blender/intern/cycles/kernel/kernel_shader.h
Brecht Van Lommel a29807cd63 Cycles: volume light sampling
* Volume multiple importace sampling support to combine equiangular and distance
  sampling, for both homogeneous and heterogeneous volumes.

* Branched path "Sample All Direct Lights" and "Sample All Indirect Lights" now
  apply to volumes as well as surfaces.

Implementation note:

For simplicity this is all done with decoupled ray marching, the only case we do
not use decoupled is for distance only sampling with one light sample. The
homogeneous case should still compile on the GPU because it only requires fixed
size storage, but the heterogeneous case will be trickier to get working.
2014-06-14 13:49:56 +02:00

1045 lines
25 KiB
C

/*
* 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
*/
/*
* ShaderData, used in four steps:
*
* Setup from incoming ray, sampled position and background.
* Execute for surface, volume or displacement.
* Evaluate one or more closures.
* Release.
*
*/
#include "closure/bsdf_util.h"
#include "closure/bsdf.h"
#include "closure/emissive.h"
#include "svm/svm.h"
CCL_NAMESPACE_BEGIN
/* ShaderData setup from incoming ray */
#ifdef __OBJECT_MOTION__
ccl_device void shader_setup_object_transforms(KernelGlobals *kg, ShaderData *sd, float time)
{
if(sd->flag & SD_OBJECT_MOTION) {
sd->ob_tfm = object_fetch_transform_motion(kg, sd->object, time);
sd->ob_itfm = transform_quick_inverse(sd->ob_tfm);
}
else {
sd->ob_tfm = object_fetch_transform(kg, sd->object, OBJECT_TRANSFORM);
sd->ob_itfm = object_fetch_transform(kg, sd->object, OBJECT_INVERSE_TRANSFORM);
}
}
#endif
ccl_device void shader_setup_from_ray(KernelGlobals *kg, ShaderData *sd,
const Intersection *isect, const Ray *ray, int bounce, int transparent_bounce)
{
#ifdef __INSTANCING__
sd->object = (isect->object == PRIM_NONE)? kernel_tex_fetch(__prim_object, isect->prim): isect->object;
#endif
sd->type = isect->type;
sd->flag = kernel_tex_fetch(__object_flag, sd->object);
/* matrices and time */
#ifdef __OBJECT_MOTION__
shader_setup_object_transforms(kg, sd, ray->time);
sd->time = ray->time;
#endif
sd->prim = kernel_tex_fetch(__prim_index, isect->prim);
sd->ray_length = isect->t;
sd->ray_depth = bounce;
sd->transparent_depth = transparent_bounce;
#ifdef __UV__
sd->u = isect->u;
sd->v = isect->v;
#endif
#ifdef __HAIR__
if(sd->type & PRIMITIVE_ALL_CURVE) {
/* curve */
float4 curvedata = kernel_tex_fetch(__curves, sd->prim);
sd->shader = __float_as_int(curvedata.z);
sd->P = bvh_curve_refine(kg, sd, isect, ray);
}
else
#endif
if(sd->type & PRIMITIVE_TRIANGLE) {
/* static triangle */
float3 Ng = triangle_normal(kg, sd->prim);
sd->shader = __float_as_int(kernel_tex_fetch(__tri_shader, sd->prim));
/* vectors */
sd->P = triangle_refine(kg, sd, isect, ray);
sd->Ng = Ng;
sd->N = Ng;
/* smooth normal */
if(sd->shader & SHADER_SMOOTH_NORMAL)
