#include <fstream>
#include <iostream>

#include "ray.h"
#include "vec3.h"

using namespace std;

//skybox

bool hit_sphere(const vec3& center, float radius, const ray& r) {
    float a, b, c;
    a = dot(r.D, r.D);
    b = 2 * (dot(r.D, (r.O - center)));
    c = dot(r.O - center, r.O - center) - radius * radius;
    return ((b * b) - (4 * a * c) >= 0);
}

vec3 color(ray& r) {
    /*
    if (hit_sphere(vec3(0, 0, -1), 0.5, r)) {
        return vec3(1, 0, 0);
    }
    */
    vec3 unit_direction = unit_vector(r.direction());
    float t = 0.5 * (unit_direction.y() + 1.0);

    return vec3(1, 1, 1) * float(1.0 - t) + float(t) * vec3(0.5, 0.7, 1.0);
}

int main() {
    int width = 200;
    int height = 100;

    fstream file;
    file.open("ray.ppm", ios::out);

    vec3 lower_left_corner(-2, -1, -1);
    vec3 origin(0, 0, 0);
    vec3 horizontal(4, 0, 0);
    vec3 vertical(0, 2, 0);
    file << "P3\n"
         << width << " " << height << "\n255\n";
    for (int j = height - 1; j >= 0; j--) {
        for (int i = 0; i < width; i++) {
            float u = float(i) / float(width);
            float v = float(j) / float(height);
            ray r = ray(origin, lower_left_corner + u * horizontal + v * vertical);
            vec3 color2 = color(r);
            file << int(color2.r() * 255) << " " << int(color2.g() * 255) << " " << int(color2.b() * 255) << "\n";
        }
    }
    file.close();
}