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blender/intern/cycles/kernel/kernel_path.h

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/*
* Copyright 2011, Blender Foundation.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include "kernel_differential.h"
#include "kernel_montecarlo.h"
#include "kernel_projection.h"
#include "kernel_object.h"
#include "kernel_triangle.h"
#ifdef __QBVH__
#include "kernel_qbvh.h"
#else
#include "kernel_bvh.h"
#endif
#include "kernel_accumulate.h"
#include "kernel_camera.h"
#include "kernel_shader.h"
#include "kernel_light.h"
#include "kernel_emission.h"
#include "kernel_random.h"
#include "kernel_passes.h"
CCL_NAMESPACE_BEGIN
typedef struct PathState {
uint flag;
int bounce;
int diffuse_bounce;
int glossy_bounce;
int transmission_bounce;
int transparent_bounce;
} PathState;
__device_inline void path_state_init(PathState *state)
{
state->flag = PATH_RAY_CAMERA|PATH_RAY_SINGULAR|PATH_RAY_MIS_SKIP;
state->bounce = 0;
state->diffuse_bounce = 0;
state->glossy_bounce = 0;
state->transmission_bounce = 0;
state->transparent_bounce = 0;
}
__device_inline void path_state_next(KernelGlobals *kg, PathState *state, int label)
{
/* ray through transparent keeps same flags from previous ray and is
* not counted as a regular bounce, transparent has separate max */
if(label & LABEL_TRANSPARENT) {
state->flag |= PATH_RAY_TRANSPARENT;
state->transparent_bounce++;
if(!kernel_data.integrator.transparent_shadows)
state->flag |= PATH_RAY_MIS_SKIP;
return;
}
state->bounce++;
/* reflection/transmission */
if(label & LABEL_REFLECT) {
state->flag |= PATH_RAY_REFLECT;
state->flag &= ~(PATH_RAY_TRANSMIT|PATH_RAY_CAMERA|PATH_RAY_TRANSPARENT);
if(label & LABEL_DIFFUSE)
state->diffuse_bounce++;
else
state->glossy_bounce++;
}
else {
kernel_assert(label & LABEL_TRANSMIT);
state->flag |= PATH_RAY_TRANSMIT;
state->flag &= ~(PATH_RAY_REFLECT|PATH_RAY_CAMERA|PATH_RAY_TRANSPARENT);
state->transmission_bounce++;
}
/* diffuse/glossy/singular */
if(label & LABEL_DIFFUSE) {
state->flag |= PATH_RAY_DIFFUSE;
state->flag &= ~(PATH_RAY_GLOSSY|PATH_RAY_SINGULAR|PATH_RAY_MIS_SKIP);
}
else if(label & LABEL_GLOSSY) {
state->flag |= PATH_RAY_GLOSSY;
state->flag &= ~(PATH_RAY_DIFFUSE|PATH_RAY_SINGULAR|PATH_RAY_MIS_SKIP);
}
else {
kernel_assert(label & LABEL_SINGULAR);
state->flag |= PATH_RAY_GLOSSY|PATH_RAY_SINGULAR|PATH_RAY_MIS_SKIP;
state->flag &= ~PATH_RAY_DIFFUSE;
}
}
__device_inline uint path_state_ray_visibility(KernelGlobals *kg, PathState *state)
{
uint flag = state->flag;
/* for visibility, diffuse/glossy are for reflection only */
if(flag & PATH_RAY_TRANSMIT)
flag &= ~(PATH_RAY_DIFFUSE|PATH_RAY_GLOSSY);
/* for camera visibility, use render layer flags */
if(flag & PATH_RAY_CAMERA)
flag |= kernel_data.integrator.layer_flag;
return flag;
}
__device_inline float path_state_terminate_probability(KernelGlobals *kg, PathState *state, const float3 throughput)
{
if(state->flag & PATH_RAY_TRANSPARENT) {
/* transparent rays treated separately */
if(state->transparent_bounce >= kernel_data.integrator.transparent_max_bounce)
return 0.0f;
else if(state->transparent_bounce <= kernel_data.integrator.transparent_min_bounce)
return 1.0f;
}
else {
/* other rays */
if((state->bounce >= kernel_data.integrator.max_bounce) ||
(state->diffuse_bounce >= kernel_data.integrator.max_diffuse_bounce) ||
(state->glossy_bounce >= kernel_data.integrator.max_glossy_bounce) ||
(state->transmission_bounce >= kernel_data.integrator.max_transmission_bounce))
{
return 0.0f;
}
else if(state->bounce <= kernel_data.integrator.min_bounce) {
return 1.0f;
}
}
/* probalistic termination */
return average(throughput);
}
__device_inline bool shadow_blocked(KernelGlobals *kg, PathState *state, Ray *ray, float3 *shadow)
{
*shadow = make_float3(1.0f, 1.0f, 1.0f);
if(ray->t == 0.0f)
return false;
Intersection isect;
bool result = scene_intersect(kg, ray, PATH_RAY_SHADOW_OPAQUE, &isect);
#ifdef __TRANSPARENT_SHADOWS__
if(result && kernel_data.integrator.transparent_shadows) {
/* transparent shadows work in such a way to try to minimize overhead
* in cases where we don't need them. after a regular shadow ray is
* cast we check if the hit primitive was potentially transparent, and
* only in that case start marching. this gives on extra ray cast for
* the cases were we do want transparency.