sd->N = triangle_smooth_normal(kg, sd->prim, sd->u, sd->v);
#ifdef __DPDU__
/* dPdu/dPdv */
triangle_dPdudv(kg, sd->prim, &sd->dPdu, &sd->dPdv);
#endif
}
else {
/* motion triangle */
motion_triangle_shader_setup(kg, sd, isect, ray, false);
}
sd->I = -ray->D;
sd->flag |= kernel_tex_fetch(__shader_flag, (sd->shader & SHADER_MASK)*2);
#ifdef __INSTANCING__
if(isect->object != OBJECT_NONE) {
/* instance transform */
object_normal_transform(kg, sd, &sd->N);
object_normal_transform(kg, sd, &sd->Ng);
#ifdef __DPDU__
object_dir_transform(kg, sd, &sd->dPdu);
object_dir_transform(kg, sd, &sd->dPdv);
#endif
}
#endif
/* backfacing test */
bool backfacing = (dot(sd->Ng, sd->I) < 0.0f);
if(backfacing) {
sd->flag |= SD_BACKFACING;
sd->Ng = -sd->Ng;
sd->N = -sd->N;
#ifdef __DPDU__
sd->dPdu = -sd->dPdu;
sd->dPdv = -sd->dPdv;
#endif
}
#ifdef __RAY_DIFFERENTIALS__
/* differentials */
differential_transfer(&sd->dP, ray->dP, ray->D, ray->dD, sd->Ng, isect->t);
differential_incoming(&sd->dI, ray->dD);
differential_dudv(&sd->du, &sd->dv, sd->dPdu, sd->dPdv, sd->dP, sd->Ng);
#endif
}
/* ShaderData setup from BSSRDF scatter */
#ifdef __SUBSURFACE__
ccl_device_inline void shader_setup_from_subsurface(KernelGlobals *kg, ShaderData *sd,
const Intersection *isect, const Ray *ray)
{
bool backfacing = sd->flag & SD_BACKFACING;
/* object, matrices, time, ray_length stay the same */
sd->flag = kernel_tex_fetch(__object_flag, sd->object);
sd->prim = kernel_tex_fetch(__prim_index, isect->prim);
sd->type = isect->type;
#ifdef __UV__
sd->u = isect->u;
sd->v = isect->v;
#endif
/* fetch triangle data */
if(sd->type == PRIMITIVE_TRIANGLE) {
float3 Ng = triangle_normal(kg, sd->prim);
sd->shader = __float_as_int(kernel_tex_fetch(__tri_shader, sd->prim));
/* static triangle */
sd->P = triangle_refine_subsurface(kg, sd, isect, ray);
sd->Ng = Ng;
sd->N = Ng;
if(sd->shader & SHADER_SMOOTH_NORMAL)
sd->N = triangle_smooth_normal(kg, sd->prim, sd->u, sd->v);
#ifdef __DPDU__
/* dPdu/dPdv */
triangle_dPdudv(kg, sd->prim, &sd->dPdu, &sd->dPdv);
#endif
}
else {
/* motion triangle */
motion_triangle_shader_setup(kg, sd, isect, ray, true);
}
sd->flag |= kernel_tex_fetch(__shader_flag, (sd->shader & SHADER_MASK)*2);
#ifdef __INSTANCING__
if(isect->object != OBJECT_NONE) {
/* instance transform */
object_normal_transform(kg, sd, &sd->N);
object_normal_transform(kg, sd, &sd->Ng);
#ifdef __DPDU__
object_dir_transform(kg, sd, &sd->dPdu);
object_dir_transform(kg, sd, &sd->dPdv);
#endif
}
#endif
/* backfacing test */
if(backfacing) {
sd->flag |= SD_BACKFACING;
sd->Ng = -sd->Ng;
sd->N = -sd->N;
#ifdef __DPDU__
sd->dPdu = -sd->dPdu;
sd->dPdv = -sd->dPdv;
#endif
}
/* should not get used in principle as the shading will only use a diffuse
* BSDF, but the shader might still access it */
sd->I = sd->N;
#ifdef __RAY_DIFFERENTIALS__
/* differentials */
differential_dudv(&sd->du, &sd->dv, sd->dPdu, sd->dPdv, sd->dP, sd->Ng);
