Colord PerfectSpecular::sample(const HitPoint& hitPoint, const Vector3d& out, Vector3d& in) const {
double normalDotOut = hitPoint.normal() * out;
in = -out + hitPoint.normal() * 2.0 * normalDotOut;
double normalDotIn = hitPoint.normal() * out;
return reflectionColor() * reflectionCoefficient() / normalDotIn;
}
Colord PhongMaterial::shade(const Raytracer* raytracer, const Rayd& ray, const HitPoint& hitPoint, State& state) const {
auto texColor = diffuseTexture() ? diffuseTexture()->evaluate(ray, hitPoint) : Colord::black();
Lambertian ambientBRDF(texColor, ambientCoefficient());
Lambertian diffuseBRDF(texColor, diffuseCoefficient());
Vector3d out = -ray.direction();
auto color = ambientBRDF.reflectance(hitPoint, out) * raytracer->scene()->ambient();
for (const auto& light : raytracer->scene()->lights()) {
Vector3d in = light->direction(hitPoint.point());
if (raytracer->scene()->intersects(Rayd(hitPoint.point(), in).epsilonShifted(), state)) {
state.shadowHit(this, "PhongMaterial");
} else {
state.shadowMiss(this, "PhongMaterial");
double normalDotIn = hitPoint.normal() * in;
if (normalDotIn > 0.0) {
color += (
diffuseBRDF(hitPoint, out, in)
+ m_specularBRDF(hitPoint, out, in)
) * light->radiance() * normalDotIn;
}
}
}
return color;
}
Colord TransparentMaterial::shade(const Raytracer* raytracer, const Rayd& ray, const HitPoint& hitPoint, State& state) const {
Vector3d out = -ray.direction();
Vector3d in;
Colord reflectedColor = m_reflectiveBRDF.sample(hitPoint, out, in);
Rayd reflected(hitPoint.point(), in);
if (m_specularBTDF.totalInternalReflection(ray, hitPoint)) {
return raytracer->rayColor(reflected.epsilonShifted(), state);
} else {
auto color = PhongMaterial::shade(raytracer, ray, hitPoint, state);
Vector3d trans;
Colord transmittedColor = m_specularBTDF.sample(hitPoint, out, trans);
Rayd transmitted(hitPoint.point(), trans);
state.recordEvent("TransparentMaterial: Tracing reflection");
color += reflectedColor * raytracer->rayColor(reflected.epsilonShifted(), state) * fabs(hitPoint.normal() * in);
state.recordEvent("TransparentMaterial: Tracing transmission");
color += transmittedColor * raytracer->rayColor(transmitted.epsilonShifted(), state) * fabs(hitPoint.normal() * trans);
return color;
}
}