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53fa389802
blender/intern/cycles/kernel/kernel_path.h
Sergey Sharybin 53fa389802 Cycles: Use dedicated debug passes for traversed nodes and intersection tests 
This way it's more clear whether some issue is caused by lots of geometry in
the node or by lots of "transparent" BVH nodes.
2017-01-12 13:44:35 +01:00

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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.
*/
#ifdef __OSL__
# include "osl_shader.h"
#endif
#include "kernel_random.h"
#include "kernel_projection.h"
#include "kernel_montecarlo.h"
#include "kernel_differential.h"
#include "kernel_camera.h"
#include "geom/geom.h"
#include "bvh/bvh.h"
#include "kernel_accumulate.h"
#include "kernel_shader.h"
#include "kernel_light.h"
#include "kernel_passes.h"
#ifdef __SUBSURFACE__
# include "kernel_subsurface.h"
#endif
#ifdef __VOLUME__
# include "kernel_volume.h"
#endif
#include "kernel_path_state.h"
#include "kernel_shadow.h"
#include "kernel_emission.h"
#include "kernel_path_common.h"
#include "kernel_path_surface.h"
#include "kernel_path_volume.h"
#ifdef __KERNEL_DEBUG__
# include "kernel_debug.h"
#endif
CCL_NAMESPACE_BEGIN
ccl_device_noinline void kernel_path_ao(KernelGlobals *kg,
ShaderData *sd,
ShaderData *emission_sd,
PathRadiance *L,
PathState *state,
RNG *rng,
float3 throughput,
float3 ao_alpha)
{
/* todo: solve correlation */
float bsdf_u, bsdf_v;
path_state_rng_2D(kg, rng, state, PRNG_BSDF_U, &bsdf_u, &bsdf_v);
float ao_factor = kernel_data.background.ao_factor;
float3 ao_N;
float3 ao_bsdf = shader_bsdf_ao(kg, sd, ao_factor, &ao_N);
float3 ao_D;
float ao_pdf;
sample_cos_hemisphere(ao_N, bsdf_u, bsdf_v, &ao_D, &ao_pdf);
if(dot(ccl_fetch(sd, Ng), ao_D) > 0.0f && ao_pdf != 0.0f) {
Ray light_ray;
float3 ao_shadow;
light_ray.P = ray_offset(ccl_fetch(sd, P), ccl_fetch(sd, Ng));
light_ray.D = ao_D;
light_ray.t = kernel_data.background.ao_distance;
#ifdef __OBJECT_MOTION__
light_ray.time = ccl_fetch(sd, time);
#endif /* __OBJECT_MOTION__ */
light_ray.dP = ccl_fetch(sd, dP);
light_ray.dD = differential3_zero();
if(!shadow_blocked(kg, emission_sd, state, &light_ray, &ao_shadow)) {
path_radiance_accum_ao(L, throughput, ao_alpha, ao_bsdf, ao_shadow, state->bounce);
}
}
}
ccl_device void kernel_path_indirect(KernelGlobals *kg,
ShaderData *sd,
ShaderData *emission_sd,
RNG *rng,
Ray *ray,
float3 throughput,
int num_samples,
PathState *state,
PathRadiance *L)
{
/* path iteration */
for(;;) {
/* intersect scene */
Intersection isect;
uint visibility = path_state_ray_visibility(kg, state);
bool hit = scene_intersect(kg,
*ray,
visibility,
&isect,
NULL,
0.0f, 0.0f);
#ifdef __LAMP_MIS__
if(kernel_data.integrator.use_lamp_mis && !(state->flag & PATH_RAY_CAMERA)) {
/* ray starting from previous non-transparent bounce */
Ray light_ray;
light_ray.P = ray->P - state->ray_t*ray->D;
state->ray_t += isect.t;
light_ray.D = ray->D;
light_ray.t = state->ray_t;
light_ray.time = ray->time;
light_ray.dD = ray->dD;
light_ray.dP = ray->dP;
/* intersect with lamp */
float3 emission;
if(indirect_lamp_emission(kg, emission_sd, state, &light_ray, &emission)) {