/* don't modify dP and dI */
#endif
}
#endif
/* ShaderData setup from position sampled on mesh */
ccl_device void shader_setup_from_sample(KernelGlobals *kg, ShaderData *sd,
const float3 P, const float3 Ng, const float3 I,
int shader, int object, int prim, float u, float v, float t, float time, int bounce, int transparent_bounce)
{
/* vectors */
sd->P = P;
sd->N = Ng;
sd->Ng = Ng;
sd->I = I;
sd->shader = shader;
sd->type = (prim == PRIM_NONE)? PRIMITIVE_NONE: PRIMITIVE_TRIANGLE;
/* primitive */
#ifdef __INSTANCING__
sd->object = object;
#endif
/* currently no access to bvh prim index for strand sd->prim*/
sd->prim = prim;
#ifdef __UV__
sd->u = u;
sd->v = v;
#endif
sd->ray_length = t;
sd->ray_depth = bounce;
sd->transparent_depth = transparent_bounce;
/* detect instancing, for non-instanced the object index is -object-1 */
#ifdef __INSTANCING__
bool instanced = false;
if(sd->prim != PRIM_NONE) {
if(sd->object >= 0)
instanced = true;
else
#endif
sd->object = ~sd->object;
#ifdef __INSTANCING__
}
#endif
sd->flag = kernel_tex_fetch(__shader_flag, (sd->shader & SHADER_MASK)*2);
if(sd->object != OBJECT_NONE) {
sd->flag |= kernel_tex_fetch(__object_flag, sd->object);
#ifdef __OBJECT_MOTION__
shader_setup_object_transforms(kg, sd, time);
}
sd->time = time;
#else
}
#endif
if(sd->type & PRIMITIVE_TRIANGLE) {
/* smooth normal */
if(sd->shader & SHADER_SMOOTH_NORMAL) {
sd->N = triangle_smooth_normal(kg, sd->prim, sd->u, sd->v);
#ifdef __INSTANCING__
if(instanced)
object_normal_transform(kg, sd, &sd->N);
#endif
}
/* dPdu/dPdv */
#ifdef __DPDU__
triangle_dPdudv(kg, sd->prim, &sd->dPdu, &sd->dPdv);
#ifdef __INSTANCING__
if(instanced) {
object_dir_transform(kg, sd, &sd->dPdu);
object_dir_transform(kg, sd, &sd->dPdv);
}
#endif
#endif
}
else {
#ifdef __DPDU__
sd->dPdu = make_float3(0.0f, 0.0f, 0.0f);
sd->dPdv = make_float3(0.0f, 0.0f, 0.0f);
#endif
}
/* backfacing test */
if(sd->prim != PRIM_NONE) {
bool backfacing = (dot(sd->Ng, sd->I) < 0.0f);
if(backfacing) {
sd->flag |= SD_BACKFACING;
sd->Ng = -sd->Ng;
sd->N = -sd->N;
#ifdef __DPDU__
sd->dPdu = -sd->dPdu;
sd->dPdv = -sd->dPdv;
#endif
}
}
#ifdef __RAY_DIFFERENTIALS__
/* no ray differentials here yet */
sd->dP = differential3_zero();
sd->dI = differential3_zero();
sd->du = differential_zero();
sd->dv = differential_zero();
#endif
}
/* ShaderData setup for displacement */
ccl_device void shader_setup_from_displace(KernelGlobals *kg, ShaderData *sd,
int object, int prim, float u, float v)
{
float3 P, Ng, I = make_float3(0.0f, 0.0f, 0.0f);
int shader;
triangle_point_normal(kg, prim, u, v, &P, &Ng, &shader);
/* force smooth shading for displacement */
shader |= SHADER_SMOOTH_NORMAL;
/* watch out: no instance transform currently */
shader_setup_from_sample(kg, sd, P, Ng, I, shader, object, prim, u, v, 0.0f, TIME_INVALID, 0, 0);
}
/* ShaderData setup from ray into background */
