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/*
* 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
#if defined(__BRANCHED_PATH__) || defined(__SUBSURFACE__) || defined(__SHADOW_TRICKS__) || defined(__BAKING__)
/* branched path tracing: connect path directly to position on one or more lights and add it to L */
ccl_device_noinline void kernel_branched_path_surface_connect_light(
KernelGlobals *kg,
ShaderData *sd,
ShaderData *emission_sd,
ccl_addr_space PathState *state,
float3 throughput,
float num_samples_adjust,
PathRadiance *L,
int sample_all_lights)
{
#ifdef __EMISSION__
/* sample illumination from lights to find path contribution */
if(!(sd->flag & SD_BSDF_HAS_EVAL))
return;
Ray light_ray;
BsdfEval L_light;
bool is_lamp;
# ifdef __OBJECT_MOTION__
light_ray.time = sd->time;
# endif
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 = ceil_to_int(num_samples_adjust*light_select_num_samples(kg, i));
float num_samples_inv = num_samples_adjust/(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++) {
float light_u, light_v;
path_branched_rng_2D(kg, lamp_rng_hash, state, j, num_samples, PRNG_LIGHT_U, &light_u, &light_v);
float terminate = path_branched_rng_light_termination(kg, lamp_rng_hash, state, j, num_samples);
LightSample ls;
if(lamp_light_sample(kg, i, light_u, light_v, sd->P, &ls)) {
/* The sampling probability returned by lamp_light_sample assumes that all lights were sampled.
* However, this code only samples lamps, so if the scene also had mesh lights, the real probability is twice as high. */
if(kernel_data.integrator.pdf_triangles != 0.0f)
ls.pdf *= 2.0f;
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, emission_sd, state, &light_ray, &shadow)) {
/* accumulate */
path_radiance_accum_light(L, state, throughput*num_samples_inv, &L_light, shadow, num_samples_inv, is_lamp);
}
else {
path_radiance_accum_total_light(L, state, throughput*num_samples_inv, &L_light);
}
}
}
}
}
/* mesh light sampling */
if(kernel_data.integrator.pdf_triangles != 0.0f) {
int num_samples = ceil_to_int(num_samples_adjust*kernel_data.integrator.mesh_light_samples);
float num_samples_inv = num_samples_adjust/num_samples;
for(int j = 0; j < num_samples; j++) {
float light_t = path_branched_rng_1D(kg, state->rng_hash, state, j, num_samples, PRNG_LIGHT);
float light_u, light_v;
path_branched_rng_2D(kg, state->rng_hash, state, j, num_samples, PRNG_LIGHT_U, &light_u, &light_v);
float terminate = path_branched_rng_light_termination(kg, state->rng_hash, state, j, num_samples);
/* only sample triangle lights */
if(kernel_data.integrator.num_all_lights)
light_t = 0.5f*light_t;
LightSample ls;
if(light_sample(kg, light_t, light_u, light_v, sd->time, sd->P, state->bounce, &ls)) {
/* Same as above, probability needs to be corrected since the sampling was forced to select a mesh light. */
if(kernel_data.integrator.num_all_lights)
ls.pdf *= 2.0f;
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, emission_sd, state, &light_ray, &shadow)) {
/* accumulate */
path_radiance_accum_light(L, state, throughput*num_samples_inv, &L_light, shadow, num_samples_inv, is_lamp);
}
else {
path_radiance_accum_total_light(L, state, throughput*num_samples_inv, &L_light);
}
}
}
}
}
}
else {
/* sample one light at random */
float light_t = path_state_rng_1D(kg, state, PRNG_LIGHT);
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_t, light_u, light_v, sd->time, sd->P, state->bounce, &ls)) {
/* sample random light */
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, emission_sd, state, &light_ray, &shadow)) {
/* accumulate */
path_radiance_accum_light(L, state, throughput*num_samples_adjust, &L_light, shadow, num_samples_adjust, is_lamp);
}
else {
path_radiance_accum_total_light(L, state, throughput*num_samples_adjust, &L_light);
}
}
}
}
#endif
}
/* branched path tracing: bounce off or through surface to with new direction stored in ray */
ccl_device bool kernel_branched_path_surface_bounce(
KernelGlobals *kg,
ShaderData *sd,
const ShaderClosure *sc,
int sample,
int num_samples,
ccl_addr_space float3 *throughput,
ccl_addr_space PathState *state,
PathRadiance *L,
ccl_addr_space Ray *ray,
float sum_sample_weight)
{
/* sample BSDF */
float bsdf_pdf;
BsdfEval bsdf_eval;
float3 bsdf_omega_in;
differential3 bsdf_domega_in;
float bsdf_u, bsdf_v;
path_branched_rng_2D(kg, state->rng_hash, state, sample, num_samples, PRNG_BSDF_U, &bsdf_u, &bsdf_v);
int label;
