forked from bartvdbraak/blender
c8a041f489
Multiple importance sampling for branched path tracing light samples needs to be calculated separately per BSDF, not with Veach's one sample model.
311 lines
9.0 KiB
C
311 lines
9.0 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.
|
|
*/
|
|
|
|
CCL_NAMESPACE_BEGIN
|
|
|
|
/* Direction Emission */
|
|
ccl_device_noinline float3 direct_emissive_eval(KernelGlobals *kg,
|
|
LightSample *ls, float3 I, differential3 dI, float t, float time, int bounce, int transparent_bounce
|
|
#ifdef __SPLIT_KERNEL__
|
|
,ShaderData *sd_input
|
|
#endif
|
|
)
|
|
{
|
|
/* setup shading at emitter */
|
|
#ifdef __SPLIT_KERNEL__
|
|
ShaderData *sd = sd_input;
|
|
#else
|
|
ShaderData sd_object;
|
|
ShaderData *sd = &sd_object;
|
|
#endif
|
|
float3 eval;
|
|
|
|
#ifdef __BACKGROUND_MIS__
|
|
if(ls->type == LIGHT_BACKGROUND) {
|
|
Ray ray;
|
|
ray.D = ls->D;
|
|
ray.P = ls->P;
|
|
ray.t = 1.0f;
|
|
#ifdef __OBJECT_MOTION__
|
|
ray.time = time;
|
|
#endif
|
|
ray.dP = differential3_zero();
|
|
ray.dD = dI;
|
|
|
|
shader_setup_from_background(kg, sd, &ray, bounce+1, transparent_bounce);
|
|
eval = shader_eval_background(kg, sd, 0, SHADER_CONTEXT_EMISSION);
|
|
}
|
|
else
|
|
#endif
|
|
{
|
|
shader_setup_from_sample(kg, sd, ls->P, ls->Ng, I, ls->shader, ls->object, ls->prim, ls->u, ls->v, t, time, bounce+1, transparent_bounce);
|
|
|
|
ls->Ng = ccl_fetch(sd, Ng);
|
|
|
|
/* no path flag, we're evaluating this for all closures. that's weak but
|
|
* we'd have to do multiple evaluations otherwise */
|
|
shader_eval_surface(kg, sd, 0.0f, 0, SHADER_CONTEXT_EMISSION);
|
|
|
|
/* evaluate emissive closure */
|
|
if(ccl_fetch(sd, flag) & SD_EMISSION)
|
|
eval = shader_emissive_eval(kg, sd);
|
|
else
|
|
eval = make_float3(0.0f, 0.0f, 0.0f);
|
|
}
|
|
|
|
eval *= ls->eval_fac;
|
|
|
|
return eval;
|
|
}
|
|
|
|
ccl_device_noinline bool direct_emission(KernelGlobals *kg, ShaderData *sd,
|
|
LightSample *ls, Ray *ray, BsdfEval *eval, bool *is_lamp,
|
|
int bounce, int transparent_bounce
|
|
#ifdef __SPLIT_KERNEL__
|
|
, ShaderData *sd_DL
|
|
#endif
|
|
)
|
|
{
|
|
if(ls->pdf == 0.0f)
|
|
return false;
|
|
|
|
/* todo: implement */
|
|
differential3 dD = differential3_zero();
|
|
|
|
/* evaluate closure */
|
|
|
|
float3 light_eval = direct_emissive_eval(kg, ls, -ls->D, dD, ls->t, ccl_fetch(sd, time),
|
|
bounce,
|
|
transparent_bounce
|
|
#ifdef __SPLIT_KERNEL__
|
|
,sd_DL
|
|
#endif
|
|
);
|
|
|
|
if(is_zero(light_eval))
|
|
return false;
|
|
|
|
/* evaluate BSDF at shading point */
|
|
|
|
#ifdef __VOLUME__
|
|
if(ccl_fetch(sd, prim) != PRIM_NONE)
|
|
shader_bsdf_eval(kg, sd, ls->D, eval, ls->pdf, ls->shader & SHADER_USE_MIS);
|
|
else {
|
|
float bsdf_pdf;
|
|
shader_volume_phase_eval(kg, sd, ls->D, eval, &bsdf_pdf);
|
|
if(ls->shader & SHADER_USE_MIS) {
|
|
/* Multiple importance sampling. */
|
|
float mis_weight = power_heuristic(ls->pdf, bsdf_pdf);
|
|
light_eval *= mis_weight;
|
|
}
|
|
}
|
|
#else
|
|
shader_bsdf_eval(kg, sd, ls->D, eval, ls->pdf, ls->shader & SHADER_USE_MIS);
|
|
#endif
|
|
|
|