ccl_device_inline void shader_setup_from_background(KernelGlobals *kg, ShaderData *sd, const Ray *ray, int bounce, int transparent_bounce)
{
/* vectors */
sd->P = ray->D;
sd->N = -ray->D;
sd->Ng = -ray->D;
sd->I = -ray->D;
sd->shader = kernel_data.background.surface_shader;
sd->flag = kernel_tex_fetch(__shader_flag, (sd->shader & SHADER_MASK)*2);
#ifdef __OBJECT_MOTION__
sd->time = ray->time;
#endif
sd->ray_length = 0.0f;
sd->ray_depth = bounce;
sd->transparent_depth = transparent_bounce;
#ifdef __INSTANCING__
sd->object = PRIM_NONE;
#endif
sd->prim = PRIM_NONE;
#ifdef __UV__
sd->u = 0.0f;
sd->v = 0.0f;
#endif
#ifdef __DPDU__
/* dPdu/dPdv */
sd->dPdu = make_float3(0.0f, 0.0f, 0.0f);
sd->dPdv = make_float3(0.0f, 0.0f, 0.0f);
#endif
#ifdef __RAY_DIFFERENTIALS__
/* differentials */
sd->dP = ray->dD;
differential_incoming(&sd->dI, sd->dP);
sd->du.dx = 0.0f;
sd->du.dy = 0.0f;
sd->dv.dx = 0.0f;
sd->dv.dy = 0.0f;
#endif
}
/* ShaderData setup from point inside volume */
ccl_device_inline void shader_setup_from_volume(KernelGlobals *kg, ShaderData *sd, const Ray *ray, int bounce, int transparent_bounce)
{
/* vectors */
sd->P = ray->P;
sd->N = -ray->D;
sd->Ng = -ray->D;
sd->I = -ray->D;
sd->shader = SHADER_NONE;
sd->flag = 0;
#ifdef __OBJECT_MOTION__
sd->time = ray->time;
#endif
sd->ray_length = 0.0f; /* todo: can we set this to some useful value? */
sd->ray_depth = bounce;
sd->transparent_depth = transparent_bounce;
#ifdef __INSTANCING__
sd->object = PRIM_NONE; /* todo: fill this for texture coordinates */
#endif
sd->prim = PRIM_NONE;
sd->type = PRIMITIVE_NONE;
#ifdef __UV__
sd->u = 0.0f;
sd->v = 0.0f;
#endif
#ifdef __DPDU__
/* dPdu/dPdv */
sd->dPdu = make_float3(0.0f, 0.0f, 0.0f);
sd->dPdv = make_float3(0.0f, 0.0f, 0.0f);
#endif
#ifdef __RAY_DIFFERENTIALS__
/* differentials */
sd->dP = ray->dD;
differential_incoming(&sd->dI, sd->dP);
sd->du = differential_zero();
sd->dv = differential_zero();
#endif
/* for NDC coordinates */
sd->ray_P = ray->P;
sd->ray_dP = ray->dP;
}
/* Merging */
#if defined(__BRANCHED_PATH__) || defined(__VOLUME__)
ccl_device void shader_merge_closures(ShaderData *sd)
{
/* merge identical closures, better when we sample a single closure at a time */
for(int i = 0; i < sd->num_closure; i++) {
ShaderClosure *sci = &sd->closure[i];
for(int j = i + 1; j < sd->num_closure; j++) {
ShaderClosure *scj = &sd->closure[j];
#ifdef __OSL__
if(sci->prim || scj->prim)
continue;
#endif
if(!(sci->type == scj->type && sci->data0 == scj->data0 && sci->data1 == scj->data1))
continue;
if(CLOSURE_IS_BSDF_OR_BSSRDF(sci->type)) {
if(sci->N != scj->N)
continue;
else if(CLOSURE_IS_BSDF_ANISOTROPIC(sci->type) && sci->T != scj->T)
continue;
}
sci->weight += scj->weight;
sci->sample_weight += scj->sample_weight;
int size = sd->num_closure - (j+1);
if(size > 0) {
for(int k = 0; k < size; k++) {
scj[k] = scj[k+1];
}
}
sd->num_closure--;