*
* also note that for this to work correct, multi close sampling must
* be used, since we don't pass a random number to shader_eval_surface */
if(shader_transparent_shadow(kg, &isect)) {
float3 throughput = make_float3(1.0f, 1.0f, 1.0f);
float3 Pend = ray->P + ray->D*ray->t;
int bounce = state->transparent_bounce;
for(;;) {
if(bounce >= kernel_data.integrator.transparent_max_bounce) {
return true;
}
else if(bounce >= kernel_data.integrator.transparent_min_bounce) {
/* todo: get random number somewhere for probabilistic terminate */
#if 0
float probability = average(throughput);
float terminate = 0.0f;
if(terminate >= probability)
return true;
throughput /= probability;
#endif
}
if(!scene_intersect(kg, ray, PATH_RAY_SHADOW_TRANSPARENT, &isect)) {
*shadow *= throughput;
return false;
}
if(!shader_transparent_shadow(kg, &isect))
return true;
ShaderData sd;
shader_setup_from_ray(kg, &sd, &isect, ray);
shader_eval_surface(kg, &sd, 0.0f, PATH_RAY_SHADOW);
throughput *= shader_bsdf_transparency(kg, &sd);
ray->P = ray_offset(sd.P, -sd.Ng);
if(ray->t != FLT_MAX)
ray->D = normalize_len(Pend - ray->P, &ray->t);
bounce++;
}
}
}
#endif
return result;
}
__device float4 kernel_path_progressive(KernelGlobals *kg, RNG *rng, int sample, Ray ray, __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);
float min_ray_pdf = FLT_MAX;
float ray_pdf = 0.0f;
PathState state;
int rng_offset = PRNG_BASE_NUM;
path_state_init(&state);
/* path iteration */
for(;; rng_offset += PRNG_BOUNCE_NUM) {
/* intersect scene */
Intersection isect;
uint visibility = path_state_ray_visibility(kg, &state);
if(!scene_intersect(kg, &ray, visibility, &isect)) {
/* 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, &ray, state.flag, ray_pdf);
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_rng(kg, rng, sample, rng_offset + PRNG_BSDF);
shader_eval_surface(kg, &sd, rbsdf, state.flag);
kernel_write_data_passes(kg, buffer, &L, &sd, sample, state.flag, 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*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);
}
}
/* 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
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
#ifdef __EMISSION__
/* emission */
if(sd.flag & SD_EMISSION) {
float3 emission = indirect_emission(kg, &sd, isect.t, state.flag, 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);
float terminate = path_rng(kg, rng, sample, rng_offset + PRNG_TERMINATE);
if(terminate >= probability)
break;
throughput /= probability;
#ifdef __AO__
/* ambient occlusion */
if(kernel_data.integrator.use_ambient_occlusion) {
/* todo: solve correlation */
float bsdf_u = path_rng(kg, rng, sample, rng_offset + PRNG_BSDF_U);
float bsdf_v = path_rng(kg, rng, sample, rng_offset + PRNG_BSDF_V);
float3 ao_D;
float ao_pdf;
sample_cos_hemisphere(sd.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 __MOTION__
light_ray.time = sd.time;
#endif
if(!shadow_blocked(kg, &state, &light_ray, &ao_shadow)) {
float3 ao_bsdf = shader_bsdf_diffuse(kg, &sd)*kernel_data.background.ao_factor;
path_radiance_accum_ao(&L, throughput, ao_bsdf, ao_shadow, state.bounce);
}
}
}
#endif
#ifdef __EMISSION__
if(kernel_data.integrator.use_direct_light) {