path_radiance_accum_emission(L,
throughput,
emission,
state->bounce);
}
}
#endif /* __LAMP_MIS__ */
#ifdef __VOLUME__
/* Sanitize volume stack. */
if(!hit) {
kernel_volume_clean_stack(kg, state->volume_stack);
}
/* volume attenuation, emission, scatter */
if(state->volume_stack[0].shader != SHADER_NONE) {
Ray volume_ray = *ray;
volume_ray.t = (hit)? isect.t: FLT_MAX;
bool heterogeneous =
volume_stack_is_heterogeneous(kg,
state->volume_stack);
# ifdef __VOLUME_DECOUPLED__
int sampling_method =
volume_stack_sampling_method(kg,
state->volume_stack);
bool decoupled = kernel_volume_use_decoupled(kg, heterogeneous, false, sampling_method);
if(decoupled) {
/* cache steps along volume for repeated sampling */
VolumeSegment volume_segment;
shader_setup_from_volume(kg,
sd,
&volume_ray);
kernel_volume_decoupled_record(kg,
state,
&volume_ray,
sd,
&volume_segment,
heterogeneous);
volume_segment.sampling_method = sampling_method;
/* emission */
if(volume_segment.closure_flag & SD_EMISSION) {
path_radiance_accum_emission(L,
throughput,
volume_segment.accum_emission,
state->bounce);
}
/* scattering */
VolumeIntegrateResult result = VOLUME_PATH_ATTENUATED;
if(volume_segment.closure_flag & SD_SCATTER) {
int all = kernel_data.integrator.sample_all_lights_indirect;
/* direct light sampling */
kernel_branched_path_volume_connect_light(kg,
rng,
sd,
emission_sd,
throughput,
state,
L,
all,
&volume_ray,
&volume_segment);
/* indirect sample. if we use distance sampling and take just
* one sample for direct and indirect light, we could share
* this computation, but makes code a bit complex */
float rphase = path_state_rng_1D_for_decision(kg, rng, state, PRNG_PHASE);
float rscatter = path_state_rng_1D_for_decision(kg, rng, state, PRNG_SCATTER_DISTANCE);
result = kernel_volume_decoupled_scatter(kg,
state,
&volume_ray,
sd,
&throughput,
rphase,
rscatter,
&volume_segment,
NULL,
true);
}
/* free cached steps */
kernel_volume_decoupled_free(kg, &volume_segment);
if(result == VOLUME_PATH_SCATTERED) {
if(kernel_path_volume_bounce(kg,
rng,
sd,
&throughput,
state,
L,
ray))
{
continue;
}
else {
break;
}
}
else {
throughput *= volume_segment.accum_transmittance;
}
}
else
# endif /* __VOLUME_DECOUPLED__ */
{
/* integrate along volume segment with distance sampling */
VolumeIntegrateResult result = kernel_volume_integrate(
kg, state, sd, &volume_ray, L, &throughput, rng, heterogeneous);
# ifdef __VOLUME_SCATTER__
if(result == VOLUME_PATH_SCATTERED) {
/* direct lighting */
kernel_path_volume_connect_light(kg,
rng,
sd,
emission_sd,
throughput,
state,
L);
/* indirect light bounce */
if(kernel_path_volume_bounce(kg,
rng,
sd,
&throughput,
state,
L,
ray))
{
continue;
}
else {
break;
}
}
# endif /* __VOLUME_SCATTER__ */
}
}
#endif /* __VOLUME__ */
if(!hit) {
#ifdef __BACKGROUND__
/* sample background shader */
float3 L_background = indirect_background(kg, emission_sd, state, ray);
path_radiance_accum_background(L,
throughput,
L_background,
state->bounce);
#endif /* __BACKGROUND__ */
break;
}
/* setup shading */
shader_setup_from_ray(kg,
sd,
&isect,
ray);
