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Code cleanup: refactor BSSRDF closure sampling, for next commit.

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This commit is contained in:
Brecht Van Lommel
2017-09-15 01:55:44 +02:00
parent d029399e6b
commit b3afc8917c
6 changed files with 125 additions and 150 deletions
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133
intern/cycles/kernel/kernel_shader.h
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@@ -497,17 +497,14 @@ ccl_device_inline void shader_merge_closures(ShaderData *sd)
/* BSDF */
ccl_device_inline void _shader_bsdf_multi_eval(KernelGlobals *kg, ShaderData *sd, const float3 omega_in, float *pdf,
int skip_bsdf, BsdfEval *result_eval, float sum_pdf, float sum_sample_weight)
const ShaderClosure *skip_sc, BsdfEval *result_eval, float sum_pdf, float sum_sample_weight)
{
/* this is the veach one-sample model with balance heuristic, some pdf
* factors drop out when using balance heuristic weighting */
for(int i = 0; i < sd->num_closure; i++) {
if(i == skip_bsdf)
continue;
const ShaderClosure *sc = &sd->closure[i];
if(CLOSURE_IS_BSDF(sc->type)) {
if(sc != skip_sc && CLOSURE_IS_BSDF(sc->type)) {
float bsdf_pdf = 0.0f;
float3 eval = bsdf_eval(kg, sd, sc, omega_in, &bsdf_pdf);
@@ -570,7 +567,7 @@ void shader_bsdf_eval(KernelGlobals *kg,
#endif
{
float pdf;
_shader_bsdf_multi_eval(kg, sd, omega_in, &pdf, -1, eval, 0.0f, 0.0f);
_shader_bsdf_multi_eval(kg, sd, omega_in, &pdf, NULL, eval, 0.0f, 0.0f);
if(use_mis) {
float weight = power_heuristic(light_pdf, pdf);
bsdf_eval_mis(eval, weight);
@@ -578,6 +575,90 @@ void shader_bsdf_eval(KernelGlobals *kg,
}
}
ccl_device_inline const ShaderClosure *shader_bsdf_pick(ShaderData *sd)
{
int sampled = 0;
if(sd->num_closure > 1) {
/* Pick a BSDF or based on sample weights. */
float sum = 0.0f;
for(int i = 0; i < sd->num_closure; i++) {
const ShaderClosure *sc = &sd->closure[i];
if(CLOSURE_IS_BSDF(sc->type)) {
sum += sc->sample_weight;
}
}
float r = sd->randb_closure*sum;
float partial_sum = 0.0f;
for(int i = 0; i < sd->num_closure; i++) {
const ShaderClosure *sc = &sd->closure[i];
if(CLOSURE_IS_BSDF(sc->type)) {
partial_sum += sc->sample_weight;
if(r <= partial_sum) {
sampled = i;
break;
}
}
}
}
return &sd->closure[sampled];
}
ccl_device_inline const ShaderClosure *shader_bssrdf_pick(ShaderData *sd,
ccl_addr_space float3 *throughput)
{
int sampled = 0;
if(sd->num_closure > 1) {
/* Pick a BSDF or BSSRDF or based on sample weights. */
float sum_bsdf = 0.0f;
float sum_bssrdf = 0.0f;
for(int i = 0; i < sd->num_closure; i++) {
const ShaderClosure *sc = &sd->closure[i];
if(CLOSURE_IS_BSDF(sc->type)) {
sum_bsdf += sc->sample_weight;
}
else if(CLOSURE_IS_BSSRDF(sc->type)) {
sum_bssrdf += sc->sample_weight;
}
}
float r = sd->randb_closure*(sum_bsdf + sum_bssrdf);
float partial_sum = 0.0f;
for(int i = 0; i < sd->num_closure; i++) {
const ShaderClosure *sc = &sd->closure[i];
if(CLOSURE_IS_BSDF_OR_BSSRDF(sc->type)) {
partial_sum += sc->sample_weight;
if(r <= partial_sum) {
if(CLOSURE_IS_BSDF(sc->type)) {
*throughput *= (sum_bsdf + sum_bssrdf) / sum_bsdf;
return NULL;
}
else {
*throughput *= (sum_bsdf + sum_bssrdf) / sum_bssrdf;
sampled = i;
break;
}
}
}
}
}
return &sd->closure[sampled];
}
ccl_device_inline int shader_bsdf_sample(KernelGlobals *kg,
ShaderData *sd,
float randu, float randv,
@@ -586,40 +667,14 @@ ccl_device_inline int shader_bsdf_sample(KernelGlobals *kg,
differential3 *domega_in,
float *pdf)
{
int sampled = 0;
if(sd->num_closure > 1) {
/* pick a BSDF closure based on sample weights */
float sum = 0.0f;
for(sampled = 0; sampled < sd->num_closure; sampled++) {
const ShaderClosure *sc = &sd->closure[sampled];
if(CLOSURE_IS_BSDF(sc->type))
sum += sc->sample_weight;
}
float r = sd->randb_closure*sum;
sum = 0.0f;
for(sampled = 0; sampled < sd->num_closure; sampled++) {
const ShaderClosure *sc = &sd->closure[sampled];
if(CLOSURE_IS_BSDF(sc->type)) {
sum += sc->sample_weight;
if(r <= sum)
break;
}
}
if(sampled == sd->num_closure) {
*pdf = 0.0f;
return LABEL_NONE;
}
const ShaderClosure *sc = shader_bsdf_pick(sd);
if(!sc) {
*pdf = 0.0f;
return LABEL_NONE;
}
const ShaderClosure *sc = &sd->closure[sampled];
/* BSSRDF should already have been handled elsewhere. */
kernel_assert(CLOSURE_IS_BSDF(sc->type));
int label;
float3 eval;
@@ -632,7 +687,7 @@ ccl_device_inline int shader_bsdf_sample(KernelGlobals *kg,
if(sd->num_closure > 1) {
float sweight = sc->sample_weight;
_shader_bsdf_multi_eval(kg, sd, *omega_in, pdf, sampled, bsdf_eval, *pdf*sweight, sweight);
_shader_bsdf_multi_eval(kg, sd, *omega_in, pdf, sc, bsdf_eval, *pdf*sweight, sweight);
}
}