/* sample illumination from lights to find path contribution */
if(sd.flag & SD_BSDF_HAS_EVAL) {
float light_t = path_rng(kg, rng, sample, rng_offset + PRNG_LIGHT);
float light_o = path_rng(kg, rng, sample, rng_offset + PRNG_LIGHT_F);
float light_u = path_rng(kg, rng, sample, rng_offset + PRNG_LIGHT_U);
float light_v = path_rng(kg, rng, sample, rng_offset + PRNG_LIGHT_V);
Ray light_ray;
BsdfEval L_light;
bool is_lamp;
#ifdef __MOTION__
light_ray.time = sd.time;
#endif
if(direct_emission(kg, &sd, -1, light_t, light_o, light_u, light_v, &light_ray, &L_light, &is_lamp)) {
/* trace shadow ray */
float3 shadow;
if(!shadow_blocked(kg, &state, &light_ray, &shadow)) {
/* accumulate */
path_radiance_accum_light(&L, throughput, &L_light, shadow, state.bounce, is_lamp);
}
}
}
}
#endif
/* no BSDF? we can stop here */
if(!(sd.flag & SD_BSDF))
break;
/* sample BSDF */
float bsdf_pdf;
BsdfEval bsdf_eval;
float3 bsdf_omega_in;
differential3 bsdf_domega_in;
float bsdf_u = path_rng(kg, rng, sample, rng_offset + PRNG_BSDF_U);
float bsdf_v = path_rng(kg, rng, sample, rng_offset + PRNG_BSDF_V);
int label;
label = shader_bsdf_sample(kg, &sd, bsdf_u, bsdf_v, &bsdf_eval,
&bsdf_omega_in, &bsdf_domega_in, &bsdf_pdf);
shader_release(kg, &sd);
if(bsdf_pdf == 0.0f || bsdf_eval_is_zero(&bsdf_eval))
break;
/* modify throughput */
path_radiance_bsdf_bounce(&L, &throughput, &bsdf_eval, bsdf_pdf, state.bounce, label);
/* set labels */
if(!(label & LABEL_TRANSPARENT)) {
ray_pdf = bsdf_pdf;
min_ray_pdf = fminf(bsdf_pdf, 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 = bsdf_omega_in;
ray.t = FLT_MAX;
#ifdef __RAY_DIFFERENTIALS__
ray.dP = sd.dP;
ray.dD = bsdf_domega_in;
#endif
}
float3 L_sum = path_radiance_sum(kg, &L);
#ifdef __CLAMP_SAMPLE__
path_radiance_clamp(&L, &L_sum, kernel_data.integrator.sample_clamp);
#endif
kernel_write_light_passes(kg, buffer, &L, sample);
return make_float4(L_sum.x, L_sum.y, L_sum.z, 1.0f - L_transparent);
}
#ifdef __NON_PROGRESSIVE__
__device void kernel_path_indirect(KernelGlobals *kg, RNG *rng, int sample, Ray ray, __global float *buffer,
float3 throughput, float min_ray_pdf, float ray_pdf, PathState state, int rng_offset, PathRadiance *L)
{
/* path iteration */
for(;; rng_offset += PRNG_BOUNCE_NUM) {
/* intersect scene */
Intersection isect;
uint visibility = path_state_ray_visibility(kg, &state);
if(!scene_intersect(kg, &ray, visibility, &isect)) {
#ifdef __BACKGROUND__
/* sample background shader */
float3 L_background = indirect_background(kg, &ray, state.flag, ray_pdf);
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_rng(kg, rng, sample, rng_offset + PRNG_BSDF);
shader_eval_surface(kg, &sd, rbsdf, state.flag);
shader_merge_closures(kg, &sd);
/* 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*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_emission(kg, &sd, isect.t, state.flag, 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);
float terminate = path_rng(kg, rng, sample, rng_offset + PRNG_TERMINATE);
if(terminate >= probability)
break;
throughput /= probability;
#ifdef __AO__
/* ambient occlusion */
if(kernel_data.integrator.use_ambient_occlusion) {
/* todo: solve correlation */
float bsdf_u = path_rng(kg, rng, sample, rng_offset + PRNG_BSDF_U);
