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Fix #34852: multilayer SSS material rendering different in progressive and

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non-progressive integrator.
This commit is contained in:
Brecht Van Lommel
2013-04-03 16:12:13 +00:00
parent 9c49e71216
commit 743552ff2a
2 changed files with 70 additions and 54 deletions
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6
intern/cycles/kernel/kernel_path.h
View File

@@ -363,7 +363,7 @@ __device float4 kernel_path_progressive(KernelGlobals *kg, RNG *rng, int sample,
/* do bssrdf scatter step if we picked a bssrdf closure */
if(sc) {
uint lcg_state = lcg_init(rbsdf);
subsurface_scatter_step(kg, &sd, state.flag, sc, &lcg_state);
subsurface_scatter_step(kg, &sd, state.flag, sc, &lcg_state, false);
}
}
#endif
@@ -587,7 +587,7 @@ __device void kernel_path_indirect(KernelGlobals *kg, RNG *rng, int sample, Ray
/* do bssrdf scatter step if we picked a bssrdf closure */
if(sc) {
uint lcg_state = lcg_init(rbsdf);
subsurface_scatter_step(kg, &sd, state.flag, sc, &lcg_state);
subsurface_scatter_step(kg, &sd, state.flag, sc, &lcg_state, false);
}
}
#endif
@@ -996,7 +996,7 @@ __device float4 kernel_path_non_progressive(KernelGlobals *kg, RNG *rng, int sam
* replace the BSSRDF with a diffuse BSDF closure */
for(int j = 0; j < num_samples; j++) {
ShaderData bssrdf_sd = sd;
subsurface_scatter_step(kg, &bssrdf_sd, state.flag, sc, &lcg_state);
subsurface_scatter_step(kg, &bssrdf_sd, state.flag, sc, &lcg_state, true);
/* compute lighting with the BSDF closure */
kernel_path_non_progressive_lighting(kg, rng, sample*num_samples + j,

