cv::Vec3f BlinnMaterial::brdf(const HitRecord &hit, QVector3D direction) const
{
QVector3D normal = hit.getSurfaceNormal();
normal.normalize();
QVector3D wo = -hit.getRay().getDirection().normalized();
QVector3D wi = -direction.normalized();
if(signum(QVector3D::dotProduct(normal, wo)) != signum(QVector3D::dotProduct(normal, wi)))
{
return cv::Vec3f();
}
if(QVector3D::dotProduct(normal, wo) < 0) normal *= -1;
QVector3D wh = wi + wo;
wh.normalize();
return kd * (1 / M_PI) + ks * D(wh, normal) * G(wi, wo, normal) / (4 * QVector3D::dotProduct(wo, normal) * QVector3D::dotProduct(wi, normal));
}
QVector3D BlinnMaterial::outDirection(const HitRecord &hit, Sample s, float &pdf, cv::Vec3f &brdf) const
{
QVector3D normal = hit.getSurfaceNormal();
normal.normalize();
QVector3D wo = -hit.getRay().getDirection().normalized();
if(QVector3D::dotProduct(normal, wo) < 0) normal *= -1;
QVector3D wh = s.getCosinePowerWeightedDirection(normal, pdf, exponent);
if(QVector3D::dotProduct(wo, wh) < 0)
{
pdf = 0;
brdf = cv::Vec3f();
return QVector3D();
}
//if(QVector3D::dotProduct(wh, normal) < 0) wh *= -1;
QVector3D out = -reflect(wo, wh);
assert(pdf >= 0);
pdf /= 4 * std::max(QVector3D::dotProduct(wo, wh), .0001f);
assert(pdf >= 0);
brdf = this->brdf(hit, out);
assert(brdf[0] >= 0 && brdf[1] >= 0 && brdf[2] >= 0);
return out;
}
cv::Vec3f AreaLight::emission(const HitRecord & hit) const
{
assert(&hit.getMaterial() == this);
return getIntensity(-hit.getRay().getDirection());
}
