init_ray.c

/* ************************************************************************** */
/*                                                                            */
/*                                                        :::      ::::::::   */
/*   init_ray.c                                         :+:      :+:    :+:   */
/*                                                    +:+ +:+         +:+     */
/*   By: kamitsui <kamitsui@student.42tokyo.jp>     +#+  +:+       +#+        */
/*                                                +#+#+#+#+#+   +#+           */
/*   Created: 2024/08/26 22:32:18 by kamitsui          #+#    #+#             */
/*   Updated: 2024/11/30 15:44:55 by kamitsui         ###   ########.fr       */
/*                                                                            */
/* ************************************************************************** */
 
#include "cub3d.h"
 
static void set_x_side(t_ray_cast *ray_cast, t_vector *view_point)
{
    t_point     grid;
    t_vector    delta_distance;
 
    grid = ray_cast->grid;
    delta_distance = ray_cast->delta_distance;
    if (ray_cast->ray_dir.x < 0)
    {
        ray_cast->step_dir.x = -1;
        ray_cast->next_distance.x
            = (view_point->x - (double)grid.x) * delta_distance.x;
    }
    else
    {
        ray_cast->step_dir.x = 1;
        ray_cast->next_distance.x
            = ((double)grid.x + 1.0 - view_point->x) * delta_distance.x;
    }
}
 
static void set_y_side(t_ray_cast *ray_cast, t_vector *view_point)
{
    t_point     grid;
    t_vector    delta_distance;
 
    grid = ray_cast->grid;
    delta_distance = ray_cast->delta_distance;
    if (ray_cast->ray_dir.y < 0)
    {
        ray_cast->step_dir.y = -1;
        ray_cast->next_distance.y
            = (view_point->y - (double)grid.y) * delta_distance.y;
    }
    else
    {
        ray_cast->step_dir.y = 1;
        ray_cast->next_distance.y
            = ((double)grid.y + 1.0 - view_point->y) * delta_distance.y;
    }
}
 
static void set_direction_and_distance_for_dda(
                t_ray_cast *ray_cast, t_vector *view_point)
{
    set_x_side(ray_cast, view_point);
    set_y_side(ray_cast, view_point);
}
 
static t_vector get_delta_distance(t_ray_cast ray_cast)
{
    t_vector    delta_distance;
 
    if (ray_cast.ray_dir.x == 0)
        delta_distance.x = 1e30;
    else
        delta_distance.x = fabs(1 / ray_cast.ray_dir.x);
    if (ray_cast.ray_dir.y == 0)
        delta_distance.y = 1e30;
    else
        delta_distance.y = fabs(1 / ray_cast.ray_dir.y);
    return ((t_vector)delta_distance);
}
 
void    init_ray(t_frame *frame, int x)
{
    t_ray_cast  ray_cast;
    t_vector    camera_forcal_plane;
    t_vector    ray_dir;
 
    camera_forcal_plane = frame->player->camera_forcal_plane;
    ray_dir = frame->player->ray_dir;
    ray_cast.camera_plane_x = 2 * x / (double)IMG_3D_WIDTH - 1;
    ray_cast.ray_dir.x
        = ray_dir.x + camera_forcal_plane.x * ray_cast.camera_plane_x;
    ray_cast.ray_dir.y
        = ray_dir.y + camera_forcal_plane.y * ray_cast.camera_plane_x;
    ray_cast.grid.x = (int)frame->player->view_point.x;
    ray_cast.grid.y = (int)frame->player->view_point.y;
    ray_cast.delta_distance = (t_vector)get_delta_distance(ray_cast);
    set_direction_and_distance_for_dda(&ray_cast, &frame->player->view_point);
    frame->ray_cast = ray_cast;
}
    //debug_ray_cast(frame, "after init_ray()", x);