90 lines
2.9 KiB
C++
90 lines
2.9 KiB
C++
#ifndef MATERIAL_H
|
|
#define MATERIAL_H
|
|
|
|
#include "rayTracer.h"
|
|
|
|
class hitRecord;
|
|
|
|
class material {
|
|
public:
|
|
virtual ~material() = default;
|
|
|
|
virtual bool scatter(const ray& rIn, const hitRecord& rec, colour& attenuation, ray& scattered) const {
|
|
return false;
|
|
}
|
|
};
|
|
|
|
class lambertian : public material {
|
|
private:
|
|
colour albedo;
|
|
|
|
public:
|
|
lambertian(const colour& albedo) : albedo(albedo) {}
|
|
|
|
bool scatter(const ray& rIn, const hitRecord& rec, colour& attenuation, ray& scattered)
|
|
const override {
|
|
auto scatterDirection = rec.normal + randomUnitVector();
|
|
|
|
// Catch degenerate scatter direction.
|
|
if (scatterDirection.nearZero()) scatterDirection = rec.normal;
|
|
|
|
scattered = ray(rec.p, scatterDirection, rIn.time());
|
|
attenuation = albedo;
|
|
return true;
|
|
}
|
|
};
|
|
|
|
class metal : public material {
|
|
private:
|
|
colour albedo;
|
|
double fuzz;
|
|
|
|
public:
|
|
metal(const colour& albedo, double fuzz) : albedo(albedo), fuzz(fuzz < 1 ? fuzz : 1) {}
|
|
|
|
bool scatter(const ray& rIn, const hitRecord& rec, colour& attenuation, ray& scattered) const override {
|
|
vec3 reflected = reflect(rIn.direction(), rec.normal);
|
|
reflected = unitVector(reflected) + (fuzz * randomUnitVector());
|
|
scattered = ray(rec.p, reflected, rIn.time());
|
|
attenuation = albedo;
|
|
return (dot(scattered.direction(), rec.normal) > 0);
|
|
}
|
|
};
|
|
|
|
class dielectric : public material {
|
|
private:
|
|
// Refractive index in vacuum or air, or the ratio of the material's refractive index over the refractive index of the enclosing media.
|
|
double refractionIndex;
|
|
|
|
static double reflectance(double cosine, double refractionIndex) {
|
|
auto r0 = (1 - refractionIndex) / (1 + refractionIndex);
|
|
r0 = r0 * r0;
|
|
return r0 + (1 - r0) * pow((1 - cosine), 5);
|
|
}
|
|
|
|
public:
|
|
dielectric(double refractionIndex) : refractionIndex(refractionIndex) {}
|
|
|
|
bool scatter(const ray& rIn, const hitRecord& rec, colour& attenuation, ray& scattered) const override {
|
|
attenuation = colour(1.0, 1.0, 1.0);
|
|
double ri = rec.frontFace ? (1.0 / refractionIndex) : refractionIndex;
|
|
|
|
vec3 unitDirection = unitVector(rIn.direction());
|
|
double cosTheta = fmin(dot(-unitDirection, rec.normal), 1.0);
|
|
double sinTheta = sqrt(1.0 - cosTheta * cosTheta);
|
|
|
|
bool cannotRefract = ri * sinTheta > 1.0;
|
|
vec3 direction;
|
|
|
|
if (cannotRefract || reflectance(cosTheta, ri) > randomDouble()) {
|
|
direction = reflect(unitDirection, rec.normal);
|
|
} else {
|
|
direction = refract(unitDirection, rec.normal, ri);
|
|
}
|
|
|
|
scattered = ray(rec.p, direction, rIn.time());
|
|
return true;
|
|
}
|
|
};
|
|
|
|
#endif |