float rbsdf = path_state_rng_1D_for_decision(kg, rng, state, PRNG_BSDF);
shader_eval_surface(kg, sd, rng, state, rbsdf, state->flag, SHADER_CONTEXT_INDIRECT);
#ifdef __BRANCHED_PATH__
shader_merge_closures(sd);
#endif /* __BRANCHED_PATH__ */
/* blurring of bsdf after bounces, for rays that have a small likelihood
* of following this particular path (diffuse, rough glossy) */
if(kernel_data.integrator.filter_glossy != FLT_MAX) {
float blur_pdf = kernel_data.integrator.filter_glossy*state->min_ray_pdf;
if(blur_pdf < 1.0f) {
float blur_roughness = sqrtf(1.0f - blur_pdf)*0.5f;
shader_bsdf_blur(kg, sd, blur_roughness);
}
}
#ifdef __EMISSION__
/* emission */
if(sd->flag & SD_EMISSION) {
float3 emission = indirect_primitive_emission(kg,
sd,
isect.t,
state->flag,
state->ray_pdf);
path_radiance_accum_emission(L, throughput, emission, state->bounce);
}
#endif /* __EMISSION__ */
/* path termination. this is a strange place to put the termination, it's
* mainly due to the mixed in MIS that we use. gives too many unneeded
* shader evaluations, only need emission if we are going to terminate */
float probability =
path_state_terminate_probability(kg,
state,
throughput*num_samples);
if(probability == 0.0f) {
break;
}
else if(probability != 1.0f) {
float terminate = path_state_rng_1D_for_decision(kg, rng, state, PRNG_TERMINATE);
if(terminate >= probability)
break;
throughput /= probability;
}
#ifdef __AO__
/* ambient occlusion */
if(kernel_data.integrator.use_ambient_occlusion || (sd->flag & SD_AO)) {
kernel_path_ao(kg, sd, emission_sd, L, state, rng, throughput, make_float3(0.0f, 0.0f, 0.0f));
}
#endif /* __AO__ */
#ifdef __SUBSURFACE__
/* bssrdf scatter to a different location on the same object, replacing
* the closures with a diffuse BSDF */
if(sd->flag & SD_BSSRDF) {
float bssrdf_probability;
ShaderClosure *sc = subsurface_scatter_pick_closure(kg, sd, &bssrdf_probability);
/* modify throughput for picking bssrdf or bsdf */
throughput *= bssrdf_probability;
/* do bssrdf scatter step if we picked a bssrdf closure */
if(sc) {
uint lcg_state = lcg_state_init(rng, state, 0x68bc21eb);
float bssrdf_u, bssrdf_v;
path_state_rng_2D(kg,
rng,
state,
PRNG_BSDF_U,
&bssrdf_u, &bssrdf_v);
subsurface_scatter_step(kg,
sd,
state,
state->flag,
sc,
&lcg_state,
bssrdf_u, bssrdf_v,
false);
}
}
#endif /* __SUBSURFACE__ */
#if defined(__EMISSION__) && defined(__BRANCHED_PATH__)
if(kernel_data.integrator.use_direct_light) {
int all = kernel_data.integrator.sample_all_lights_indirect;
kernel_branched_path_surface_connect_light(kg,
rng,
sd,
emission_sd,
state,
throughput,
1.0f,
L,
all);
}
#endif /* defined(__EMISSION__) && defined(__BRANCHED_PATH__) */
if(!kernel_path_surface_bounce(kg, rng, sd, &throughput, state, L, ray))
break;
}
}
#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,
PathState *state,
RNG *rng,
Ray *ray,
float3 *throughput,
SubsurfaceIndirectRays *ss_indirect)
{
float bssrdf_probability;
ShaderClosure *sc = subsurface_scatter_pick_closure(kg, sd, &bssrdf_probability);
/* modify throughput for picking bssrdf or bsdf */
*throughput *= bssrdf_probability;
/* 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(!ss_indirect->tracing);