float bsdf_v = path_rng(kg, rng, sample, rng_offset + PRNG_BSDF_V);
float3 ao_D;
float ao_pdf;
sample_cos_hemisphere(sd.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 __MOTION__
light_ray.time = sd.time;
#endif
if(!shadow_blocked(kg, &state, &light_ray, &ao_shadow)) {
float3 ao_bsdf = shader_bsdf_diffuse(kg, &sd)*kernel_data.background.ao_factor;
path_radiance_accum_ao(L, throughput, ao_bsdf, ao_shadow, state.bounce);
}
}
}
#endif
#ifdef __EMISSION__
if(kernel_data.integrator.use_direct_light) {
/* sample illumination from lights to find path contribution */
if(sd.flag & SD_BSDF_HAS_EVAL) {
float light_t = path_rng(kg, rng, sample, rng_offset + PRNG_LIGHT);
float light_o = path_rng(kg, rng, sample, rng_offset + PRNG_LIGHT_F);
float light_u = path_rng(kg, rng, sample, rng_offset + PRNG_LIGHT_U);
float light_v = path_rng(kg, rng, sample, rng_offset + PRNG_LIGHT_V);
Ray light_ray;
BsdfEval L_light;
bool is_lamp;
#ifdef __MOTION__
light_ray.time = sd.time;
#endif
/* sample random light */
if(direct_emission(kg, &sd, -1, light_t, light_o, light_u, light_v, &light_ray, &L_light, &is_lamp)) {
/* trace shadow ray */
float3 shadow;
if(!shadow_blocked(kg, &state, &light_ray, &shadow)) {
/* accumulate */
path_radiance_accum_light(L, throughput, &L_light, shadow, state.bounce, is_lamp);
}
}
}
}
#endif
/* no BSDF? we can stop here */
if(!(sd.flag & SD_BSDF))
break;
/* sample BSDF */
float bsdf_pdf;
BsdfEval bsdf_eval;
float3 bsdf_omega_in;
differential3 bsdf_domega_in;
float bsdf_u = path_rng(kg, rng, sample, rng_offset + PRNG_BSDF_U);
float bsdf_v = path_rng(kg, rng, sample, rng_offset + PRNG_BSDF_V);
int label;
label = shader_bsdf_sample(kg, &sd, bsdf_u, bsdf_v, &bsdf_eval,
&bsdf_omega_in, &bsdf_domega_in, &bsdf_pdf);
shader_release(kg, &sd);
if(bsdf_pdf == 0.0f || bsdf_eval_is_zero(&bsdf_eval))
break;
/* modify throughput */
path_radiance_bsdf_bounce(L, &throughput, &bsdf_eval, bsdf_pdf, state.bounce, label);
/* set labels */
if(!(label & LABEL_TRANSPARENT)) {
ray_pdf = bsdf_pdf;
min_ray_pdf = fminf(bsdf_pdf, 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 = bsdf_omega_in;
ray.t = FLT_MAX;
#ifdef __RAY_DIFFERENTIALS__
ray.dP = sd.dP;
ray.dD = bsdf_domega_in;
#endif
}
}
__device float4 kernel_path_non_progressive(KernelGlobals *kg, RNG *rng, int sample, Ray ray, __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);
float ray_pdf = 0.0f;
PathState state;
int rng_offset = PRNG_BASE_NUM;
path_state_init(&state);
for(;; rng_offset += PRNG_BOUNCE_NUM) {
/* intersect scene */
Intersection isect;
uint visibility = path_state_ray_visibility(kg, &state);
if(!scene_intersect(kg, &ray, visibility, &isect)) {
/* eval background shader if nothing hit */
if(kernel_data.background.transparent) {
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, &ray, state.flag, ray_pdf);
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_rng(kg, rng, sample, rng_offset + PRNG_BSDF);
shader_eval_surface(kg, &sd, rbsdf, state.flag);
shader_merge_closures(kg, &sd);
kernel_write_data_passes(kg, buffer, &L, &sd, sample, state.flag, throughput);
/* holdout */
#ifdef __HOLDOUT__
if((sd.flag & (SD_HOLDOUT|SD_HOLDOUT_MASK))) {
