main.cpp

#include <iostream>
#include "sphere.h"
#include "hitable_list.h"
#include "float.h"
#include "camera.h"
#include "material.h"

vec3 color(const ray& r, hitable *world, int depth) {
    hit_record rec;

    if (world->hit(r, 0.001, FLT_MAX, rec)) {
        ray scattered;
        vec3 attenuation;

        if (depth < 50 && rec.mat_ptr->scatter(r, rec, attenuation, scattered)) {
            return attenuation*color(scattered, world, depth + 1);
        }
        else {
            return vec3(0, 0, 0);
        }
    }
    else {
        vec3 unit_direction = unit_vector(r.direction());
        float t = 0.5*(unit_direction.y() + 1.0);
        return (1.0 - t)*vec3(1.0, 1.0, 1.0) + t*vec3(0.5, 0.7, 1.0);
    }
}

hitable *random_scene() {
    int n = 500;
    hitable **list = new hitable*[n+1];
    list[0] = new sphere(vec3(0, -1000, 0), 1000, new lambertian(vec3(0.5, 0.5, 0.5)));
    int i = 1;

    for (int a = -11; a < 11; a++) {
        for (int b = -11; b < 11; b++){

            float choose_mat = drand48();
            vec3 center(a + 0.9*drand48(), 0.2, b + 0.9*drand48());

            if ((center - vec3(4, 0.2, 0)).length() > 0.9){
                if (choose_mat < 0.7) {  // diffuse
                    list[i++] = new sphere(center,
                                           0.2,
                                           new lambertian(vec3(
                                                               drand48()*drand48(),
                                                               drand48()*drand48(),
                                                               drand48()*drand48())));
                }
                else if (choose_mat < .9) { // metal
                    list[i++] = new sphere(center,
                                           0.2,
                                           new metal(vec3(
                                                          0.5*(1 + drand48()),
                                                          0.5*(1 + drand48()),
                                                          0.5*(1 + drand48())),
                                                     0.5*drand48()));
                }
                else { // glass
                    list[i++] = new sphere(center, 0.2, new dielectric(1.5));
                }
            }
        }
    }

    list[i++] = new sphere(vec3(0, 1, 0), 1.0, new dielectric(1.5));
    list[i++] = new sphere(vec3(-4, 1, 0), 1.0, new lambertian(vec3(0.4, 0.2, 0.1)));
    list[i++] = new sphere(vec3(4, 1, 0), 1.0, new metal(vec3(0.7, 0.6, 0.5), 0.0));

    return new hitable_list(list, i);
}

int main() {
    int nx = 900;
    int ny = 600;
    int ns = 100;

    std::cout << "P3\n" << nx << " " << ny << "\n255\n";

    // hitable *list[5];

    // list[0] = new sphere(vec3(0, 0, -1), 0.5, new lambertian(vec3(0.1, 0.2, 0.5)));
    // list[1] = new sphere(vec3(0, -100.5, -1), 100, new lambertian(vec3(0.8, 0.8, 0.0)));
    // list[2] = new sphere(vec3(1, 0, -1), 0.5, new metal(vec3(0.8, 0.6, 0.2), 0.0));
    // list[3] = new sphere(vec3(-1, 0, -1), 0.5, new dielectric(1.5));
    // list[4] = new sphere(vec3(-1, 0, -1), -0.45, new dielectric(1.5));

    // hitable *world = new hitable_list(list, 5);
    hitable *world;
    world = random_scene();

    vec3 lookfrom(13, 2, 2);
    vec3 lookat(0, 0, 0);

    float dist_to_focus = (lookfrom - lookat).length();
    float aperture = .1;

    camera cam(lookfrom, lookat, vec3(0, 1, 0), 40,
               float(nx)/float(ny), aperture, dist_to_focus);

    for (int j = ny - 1; j >= 0; j--){
        for (int i = 0; i < nx; i++){
            vec3 col(0, 0, 0);

            for (int s = 0; s < ns; s++) {
                float u = float(i + drand48()) / float(nx);
                float v = float(j + drand48()) / float(ny);

                ray r = cam.get_ray(u, v);

                vec3 p = r.point_at_parameter(2.0);
                col += color(r, world, 0);
            }

            col /= float(ns);
            col = vec3(sqrt(col[0]), sqrt(col[1]), sqrt(col[2]));

            int ir = int(255.99 * col[0]);
            int ig = int(255.99 * col[1]);
            int ib = int(255.99 * col[2]);

            std::cout << ir << " " << ig << " " << ib << "\n";
        }
    }
}