uint lcg_state = lcg_state_init(rng, state, 0x68bc21eb);
SubsurfaceIntersection ss_isect;
float bssrdf_u, bssrdf_v;
path_state_rng_2D(kg, rng, state, PRNG_BSDF_U, &bssrdf_u, &bssrdf_v);
int num_hits = subsurface_scatter_multi_intersect(kg,
&ss_isect,
sd,
sc,
&lcg_state,
bssrdf_u, bssrdf_v,
false);
# ifdef __VOLUME__
ss_indirect->need_update_volume_stack =
kernel_data.integrator.use_volumes &&
ccl_fetch(sd, 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);
PathState *hit_state = &ss_indirect->state[ss_indirect->num_rays];
Ray *hit_ray = &ss_indirect->rays[ss_indirect->num_rays];
float3 *hit_tp = &ss_indirect->throughputs[ss_indirect->num_rays];
PathRadiance *hit_L = &ss_indirect->L[ss_indirect->num_rays];
*hit_state = *state;
*hit_ray = *ray;
*hit_tp = *throughput;
hit_state->rng_offset += PRNG_BOUNCE_NUM;
path_radiance_init(hit_L, kernel_data.film.use_light_pass);
hit_L->direct_throughput = L->direct_throughput;
path_radiance_copy_indirect(hit_L, L);
kernel_path_surface_connect_light(kg, rng, sd, emission_sd, *hit_tp, state, hit_L);
if(kernel_path_surface_bounce(kg,
rng,
sd,
hit_tp,
hit_state,
hit_L,
hit_ray))
{
# ifdef __LAMP_MIS__
hit_state->ray_t = 0.0f;
# endif /* __LAMP_MIS__ */
# ifdef __VOLUME__
if(ss_indirect->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__ */
path_radiance_reset_indirect(L);
ss_indirect->num_rays++;
}
else {
path_radiance_accum_sample(L, hit_L, 1);
}
}
return true;
}
return false;
}
ccl_device_inline void kernel_path_subsurface_init_indirect(
SubsurfaceIndirectRays *ss_indirect)
{
ss_indirect->tracing = false;
ss_indirect->num_rays = 0;
}
ccl_device void kernel_path_subsurface_accum_indirect(
SubsurfaceIndirectRays *ss_indirect,
PathRadiance *L)
{
if(ss_indirect->tracing) {
path_radiance_sum_indirect(L);
path_radiance_accum_sample(&ss_indirect->direct_L, L, 1);
if(ss_indirect->num_rays == 0) {
*L = ss_indirect->direct_L;
}
}
}
ccl_device void kernel_path_subsurface_setup_indirect(
KernelGlobals *kg,
SubsurfaceIndirectRays *ss_indirect,
PathState *state,
Ray *ray,
PathRadiance *L,
float3 *throughput)
{
if(!ss_indirect->tracing) {
ss_indirect->direct_L = *L;
}
ss_indirect->tracing = true;
/* Setup state, ray and throughput for indirect SSS rays. */
ss_indirect->num_rays--;
Ray *indirect_ray = &ss_indirect->rays[ss_indirect->num_rays];
PathRadiance *indirect_L = &ss_indirect->L[ss_indirect->num_rays];
*state = ss_indirect->state[ss_indirect->num_rays];
*ray = *indirect_ray;
*L = *indirect_L;
*throughput = ss_indirect->throughputs[ss_indirect->num_rays];
state->rng_offset += ss_indirect->num_rays * PRNG_BOUNCE_NUM;
}
#endif /* __SUBSURFACE__ */
ccl_device_inline float4 kernel_path_integrate(KernelGlobals *kg,
RNG *rng,
int sample,
Ray ray,
ccl_global float *buffer)
{
/* initialize */
PathRadiance L;
float3 throughput = make_float3(1.0f, 1.0f, 1.0f);
float L_transparent = 0.0f;
path_radiance_init(&L, kernel_data.film.use_light_pass);
/* shader data memory used for both volumes and surfaces, saves stack space */
ShaderData sd;
/* shader data used by emission, shadows, volume stacks */
ShaderData emission_sd;
