Refraction
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3 changed files with 97 additions and 73 deletions
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@ -12,71 +12,72 @@
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#include <memory>
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color ray_color(const ray &r, const hittable &world, int depth) {
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hit_record rec;
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hit_record rec;
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// If we've exceeded the ray bounce limit, no more light is gathered.
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if (depth <= 0)
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return color(0,0,0);
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// If we've exceeded the ray bounce limit, no more light is gathered.
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if (depth <= 0)
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return color(0, 0, 0);
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if (world.hit(r, 0.000001, infinity, rec)) {
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ray scattered;
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color attenuation;
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if (rec.mat_ptr->scatter(r, rec, attenuation, scattered))
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return attenuation * ray_color(scattered, world, depth-1);
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return color(0,0,0);
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}
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if (world.hit(r, 0.000001, infinity, rec)) {
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ray scattered;
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color attenuation;
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if (rec.mat_ptr->scatter(r, rec, attenuation, scattered))
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return attenuation * ray_color(scattered, world, depth - 1);
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return color(0, 0, 0);
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}
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vec3 unit_direction = unit_vector(r.direction());
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auto t = 0.5*(unit_direction.y() + 1.0);
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return (1.0-t)*color(1.0, 1.0, 1.0) + t*color(0.5, 0.7, 1.0);
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vec3 unit_direction = unit_vector(r.direction());
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auto t = 0.5 * (unit_direction.y() + 1.0);
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return (1.0 - t) * color(1.0, 1.0, 1.0) + t * color(0.5, 0.7, 1.0);
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}
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int main() {
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// Image
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// Image
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const auto aspect_ratio = 16.0 / 9.0;
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const int image_width = 400;
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const int image_height = static_cast<int>(image_width / aspect_ratio);
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const int samples_per_pixel = 100;
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const int max_depth = 50;
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const auto aspect_ratio = 16.0 / 9.0;
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const int image_width = 400;
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const int image_height = static_cast<int>(image_width / aspect_ratio);
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const int samples_per_pixel = 100;
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const int max_depth = 50;
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// World
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// World
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hittable_list world;
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hittable_list world;
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auto material_ground = make_shared<lambertian>(color(0.8, 0.8, 0.0));
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auto material_center = make_shared<lambertian>(color(0.7, 0.3, 0.3));
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auto material_left = make_shared<metal>(color(0.8, 0.8, 0.8), 0.3);
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auto material_right = make_shared<metal>(color(0.8, 0.6, 0.2), 1.0);
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auto material_ground = make_shared<lambertian>(color(0.8, 0.8, 0.0));
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auto material_center = make_shared<dielectric>(1.5);
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auto material_left = make_shared<dielectric>(1.5);
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auto material_right = make_shared<metal>(color(0.8, 0.6, 0.2), 1.0);
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world.add(make_shared<sphere>(point3( 0.0, -100.5, -1.0), 100.0, material_ground));
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world.add(make_shared<sphere>(point3( 0.0, 0.0, -1.0), 0.5, material_center));
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world.add(make_shared<sphere>(point3(-1.0, 0.0, -1.0), 0.5, material_left));
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world.add(make_shared<sphere>(point3( 1.0, 0.0, -1.0), 0.5, material_right));
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world.add(
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make_shared<sphere>(point3(0.0, -100.5, -1.0), 100.0, material_ground));
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world.add(make_shared<sphere>(point3(0.0, 0.0, -1.0), 0.5, material_center));
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world.add(make_shared<sphere>(point3(-1.0, 0.0, -1.0), 0.5, material_left));
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world.add(make_shared<sphere>(point3(1.0, 0.0, -1.0), 0.5, material_right));
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// Camera
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// Camera
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camera cam;
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camera cam;
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// Render
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// Render
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std::cout << "P3\n" << image_width << " " << image_height << "\n255\n";
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std::cout << "P3\n" << image_width << " " << image_height << "\n255\n";
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for (int j = image_height-1; j >= 0; --j) {
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std::cerr << "\rScanlines remaining: " << j << ' ' << std::flush;
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for (int i = 0; i < image_width; ++i) {
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color pixel_color(0, 0, 0);
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for (int s = 0; s < samples_per_pixel; ++s) {
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auto u = (i + random_double()) / (image_width-1);
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auto v = (j + random_double()) / (image_height-1);
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ray r = cam.get_ray(u, v);
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pixel_color += ray_color(r, world, max_depth);
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}
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write_color(std::cout, pixel_color, samples_per_pixel);
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}
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for (int j = image_height - 1; j >= 0; --j) {
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std::cerr << "\rScanlines remaining: " << j << ' ' << std::flush;