118
intern/cycles/kernel/kernel_subsurface.h
View File

@@ -63,69 +63,85 @@ __device ShaderClosure *subsurface_scatter_pick_closure(KernelGlobals *kg, Shade
bssrdf_sum += sc->sample_weight;
}
/* pick a random bsdf or bssrdf */
/* use bsdf or bssrdf? */
float r = sd->randb_closure*(bsdf_sum + bssrdf_sum);
float sum = 0.0f;
int sampled;
for(sampled = 0; sampled < sd->num_closure; sampled++) {
ShaderClosure *sc = &sd->closure[sampled];
if(CLOSURE_IS_BSDF(sc->type) || CLOSURE_IS_BSSRDF(sc->type)) {
sum += sc->sample_weight;
if(r <= sum) {
/* if we picked a bssrdf, return the closure. also return probability
* to adjust throughput depending if we picked a bsdf or bssrdf */
if(CLOSURE_IS_BSSRDF(sc->type)) {
sd->randb_closure = 0.0f; /* not needed anymore */
#ifdef BSSRDF_MULTI_EVAL
*probability = (bssrdf_sum > 0.0f)? (bsdf_sum + bssrdf_sum)/bssrdf_sum: 1.0f;
#else
*probability = (bssrdf_sum > 0.0f)? (bsdf_sum + bssrdf_sum)/sc->sample_weight: 1.0f;
#endif
return sc;
}
else {
/* reuse randb for picking a bsdf */
sd->randb_closure = (sd->randb_closure - sum - sc->sample_weight)/sc->sample_weight;
*probability = (bsdf_sum > 0.0f)? (bsdf_sum + bssrdf_sum)/bsdf_sum: 1.0f;
return NULL;
}
}
}
if(r < bsdf_sum) {
/* use bsdf, and adjust randb so we can reuse it for picking a bsdf */
sd->randb_closure = r/bsdf_sum;
*probability = (bsdf_sum > 0.0f)? (bsdf_sum + bssrdf_sum)/bsdf_sum: 1.0f;
return NULL;
}
*probability = 1.0f;
return NULL;
}
/* use bssrdf */
r -= bsdf_sum;
sd->randb_closure = 0.0f; /* not needed anymore */
#ifdef BSSRDF_MULTI_EVAL
__device float3 subsurface_scatter_multi_eval(KernelGlobals *kg, ShaderData *sd, bool hit, float refl, float *r, int num_r)
{
/* compute pdf */
float3 eval_sum = make_float3(0.0f, 0.0f, 0.0f);
float pdf_sum = 0.0f;
float sample_weight_sum = 0.0f;
float sum = 0.0f;
for(int i = 0; i < sd->num_closure; i++) {
ShaderClosure *sc = &sd->closure[i];
if(CLOSURE_IS_BSSRDF(sc->type)) {
float pdf = 1.0f;
for(int i = 0; i < num_r; i++)
pdf *= bssrdf_pdf(kg, sc->data0, refl, r[i]);
//float pdf = bssrdf_pdf(kg, sc->data0, refl, r[num_r-1]);
sum += sc->sample_weight;
eval_sum += sc->weight*pdf;
pdf_sum += sc->sample_weight*pdf;
sample_weight_sum += sc->sample_weight;
if(r <= sum) {
#ifdef BSSRDF_MULTI_EVAL
*probability = (bssrdf_sum > 0.0f)? (bsdf_sum + bssrdf_sum)/bssrdf_sum: 1.0f;
#else
*probability = (bssrdf_sum > 0.0f)? (bsdf_sum + bssrdf_sum)/sc->sample_weight: 1.0f;
#endif
return sc;
}
}
}
float inv_pdf_sum = (pdf_sum > 0.0f)? sample_weight_sum/pdf_sum: 0.0f;
/* should never happen */
*probability = 1.0f;
return NULL;
}
#ifdef BSSRDF_MULTI_EVAL
__device float3 subsurface_scatter_multi_eval(KernelGlobals *kg, ShaderData *sd, bool hit, float refl, float *r, int num_r, bool all)
{
/* compute pdf */
float3 eval_sum = make_float3(0.0f, 0.0f, 0.0f);
float pdf_sum = 0.0f;
float sample_weight_sum = 0.0f;
int num_bssrdf = 0;
for(int i = 0; i < sd->num_closure; i++) {
ShaderClosure *sc = &sd->closure[i];
if(CLOSURE_IS_BSSRDF(sc->type)) {
float sample_weight = (all)? 1.0f: sc->sample_weight;
/* compute pdf */
float pdf = 1.0f;
for(int i = 0; i < num_r; i++)
pdf *= bssrdf_pdf(kg, sc->data0, refl, r[i]);
eval_sum += sc->weight*pdf;
pdf_sum += sample_weight*pdf;
sample_weight_sum += sample_weight;
num_bssrdf++;
}
}
float inv_pdf_sum;
if(pdf_sum > 0.0f) {
/* in case of non-progressive integrate we sample all bssrdf's once,
* for progressive we pick one, so adjust pdf for that */
if(all)
inv_pdf_sum = 1.0f/pdf_sum;
else
inv_pdf_sum = sample_weight_sum/pdf_sum;
}
else
inv_pdf_sum = 0.0f;
float3 weight = eval_sum * inv_pdf_sum;
return weight;
@@ -152,7 +168,7 @@ __device void subsurface_scatter_setup_diffuse_bsdf(ShaderData *sd, float3 weigh
}
/* subsurface scattering step, from a point on the surface to another nearby point on the same object */
__device void subsurface_scatter_step(KernelGlobals *kg, ShaderData *sd, int state_flag, ShaderClosure *sc, uint *lcg_state)
__device void subsurface_scatter_step(KernelGlobals *kg, ShaderData *sd, int state_flag, ShaderClosure *sc, uint *lcg_state, bool all)
{
float radius = sc->data0;
float refl = max(average(sc->weight)*3.0f, 0.0f);
@@ -207,7 +223,7 @@ __device void subsurface_scatter_step(KernelGlobals *kg, ShaderData *sd, int sta
/* evaluate subsurface scattering closures */
#ifdef BSSRDF_MULTI_EVAL
weight *= subsurface_scatter_multi_eval(kg, sd, hit, refl, r_attempts, num_attempts);
weight *= subsurface_scatter_multi_eval(kg, sd, hit, refl, r_attempts, num_attempts, all);
#else
weight *= sc->weight;
#endif