PathState state;
path_state_init(kg, &emission_sd, &state, rng, sample, &ray);
#ifdef __KERNEL_DEBUG__
DebugData debug_data;
debug_data_init(&debug_data);
#endif /* __KERNEL_DEBUG__ */
#ifdef __SUBSURFACE__
SubsurfaceIndirectRays ss_indirect;
kernel_path_subsurface_init_indirect(&ss_indirect);
for(;;) {
#endif /* __SUBSURFACE__ */
/* path iteration */
for(;;) {
/* intersect scene */
Intersection isect;
uint visibility = path_state_ray_visibility(kg, &state);
#ifdef __HAIR__
float difl = 0.0f, extmax = 0.0f;
uint lcg_state = 0;
if(kernel_data.bvh.have_curves) {
if((kernel_data.cam.resolution == 1) && (state.flag & PATH_RAY_CAMERA)) {
float3 pixdiff = ray.dD.dx + ray.dD.dy;
/*pixdiff = pixdiff - dot(pixdiff, ray.D)*ray.D;*/
difl = kernel_data.curve.minimum_width * len(pixdiff) * 0.5f;
}
extmax = kernel_data.curve.maximum_width;
lcg_state = lcg_state_init(rng, &state, 0x51633e2d);
}
bool hit = scene_intersect(kg, ray, visibility, &isect, &lcg_state, difl, extmax);
#else
bool hit = scene_intersect(kg, ray, visibility, &isect, NULL, 0.0f, 0.0f);
#endif /* __HAIR__ */
#ifdef __KERNEL_DEBUG__
if(state.flag & PATH_RAY_CAMERA) {
debug_data.num_bvh_traversed_nodes += isect.num_traversed_nodes;
debug_data.num_bvh_traversed_instances += isect.num_traversed_instances;
debug_data.num_bvh_intersections += isect.num_intersections;
}
debug_data.num_ray_bounces++;
#endif /* __KERNEL_DEBUG__ */
#ifdef __LAMP_MIS__
if(kernel_data.integrator.use_lamp_mis && !(state.flag & PATH_RAY_CAMERA)) {
/* ray starting from previous non-transparent bounce */
Ray light_ray;
light_ray.P = ray.P - state.ray_t*ray.D;
state.ray_t += isect.t;
light_ray.D = ray.D;
light_ray.t = state.ray_t;
light_ray.time = ray.time;
light_ray.dD = ray.dD;
light_ray.dP = ray.dP;
/* intersect with lamp */
float3 emission;
if(indirect_lamp_emission(kg, &emission_sd, &state, &light_ray, &emission))
path_radiance_accum_emission(&L, throughput, emission, state.bounce);
}
#endif /* __LAMP_MIS__ */
#ifdef __VOLUME__
/* Sanitize volume stack. */
if(!hit) {
kernel_volume_clean_stack(kg, state.volume_stack);
}
/* volume attenuation, emission, scatter */
if(state.volume_stack[0].shader != SHADER_NONE) {
Ray volume_ray = ray;
volume_ray.t = (hit)? isect.t: FLT_MAX;
bool heterogeneous = volume_stack_is_heterogeneous(kg, state.volume_stack);
# ifdef __VOLUME_DECOUPLED__
int sampling_method = volume_stack_sampling_method(kg, state.volume_stack);
bool decoupled = kernel_volume_use_decoupled(kg, heterogeneous, true, sampling_method);
if(decoupled) {
/* cache steps along volume for repeated sampling */
VolumeSegment volume_segment;
shader_setup_from_volume(kg, &sd, &volume_ray);
kernel_volume_decoupled_record(kg, &state,
&volume_ray, &sd, &volume_segment, heterogeneous);
volume_segment.sampling_method = sampling_method;
/* emission */
if(volume_segment.closure_flag & SD_EMISSION)
path_radiance_accum_emission(&L, throughput, volume_segment.accum_emission, state.bounce);
/* scattering */
VolumeIntegrateResult result = VOLUME_PATH_ATTENUATED;
if(volume_segment.closure_flag & SD_SCATTER) {
int all = false;
/* direct light sampling */