j--;
}
}
}
#endif
/* BSDF */
ccl_device_inline void _shader_bsdf_multi_eval(KernelGlobals *kg, const ShaderData *sd, const float3 omega_in, float *pdf,
int skip_bsdf, 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)) {
float bsdf_pdf = 0.0f;
float3 eval = bsdf_eval(kg, sd, sc, omega_in, &bsdf_pdf);
if(bsdf_pdf != 0.0f) {
bsdf_eval_accum(result_eval, sc->type, eval*sc->weight);
sum_pdf += bsdf_pdf*sc->sample_weight;
}
sum_sample_weight += sc->sample_weight;
}
}
*pdf = (sum_sample_weight > 0.0f)? sum_pdf/sum_sample_weight: 0.0f;
}
ccl_device void shader_bsdf_eval(KernelGlobals *kg, const ShaderData *sd,
const float3 omega_in, BsdfEval *eval, float *pdf)
{
bsdf_eval_init(eval, NBUILTIN_CLOSURES, make_float3(0.0f, 0.0f, 0.0f), kernel_data.film.use_light_pass);
_shader_bsdf_multi_eval(kg, sd, omega_in, pdf, -1, eval, 0.0f, 0.0f);
}
ccl_device int shader_bsdf_sample(KernelGlobals *kg, const ShaderData *sd,
float randu, float randv, BsdfEval *bsdf_eval,
float3 *omega_in, 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 = &sd->closure[sampled];
int label;
float3 eval;
*pdf = 0.0f;
label = bsdf_sample(kg, sd, sc, randu, randv, &eval, omega_in, domega_in, pdf);
if(*pdf != 0.0f) {
bsdf_eval_init(bsdf_eval, sc->type, eval*sc->weight, kernel_data.film.use_light_pass);
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);
}
}
return label;
}
ccl_device int shader_bsdf_sample_closure(KernelGlobals *kg, const ShaderData *sd,
const ShaderClosure *sc, float randu, float randv, BsdfEval *bsdf_eval,
float3 *omega_in, differential3 *domega_in, float *pdf)
{
int label;
float3 eval;
*pdf = 0.0f;
label = bsdf_sample(kg, sd, sc, randu, randv, &eval, omega_in, domega_in, pdf);
if(*pdf != 0.0f)
bsdf_eval_init(bsdf_eval, sc->type, eval*sc->weight, kernel_data.film.use_light_pass);
return label;
}
ccl_device void shader_bsdf_blur(KernelGlobals *kg, ShaderData *sd, float roughness)
{
for(int i = 0; i< sd->num_closure; i++) {
ShaderClosure *sc = &sd->closure[i];
if(CLOSURE_IS_BSDF(sc->type))
bsdf_blur(kg, sc, roughness);
}
}
ccl_device float3 shader_bsdf_transparency(KernelGlobals *kg, ShaderData *sd)
{
if(sd->flag & SD_HAS_ONLY_VOLUME)
return make_float3(1.0f, 1.0f, 1.0f);
float3 eval = make_float3(0.0f, 0.0f, 0.0f);
for(int i = 0; i< sd->num_closure; i++) {
ShaderClosure *sc = &sd->closure[i];
if(sc->type == CLOSURE_BSDF_TRANSPARENT_ID) // todo: make this work for osl
eval += sc->weight;
}
return eval;
}
ccl_device float3 shader_bsdf_alpha(KernelGlobals *kg, ShaderData *sd)
{
float3 alpha = make_float3(1.0f, 1.0f, 1.0f) - shader_bsdf_transparency(kg, sd);
alpha = max(alpha, make_float3(0.0f, 0.0f, 0.0f));
alpha = min(alpha, make_float3(1.0f, 1.0f, 1.0f));
return alpha;
}
ccl_device float3 shader_bsdf_diffuse(KernelGlobals *kg, ShaderData *sd)
{
float3 eval = make_float3(0.0f, 0.0f, 0.0f);
for(int i = 0; i< sd->num_closure; i++) {
