snoopy/include/scene.h

#pragma once

#include "math.h"
#include "sphere.h"
#include "colour.h"
#include "material.h"
#include "hittable.h"
#include "hittable_list.h"

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

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

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

        return grey;
    }

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

    return lerp(grey, pink, t);
}

hittable_list random_scene()
{
    hittable_list world;


    //auto ground_material = make_shared<lambertian>(pink);
    //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>(pink);
    //                world.add(make_shared<sphere>(centre, 0.2, sphere_material));
    //            }
    //            else if (choose_mat < 0.95)
    //            {
    //                // metal
    //                auto fuzz = random_double(0, 0.5);
    //                sphere_material = make_shared<metal>(pink, 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, 0, 0), 3.0, material1));

    //auto material2 = make_shared<lambertian>(pink);
    //world.add(make_shared<sphere>(point3(-4, 1, 0), 1.0, material2));
    
    auto material3 = make_shared<metal>(pink, 0.5);
    int sphere_count = 10;
    for (int i = 0; i < sphere_count; i++)
    {
        float a = 6.28 * (float)i/sphere_count - 100.0;
        float r = 8.0;
        float x = r*sin(a);
        float y = 2.0*cos(a);
        float z = r*cos(a);
        point3 pos(x,y,z);
        world.add(make_shared<sphere>(pos, 2.0, material3));
    }

    return world;
}