rot-js/lib/map/dividedmaze.js

A roguelike toolkit in JavaScript

import Map from "./map.js";
import RNG from "../rng.js";
/**
 * @class Recursively divided maze, http://en.wikipedia.org/wiki/Maze_generation_algorithm#Recursive_division_method
 * @augments ROT.Map
 */
export default class DividedMaze extends Map {
    constructor() {
        super(...arguments);
        this._stack = [];
        this._map = [];
    }
    create(callback) {
        let w = this._width;
        let h = this._height;
        this._map = [];
        for (let i = 0; i < w; i++) {
            this._map.push([]);
            for (let j = 0; j < h; j++) {
                let border = (i == 0 || j == 0 || i + 1 == w || j + 1 == h);
                this._map[i].push(border ? 1 : 0);
            }
        }
        this._stack = [
            [1, 1, w - 2, h - 2]
        ];
        this._process();
        for (let i = 0; i < w; i++) {
            for (let j = 0; j < h; j++) {
                callback(i, j, this._map[i][j]);
            }
        }
        this._map = [];
        return this;
    }
    _process() {
        while (this._stack.length) {
            let room = this._stack.shift(); /* [left, top, right, bottom] */
            this._partitionRoom(room);
        }
    }
    _partitionRoom(room) {
        let availX = [];
        let availY = [];
        for (let i = room[0] + 1; i < room[2]; i++) {
            let top = this._map[i][room[1] - 1];
            let bottom = this._map[i][room[3] + 1];
            if (top && bottom && !(i % 2)) {
                availX.push(i);
            }
        }
        for (let j = room[1] + 1; j < room[3]; j++) {
            let left = this._map[room[0] - 1][j];
            let right = this._map[room[2] + 1][j];
            if (left && right && !(j % 2)) {
                availY.push(j);
            }
        }
        if (!availX.length || !availY.length) {
            return;
        }
        let x = RNG.getItem(availX);
        let y = RNG.getItem(availY);
        this._map[x][y] = 1;
        let walls = [];
        let w = [];
        walls.push(w); /* left part */
        for (let i = room[0]; i < x; i++) {
            this._map[i][y] = 1;
            if (i % 2)
                w.push([i, y]);
        }
        w = [];
        walls.push(w); /* right part */
        for (let i = x + 1; i <= room[2]; i++) {
            this._map[i][y] = 1;
            if (i % 2)
                w.push([i, y]);
        }
        w = [];
        walls.push(w); /* top part */
        for (let j = room[1]; j < y; j++) {
            this._map[x][j] = 1;
            if (j % 2)
                w.push([x, j]);
        }
        w = [];
        walls.push(w); /* bottom part */
        for (let j = y + 1; j <= room[3]; j++) {
            this._map[x][j] = 1;
            if (j % 2)
                w.push([x, j]);
        }
        let solid = RNG.getItem(walls);
        for (let i = 0; i < walls.length; i++) {
            let w = walls[i];
            if (w == solid) {
                continue;
            }
            let hole = RNG.getItem(w);
            this._map[hole[0]][hole[1]] = 0;
        }
        this._stack.push([room[0], room[1], x - 1, y - 1]); /* left top */
        this._stack.push([x + 1, room[1], room[2], y - 1]); /* right top */
        this._stack.push([room[0], y + 1, x - 1, room[3]]); /* left bottom */
        this._stack.push([x + 1, y + 1, room[2], room[3]]); /* right bottom */
    }
}