#ifndef CAMERA_H
#define CAMERA_H

#include "rtweekend.hpp"

struct camera {
    /* Attributes */
    point3 origin;
    point3 lower_left_corner;
    vec3 horizontal;
    vec3 vertical;
    vec3 u,v,w;
    float lens_radius;
    
    /* Constructors */
    camera(point3 lookfrom,
           point3 lookat,
           vec3 vup,
           float vfov,
           float aspect_ratio,
           float aperture,
           float focus_dist)
    {
        float theta = degrees_to_radians(vfov);
        float h = tan(theta/2);
        float viewport_height = 2.0 * h;
        float viewport_width = aspect_ratio * viewport_height;

        w = normalize(lookfrom - lookat);
        u = normalize(cross(vup,w));
        v = cross(w, u);

        origin = lookfrom;
        horizontal = focus_dist * viewport_width * u;
        vertical = focus_dist * viewport_height * v;
        lower_left_corner = origin - horizontal/2 - vertical/2 - focus_dist*w;

        lens_radius = aperture/2;
    }

    /* Methods */    

    ray get_ray(float s, float t, int32_t thread_id = 0) const
    {        
        vec3 rd = lens_radius * random_in_unit_disk(thread_id);
        vec3 offset = u * rd.x + v * rd.y;

        return ray(origin + offset, lower_left_corner + s*horizontal + t*vertical - origin - offset);
    };
};

#endif