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
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
#ifdef __EMISSION__
/* emission */
if(sd.flag & SD_EMISSION) {
float3 emission = indirect_emission(kg, &sd, isect.t, state.flag, ray_pdf);
path_radiance_accum_emission(&L, throughput, emission, state.bounce);
}
#endif
/* transparency termination */
if(state.flag & PATH_RAY_TRANSPARENT) {
/* 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);
float terminate = path_rng(kg, rng, sample, rng_offset + PRNG_TERMINATE);
if(terminate >= probability)
break;
throughput /= probability;
}
#ifdef __AO__
/* ambient occlusion */
if(kernel_data.integrator.use_ambient_occlusion) {
int num_samples = kernel_data.integrator.ao_samples;
float num_samples_inv = 1.0f/num_samples;
float ao_factor = kernel_data.background.ao_factor/num_samples;
for(int j = 0; j < num_samples; j++) {
/* todo: solve correlation */
float bsdf_u = path_rng(kg, rng, sample*num_samples + j, rng_offset + PRNG_BSDF_U);
float bsdf_v = path_rng(kg, rng, sample*num_samples + j, rng_offset + PRNG_BSDF_V);
float3 ao_D;
float ao_pdf;
sample_cos_hemisphere(sd.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 __MOTION__
light_ray.time = sd.time;
#endif
if(!shadow_blocked(kg, &state, &light_ray, &ao_shadow)) {
float3 ao_bsdf = shader_bsdf_diffuse(kg, &sd)*ao_factor;
path_radiance_accum_ao(&L, throughput*num_samples_inv, ao_bsdf, ao_shadow, state.bounce);
}
}
}
}
#endif
#ifdef __EMISSION__
/* sample illumination from lights to find path contribution */
if(sd.flag & SD_BSDF_HAS_EVAL) {
Ray light_ray;
BsdfEval L_light;
bool is_lamp;
#ifdef __MOTION__
light_ray.time = sd.time;
#endif
/* lamp sampling */
for(int i = 0; i < kernel_data.integrator.num_all_lights; i++) {
int num_samples = light_select_num_samples(kg, i);
float num_samples_inv = 1.0f/(num_samples*kernel_data.integrator.num_all_lights);
if(kernel_data.integrator.pdf_triangles != 0.0f)
num_samples_inv *= 0.5f;
for(int j = 0; j < num_samples; j++) {
float light_u = path_rng(kg, rng, sample*num_samples + j, rng_offset + PRNG_LIGHT_U);
float light_v = path_rng(kg, rng, sample*num_samples + j, rng_offset + PRNG_LIGHT_V);
if(direct_emission(kg, &sd, i, 0.0f, 0.0f, light_u, light_v, &light_ray, &L_light, &is_lamp)) {
/* trace shadow ray */
float3 shadow;
if(!shadow_blocked(kg, &state, &light_ray, &shadow)) {
/* accumulate */
path_radiance_accum_light(&L, throughput*num_samples_inv, &L_light, shadow, state.bounce, 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;
if(kernel_data.integrator.num_all_lights)
num_samples_inv *= 0.5f;
for(int j = 0; j < num_samples; j++) {
float light_t = path_rng(kg, rng, sample*num_samples + j, rng_offset + PRNG_LIGHT);
float light_u = path_rng(kg, rng, sample*num_samples + j, rng_offset + PRNG_LIGHT_U);
float light_v = path_rng(kg, rng, sample*num_samples + j, rng_offset + PRNG_LIGHT_V);
/* only sample triangle lights */
if(kernel_data.integrator.num_all_lights)
light_t = 0.5f*light_t;
if(direct_emission(kg, &sd, -1, light_t, 0.0f, light_u, light_v, &light_ray, &L_light, &is_lamp)) {
/* trace shadow ray */
float3 shadow;
if(!shadow_blocked(kg, &state, &light_ray, &shadow)) {
/* accumulate */