ShaderClosure *sc = &sd->closure[i];
if(CLOSURE_IS_BSDF_DIFFUSE(sc->type))
eval += sc->weight;
}
return eval;
}
ccl_device float3 shader_bsdf_glossy(KernelGlobals *kg, ShaderData *sd)
{
float3 eval = make_float3(0.0f, 0.0f, 0.0f);
for(int i = 0; i< sd->num_closure; i++) {
ShaderClosure *sc = &sd->closure[i];
if(CLOSURE_IS_BSDF_GLOSSY(sc->type))
eval += sc->weight;
}
return eval;
}
ccl_device float3 shader_bsdf_transmission(KernelGlobals *kg, ShaderData *sd)
{
float3 eval = make_float3(0.0f, 0.0f, 0.0f);
for(int i = 0; i< sd->num_closure; i++) {
ShaderClosure *sc = &sd->closure[i];
if(CLOSURE_IS_BSDF_TRANSMISSION(sc->type))
eval += sc->weight;
}
return eval;
}
ccl_device float3 shader_bsdf_subsurface(KernelGlobals *kg, ShaderData *sd)
{
float3 eval = make_float3(0.0f, 0.0f, 0.0f);
for(int i = 0; i< sd->num_closure; i++) {
ShaderClosure *sc = &sd->closure[i];
if(CLOSURE_IS_BSSRDF(sc->type))
eval += sc->weight;
}
return eval;
}
ccl_device float3 shader_bsdf_ao(KernelGlobals *kg, ShaderData *sd, float ao_factor, float3 *N_)
{
float3 eval = make_float3(0.0f, 0.0f, 0.0f);
float3 N = make_float3(0.0f, 0.0f, 0.0f);
for(int i = 0; i< sd->num_closure; i++) {
ShaderClosure *sc = &sd->closure[i];
if(CLOSURE_IS_BSDF_DIFFUSE(sc->type)) {
eval += sc->weight*ao_factor;
N += sc->N*average(sc->weight);
}
else if(CLOSURE_IS_AMBIENT_OCCLUSION(sc->type)) {
eval += sc->weight;
N += sd->N*average(sc->weight);
}
}
if(is_zero(N))
N = sd->N;
else
N = normalize(N);
*N_ = N;
return eval;
}
ccl_device float3 shader_bssrdf_sum(ShaderData *sd, float3 *N_, float *texture_blur_)
{
float3 eval = make_float3(0.0f, 0.0f, 0.0f);
float3 N = make_float3(0.0f, 0.0f, 0.0f);
float texture_blur = 0.0f, weight_sum = 0.0f;
for(int i = 0; i< sd->num_closure; i++) {
ShaderClosure *sc = &sd->closure[i];
if(CLOSURE_IS_BSSRDF(sc->type)) {
float avg_weight = fabsf(average(sc->weight));
N += sc->N*avg_weight;
eval += sc->weight;
texture_blur += sc->data1*avg_weight;
weight_sum += avg_weight;
}
}
if(N_)
*N_ = (is_zero(N))? sd->N: normalize(N);
if(texture_blur_)
*texture_blur_ = texture_blur/weight_sum;
return eval;
}
/* Emission */
ccl_device float3 emissive_eval(KernelGlobals *kg, ShaderData *sd, ShaderClosure *sc)
{
return emissive_simple_eval(sd->Ng, sd->I);
}
ccl_device float3 shader_emissive_eval(KernelGlobals *kg, ShaderData *sd)
{
float3 eval;
eval = make_float3(0.0f, 0.0f, 0.0f);
for(int i = 0; i < sd->num_closure; i++) {
ShaderClosure *sc = &sd->closure[i];
if(CLOSURE_IS_EMISSION(sc->type))
eval += emissive_eval(kg, sd, sc)*sc->weight;
}
return eval;
}
/* Holdout */
ccl_device float3 shader_holdout_eval(KernelGlobals *kg, ShaderData *sd)
{
float3 weight = make_float3(0.0f, 0.0f, 0.0f);
for(int i = 0; i < sd->num_closure; i++) {
ShaderClosure *sc = &sd->closure[i];
if(CLOSURE_IS_HOLDOUT(sc->type))
weight += sc->weight;
}
return weight;
}
/* Surface Evaluation */
