rpuzonas/raytracing-in-a-weekend-oop
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feat: add dialectric material

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Rokas Puzonas 2022-03-13 20:30:56 +02:00
parent 14ac9f2ec0
commit 4d2b7757d4
4 changed files with 74191 additions and 74145 deletions
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148272
image.ppm
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11
main.cc
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@ -33,20 +33,21 @@ int main() {
const auto aspect_ratio = 16.0 / 9.0;
const int image_width = 400;
const int image_height = static_cast<int>(image_width / aspect_ratio);
const int samples_per_pixel = 16;
const int max_depth = 25;
const int samples_per_pixel = 32;
const int max_depth = 32;
// World
hittable_list world;
auto material_ground = make_shared<lambertian>(color(0.8, 0.8, 0.0));
auto material_center = make_shared<lambertian>(color(0.7, 0.3, 0.3));
auto material_left = make_shared<metal>(color(0.8, 0.8, 0.8), 0.3);
auto material_right = make_shared<metal>(color(0.8, 0.6, 0.2), 1.0);
auto material_center = make_shared<lambertian>(color(0.1, 0.2, 0.5));
auto material_left = make_shared<dialectric>(1.5);
auto material_right = make_shared<metal>(color(0.8, 0.6, 0.2), 0.1);
world.add(make_shared<sphere>(point3( 0, -100.5, -1), 100, material_ground));
world.add(make_shared<sphere>(point3( 0, 0, -1), 0.5, material_center));
world.add(make_shared<sphere>(point3(-1, 0, -1), 0.5, material_left));
world.add(make_shared<sphere>(point3(-1, 0, -1), -0.4, material_left));
world.add(make_shared<sphere>(point3( 1, 0, -1), 0.5, material_right));
// Camera

38
material.h
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@ -53,4 +53,42 @@ class metal : public material {
double fuzz;
};
class dialectric : public material {
public:
dialectric(double index_of_refraction): ir(index_of_refraction) {}
bool scatter(
const ray &r_in, const hit_record &rec, color &attenuation, ray &scattered
) const override {
attenuation = color(1.0, 1.0, 1.0);
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 - 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);
return true;
}
public:
double ir; // Index of Refraction
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);
}
};
#endif

7
vec3.h
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@ -138,4 +138,11 @@ vec3 reflect(const vec3& v, const vec3& n) {
return v - 2*dot(v,n)*n;
}
vec3 refract(const vec3& uv, const vec3& n, double etai_over_etat) {
auto cos_theta = fmin(dot(-uv, n), 1.0);
vec3 r_out_perp = etai_over_etat * (uv + cos_theta*n);
vec3 r_out_parrallel = -sqrt(fabs(1.0 - r_out_perp.length_squared())) * n;
return r_out_perp + r_out_parrallel;
}
#endif