void configure() {
m_usesRayDifferentials = false;
size_t componentCount = 0;
if (m_bsdfs.size() != m_weights.size())
Log(EError, "BSDF count mismatch: " SIZE_T_FMT " bsdfs, but specified " SIZE_T_FMT " weights",
m_bsdfs.size(), m_bsdfs.size());
Float totalWeight = 0;
for (size_t i=0; i<m_weights.size(); ++i)
totalWeight += m_weights[i];
if (totalWeight <= 0)
Log(EError, "The weights must sum to a value greater than zero!");
if (m_ensureEnergyConservation && totalWeight > 1) {
std::ostringstream oss;
Float scale = 1.0f / totalWeight;
oss << "The BSDF" << endl << toString() << endl
<< "potentially violates energy conservation, since the weights "
<< "sum to " << totalWeight << ", which is greater than one! "
<< "They will be re-scaled to avoid potential issues. Specify "
<< "the parameter ensureEnergyConservation=false to prevent "
<< "this from happening.";
Log(EWarn, "%s", oss.str().c_str());
for (size_t i=0; i<m_weights.size(); ++i)
m_weights[i] *= scale;
}
for (size_t i=0; i<m_bsdfs.size(); ++i)
componentCount += m_bsdfs[i]->getComponentCount();
m_pdf = DiscreteDistribution(m_bsdfs.size());
m_components.reserve(componentCount);
m_components.clear();
m_indices.reserve(componentCount);
m_indices.clear();
m_offsets.reserve(m_bsdfs.size());
m_offsets.clear();
int offset = 0;
for (size_t i=0; i<m_bsdfs.size(); ++i) {
const BSDF *bsdf = m_bsdfs[i];
m_offsets.push_back(offset);
for (int j=0; j<bsdf->getComponentCount(); ++j) {
int componentType = bsdf->getType(j);
m_components.push_back(componentType);
m_indices.push_back(std::make_pair((int) i, j));
}
offset += bsdf->getComponentCount();
m_usesRayDifferentials |= bsdf->usesRayDifferentials();
m_pdf.append(m_weights[i]);
}
m_pdf.normalize();
BSDF::configure();
}
inline DiscreteDistribution computePowerBasedDistribution(const Scene& scene) {
const auto& lightContainer = scene.getLightContainer();
std::vector<float> powers;
powers.reserve(lightContainer.size());
for(const auto& pLight: lightContainer) {
powers.emplace_back(luminance(pLight->getPowerUpperBound(scene)));
}
return DiscreteDistribution(powers.size(), powers.data());
}