bsdf_eval_mul(eval, light_eval/ls->pdf);
|
|
|
|
#ifdef __PASSES__
|
|
/* use visibility flag to skip lights */
|
|
if(ls->shader & SHADER_EXCLUDE_ANY) {
|
|
if(ls->shader & SHADER_EXCLUDE_DIFFUSE)
|
|
eval->diffuse = make_float3(0.0f, 0.0f, 0.0f);
|
|
if(ls->shader & SHADER_EXCLUDE_GLOSSY)
|
|
eval->glossy = make_float3(0.0f, 0.0f, 0.0f);
|
|
if(ls->shader & SHADER_EXCLUDE_TRANSMIT)
|
|
eval->transmission = make_float3(0.0f, 0.0f, 0.0f);
|
|
if(ls->shader & SHADER_EXCLUDE_SCATTER)
|
|
eval->scatter = make_float3(0.0f, 0.0f, 0.0f);
|
|
}
|
|
#endif
|
|
|
|
if(bsdf_eval_is_zero(eval))
|
|
return false;
|
|
|
|
if(ls->shader & SHADER_CAST_SHADOW) {
|
|
/* setup ray */
|
|
bool transmit = (dot(ccl_fetch(sd, Ng), ls->D) < 0.0f);
|
|
ray->P = ray_offset(ccl_fetch(sd, P), (transmit)? -ccl_fetch(sd, Ng): ccl_fetch(sd, Ng));
|
|
|
|
if(ls->t == FLT_MAX) {
|
|
/* distant light */
|
|
ray->D = ls->D;
|
|
ray->t = ls->t;
|
|
}
|
|
else {
|
|
/* other lights, avoid self-intersection */
|
|
ray->D = ray_offset(ls->P, ls->Ng) - ray->P;
|
|
ray->D = normalize_len(ray->D, &ray->t);
|
|
}
|
|
|
|
ray->dP = ccl_fetch(sd, dP);
|
|
ray->dD = differential3_zero();
|
|
}
|
|
else {
|
|
/* signal to not cast shadow ray */
|
|
ray->t = 0.0f;
|
|
}
|
|
|
|
/* return if it's a lamp for shadow pass */
|
|
*is_lamp = (ls->prim == PRIM_NONE && ls->type != LIGHT_BACKGROUND);
|
|
|
|
return true;
|
|
}
|
|
|
|
/* Indirect Primitive Emission */
|
|
|
|
ccl_device_noinline float3 indirect_primitive_emission(KernelGlobals *kg, ShaderData *sd, float t, int path_flag, float bsdf_pdf)
|
|
{
|
|
/* evaluate emissive closure */
|
|
float3 L = shader_emissive_eval(kg, sd);
|
|
|
|
#ifdef __HAIR__
|
|
if(!(path_flag & PATH_RAY_MIS_SKIP) && (ccl_fetch(sd, flag) & SD_USE_MIS) && (ccl_fetch(sd, type) & PRIMITIVE_ALL_TRIANGLE))
|
|
#else
|
|
if(!(path_flag & PATH_RAY_MIS_SKIP) && (ccl_fetch(sd, flag) & SD_USE_MIS))
|
|
#endif
|
|
{
|
|
/* multiple importance sampling, get triangle light pdf,
|
|
* and compute weight with respect to BSDF pdf */
|
|
float pdf = triangle_light_pdf(kg, ccl_fetch(sd, Ng), ccl_fetch(sd, I), t);
|
|
float mis_weight = power_heuristic(bsdf_pdf, pdf);
|
|
|
|
return L*mis_weight;
|
|
}
|
|
|
|
return L;
|
|
}
|
|
|
|
/* Indirect Lamp Emission */
|
|
|
|
ccl_device_noinline bool indirect_lamp_emission(KernelGlobals *kg, PathState *state, Ray *ray, float3 *emission
|
|
#ifdef __SPLIT_KERNEL__
|
|
,ShaderData *sd
|
|
#endif
|
|
)
|
|
{
|
|
bool hit_lamp = false;
|
|
|
|
*emission = make_float3(0.0f, 0.0f, 0.0f);
|
|
|
|
for(int lamp = 0; lamp < kernel_data.integrator.num_all_lights; lamp++) {
|
|
LightSample ls;
|
|
|
|
if(!lamp_light_eval(kg, lamp, ray->P, ray->D, ray->t, &ls))
|
|
continue;
|
|
|
|
#ifdef __PASSES__
|
|
/* use visibility flag to skip lights */
|
|
if(ls.shader & SHADER_EXCLUDE_ANY) {
|
|
if(((ls.shader & SHADER_EXCLUDE_DIFFUSE) && (state->flag & PATH_RAY_DIFFUSE)) ||
|
|
((ls.shader & SHADER_EXCLUDE_GLOSSY) &&
|
|
((state->flag & (PATH_RAY_GLOSSY|PATH_RAY_REFLECT)) == (PATH_RAY_GLOSSY|PATH_RAY_REFLECT))) ||
|
|
