snoopy/src/main.cpp

#include "rtweekend.h"

#include "hittable_list.h"
#include "sphere.h"
#include "colour.h"
#include "camera.h"
#include "material.h"

#include <iostream>

const double ASPECT_RATIO = 32.0 / 9.0;
const int WIDTH = 800;
const int HEIGHT = static_cast<int>(WIDTH / ASPECT_RATIO);
const int SAMPLES_PER_PIXEL = 32;
const int MAX_DEPTH = 16;

colour ray_colour(const ray& r, const hittable& world, int depth)
{
    hit_record rec;
    if (depth <= 0)
    {
        return colour(0,0,0);
    }

    if (world.hit(r, 0.001, infinity, rec))
    {
        ray     scattered;
        colour  attenuation;

        if (rec.mat_ptr->scatter(r, rec, attenuation, scattered))
        {
            return attenuation * ray_colour(scattered, world, depth-1);
        }

        return colour(0,0,0);
    }

    vec3 unit_direction = unit_vector(r.direction());
    auto t = 0.5 * (unit_direction.y() + 1.0);

    auto a = colour(0.8, 0.7, 1.0);
    auto b = colour(1.0, 1.0, 1.0);

    return lerp(a, b, t);
}

hittable_list random_scene()
{
    hittable_list world;

    auto ground_material = make_shared<lambertian>(colour(0.5, 0.5, 0.5));
    world.add(make_shared<sphere>(point3(0,-1000,0), 1000, ground_material));

    for (int a = -11; a < 11; a++)
    {
        for (int b = -11; b < 11; b++)
        {
            auto choose_mat = random_double();
            point3 centre(a + 0.9*random_double(), 0.2, b + 0.9*random_double());

            if ((centre - point3(4, 0.2, 0)).length() > 0.9)
            {
                shared_ptr<material> sphere_material;

                if (choose_mat < 0.8)
                {
                    // diffuse
                    auto albedo = colour::random() * colour::random();
                    sphere_material = make_shared<lambertian>(albedo);
                    world.add(make_shared<sphere>(centre, 0.2, sphere_material));
                }
                else if (choose_mat < 0.95)
                {
                    // metal
                    auto albedo = colour::random(0.5, 1);
                    auto fuzz = random_double(0, 0.5);
                    sphere_material = make_shared<metal>(albedo, fuzz);
                    world.add(make_shared<sphere>(centre, 0.2, sphere_material));
                }
                else
                {
                    // glass
                    sphere_material = make_shared<dielectric>(1.5);
                    world.add(make_shared<sphere>(centre,0.2, sphere_material));
                }
            }
        }
    }

    auto material1 = make_shared<dielectric>(1.5);
    world.add(make_shared<sphere>(point3(0, 1, 0), 1.0, material1));

    auto material2 = make_shared<lambertian>(colour(0.4, 0.2, 0.1));
    world.add(make_shared<sphere>(point3(-4, 1, 0), 1.0, material2));
    
    auto material3 = make_shared<metal>(colour(0.7, 0.6, 0.5), 0.0);
    world.add(make_shared<sphere>(point3(4, 1, 0), 1.0, material3));

    return world;
}

int main()
{
    std::cout << "P3\n" << WIDTH << ' ' << HEIGHT << "\n255\n";

    hittable_list world = random_scene();

    point3 lookfrom(13,2,3);
    point3 lookat(0,0,0);
    vec3 vup(0,1,0);
    auto dist_to_focus = 10.0;
    auto aperture = 0.1;

    camera cam(lookfrom, lookat, vup, 20, ASPECT_RATIO, aperture, dist_to_focus);

    for (int j = HEIGHT - 1; j >= 0; --j)
    {
        std::cerr << "\rScanlines remaining: " << j << ' ' << std::flush;
        for (int i = 0; i < WIDTH; ++i)
        {
            colour pixel_colour(0,0,0);

            for (int s = 0; s < SAMPLES_PER_PIXEL; ++s)
            {
                auto u = (i + random_double()) / (WIDTH-1);
                auto v = (j + random_double()) / (HEIGHT-1);
                ray r = cam.get_ray(u, v);
                pixel_colour += ray_colour(r, world, MAX_DEPTH);
            }

            write_colour(std::cout, pixel_colour, SAMPLES_PER_PIXEL);
        }
    }

    std::cerr << "\nDone." << std::endl;
}