ccl_device void shader_eval_surface(KernelGlobals *kg, ShaderData *sd,
float randb, int path_flag, ShaderContext ctx)
{
sd->num_closure = 0;
sd->randb_closure = randb;
#ifdef __OSL__
if(kg->osl)
OSLShader::eval_surface(kg, sd, path_flag, ctx);
else
#endif
{
#ifdef __SVM__
svm_eval_nodes(kg, sd, SHADER_TYPE_SURFACE, path_flag);
#else
sd->closure.weight = make_float3(0.8f, 0.8f, 0.8f);
sd->closure.N = sd->N;
sd->flag |= bsdf_diffuse_setup(&sd->closure);
#endif
}
}
/* Background Evaluation */
ccl_device float3 shader_eval_background(KernelGlobals *kg, ShaderData *sd, int path_flag, ShaderContext ctx)
{
sd->num_closure = 0;
sd->randb_closure = 0.0f;
#ifdef __OSL__
if(kg->osl) {
return OSLShader::eval_background(kg, sd, path_flag, ctx);
}
else
#endif
{
#ifdef __SVM__
svm_eval_nodes(kg, sd, SHADER_TYPE_SURFACE, path_flag);
float3 eval = make_float3(0.0f, 0.0f, 0.0f);
for(int i = 0; i< sd->num_closure; i++) {
const ShaderClosure *sc = &sd->closure[i];
if(CLOSURE_IS_BACKGROUND(sc->type))
eval += sc->weight;
}
return eval;
#else
return make_float3(0.8f, 0.8f, 0.8f);
#endif
}
}
/* Volume */
#ifdef __VOLUME__
ccl_device_inline void _shader_volume_phase_multi_eval(const ShaderData *sd, const float3 omega_in, float *pdf,
int skip_phase, BsdfEval *result_eval, float sum_pdf, float sum_sample_weight)
{
for(int i = 0; i< sd->num_closure; i++) {
if(i == skip_phase)
continue;
const ShaderClosure *sc = &sd->closure[i];
if(CLOSURE_IS_PHASE(sc->type)) {
float phase_pdf = 0.0f;
float3 eval = volume_phase_eval(sd, sc, omega_in, &phase_pdf);
if(phase_pdf != 0.0f) {
bsdf_eval_accum(result_eval, sc->type, eval);
sum_pdf += phase_pdf*sc->sample_weight;
}
sum_sample_weight += sc->sample_weight;
}
}
*pdf = (sum_sample_weight > 0.0f)? sum_pdf/sum_sample_weight: 0.0f;
}
ccl_device void shader_volume_phase_eval(KernelGlobals *kg, const ShaderData *sd,
const float3 omega_in, BsdfEval *eval, float *pdf)
{
bsdf_eval_init(eval, NBUILTIN_CLOSURES, make_float3(0.0f, 0.0f, 0.0f), kernel_data.film.use_light_pass);
_shader_volume_phase_multi_eval(sd, omega_in, pdf, -1, eval, 0.0f, 0.0f);
}
ccl_device int shader_volume_phase_sample(KernelGlobals *kg, const ShaderData *sd,
float randu, float randv, BsdfEval *phase_eval,
float3 *omega_in, differential3 *domega_in, float *pdf)
{
int sampled = 0;
if(sd->num_closure > 1) {
/* pick a phase 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_PHASE(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_PHASE(sc->type)) {
sum += sc->sample_weight;
if(r <= sum)
break;
}
}
if(sampled == sd->num_closure) {
*pdf = 0.0f;
return LABEL_NONE;
}
}
/* todo: this isn't quite correct, we don't weight anisotropy properly
* depending on color channels, even if this is perhaps not a common case */
const ShaderClosure *sc = &sd->closure[sampled];
int label;
float3 eval;
*pdf = 0.0f;
label = volume_phase_sample(sd, sc, randu, randv, &eval, omega_in, domega_in, pdf);
