A Scene Testing All New Features

Let’s put it all together, with a big thin mist covering everything, and a blue subsurface reflection sphere (we didn’t implement that explicitly, but a volume inside a dielectric is what a subsurface material is). The biggest limitation left in the renderer is no shadow rays, but that is why we get caustics and subsurface for free. It’s a double-edged design decision.

Also note that we'll parameterize this final scene to support a lower quality render for quick testing.

Final scene

#include "bvh.h"
...
void final_scene(int image_width, int samples_per_pixel, int max_depth) {
    hittable_list boxes1;
    auto ground = make_shared<lambertian>(color(0.48, 0.83, 0.53));

    int boxes_per_side = 20;
    for (int i = 0; i < boxes_per_side; i++) {
        for (int j = 0; j < boxes_per_side; j++) {
            auto w = 100.0;
            auto x0 = -1000.0 + i*w;
            auto z0 = -1000.0 + j*w;
            auto y0 = 0.0;
            auto x1 = x0 + w;
            auto y1 = random_double(1,101);
            auto z1 = z0 + w;

            boxes1.add(box(point3(x0,y0,z0), point3(x1,y1,z1), ground));
        }
    }

    hittable_list world;

    world.add(make_shared<bvh_node>(boxes1));

    auto light = make_shared<diffuse_light>(color(7, 7, 7));
    world.add(make_shared<quad>(point3(123,554,147), vec3(300,0,0), vec3(0,0,265), light));

    auto center1 = point3(400, 400, 200);
    auto center2 = center1 + vec3(30,0,0);
    auto sphere_material = make_shared<lambertian>(color(0.7, 0.3, 0.1));
    world.add(make_shared<sphere>(center1, center2, 50, sphere_material));

    world.add(make_shared<sphere>(point3(260, 150, 45), 50, make_shared<dielectric>(1.5)));
    world.add(make_shared<sphere>(
        point3(0, 150, 145), 50, make_shared<metal>(color(0.8, 0.8, 0.9), 1.0)
    ));

    auto boundary = make_shared<sphere>(point3(360,150,145), 70, make_shared<dielectric>(1.5));
    world.add(boundary);
    world.add(make_shared<constant_medium>(boundary, 0.2, color(0.2, 0.4, 0.9)));
    boundary = make_shared<sphere>(point3(0,0,0), 5000, make_shared<dielectric>(1.5));
    world.add(make_shared<constant_medium>(boundary, .0001, color(1,1,1)));

    auto emat = make_shared<lambertian>(make_shared<image_texture>("earthmap.jpg"));
    world.add(make_shared<sphere>(point3(400,200,400), 100, emat));
    auto pertext = make_shared<noise_texture>(0.1);
    world.add(make_shared<sphere>(point3(220,280,300), 80, make_shared<lambertian>(pertext)));

    hittable_list boxes2;
    auto white = make_shared<lambertian>(color(.73, .73, .73));
    int ns = 1000;
    for (int j = 0; j < ns; j++) {
        boxes2.add(make_shared<sphere>(point3::random(0,165), 10, white));
    }

    world.add(make_shared<translate>(
        make_shared<rotate_y>(
            make_shared<bvh_node>(boxes2), 15),
            vec3(-100,270,395)
        )
    );

    camera cam;

    cam.aspect_ratio      = 1.0;
    cam.image_width       = image_width;
    cam.samples_per_pixel = samples_per_pixel;
    cam.max_depth         = max_depth;
    cam.background        = color(0,0,0);

    cam.vfov     = 40;
    cam.lookfrom = point3(478, 278, -600);
    cam.lookat   = point3(278, 278, 0);
    cam.vup      = vec3(0,1,0);

    cam.defocus_angle = 0;

    cam.render(world);
}

int main() {
    switch (0) {
        case 1:  random_spheres();            break;
        case 2:  two_spheres();               break;
        case 3:  earth();                     break;
        case 4:  two_perlin_spheres();        break;
        case 5:  quads();                     break;
        case 6:  simple_light();              break;
        case 7:  cornell_box();               break;
        case 8:  cornell_smoke();             break;
        case 9:  final_scene(800, 10000, 40); break;
        default: final_scene(400,   250,  4); break;
    }
}

Running it with 10,000 rays per pixel (sweet dreams) yields:

Now go off and make a really cool image of your own! See https://in1weekend.blogspot.com/ for pointers to further reading and features, and feel free to email questions, comments, and cool images to me at ptrshrl@gmail.com.

---

Last update: 2023-08-13