void SphericalMapping2D::sphere(const Point &p, float *s, float *t) const {
Vector vec = Normalize(WorldToTexture(p) - Point(0,0,0));
float theta = SphericalTheta(vec);
float phi = SphericalPhi(vec);
*s = theta * INV_PI;
*t = phi * INV_TWOPI;
}
Spectrum Scale(const Vector &w) const {
Vector wp = Normalize(WorldToLight(w));
swap(wp.y, wp.z);
float theta = SphericalTheta(wp);
float phi = SphericalPhi(wp);
float s = phi * INV_TWOPI, t = theta * INV_PI;
return mipmap ? mipmap->Lookup(s, t) : 1.f;
}
Float InfiniteAreaLight::Pdf_Li(const Interaction &, const Vector3f &w) const {
Vector3f wi = WorldToLight(w);
Float theta = SphericalTheta(wi), phi = SphericalPhi(wi);
Float sinTheta = std::sin(theta);
if (sinTheta == 0) return 0;
return distribution->Pdf(Point2f(phi * Inv2Pi, theta * InvPi)) /
(2 * Pi * Pi * sinTheta);
}
void InfiniteAreaLight::Pdf_Le(const Ray &ray, const Normal3f &, Float *pdfPos,
Float *pdfDir) const {
Vector3f d = -WorldToLight(ray.d);
Float theta = SphericalTheta(d), phi = SphericalPhi(d);
Point2f uv(phi * Inv2Pi, theta * InvPi);
Float mapPdf = distribution->Pdf(uv);
*pdfDir = mapPdf / (2 * Pi * Pi * std::sin(theta));
*pdfPos = 1 / (Pi * worldRadius * worldRadius);
}
float InfiniteAreaLightIS::Pdf(const Point &,
const Vector &w) const {
Vector wi = WorldToLight(w);
float theta = SphericalTheta(wi), phi = SphericalPhi(wi);
int u = Clamp(Float2Int(phi * INV_TWOPI * uDistrib->count),
0, uDistrib->count-1);
int v = Clamp(Float2Int(theta * INV_PI * vDistribs[u]->count),
0, vDistribs[u]->count-1);
return (uDistrib->func[u] * vDistribs[u]->func[v]) /
(uDistrib->funcInt * vDistribs[u]->funcInt) *
1.f / (2.f * M_PI * M_PI * sin(theta));
}
Spectrum
InfiniteAreaLightIS::Le(const RayDifferential &r) const {
Vector w = r.d;
// Compute infinite light radiance for direction
Spectrum L = Lbase;
if (radianceMap != NULL) {
Vector wh = Normalize(WorldToLight(w));
float s = SphericalPhi(wh) * INV_TWOPI;
float t = SphericalTheta(wh) * INV_PI;
L *= radianceMap->Lookup(s, t);
}
return L;
}
Spectrum InfiniteAreaLight::Le(const RayDifferential &ray) const {
Vector3f w = Normalize(WorldToLight(ray.d));
Point2f st(SphericalPhi(w) * Inv2Pi, SphericalTheta(w) * InvPi);
return Spectrum(Lmap->Lookup(st), SpectrumType::Illuminant);
}
Point2f SphericalMapping2D::sphere(const Point3f &p) const {
Vector3f vec = Normalize(WorldToTexture(p) - Point3f(0, 0, 0));
Float theta = SphericalTheta(vec), phi = SphericalPhi(vec);
return Point2f(theta * InvPi, phi * Inv2Pi);
}