blender/intern/cycles/kernel/kernel_emission.h
Brecht Van Lommel 4ba456d175 Cycles: first step for implementation of non-progressive sampler that handles
direct and indirect lighting differently. Rather than picking one light for each
point on the path, it now loops over all lights for direct lighting. For indirect
lighting it still picks a random light each time.

It gives control over the number of AA samples, and the number of Diffuse, Glossy,
Transmission, AO, Mesh Light, Background and Lamp samples for each AA sample.

This helps tuning render performance/noise and tends to give less noise for renders
dominated by direct lighting.

This sampling mode only works on the CPU, and still needs proper tile rendering
to show progress (will follow tommorrow or so), because each AA sample can be quite
slow now and so the delay between each update wil be too long.
2012-06-13 11:44:48 +00:00

191 lines
4.8 KiB
C

/*
* Copyright 2011, Blender Foundation.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
CCL_NAMESPACE_BEGIN
/* Direction Emission */
__device float3 direct_emissive_eval(KernelGlobals *kg, float rando,
LightSample *ls, float u, float v, float3 I, float t, float time)
{
/* setup shading at emitter */
ShaderData sd;
float3 eval;
#ifdef __BACKGROUND_MIS__
if(ls->type == LIGHT_BACKGROUND) {
Ray ray;
ray.D = ls->D;
ray.P = ls->P;
ray.dP.dx = make_float3(0.0f, 0.0f, 0.0f);
ray.dP.dy = make_float3(0.0f, 0.0f, 0.0f);
shader_setup_from_background(kg, &sd, &ray);
eval = shader_eval_background(kg, &sd, 0);
}
else
#endif
{
shader_setup_from_sample(kg, &sd, ls->P, ls->Ng, I, ls->shader, ls->object, ls->prim, u, v, t, time);
ls->Ng = 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, rando, 0);
/* evaluate emissive closure */
if(sd.flag & SD_EMISSION)
eval = shader_emissive_eval(kg, &sd);
else
eval = make_float3(0.0f, 0.0f, 0.0f);
}
shader_release(kg, &sd);
return eval;
}
__device bool direct_emission(KernelGlobals *kg, ShaderData *sd, int lindex,
float randt, float rando, float randu, float randv, Ray *ray, BsdfEval *eval,
bool *is_lamp)
{
LightSample ls;
float pdf = -1.0f;
#ifdef __NON_PROGRESSIVE__
if(lindex != -1) {
/* sample position on a specified light */
light_select(kg, lindex, randu, randv, sd->P, &ls, &pdf);
}
else
#endif
{
/* sample a light and position on int */
light_sample(kg, randt, randu, randv, sd->time, sd->P, &ls, &pdf);
}
/* compute pdf */
if(pdf < 0.0f)
pdf = light_sample_pdf(kg, &ls, -ls.D, ls.t);
if(pdf == 0.0f)
return false;
/* evaluate closure */
float3 light_eval = direct_emissive_eval(kg, rando, &ls, randu, randv, -ls.D, ls.t, sd->time);
if(is_zero(light_eval))
return false;
/* todo: use visbility flag to skip lights */
/* evaluate BSDF at shading point */
float bsdf_pdf;
shader_bsdf_eval(kg, sd, ls.D, eval, &bsdf_pdf);
if(ls.prim != ~0 || ls.type == LIGHT_BACKGROUND) {
/* multiple importance sampling */
float mis_weight = power_heuristic(pdf, bsdf_pdf);
light_eval *= mis_weight;
}
bsdf_eval_mul(eval, light_eval*(ls.eval_fac/pdf));
if(bsdf_eval_is_zero(eval))
return false;
if(ls.shader & SHADER_CAST_SHADOW) {
/* setup ray */
bool transmit = (dot(sd->Ng, ls.D) < 0.0f);
ray->P = ray_offset(sd->P, (transmit)? -sd->Ng: 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);
}
}
else {
/* signal to not cast shadow ray */
ray->t = 0.0f;
}
*is_lamp = (ls.prim == ~0);
return true;
}
/* Indirect Emission */
__device float3 indirect_emission(KernelGlobals *kg, ShaderData *sd, float t, int path_flag, float bsdf_pdf)
{
/* evaluate emissive closure */
float3 L = shader_emissive_eval(kg, sd);
if(!(path_flag & PATH_RAY_MIS_SKIP) && (sd->flag & SD_SAMPLE_AS_LIGHT)) {
/* multiple importance sampling, get triangle light pdf,
* and compute weight with respect to BSDF pdf */
float pdf = triangle_light_pdf(kg, sd->Ng, sd->I, t);
float mis_weight = power_heuristic(bsdf_pdf, pdf);
return L*mis_weight;
}
return L;
}
/* Indirect Background */
__device float3 indirect_background(KernelGlobals *kg, Ray *ray, int path_flag, float bsdf_pdf)
{
#ifdef __BACKGROUND__
/* evaluate background closure */
ShaderData sd;
shader_setup_from_background(kg, &sd, ray);
float3 L = shader_eval_background(kg, &sd, path_flag);
shader_release(kg, &sd);
#ifdef __BACKGROUND_MIS__
/* check if background light exists or if we should skip pdf */
int res = kernel_data.integrator.pdf_background_res;
if(!(path_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->D);
float mis_weight = power_heuristic(bsdf_pdf, pdf);
return L*mis_weight;
}
#endif
return L;
#else
return make_float3(0.8f, 0.8f, 0.8f);
#endif
}
CCL_NAMESPACE_END