kernel_branched_path_volume_connect_light(kg, rng, &sd,
&emission_sd, throughput, &state, &L, all,
&volume_ray, &volume_segment);
/* indirect sample. if we use distance sampling and take just
* one sample for direct and indirect light, we could share
* this computation, but makes code a bit complex */
float rphase = path_state_rng_1D_for_decision(kg, rng, &state, PRNG_PHASE);
float rscatter = path_state_rng_1D_for_decision(kg, rng, &state, PRNG_SCATTER_DISTANCE);
result = kernel_volume_decoupled_scatter(kg,
&state, &volume_ray, &sd, &throughput,
rphase, rscatter, &volume_segment, NULL, true);
}
/* free cached steps */
kernel_volume_decoupled_free(kg, &volume_segment);
if(result == VOLUME_PATH_SCATTERED) {
if(kernel_path_volume_bounce(kg, rng, &sd, &throughput, &state, &L, &ray))
continue;
else
break;
}
else {
throughput *= volume_segment.accum_transmittance;
}
}
else
# endif /* __VOLUME_DECOUPLED__ */
{
/* integrate along volume segment with distance sampling */
VolumeIntegrateResult result = kernel_volume_integrate(
kg, &state, &sd, &volume_ray, &L, &throughput, rng, heterogeneous);
# ifdef __VOLUME_SCATTER__
if(result == VOLUME_PATH_SCATTERED) {
/* direct lighting */
kernel_path_volume_connect_light(kg, rng, &sd, &emission_sd, throughput, &state, &L);
/* indirect light bounce */
if(kernel_path_volume_bounce(kg, rng, &sd, &throughput, &state, &L, &ray))
continue;
else
break;
}
# endif /* __VOLUME_SCATTER__ */
}
}
#endif /* __VOLUME__ */
if(!hit) {
/* eval background shader if nothing hit */
if(kernel_data.background.transparent && (state.flag & PATH_RAY_CAMERA)) {
L_transparent += average(throughput);
#ifdef __PASSES__
if(!(kernel_data.film.pass_flag & PASS_BACKGROUND))
#endif /* __PASSES__ */
break;
}
#ifdef __BACKGROUND__
/* sample background shader */
float3 L_background = indirect_background(kg, &emission_sd, &state, &ray);
path_radiance_accum_background(&L, throughput, L_background, state.bounce);
#endif /* __BACKGROUND__ */
break;
}
/* setup shading */
shader_setup_from_ray(kg, &sd, &isect, &ray);
float rbsdf = path_state_rng_1D_for_decision(kg, rng, &state, PRNG_BSDF);
shader_eval_surface(kg, &sd, rng, &state, rbsdf, state.flag, SHADER_CONTEXT_MAIN);
/* holdout */
#ifdef __HOLDOUT__
if((sd.flag & (SD_HOLDOUT|SD_HOLDOUT_MASK)) && (state.flag & PATH_RAY_CAMERA)) {
if(kernel_data.background.transparent) {
float3 holdout_weight;
if(sd.flag & SD_HOLDOUT_MASK)
holdout_weight = make_float3(1.0f, 1.0f, 1.0f);
else
holdout_weight = shader_holdout_eval(kg, &sd);
/* any throughput is ok, should all be identical here */
L_transparent += average(holdout_weight*throughput);
}
if(sd.flag & SD_HOLDOUT_MASK)
break;
}
#endif /* __HOLDOUT__ */
/* holdout mask objects do not write data passes */
kernel_write_data_passes(kg, buffer, &L, &sd, sample, &state, throughput);
/* blurring of bsdf after bounces, for rays that have a small likelihood
* of following this particular path (diffuse, rough glossy) */
if(kernel_data.integrator.filter_glossy != FLT_MAX) {
float blur_pdf = kernel_data.integrator.filter_glossy*state.min_ray_pdf;
if(blur_pdf < 1.0f) {
