diff options
Diffstat (limited to 'intern/cycles/kernel/kernel_shader.h')
| -rw-r--r-- | intern/cycles/kernel/kernel_shader.h | 175 |
1 files changed, 137 insertions, 38 deletions
diff --git a/intern/cycles/kernel/kernel_shader.h b/intern/cycles/kernel/kernel_shader.h index 5964aca0c78..bb3add5d7ca 100644 --- a/intern/cycles/kernel/kernel_shader.h +++ b/intern/cycles/kernel/kernel_shader.h @@ -494,20 +494,45 @@ ccl_device_inline void shader_merge_closures(ShaderData *sd) } #endif +/* Defensive sampling. */ + +ccl_device_inline void shader_prepare_closures(ShaderData *sd, + ccl_addr_space PathState *state) +{ + /* We can likely also do defensive sampling at deeper bounces, particularly + * for cases like a perfect mirror but possibly also others. This will need + * a good heuristic. */ + if(state->bounce + state->transparent_bounce == 0 && sd->num_closure > 1) { + float sum = 0.0f; + + for(int i = 0; i < sd->num_closure; i++) { + ShaderClosure *sc = &sd->closure[i]; + if(CLOSURE_IS_BSDF_OR_BSSRDF(sc->type)) { + sum += sc->sample_weight; + } + } + + for(int i = 0; i < sd->num_closure; i++) { + ShaderClosure *sc = &sd->closure[i]; + if(CLOSURE_IS_BSDF_OR_BSSRDF(sc->type)) { + sc->sample_weight = max(sc->sample_weight, 0.125f * sum); + } + } + } +} + + /* 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 +595,7 @@ 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); @@ -578,48 +603,120 @@ void shader_bsdf_eval(KernelGlobals *kg, } } -ccl_device_inline int shader_bsdf_sample(KernelGlobals *kg, - ShaderData *sd, - float randu, float randv, - BsdfEval *bsdf_eval, - float3 *omega_in, - differential3 *domega_in, - float *pdf) +ccl_device_inline const ShaderClosure *shader_bsdf_pick(ShaderData *sd, + float *randu) { int sampled = 0; if(sd->num_closure > 1) { - /* pick a BSDF closure based on sample weights */ + /* Pick a BSDF or 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)) + 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; - sum = 0.0f; + float r = (*randu)*sum; + float partial_sum = 0.0f; + + for(int i = 0; i < sd->num_closure; i++) { + const ShaderClosure *sc = &sd->closure[i]; - 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 next_sum = partial_sum + sc->sample_weight; + + if(r < next_sum) { + sampled = i; - if(r <= sum) + /* Rescale to reuse for direction sample, to better + * preserve stratifaction. */ + *randu = (r - partial_sum) / sc->sample_weight; break; + } + + partial_sum = next_sum; } } + } - if(sampled == sd->num_closure) { - *pdf = 0.0f; - return LABEL_NONE; + return &sd->closure[sampled]; +} + +ccl_device_inline const ShaderClosure *shader_bssrdf_pick(ShaderData *sd, + ccl_addr_space float3 *throughput, + float *randu) +{ + 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 = (*randu)*(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)) { + float next_sum = partial_sum + sc->sample_weight; + + if(r < next_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; + + /* Rescale to reuse for direction sample, to better + * preserve stratifaction. */ + *randu = (r - partial_sum) / sc->sample_weight; + break; + } + } + + partial_sum = next_sum; + } } } - const ShaderClosure *sc = &sd->closure[sampled]; + return &sd->closure[sampled]; +} + +ccl_device_inline int shader_bsdf_sample(KernelGlobals *kg, + ShaderData *sd, + float randu, float randv, + BsdfEval *bsdf_eval, + float3 *omega_in, + differential3 *domega_in, + float *pdf) +{ + const ShaderClosure *sc = shader_bsdf_pick(sd, &randu); + if(!sc) { + *pdf = 0.0f; + return LABEL_NONE; + } + + /* BSSRDF should already have been handled elsewhere. */ + kernel_assert(CLOSURE_IS_BSDF(sc->type)); int label; float3 eval; @@ -632,7 +729,7 @@ 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); } } @@ -868,11 +965,10 @@ ccl_device float3 shader_holdout_eval(KernelGlobals *kg, ShaderData *sd) /* Surface Evaluation */ ccl_device void shader_eval_surface(KernelGlobals *kg, ShaderData *sd, - ccl_addr_space PathState *state, float randb, int path_flag) + ccl_addr_space PathState *state, int path_flag) { sd->num_closure = 0; sd->num_closure_extra = 0; - sd->randb_closure = randb; #ifdef __OSL__ if(kg->osl) @@ -903,7 +999,6 @@ ccl_device float3 shader_eval_background(KernelGlobals *kg, ShaderData *sd, { sd->num_closure = 0; sd->num_closure_extra = 0; - sd->randb_closure = 0.0f; #ifdef __SVM__ #ifdef __OSL__ @@ -985,17 +1080,22 @@ ccl_device int shader_volume_phase_sample(KernelGlobals *kg, const ShaderData *s sum += sc->sample_weight; } - float r = sd->randb_closure*sum; - sum = 0.0f; + float r = randu*sum; + float partial_sum = 0.0f; for(sampled = 0; sampled < sd->num_closure; sampled++) { const ShaderClosure *sc = &sd->closure[sampled]; if(CLOSURE_IS_PHASE(sc->type)) { - sum += sc->sample_weight; + float next_sum = partial_sum + sc->sample_weight; - if(r <= sum) + if(r <= next_sum) { + /* Rescale to reuse for BSDF direction sample. */ + randu = (r - partial_sum) / sc->sample_weight; break; + } + + partial_sum = next_sum; } } @@ -1099,7 +1199,6 @@ ccl_device void shader_eval_displacement(KernelGlobals *kg, ShaderData *sd, ccl_ { sd->num_closure = 0; sd->num_closure_extra = 0; - sd->randb_closure = 0.0f; /* this will modify sd->P */ #ifdef __SVM__ |