1  /* ************************************************************************** */
 2  /*                                                                            */
 3  /*                                                        :::      ::::::::   */
 4  /*   camera.c                                           :+:      :+:    :+:   */
 5  /*                                                    +:+ +:+         +:+     */
 6  /*   By: salee2 <salee2@student.42seoul.kr>         +#+  +:+       +#+        */
 7  /*                                                +#+#+#+#+#+   +#+           */
 8  /*   Created: 2023/05/24 20:20:48 by salee2            #+#    #+#             */
 9  /*   Updated: 2023/05/24 20:20:51 by salee2           ###   ########.fr       */
10  /*                                                                            */
11  /* ************************************************************************** */
12  
13  #include "include/minirt.h"
14  
15  double	degree_to_radian(double degree)
16  {
17  	return (degree * M_PI / 180.0);
18  }
19  
20  double	get_width(double h_fov)
21  {
22  	const double	theta = degree_to_radian(h_fov);
23  	const double	width = tan(theta / 2);
24  
25  	return (width);
26  }
27  
28  t_camera	camera_(t_canvas *canvas, t_point3 look_from, t_point3 look_at, \
29  double h_fov)
30  {
31  	t_camera		this;
32  	const t_vec3	jup = vec3_(0, 1, 0);
33  	const t_vec3	k = norm(sub(look_from, look_at));
34  	const t_vec3	i = norm(cross(jup, k));
35  	const t_vec3	j = cross(k, i);
36  
37  	this.viewport_w = 2.0 * get_width(h_fov);
38  	this.viewport_h = this.viewport_w / canvas->aspect_ratio;
39  	this.origin = look_from;
40  	this.ai = scl_mul(this.viewport_w, i);
41  	this.bj = scl_mul(this.viewport_h, j);
42  	this.lower_left_corner = sub(sub(sub(this.origin, \
43  	scl_mul(1.0 / 2.0, this.ai)), scl_mul(1.0 / 2.0, this.bj)), k);
44  	return (this);
45  }