Spectrum sample(BSDFSamplingRecord &bRec, Float &pdf, const Point2 &sample) const {
const Intersection& its = bRec.its;
Intersection perturbed(its);
perturbed.shFrame = getFrame(its);
BSDFSamplingRecord perturbedQuery(perturbed, bRec.sampler, bRec.mode);
perturbedQuery.wi = perturbed.toLocal(its.toWorld(bRec.wi));
perturbedQuery.typeMask = bRec.typeMask;
perturbedQuery.component = bRec.component;
Float temporaryPdf = (Float)0;
Spectrum result = m_nested->sample(perturbedQuery, temporaryPdf, sample);
if (temporaryPdf > 0) {
bRec.sampledComponent = perturbedQuery.sampledComponent;
bRec.sampledType = perturbedQuery.sampledType;
bRec.wo = its.toLocal(perturbed.toWorld(perturbedQuery.wo));
bRec.eta = perturbedQuery.eta;
if (Frame::cosTheta(bRec.wo) * Frame::cosTheta(perturbedQuery.wo) <= 0)
return Spectrum(0.0f);
pdf = temporaryPdf;
}
return result;
}
Spectrum eval(const BSDFSamplingRecord &bRec, EMeasure measure) const {
const Intersection& its = bRec.its;
Intersection perturbed(its);
perturbed.shFrame = getFrame(its);
BSDFSamplingRecord perturbedQuery(perturbed,
perturbed.toLocal(its.toWorld(bRec.wi)),
perturbed.toLocal(its.toWorld(bRec.wo)), bRec.mode);
if (Frame::cosTheta(bRec.wo) * Frame::cosTheta(perturbedQuery.wo) <= 0)
return Spectrum(0.0f);
perturbedQuery.sampler = bRec.sampler;
perturbedQuery.typeMask = bRec.typeMask;
perturbedQuery.component = bRec.component;
return m_nested->eval(perturbedQuery, measure);
}
