void SpotLight::Pdf_Le(const Ray &ray, const Normal3f &, Float *pdfPos,
Float *pdfDir) const {
*pdfPos = 0;
*pdfDir = (CosTheta(WorldToLight(ray.d)) >= cosTotalWidth)
? UniformConePdf(cosTotalWidth)
: 0;
}
void ProjectionLight::Pdf_Le(const Ray &ray, const Normal3f &, Float *pdfPos,
Float *pdfDir) const {
ProfilePhase _(Prof::LightPdf);
*pdfPos = 0.f;
*pdfDir = (CosTheta(WorldToLight(ray.d)) >= cosTotalWidth)
? UniformConePdf(cosTotalWidth)
: 0;
}
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);
}
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;
}
void InfiniteAreaLight::Pdf(const Ray &ray, const Normal3f &, Float *pdfPos,
Float *pdfDir) const {
Vector3f d = -WorldToLight(ray.d);
Float theta = std::acos(d.z), phi = std::atan2(d.y, d.x);
Point2f uv(phi * Inv2Pi, theta * InvPi);
Float mapPdf = distribution->Pdf(uv);
*pdfDir = mapPdf / (2 * Pi * Pi * std::sin(theta));
*pdfPos = 1 / (Pi * worldRadius * worldRadius);
}
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 SpotLight::Falloff(const Vector3f &w) const {
Vector3f wl = Normalize(WorldToLight(w));
Float cosTheta = wl.z;
if (cosTheta < cosTotalWidth) return 0;
if (cosTheta > cosFalloffStart) return 1;
// Compute falloff inside spotlight cone
Float delta =
(cosTheta - cosTotalWidth) / (cosFalloffStart - cosTotalWidth);
return (delta * delta) * (delta * delta);
}
float SpotLight::Falloff(const Vector &w) const {
Vector wl = Normalize(WorldToLight(w));
float costheta = wl.z;
if (costheta < cosTotalWidth) return 0.;
if (costheta > cosFalloffStart) return 1.;
// Compute falloff inside spotlight cone
float delta = (costheta - cosTotalWidth) /
(cosFalloffStart - cosTotalWidth);
return delta*delta*delta*delta;
}
Spectrum ProjectionLight::Projection(const Vector3f &w) const {
Vector3f wl = WorldToLight(w);
// Discard directions behind projection light
if (wl.z < hither) return 0;
// Project point onto projection plane and compute light
Point3f p = lightProjection(Point3f(wl.x, wl.y, wl.z));
if (!Inside(Point2f(p.x, p.y), screenBounds)) return 0.f;
if (!projectionMap) return 1;
Point2f st = Point2f(screenBounds.Offset(Point2f(p.x, p.y)));
return Spectrum(projectionMap->Lookup(st), SpectrumType::Illuminant);
}
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 ProjectionLight::Projection(const Vector &w) const {
Vector wl = WorldToLight(w);
// Discard directions behind projection light
if (wl.z < hither) return 0.;
// Project point onto projection plane and compute light
Point Pl = lightProjection(Point(wl.x, wl.y, wl.z));
if (Pl.x < screenX0 || Pl.x > screenX1 ||
Pl.y < screenY0 || Pl.y > screenY1) return 0.;
if (!projectionMap) return 1;
float s = (Pl.x - screenX0) / (screenX1 - screenX0);
float t = (Pl.y - screenY0) / (screenY1 - screenY0);
return Spectrum(projectionMap->Lookup(s, t), SPECTRUM_ILLUMINANT);
}
Vector ProjectionLight::Projection(const Point& p) const
{
Vector w = Normalize(lightPos - p);
Vector wl = WorldToLight(w);
// Discard directions behind projection light
if (wl.z < hither) return Vector();
// Project point onto projection plane and compute light
Point Pl = lightProjection(Point(wl.x, wl.y, wl.z));
if (Pl.x < screenX0 || Pl.x > screenX1 ||
Pl.y < screenY0 || Pl.y > screenY1) return Vector();
float s = (Pl.x - screenX0) / (screenX1 - screenX0);
float t = (Pl.y - screenY0) / (screenY1 - screenY0);
// change s,t to image coordinate
int u = texture->cols - int(texture->cols * s);
int v = int(texture->rows * t);
cv::Vec3b texLight = texture->at<cv::Vec3b>(v, u);
return Vector(float(texLight[0])/256.f, float(texLight[1])/256.f, float(texLight[2])/256.f);
}
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);
}