label = shader_bsdf_sample_closure(kg, sd, sc, bsdf_u, bsdf_v, &bsdf_eval,
&bsdf_omega_in, &bsdf_domega_in, &bsdf_pdf);
if(bsdf_pdf == 0.0f || bsdf_eval_is_zero(&bsdf_eval))
return false;
/* modify throughput */
path_radiance_bsdf_bounce(L, throughput, &bsdf_eval, bsdf_pdf, state->bounce, label);
#ifdef __DENOISING_FEATURES__
state->denoising_feature_weight *= sc->sample_weight / (sum_sample_weight * num_samples);
#endif
/* modify path state */
path_state_next(kg, state, label);
/* setup ray */
ray->P = ray_offset(sd->P, (label & LABEL_TRANSMIT)? -sd->Ng: sd->Ng);
ray->D = normalize(bsdf_omega_in);
ray->t = FLT_MAX;
#ifdef __RAY_DIFFERENTIALS__
ray->dP = sd->dP;
ray->dD = bsdf_domega_in;
#endif
#ifdef __OBJECT_MOTION__
ray->time = sd->time;
#endif
#ifdef __VOLUME__
/* enter/exit volume */
if(label & LABEL_TRANSMIT)
kernel_volume_stack_enter_exit(kg, sd, state->volume_stack);
#endif
/* branch RNG state */
path_state_branch(state, sample, num_samples);
/* set MIS state */
state->min_ray_pdf = fminf(bsdf_pdf, FLT_MAX);
state->ray_pdf = bsdf_pdf;
#ifdef __LAMP_MIS__
state->ray_t = 0.0f;
#endif
return true;
}
#endif
/* path tracing: connect path directly to position on a light and add it to L */
ccl_device_inline void kernel_path_surface_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 && (sd->flag & SD_BSDF_HAS_EVAL)))
return;
#ifdef __SHADOW_TRICKS__
if(state->flag & PATH_RAY_SHADOW_CATCHER) {
kernel_branched_path_surface_connect_light(kg,
sd,
emission_sd,
state,
throughput,
1.0f,
L,
1);
return;
}
#endif
/* sample illumination from lights to find path contribution */
float light_t = path_state_rng_1D(kg, state, PRNG_LIGHT);
float light_u, light_v;
path_state_rng_2D(kg, state, PRNG_LIGHT_U, &light_u, &light_v);
Ray light_ray;
BsdfEval L_light;
bool is_lamp;
#ifdef __OBJECT_MOTION__
light_ray.time = sd->time;
#endif
LightSample ls;
if(light_sample(kg, light_t, 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, emission_sd, state, &light_ray, &shadow)) {
/* accumulate */
path_radiance_accum_light(L, state, throughput, &L_light, shadow, 1.0f, is_lamp);
}
else {
path_radiance_accum_total_light(L, state, throughput, &L_light);
}
}
}
#endif
}
/* path tracing: bounce off or through surface to with new direction stored in ray */
ccl_device bool kernel_path_surface_bounce(KernelGlobals *kg,
ShaderData *sd,
ccl_addr_space float3 *throughput,
ccl_addr_space PathState *state,
PathRadiance *L,
ccl_addr_space Ray *ray)
{
/* no BSDF? we can stop here */
if(sd->flag & SD_BSDF) {
/* sample BSDF */
float bsdf_pdf;
BsdfEval bsdf_eval;
float3 bsdf_omega_in;
differential3 bsdf_domega_in;
float bsdf_u, bsdf_v;
path_state_rng_2D(kg, state, PRNG_BSDF_U, &bsdf_u, &bsdf_v);
int label;
label = shader_bsdf_sample(kg, sd, bsdf_u, bsdf_v, &bsdf_eval,
&bsdf_omega_in, &bsdf_domega_in, &bsdf_pdf);
if(bsdf_pdf == 0.0f || bsdf_eval_is_zero(&bsdf_eval))
return false;
/* modify throughput */
path_radiance_bsdf_bounce(L, throughput, &bsdf_eval, bsdf_pdf, state->bounce, label);
/* set labels */
if(!(label & LABEL_TRANSPARENT)) {
state->ray_pdf = bsdf_pdf;
#ifdef __LAMP_MIS__
state->ray_t = 0.0f;
#endif
state->min_ray_pdf = fminf(bsdf_pdf, state->min_ray_pdf);
}
/* update path state */
path_state_next(kg, state, label);
/* setup ray */
ray->P = ray_offset(sd->P, (label & LABEL_TRANSMIT)? -sd->Ng: sd->Ng);
ray->D = normalize(bsdf_omega_in);
if(state->bounce == 0)
ray->t -= sd->ray_length; /* clipping works through transparent */
else
ray->t = FLT_MAX;
#ifdef __RAY_DIFFERENTIALS__
ray->dP = sd->dP;
ray->dD = bsdf_domega_in;
#endif
#ifdef __VOLUME__
/* enter/exit volume */
if(label & LABEL_TRANSMIT)
kernel_volume_stack_enter_exit(kg, sd, state->volume_stack);
#endif
return true;
}
#ifdef __VOLUME__
else if(sd->flag & SD_HAS_ONLY_VOLUME) {
/* no surface shader but have a volume shader? act transparent */
/* update path state, count as transparent */
path_state_next(kg, state, LABEL_TRANSPARENT);
if(state->bounce == 0)
ray->t -= sd->ray_length; /* clipping works through transparent */
else
ray->t = FLT_MAX;
/* setup ray position, direction stays unchanged */
ray->P = ray_offset(sd->P, -sd->Ng);
#ifdef __RAY_DIFFERENTIALS__
ray->dP = sd->dP;
#endif
/* enter/exit volume */
kernel_volume_stack_enter_exit(kg, sd, state->volume_stack);
return true;
}
#endif
else {
/* no bsdf or volume? */
return false;
}
}
CCL_NAMESPACE_END
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