float blur_roughness = sqrtf(1.0f - blur_pdf)*0.5f;
shader_bsdf_blur(kg, &sd, blur_roughness);
}
}
#ifdef __EMISSION__
/* emission */
if(sd.flag & SD_EMISSION) {
/* todo: is isect.t wrong here for transparent surfaces? */
float3 emission = indirect_primitive_emission(kg, &sd, isect.t, state.flag, state.ray_pdf);
path_radiance_accum_emission(&L, throughput, emission, state.bounce);
}
#endif /* __EMISSION__ */
/* path termination. this is a strange place to put the termination, it's
* mainly due to the mixed in MIS that we use. gives too many unneeded
* shader evaluations, only need emission if we are going to terminate */
float probability = path_state_terminate_probability(kg, &state, throughput);
if(probability == 0.0f) {
break;
}
else if(probability != 1.0f) {
float terminate = path_state_rng_1D_for_decision(kg, rng, &state, PRNG_TERMINATE);
if(terminate >= probability)
break;
throughput /= probability;
}
#ifdef __AO__
/* ambient occlusion */
if(kernel_data.integrator.use_ambient_occlusion || (sd.flag & SD_AO)) {
kernel_path_ao(kg, &sd, &emission_sd, &L, &state, rng, throughput, shader_bsdf_alpha(kg, &sd));
}
#endif /* __AO__ */
#ifdef __SUBSURFACE__
/* bssrdf scatter to a different location on the same object, replacing
* the closures with a diffuse BSDF */
if(sd.flag & SD_BSSRDF) {
if(kernel_path_subsurface_scatter(kg,
&sd,
&emission_sd,
&L,
&state,
rng,
&ray,
&throughput,
&ss_indirect))
{
break;
}
}
#endif /* __SUBSURFACE__ */
/* direct lighting */
kernel_path_surface_connect_light(kg, rng, &sd, &emission_sd, throughput, &state, &L);
/* compute direct lighting and next bounce */
if(!kernel_path_surface_bounce(kg, rng, &sd, &throughput, &state, &L, &ray))
break;
}
#ifdef __SUBSURFACE__
kernel_path_subsurface_accum_indirect(&ss_indirect, &L);
/* Trace indirect subsurface rays by restarting the loop. this uses less
* stack memory than invoking kernel_path_indirect.
*/
if(ss_indirect.num_rays) {
kernel_path_subsurface_setup_indirect(kg,
&ss_indirect,
&state,
&ray,
&L,
&throughput);
}
else {
break;
}
}
#endif /* __SUBSURFACE__ */
float3 L_sum = path_radiance_clamp_and_sum(kg, &L);
kernel_write_light_passes(kg, buffer, &L, sample);
#ifdef __KERNEL_DEBUG__
kernel_write_debug_passes(kg, buffer, &state, &debug_data, sample);
#endif /* __KERNEL_DEBUG__ */
return make_float4(L_sum.x, L_sum.y, L_sum.z, 1.0f - L_transparent);
}
ccl_device void kernel_path_trace(KernelGlobals *kg,
ccl_global float *buffer, ccl_global uint *rng_state,
int sample, int x, int y, int offset, int stride)
{
/* buffer offset */
int index = offset + x + y*stride;
int pass_stride = kernel_data.film.pass_stride;
rng_state += index;
buffer += index*pass_stride;
/* initialize random numbers and ray */
RNG rng;
Ray ray;
kernel_path_trace_setup(kg, rng_state, sample, x, y, &rng, &ray);
/* integrate */
float4 L;
if(ray.t != 0.0f)
L = kernel_path_integrate(kg, &rng, sample, ray, buffer);
else
L = make_float4(0.0f, 0.0f, 0.0f, 0.0f);
/* accumulate result in output buffer */
kernel_write_pass_float4(buffer, sample, L);
path_rng_end(kg, rng_state, rng);
}
CCL_NAMESPACE_END
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