Color RayTracer::TraceSpecularTransmit(const Scene *scene, const Ray& ray, const LocalGeo& geom, int depth, const CameraSample& samplebuf){
Vec3 wo = -ray.dir, wi;
float pdf;
Color color;
Color f = geom.bsdf->SampleDirect(wo, geom, Sample(), &wi, &pdf, BSDFType(BSDF_TRANSMISSION | BSDF_SPECULAR));
float absdot_wi_n = Math::AbsDot(wi, geom.normal);
if (pdf > 0.f && f != Color::BLACK && absdot_wi_n != 0.f){
Ray refracted(geom.point, wi);
//TODO differential
color = f * Li(scene, refracted, depth, samplebuf) * absdot_wi_n / pdf;
}
return color;
}
Color RayTracer::EstimateDirect(const Scene *scene, const Ray& ray, const LocalGeo& geom, const Light *light, const Sample *lightsample, const Sample *bsdfsample){
Vec3 wo = -ray.dir; // dir to camera
Ray lightray;
float light_pdf, bsdf_pdf;
Color color, lightcolor, surfacecolor;
// sample light sources with multiple importance sampling
light->SampleDirect(geom.point, lightsample, &lightray, &lightcolor, &light_pdf);
if (light_pdf > 0.f && lightcolor != Color::BLACK){
surfacecolor = geom.bsdf->Eval(lightray.dir, wo, geom, BSDFType(BSDF_ALL & ~BSDF_SPECULAR));
if (surfacecolor != Color::BLACK && !scene->Occlude(lightray)){
if (light->IsDelta())
color = surfacecolor * lightcolor * (Math::AbsDot(lightray.dir, geom.normal));
else{
bsdf_pdf = geom.bsdf->Pdf(wo, lightray.dir, geom);
color = surfacecolor * lightcolor * (Math::AbsDot(lightray.dir, geom.normal) / light_pdf * PowerHeuristic(1, light_pdf, 1, bsdf_pdf));
}
}
}
if (light->IsDelta())
return color;
// sample bsdf with multiple importance sampling
surfacecolor = geom.bsdf->SampleDirect(wo, geom, *bsdfsample, &(lightray.dir), &bsdf_pdf, BSDFType(BSDF_ALL & ~BSDF_SPECULAR));
if (bsdf_pdf > 0.f && surfacecolor != Color::BLACK){
lightcolor = Color::BLACK;
LocalGeo geom_light;
if (scene->Intersect(lightray, geom_light)){
if (light == geom_light.prim->GetAreaLight()){
scene->PostIntersect(lightray, geom_light);
light_pdf = geom_light.prim->Pdf(geom_light.triId, geom.point, lightray.dir);
geom_light.Emit(-lightray.dir, &lightcolor);
}
}
//else
// light->Emit(lightray, &lightcolor);
if (lightcolor != Color::BLACK){
color += surfacecolor * lightcolor * (Math::AbsDot(lightray.dir, geom.normal) / bsdf_pdf * PowerHeuristic(1, bsdf_pdf, 1, light_pdf));
}
}
return color;
}
void PhotonMap::ShootCausticsPhoton(const Vector &dir, const Vector &pi, const Color &color, Shape *shape, int depth)
{
if ( depth >= confPhotonCausticsMaximumDepth ) return;
if ( depth != 0 && shape->mMaterial->MatchesBSDFFlags(BSDF_DIFFUSE) ) {
// Diffuse material, add photon
Photon *photon = new Photon(color, dir);
AddPhoton(causticsMap, pi, photon);
} else if ( shape->mMaterial->MatchesBSDFFlags(BSDF_SPECULAR) ) {
// Specular material, continue build photon
Vector N = shape->GetNormal(pi);
for ( uint32_t i = 0; i < shape->mMaterial->BSDFs.size(); i++ ) {
BSDF *bsdf = shape->mMaterial->BSDFs[i];
if ( !bsdf->MatchesFlags(BSDFType(BSDF_SPECULAR)) ) continue;
Vector newDir;
Color matColor;
Vector *vos = NULL;
int voNum = 0;
if ( bsdf->G(-dir, vos, voNum, N, matColor, 1.f) ) {
_ASSERT(voNum > 0);
newDir = vos[0];
delete [] vos;
vos = NULL;
matColor *= shape->GetColor(pi);
if ( matColor.IsBlack() ) continue;
float dist = MAXDISTANCE;
Shape *newShape;
Vector norm = N.Dot(dir) > 0 ? -N : N;
if ( bsdf->MatchesFlags(BSDF_TRANSMISSION) ) norm = -norm;
if ( scene->FindNearest(Ray(pi + norm * EPSILON, newDir), dist, newShape) == IR_MISS )
continue;
ShootCausticsPhoton(newDir, pi + newDir * dist, color * matColor, newShape, depth + 1);
}
}
}
}
