raytracing-in-a-weekend-oop/camera.h

#ifndef CAMERA_H
#define CAMERA_H

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

class camera {
	public:
		camera(
				point3 lookfrom,
				point3 lookat,
				vec3 vup,
				double vfov, // vertical field-of-view in degrees,
				double aspect_ratio,
				double aperture,
				double focus_dist
		) {
			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;
		}

		ray get_ray(double s, double t) const {
			vec3 rd = lens_radius * random_in_unit_sphere();
			vec3 offset = u* rd.x() + v * rd.y();
			return ray(
				origin + offset,
				lower_left_corner + s*horizontal + t*vertical - origin - offset
			);
		}

	private:
		point3 origin;
		point3 lower_left_corner;
		vec3 horizontal;
		vec3 vertical;
		vec3 u, v, w;
		double lens_radius;
};

#endif