material.h

#ifndef MATERIAL_H
#define MATERIAL_H

#include "rtpp.h"
#include "hittables/hittable.h"

class material {
public:
	virtual ~material() = default;

	virtual bool scatter(
	const ray& r_in, const hit_record& rec, color& attenuation, ray& scattered
		) const {
		return false;
	}
};

class lambertian : public material {
public:
	lambertian(const color& albedo) : albedo(albedo) {}

	bool scatter(const ray& r_in, const hit_record& rec, color& attenuation, ray& scattered) const override {
		auto scatter_direction = rec.normal + random_unit_vector();

		if (scatter_direction.near_zero())
			scatter_direction = rec.normal;

		scattered = ray(rec.p, scatter_direction);
		attenuation = albedo;
		return true;
	}

private:
	color albedo;
};

class metal : public material {
public:

	metal(const color& albedo, double fuzz) : albedo(albedo), fuzz(fuzz < 1 ? fuzz : 1) {}

	bool scatter(const ray& r_in, const hit_record& rec, color& attenuation, ray& scattered) const override {
		vec3 reflected = reflect(r_in.direction(), rec.normal);
		reflected = unit_vector(reflected) + (fuzz * random_unit_vector());
		scattered = ray(rec.p, reflected);
		attenuation = albedo;
		return (dot(scattered.direction(), rec.normal) > 0);
	}

private:
	color albedo;
	double fuzz;
};

#endif