perform_dda.c

/* ************************************************************************** */
/*                                                                            */
/*                                                        :::      ::::::::   */
/*   perform_dda.c                                      :+:      :+:    :+:   */
/*                                                    +:+ +:+         +:+     */
/*   By: kamitsui <kamitsui@student.42tokyo.jp>     +#+  +:+       +#+        */
/*                                                +#+#+#+#+#+   +#+           */
/*   Created: 2024/08/26 22:33:05 by kamitsui          #+#    #+#             */
/*   Updated: 2024/11/30 15:46:35 by kamitsui         ###   ########.fr       */
/*                                                                            */
/* ************************************************************************** */
 
#include "cub3d.h"
 
static int  get_line_type(t_ray_cast ray_cast)
{
    if (ray_cast.next_distance.x < ray_cast.next_distance.y)
        return (ON_VERTICAL_LINE);
    else
        return (ON_HORIZONTAL_LINE);
}
 
static bool is_hit_wall(t_map *map, t_ray_cast *ray_cast)
{
    return (map->data[ray_cast->grid.y][ray_cast->grid.x] == '1');
}
 
static void move_next_grid_line(t_ray_cast *ray_cast, int type)
{
    if (type == ON_VERTICAL_LINE)
    {
        ray_cast->next_distance.x += ray_cast->delta_distance.x;
        ray_cast->grid.x += ray_cast->step_dir.x;
    }
    else
    {
        ray_cast->next_distance.y += ray_cast->delta_distance.y;
        ray_cast->grid.y += ray_cast->step_dir.y;
    }
}
 
static double   calculate_distance(t_ray_cast ray_cast, int type)
{
    if (type == ON_VERTICAL_LINE)
        return (ray_cast.next_distance.x - ray_cast.delta_distance.x);
    else
        return (ray_cast.next_distance.y - ray_cast.delta_distance.y);
}
 
void    perform_dda(t_frame *frame, int x)
{
    bool        hit;
    int         type;
 
    hit = false;
    type = START_POINT;
    while (hit == 0)
    {
        type = get_line_type(frame->ray_cast);
        move_next_grid_line(&frame->ray_cast, type);
        hit = is_hit_wall(frame->map, &frame->ray_cast);
    }
    frame->dda.type_of_grid_line = type;
    frame->dda.perp_wall_dist = calculate_distance(frame->ray_cast, type);
    (void)x;
}
// debug code
//{
//  bool        hit;
//  int         type;
//
//  hit = false;
//  type = START_POINT;
//  debug_dda(frame, type, "perform_dda() ... start");
//  while (hit == 0)
//  {
//      type = get_line_type(frame->ray_cast);
//      move_next_grid_line(&frame->ray_cast, type);
//      hit = is_hit_wall(frame->map, &frame->ray_cast);
//      debug_dda(frame, type, "perform_dda() ... loop until hit wall");
//  }
//  frame->dda.type_of_grid_line = type;
//  frame->dda.perp_wall_dist = calculate_distance(frame->ray_cast, type);
//  (void)x;
//}
// reference cub3d.h 
//# define START_POINT -1
//# define ON_VERTICAL_LINE 0
//# define ON_HORIZONTAL_LINE 1