NULL, false);
/* todo: split up light_sample so we don't have to call it again with new position */
if(result == VOLUME_PATH_SCATTERED &&
light_sample(kg, light_u, light_v, sd->time, sd->P, state->bounce, &ls)) {
/* sample random light */
float terminate = path_state_rng_light_termination(kg, state);
if(direct_emission(kg, sd, emission_sd, &ls, state, &light_ray, &L_light, &is_lamp, terminate)) {
/* trace shadow ray */
float3 shadow;
if(!shadow_blocked(kg, sd, emission_sd, state, &light_ray, &shadow)) {
/* accumulate */
path_radiance_accum_light(L, state, tp, &L_light, shadow, 1.0f, is_lamp);
}
}
}
}
#endif /* __EMISSION__ */
}
#endif /* __SPLIT_KERNEL__ */
#endif /* __VOLUME_SCATTER__ */
CCL_NAMESPACE_END