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for (int i = 0; i < image_width; ++i) {
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color pixel_color(0, 0, 0);
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for (int s = 0; s < samples_per_pixel; ++s) {
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auto u = (i + random_double()) / (image_width - 1);
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auto v = (j + random_double()) / (image_height - 1);
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ray r = cam.get_ray(u, v);
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pixel_color += ray_color(r, world, max_depth);
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}
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write_color(std::cout, pixel_color, samples_per_pixel);
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}
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}
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std::cerr << "\nDone.\n";
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std::cerr << "\nDone.\n";
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return 0;
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}
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@ -13,46 +13,62 @@ public:
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color &attenuation, ray &scattered) const = 0;
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};
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class lambertian : public material {
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public:
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lambertian(const color& a) : albedo(a) {}
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lambertian(const color &a) : albedo(a) {}
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virtual bool scatter(
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const ray& r_in, const hit_record& rec, color& attenuation, ray& scattered
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) const override {
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auto scatter_direction = rec.normal+random_in_unit_sphere();
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virtual bool scatter(const ray &r_in, const hit_record &rec,
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color &attenuation, ray &scattered) const override {
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auto scatter_direction = rec.normal + random_in_unit_sphere();
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// Catch degenerate scatter direction
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if (scatter_direction.near_zero())
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scatter_direction = rec.normal;
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// Catch degenerate scatter direction
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if (scatter_direction.near_zero())
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scatter_direction = rec.normal;
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scattered = ray(rec.p, scatter_direction);
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attenuation = albedo;
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return true;
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}
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scattered = ray(rec.p, scatter_direction);
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attenuation = albedo;
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return true;
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}
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public:
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color albedo;
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color albedo;
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};
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class metal : public material {
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public:
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metal(const color& a, double f) : albedo(a), fuzz(f<1 ? f: 1) {}
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metal(const color &a, double f) : albedo(a), fuzz(f < 1 ? f : 1) {}
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virtual bool scatter(
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const ray& r_in, const hit_record& rec, color& attenuation, ray& scattered
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) const override {
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vec3 reflected = reflect(unit_vector(r_in.direction()), rec.normal);
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scattered = ray(rec.p, reflected + fuzz*random_in_unit_sphere());
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attenuation = albedo;
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return true;
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}
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virtual bool scatter(const ray &r_in, const hit_record &rec,
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color &attenuation, ray &scattered) const override {
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vec3 reflected = reflect(unit_vector(r_in.direction()), rec.normal);
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scattered = ray(rec.p, reflected + fuzz * random_in_unit_sphere());
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attenuation = albedo;
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return true;
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}
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public:
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color albedo;
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double fuzz;
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color albedo;
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double fuzz;
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};
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class dielectric : public material {
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public:
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dielectric(double index_of_refraction) : ir(index_of_refraction) {}
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virtual bool scatter(const ray &r_in, const hit_record &rec,
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color &attenuation, ray &scattered) const override {
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attenuation = color(1.0, 1.0, 1.0);
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double refraction_ratio = rec.front_face ? (1.0 / ir) : ir;
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vec3 unit_direction = unit_vector(r_in.direction());
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vec3 refracted = refract(unit_direction, rec.normal, refraction_ratio);
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scattered = ray(rec.p, refracted);
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return true;
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}
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public:
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double ir;
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};
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#endif // MATERIAL_H_
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@ -124,4 +124,11 @@ vec3 random_in_hemisphere(const vec3 &normal) {
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vec3 reflect(const vec3 &v, const vec3 &n) { return v - 2 * dot(v, n) * n; }
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vec3 refract(const vec3 &v, const vec3 &n, double etai_over_etat) {
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auto cos_theta = fmin(dot(-v, n), 1.0);
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vec3 r_out_perp = etai_over_etat * (v + cos_theta * n);
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vec3 r_out_parallel = -sqrt(fabs(1.0 - r_out_perp.length_squared())) * n;
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return r_out_perp + r_out_parallel;
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}
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#endif // RTIWW_VEC3_H
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