camera.h

#ifndef CAMERA_H
#define CAMERA_H

#include "rtweekend.h"

class camera {
    public:
	camera(point3 lookfrom, point3 lookat, vec3 vup, double vfov, double aspect_ratio, double aperture, double focus_dist, double _time0 = 0, double _time1 = 0) {	// vfov = vertical field-of-view in degress

	    auto theta = degrees_to_radians(vfov);
	    auto h = tan(theta/2);
	    auto viewport_height = 2.0 * h;
	    auto viewport_width = aspect_ratio * viewport_height;

	    w = unit_vector(lookfrom - lookat);
	    u = unit_vector(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;
	    time0 = _time0;
	    time1 = _time1;

	}

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

	    return ray(origin + offset, lower_left_corner + s*horizontal + t*vertical - origin - offset, random_double(time0, time1));
	} 

	private:
	    point3 origin;
	    point3 lower_left_corner;
	    vec3 horizontal;
	    vec3 vertical;
	    vec3 u, v, w;
	    double lens_radius;
	    double time0, time1;	// shutter open/close times
};

#endif