flood_fill.c

/* ************************************************************************** */
/*                                                                            */
/*                                                        :::      ::::::::   */
/*   flood_fill.c                                       :+:      :+:    :+:   */
/*                                                    +:+ +:+         +:+     */
/*   By: kamitsui <kamitsui@student.42tokyo.jp>     +#+  +:+       +#+        */
/*                                                +#+#+#+#+#+   +#+           */
/*   Created: 2024/12/01 02:42:15 by kamitsui          #+#    #+#             */
/*   Updated: 2024/12/17 03:20:15 by kamitsui         ###   ########.fr       */
/*                                                                            */
/* ************************************************************************** */
 
#include "cub3d.h"
 
int init_stack(t_stack *stack, int initial_capacity)
{
    stack->data = (t_point *)malloc(initial_capacity * sizeof(t_point));
    if (stack->data == NULL)
    {
        perror("Failed to allocate stack\n");
        return (EXIT_FAILURE);
    }
    stack->top = 0;
    stack->capacity = initial_capacity;
    return (EXIT_SUCCESS);
}
 
static int  push_neighbors_onto_stack(int x, int y, t_stack *stack)
{
    static int  dx[4] = {0, 0, -1, 1};
    static int  dy[4] = {-1, 1, 0, 0};
    int         new_x;
    int         new_y;
    int         i;
 
    i = 0;
    while (i < 4)
    {
        new_x = x + dx[i];
        new_y = y + dy[i];
        if (push(stack, (t_point){new_x, new_y}) != EXIT_SUCCESS)
            return (EXIT_FAILURE);
        i++;
    }
    return (EXIT_SUCCESS);
}
 
int check_grid_is_not_visited(t_point current, t_map *map,
        t_bool *is_surrounded, bool **visited)
{
    if (current.x < 0 || current.x >= map->width
        || current.y < 0 || current.y >= map->height)
    {
        *is_surrounded = ENUM_FALSE;
        return (CONTINUE);
    }
    if (visited[current.y][current.x] == true
        || map->data[current.y][current.x] == '1')
    {
        if (map->data[current.y][current.x] != '0'
            && map->data[current.y][current.x] != '1')
            *is_surrounded = ENUM_FALSE;
        return (CONTINUE);
    }
    return (EXIT_SUCCESS);
}
 
int initialize_for_flood_fill(t_stack *stack, int start_x, int start_y)
{
    if (init_stack(stack, DFLT_STACK_SIZE) != EXIT_SUCCESS)
        return (EXIT_FAILURE);
    if (push(stack, (t_point){start_x, start_y}) != EXIT_SUCCESS)
    {
        free(stack->data);
        return (EXIT_FAILURE);
    }
    return (EXIT_SUCCESS);
}
 
t_bool  flood_fill(t_map *map, int start_x, int start_y, bool **visited)
{
    t_stack     stack;
    t_bool      is_surrounded;
    t_point     current;
 
    if (initialize_for_flood_fill(&stack, start_x, start_y) != EXIT_SUCCESS)
        return (ENUM_ERROR);
    is_surrounded = ENUM_TRUE;
    while (is_empty(&stack) == false)
    {
        current = pop(&stack);
        if (check_grid_is_not_visited(current, map, &is_surrounded, visited)
            == CONTINUE)
            continue ;
        visited[current.y][current.x] = true;
        if (push_neighbors_onto_stack(current.x, current.y, &stack)
            != EXIT_SUCCESS)
        {
            is_surrounded = ENUM_ERROR;
            break ;
        }
    }
    free(stack.data);
    return (is_surrounded);
}