path_radiance_accum_light(&L, throughput*num_samples_inv, &L_light, shadow, state.bounce, is_lamp);
}
}
}
}
}
#endif
for(int i = 0; i< sd.num_closure; i++) {
const ShaderClosure *sc = &sd.closure[i];
if(!CLOSURE_IS_BSDF(sc->type))
continue;
/* transparency is not handled here, but in outer loop */
if(sc->type == CLOSURE_BSDF_TRANSPARENT_ID)
continue;
int num_samples;
if(CLOSURE_IS_BSDF_DIFFUSE(sc->type))
num_samples = kernel_data.integrator.diffuse_samples;
else if(CLOSURE_IS_BSDF_GLOSSY(sc->type))
num_samples = kernel_data.integrator.glossy_samples;
else
num_samples = kernel_data.integrator.transmission_samples;
float num_samples_inv = 1.0f/num_samples;
for(int j = 0; j < num_samples; j++) {
/* sample BSDF */
float bsdf_pdf;
BsdfEval bsdf_eval;
float3 bsdf_omega_in;
differential3 bsdf_domega_in;
float bsdf_u = path_rng(kg, rng, sample*num_samples + j, rng_offset + PRNG_BSDF_U);
float bsdf_v = path_rng(kg, rng, sample*num_samples + j, rng_offset + PRNG_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))
continue;
/* modify throughput */
float3 tp = throughput;
path_radiance_bsdf_bounce(&L, &tp, &bsdf_eval, bsdf_pdf, state.bounce, label);
/* set labels */
float min_ray_pdf = FLT_MAX;
if(!(label & LABEL_TRANSPARENT))
min_ray_pdf = fminf(bsdf_pdf, min_ray_pdf);
/* modify path state */
PathState ps = state;
path_state_next(kg, &ps, label);
/* setup ray */
ray.P = ray_offset(sd.P, (label & LABEL_TRANSMIT)? -sd.Ng: sd.Ng);
ray.D = bsdf_omega_in;
ray.t = FLT_MAX;
#ifdef __RAY_DIFFERENTIALS__
ray.dP = sd.dP;
ray.dD = bsdf_domega_in;
#endif
kernel_path_indirect(kg, rng, sample*num_samples, ray, buffer,
tp*num_samples_inv, min_ray_pdf, bsdf_pdf, ps, rng_offset+PRNG_BOUNCE_NUM, &L);
}
}
/* continue in case of transparency */
throughput *= shader_bsdf_transparency(kg, &sd);
shader_release(kg, &sd);
if(is_zero(throughput))
break;
path_state_next(kg, &state, LABEL_TRANSPARENT);
ray.P = ray_offset(sd.P, -sd.Ng);
}
float3 L_sum = path_radiance_sum(kg, &L);
#ifdef __CLAMP_SAMPLE__
path_radiance_clamp(&L, &L_sum, kernel_data.integrator.sample_clamp);
#endif
kernel_write_light_passes(kg, buffer, &L, sample);
return make_float4(L_sum.x, L_sum.y, L_sum.z, 1.0f - L_transparent);
}
#endif
__device void kernel_path_trace(KernelGlobals *kg,
__global float *buffer, __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 */
RNG rng;
float filter_u;
float filter_v;
path_rng_init(kg, rng_state, sample, &rng, x, y, &filter_u, &filter_v);
/* sample camera ray */
Ray ray;
float lens_u = path_rng(kg, &rng, sample, PRNG_LENS_U);
float lens_v = path_rng(kg, &rng, sample, PRNG_LENS_V);
#ifdef __MOTION__
float time = path_rng(kg, &rng, sample, PRNG_TIME);
#else
float time = 0.0f;
#endif
camera_sample(kg, x, y, filter_u, filter_v, lens_u, lens_v, time, &ray);
/* integrate */
float4 L;
if (ray.t != 0.0f) {
#ifdef __NON_PROGRESSIVE__
if(kernel_data.integrator.progressive)
#endif
L = kernel_path_progressive(kg, &rng, sample, ray, buffer);
#ifdef __NON_PROGRESSIVE__
else
L = kernel_path_non_progressive(kg, &rng, sample, ray, buffer);
#endif
}
else
L = make_float4(0.f, 0.f, 0.f, 0.f);
/* 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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