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blender/intern/cycles/kernel/kernel_path.h
Sergey Sharybin 1f273cec00 Cycles: Tweak inline policy for some functions 
The goal is to make Experimental kernel closer in performance to the
official kernel, avoiding spills and such.

There should not be big impact on official kernel, own tests showed
few percent performance drop on laptop's GPU. CPU was always the
same speed on AVX, AVX2 and SSE4.1 CPUs i've been testing here.

This seems to be the last essential step before we can get rid of
Experimental kernel and enable SSS officially on GPU without causing
some major performance issues.

Surely some more tweaks are possibly required, but that we can do
for until cows go home anyway.
2016-01-14 14:53:05 +05:00

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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 "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 void kernel_path_indirect(KernelGlobals *kg,
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, state, &light_ray, &emission)) {
path_radiance_accum_emission(L,
throughput,
emission,
state->bounce);
}
}
#endif
#ifdef __VOLUME__
/* 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;
ShaderData volume_sd;
shader_setup_from_volume(kg,
&volume_sd,
&volume_ray);
kernel_volume_decoupled_record(kg,
state,
&volume_ray,
&volume_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) {
bool all = kernel_data.integrator.sample_all_lights_indirect;
/* direct light sampling */
kernel_branched_path_volume_connect_light(kg,
rng,
&volume_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,
&volume_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,
&volume_sd,
&throughput,
state,
L,
ray))
{
continue;
}
else {
break;
}
}
else {
throughput *= volume_segment.accum_transmittance;
}
}
else
#endif
{
/* integrate along volume segment with distance sampling */
ShaderData volume_sd;
VolumeIntegrateResult result = kernel_volume_integrate(
kg, state, &volume_sd, &volume_ray, L, &throughput, rng, heterogeneous);
#ifdef __VOLUME_SCATTER__
if(result == VOLUME_PATH_SCATTERED) {
/* direct lighting */
kernel_path_volume_connect_light(kg,
rng,
&volume_sd,
throughput,
state,
L);
/* indirect light bounce */
if(kernel_path_volume_bounce(kg,
rng,
&volume_sd,
&throughput,
state,
L,
ray))
{
continue;
}
else {
break;
}
}
#endif
}
}
#endif
if(!hit) {
#ifdef __BACKGROUND__
/* sample background shader */
float3 L_background = indirect_background(kg, state, ray);
path_radiance_accum_background(L,
throughput,
L_background,
state->bounce);
#endif
break;
}
/* setup shading */
ShaderData sd;
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, state, rbsdf, state->flag, SHADER_CONTEXT_INDIRECT);
#ifdef __BRANCHED_PATH__
shader_merge_closures(&sd);
#endif
/* 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
/* 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)) {
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;
float3 ao_alpha = make_float3(0.0f, 0.0f, 0.0f);
sample_cos_hemisphere(ao_N, bsdf_u, bsdf_v, &ao_D, &ao_pdf);
if(dot(sd.Ng, ao_D) > 0.0f && ao_pdf != 0.0f) {
Ray light_ray;
float3 ao_shadow;
light_ray.P = ray_offset(sd.P, sd.Ng);
light_ray.D = ao_D;
light_ray.t = kernel_data.background.ao_distance;
#ifdef __OBJECT_MOTION__
light_ray.time = sd.time;
#endif
light_ray.dP = sd.dP;
light_ray.dD = differential3_zero();
if(!shadow_blocked(kg, state, &light_ray, &ao_shadow)) {
path_radiance_accum_ao(L,
throughput,
ao_alpha,
ao_bsdf,
ao_shadow,
state->bounce);
}
}
}
#endif
#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
#if defined(__EMISSION__) && defined(__BRANCHED_PATH__)
if(kernel_data.integrator.use_direct_light) {
bool all = kernel_data.integrator.sample_all_lights_indirect;
kernel_branched_path_surface_connect_light(kg,
rng,
&sd,
state,
throughput,
1.0f,
L,
all);
}
#endif
if(!kernel_path_surface_bounce(kg, rng, &sd, &throughput, state, L, ray))
break;
}
}
ccl_device_noinline void kernel_path_ao(KernelGlobals *kg,
ShaderData *sd,
PathRadiance *L,
PathState *state,
RNG *rng,
float3 throughput)
{
/* 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;
float3 ao_alpha = shader_bsdf_alpha(kg, sd);
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
light_ray.dP = ccl_fetch(sd, dP);
light_ray.dD = differential3_zero();
if(!shadow_blocked(kg, state, &light_ray, &ao_shadow))
path_radiance_accum_ao(L, throughput, ao_alpha, ao_bsdf, ao_shadow, state->bounce);
}
}
#ifdef __SUBSURFACE__
ccl_device bool kernel_path_subsurface_scatter(
KernelGlobals *kg,
ShaderData *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
/* 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, *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
#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,
&volume_ray,
hit_state->volume_stack);
}
#endif
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);
PathState state;
path_state_init(kg, &state, rng, sample, &ray);
#ifdef __KERNEL_DEBUG__
DebugData debug_data;
debug_data_init(&debug_data);
#endif
#ifdef __SUBSURFACE__
SubsurfaceIndirectRays ss_indirect;
kernel_path_subsurface_init_indirect(&ss_indirect);
for(;;) {
#endif
/* 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
#ifdef __KERNEL_DEBUG__
if(state.flag & PATH_RAY_CAMERA) {
debug_data.num_bvh_traversal_steps += isect.num_traversal_steps;
debug_data.num_bvh_traversed_instances += isect.num_traversed_instances;
}
debug_data.num_ray_bounces++;
#endif
#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, &state, &light_ray, &emission))
path_radiance_accum_emission(&L, throughput, emission, state.bounce);
}
#endif
#ifdef __VOLUME__
/* 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;
ShaderData volume_sd;
shader_setup_from_volume(kg, &volume_sd, &volume_ray);
kernel_volume_decoupled_record(kg, &state,
&volume_ray, &volume_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) {
bool all = false;
/* direct light sampling */
kernel_branched_path_volume_connect_light(kg, rng, &volume_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, &volume_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, &volume_sd, &throughput, &state, &L, &ray))
continue;
else
break;
}
else {
throughput *= volume_segment.accum_transmittance;
}
}
else
#endif
{
/* integrate along volume segment with distance sampling */
ShaderData volume_sd;
VolumeIntegrateResult result = kernel_volume_integrate(
kg, &state, &volume_sd, &volume_ray, &L, &throughput, rng, heterogeneous);
#ifdef __VOLUME_SCATTER__
if(result == VOLUME_PATH_SCATTERED) {
/* direct lighting */
kernel_path_volume_connect_light(kg, rng, &volume_sd, throughput, &state, &L);
/* indirect light bounce */
if(kernel_path_volume_bounce(kg, rng, &volume_sd, &throughput, &state, &L, &ray))
continue;
else
break;
}
#endif
}
}
#endif
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
break;
}
#ifdef __BACKGROUND__
/* sample background shader */
float3 L_background = indirect_background(kg, &state, &ray);
path_radiance_accum_background(&L, throughput, L_background, state.bounce);
#endif
break;
}
/* setup shading */
ShaderData sd;
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, &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 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
/* 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, &L, &state, rng, throughput);
}
#endif
#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,
&L,
&state,
rng,
&ray,
&throughput,
&ss_indirect))
{
break;
}
}
#endif /* __SUBSURFACE__ */
/* direct lighting */
kernel_path_surface_connect_light(kg, rng, &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
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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