if(*pdf != 0.0f) {
bsdf_eval_init(phase_eval, sc->type, eval, kernel_data.film.use_light_pass);
}
return label;
}
ccl_device int shader_phase_sample_closure(KernelGlobals *kg, const ShaderData *sd,
const ShaderClosure *sc, float randu, float randv, BsdfEval *phase_eval,
float3 *omega_in, differential3 *domega_in, float *pdf)
{
int label;
float3 eval;
*pdf = 0.0f;
label = volume_phase_sample(sd, sc, randu, randv, &eval, omega_in, domega_in, pdf);
if(*pdf != 0.0f)
bsdf_eval_init(phase_eval, sc->type, eval, kernel_data.film.use_light_pass);
return label;
}
/* Volume Evaluation */
ccl_device void shader_eval_volume(KernelGlobals *kg, ShaderData *sd,
VolumeStack *stack, int path_flag, ShaderContext ctx)
{
/* reset closures once at the start, we will be accumulating the closures
* for all volumes in the stack into a single array of closures */
sd->num_closure = 0;
sd->flag = 0;
for(int i = 0; stack[i].shader != SHADER_NONE; i++) {
/* setup shaderdata from stack. it's mostly setup already in
* shader_setup_from_volume, this switching should be quick */
sd->object = stack[i].object;
sd->shader = stack[i].shader;
sd->flag &= ~(SD_SHADER_FLAGS|SD_OBJECT_FLAGS);
sd->flag |= kernel_tex_fetch(__shader_flag, (sd->shader & SHADER_MASK)*2);
if(sd->object != OBJECT_NONE) {
sd->flag |= kernel_tex_fetch(__object_flag, sd->object);
#ifdef __OBJECT_MOTION__
/* todo: this is inefficient for motion blur, we should be
* caching matrices instead of recomputing them each step */
shader_setup_object_transforms(kg, sd, sd->time);
#endif
}
/* evaluate shader */
#ifdef __SVM__
#ifdef __OSL__
if(kg->osl) {
OSLShader::eval_volume(kg, sd, path_flag, ctx);
}
else
#endif
{
svm_eval_nodes(kg, sd, SHADER_TYPE_VOLUME, path_flag);
}
#endif
/* merge closures to avoid exceeding number of closures limit */
if(i > 0)
shader_merge_closures(sd);
}
}
#endif
/* Displacement Evaluation */
ccl_device void shader_eval_displacement(KernelGlobals *kg, ShaderData *sd, ShaderContext ctx)
{
sd->num_closure = 0;
sd->randb_closure = 0.0f;
/* this will modify sd->P */
#ifdef __SVM__
#ifdef __OSL__
if(kg->osl)
OSLShader::eval_displacement(kg, sd, ctx);
else
#endif
{
svm_eval_nodes(kg, sd, SHADER_TYPE_DISPLACEMENT, 0);
}
#endif
}
/* Transparent Shadows */
#ifdef __TRANSPARENT_SHADOWS__
ccl_device bool shader_transparent_shadow(KernelGlobals *kg, Intersection *isect)
{
int prim = kernel_tex_fetch(__prim_index, isect->prim);
int shader = 0;
#ifdef __HAIR__
if(kernel_tex_fetch(__prim_type, isect->prim) & PRIMITIVE_ALL_TRIANGLE) {
#endif
shader = __float_as_int(kernel_tex_fetch(__tri_shader, prim));
#ifdef __HAIR__
}
else {
float4 str = kernel_tex_fetch(__curves, prim);
shader = __float_as_int(str.z);
}
#endif
int flag = kernel_tex_fetch(__shader_flag, (shader & SHADER_MASK)*2);
return (flag & SD_HAS_TRANSPARENT_SHADOW) != 0;
}
#endif
CCL_NAMESPACE_END