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material.h
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material.h
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#ifndef MATERIAL_H
#define MATERIAL_H
#include "rtweekend.h"
#include "hittable.h"
#include "texture.h"
#include "perlin.h"
#include "ONB.h"
#include "pdf.h"
struct hit_record;
// inline vec3 random_cosine_direction() {
// auto r1 = random_double();
// auto r2 = random_double();
// auto z = sqrt(1-r2);
// auto phi = 2*pi*r1;
// auto x = cos(phi)*sqrt(r2);
// auto y = sin(phi)*sqrt(r2);
// return vec3(x, y, z);
// }
class material {
public:
virtual bool scatter(
const ray& r_in, const hit_record& rec, color& albedo, ray& scattered, double& pdf
) const {
return false;
}
virtual double scattering_pdf(
const ray& r_in, const hit_record& rec, const ray& scattered
) const {
return 0;
}
virtual color emitted(
const ray& r_in, const hit_record& rec, double u, double v, const point3& p
) const {
return color(0,0,0);
}
};
class lambertian : public material {
public:
lambertian(const color& a) : albedo(make_shared<solid_color>(a)) {}
lambertian(shared_ptr<texture> a) : albedo(a) {}
virtual bool scatter(
const ray& r_in, const hit_record& rec, color& alb, ray& scattered, double& pdf
) const override {
onb uvw;
uvw.build_from_w(rec.normal);
auto direction = uvw.local(random_cosine_direction());
scattered = ray(rec.p, unit_vector(direction), r_in.time());
alb = albedo->value(rec.u, rec.v, rec.p);
pdf = dot(uvw.w(), scattered.direction()) / pi;
return true;
}
double scattering_pdf(
const ray& r_in, const hit_record& rec, const ray& scattered
) const {
auto cosine = dot(rec.normal, unit_vector(scattered.direction()));
return cosine < 0 ? 0 : cosine/pi;
}
public:
shared_ptr<texture> albedo;
};
// class nayer : public material {
// public:
// nayer(const color& a) : albedo(make_shared<solid_color>(a)) {}
// nayer(shared_ptr<texture> a) : albedo(a) {}
// virtual bool scatter(
// const ray& r_in, const hit_record& rec, color& attenuation, ray& scattered
// ) const override {
// auto scatter_direction = rec.normal + random_unit_vector();
// // Catch degenerate scatter direction
// if (scatter_direction.near_zero())
// scatter_direction = rec.normal;
// scattered = ray(rec.p, scatter_direction, r_in.time());
// auto rho = 0.25;
// auto sigma = 0.3;
// auto A = 1 / (pi + (pi/2 - 2/3)*sigma);
// auto B = sigma / (pi + (pi/2 - 2/3)*sigma);
// auto s = dot(r_in.direction(), scattered.direction()) - dot(rec.normal, r_in.direction())*dot(rec.normal, r_in.direction());
// auto max = dot(rec.normal, r_in.direction()) < dot(rec.normal, r_in.direction()) ? dot(rec.normal, r_in.direction()) : dot(rec.normal, r_in.direction());
// auto t = s <= 0 ? 1 : max;
// auto ON = rho * dot(rec.normal, r_in.direction())*(A+B*(s/t));
// attenuation = 0.05 * ON * albedo->value(rec.u, rec.v, rec.p);
// return true;
// }
// public:
// shared_ptr<texture> albedo;
// };
// class metal : public material {
// public:
// metal(const color& a, double f) : albedo(a), fuzz(f < 1 ? f : 1) {}
// virtual bool scatter(
// const ray& r_in, const hit_record& rec, color& attenuation, ray& scattered
// ) const override {
// vec3 reflected = reflect(unit_vector(r_in.direction()), rec.normal);
// scattered = ray(rec.p, reflected + fuzz * random_in_unit_sphere(), r_in.time());
// attenuation = albedo;
// return (dot(scattered.direction(), rec.normal) > 0);
// }
// public:
// color albedo;
// double fuzz;
// };
// class dielectric : public material {
// public:
// dielectric(double index_of_refraction, shared_ptr<texture> a) : ir(index_of_refraction), albedo(a) {}
// dielectric(double index_of_refraction, const color & a) : ir(index_of_refraction), albedo(make_shared<solid_color>(a)) {}
// dielectric(double index_of_refraction) : ir(index_of_refraction) {}
// virtual bool scatter(
// const ray& r_in, const hit_record& rec, color& attenuation, ray& scattered
// ) const override {
// attenuation = albedo->value(rec.u, rec.v, rec.p);
// double refraction_ratio = rec.front_face ? (1.0/ir) : ir;
// vec3 unit_direction = unit_vector(r_in.direction());
// double cos_theta = fmin(dot(-unit_direction, rec.normal), 1.0);
// double sin_theta = sqrt(1.0 - cos_theta*cos_theta);
// bool cannot_refract = refraction_ratio * sin_theta > 1.0;
// vec3 direction;
// if (cannot_refract || reflectance(cos_theta, refraction_ratio) > random_double())
// direction = reflect(unit_direction, rec.normal);
// else
// direction = refract(unit_direction, rec.normal, refraction_ratio);
// scattered = ray(rec.p, direction, r_in.time());
// return true;
// }
// public:
// double ir; // Index of Refraction
// shared_ptr<texture> albedo;
// private:
// static double reflectance(double cosine, double ref_idx) {
// // Use Schlick's approximation for reflectance.
// auto r0 = (1-ref_idx) / (1+ref_idx);
// r0 = r0*r0;
// return r0 + (1-r0)*pow((1 - cosine),5);
// }
// };
class diffuse_light : public material {
public:
diffuse_light(shared_ptr<texture> a) : emit(a) {}
diffuse_light(color c) : emit(make_shared<solid_color>(c)) {}
virtual bool scatter(
const ray& r_in, const hit_record& rec, color& albedo, ray& scattered, double& pdf
) const override {
return false;
}
virtual color emitted(const ray& r_in, const hit_record& rec, double u, double v,
const point3& p) const override {
if (rec.front_face)
return emit->value(u, v, p);
else
return color(0,0,0);
}
public:
shared_ptr<texture> emit;
};
// class isotropic : public material {
// public:
// isotropic(color c) : albedo(make_shared<solid_color>(c)) {}
// isotropic(shared_ptr<texture> a) : albedo(a) {}
// virtual bool scatter(
// const ray& r_in, const hit_record& rec, color& attenuation, ray& scattered
// ) const override {
// scattered = ray(rec.p, random_in_unit_sphere(), r_in.time());
// attenuation = albedo->value(rec.u, rec.v, rec.p);
// return true;
// }
// public:
// shared_ptr<texture> albedo;
// };
// class cloud : public material {
// public:
// cloud(color c) : albedo(make_shared<solid_color>(c)) {}
// cloud(shared_ptr<texture> a) : albedo(a) {}
// virtual bool scatter(
// const ray& r_in, const hit_record& rec, color& attenuation, ray& scattered
// ) const override {
// perlin noise;
// scattered = ray(rec.p, random_in_unit_sphere(), r_in.time());
// color c_val = albedo->value(rec.u, rec.v, rec.p);
// double r = c_val.x() * noise.turb(rec.p);
// double g = c_val.y() * noise.turb(rec.p);
// double b = c_val.z() * noise.turb(rec.p);
// attenuation = color(r, g, b);
// return true;
// }
// public:
// shared_ptr<texture> albedo;
// };
#endif