((ls.shader & SHADER_EXCLUDE_TRANSMIT) && (state->flag & PATH_RAY_TRANSMIT)) ||
|
|
((ls.shader & SHADER_EXCLUDE_SCATTER) && (state->flag & PATH_RAY_VOLUME_SCATTER)))
|
|
continue;
|
|
}
|
|
#endif
|
|
|
|
float3 L = direct_emissive_eval(kg, &ls, -ray->D, ray->dD, ls.t, ray->time,
|
|
state->bounce,
|
|
state->transparent_bounce
|
|
#ifdef __SPLIT_KERNEL__
|
|
,sd
|
|
#endif
|
|
);
|
|
|
|
#ifdef __VOLUME__
|
|
if(state->volume_stack[0].shader != SHADER_NONE) {
|
|
/* shadow attenuation */
|
|
Ray volume_ray = *ray;
|
|
volume_ray.t = ls.t;
|
|
float3 volume_tp = make_float3(1.0f, 1.0f, 1.0f);
|
|
kernel_volume_shadow(kg, state, &volume_ray, &volume_tp);
|
|
L *= volume_tp;
|
|
}
|
|
#endif
|
|
|
|
if(!(state->flag & PATH_RAY_MIS_SKIP)) {
|
|
/* multiple importance sampling, get regular light pdf,
|
|
* and compute weight with respect to BSDF pdf */
|
|
float mis_weight = power_heuristic(state->ray_pdf, ls.pdf);
|
|
L *= mis_weight;
|
|
}
|
|
|
|
*emission += L;
|
|
hit_lamp = true;
|
|
}
|
|
|
|
return hit_lamp;
|
|
}
|
|
|
|
/* Indirect Background */
|
|
|
|
ccl_device_noinline float3 indirect_background(KernelGlobals *kg, ccl_addr_space PathState *state, ccl_addr_space Ray *ray
|
|
#ifdef __SPLIT_KERNEL__
|
|
,ShaderData *sd_global
|
|
#endif
|
|
)
|
|
{
|
|
#ifdef __BACKGROUND__
|
|
int shader = kernel_data.background.surface_shader;
|
|
|
|
/* use visibility flag to skip lights */
|
|
if(shader & SHADER_EXCLUDE_ANY) {
|
|
if(((shader & SHADER_EXCLUDE_DIFFUSE) && (state->flag & PATH_RAY_DIFFUSE)) ||
|
|
((shader & SHADER_EXCLUDE_GLOSSY) &&
|
|
((state->flag & (PATH_RAY_GLOSSY|PATH_RAY_REFLECT)) == (PATH_RAY_GLOSSY|PATH_RAY_REFLECT))) ||
|
|
((shader & SHADER_EXCLUDE_TRANSMIT) && (state->flag & PATH_RAY_TRANSMIT)) ||
|
|
((shader & SHADER_EXCLUDE_CAMERA) && (state->flag & PATH_RAY_CAMERA)) ||
|
|
((shader & SHADER_EXCLUDE_SCATTER) && (state->flag & PATH_RAY_VOLUME_SCATTER)))
|
|
return make_float3(0.0f, 0.0f, 0.0f);
|
|
}
|
|
|
|
#ifdef __SPLIT_KERNEL__
|
|
/* evaluate background closure */
|
|
Ray priv_ray = *ray;
|
|
shader_setup_from_background(kg, sd_global, &priv_ray, state->bounce+1, state->transparent_bounce);
|
|
float3 L = shader_eval_background(kg, sd_global, state->flag, SHADER_CONTEXT_EMISSION);
|
|
#else
|
|
ShaderData sd;
|
|
shader_setup_from_background(kg, &sd, ray, state->bounce+1, state->transparent_bounce);
|
|
|
|
float3 L = shader_eval_background(kg, &sd, state->flag, SHADER_CONTEXT_EMISSION);
|
|
#endif
|
|
|
|
#ifdef __BACKGROUND_MIS__
|
|
/* check if background light exists or if we should skip pdf */
|
|
int res = kernel_data.integrator.pdf_background_res;
|
|
|
|
if(!(state->flag & PATH_RAY_MIS_SKIP) && res) {
|
|
/* multiple importance sampling, get background light pdf for ray
|
|
* direction, and compute weight with respect to BSDF pdf */
|
|
float pdf = background_light_pdf(kg, ray->P, ray->D);
|
|
float mis_weight = power_heuristic(state->ray_pdf, pdf);
|
|
|
|
return L*mis_weight;
|
|
}
|
|
#endif
|
|
|
|
return L;
|
|
#else
|
|
return make_float3(0.8f, 0.8f, 0.8f);
|
|
#endif
|
|
}
|
|
|
|
CCL_NAMESPACE_END
|
|
|