rot-js/lib/map/iceymaze.js

A roguelike toolkit in JavaScript

import Map from "./map.js";
import RNG from "../rng.js";
/**
 * Icey's Maze generator
 * See http://roguebasin.com/index.php/Simple_maze for explanation
 */
export default class IceyMaze extends Map {
    constructor(width, height, regularity = 0) {
        super(width, height);
        this._regularity = regularity;
        this._map = [];
    }
    create(callback) {
        let width = this._width;
        let height = this._height;
        let map = this._fillMap(1);
        width -= (width % 2 ? 1 : 2);
        height -= (height % 2 ? 1 : 2);
        let cx = 0;
        let cy = 0;
        let nx = 0;
        let ny = 0;
        let done = 0;
        let blocked = false;
        let dirs = [
            [0, 0],
            [0, 0],
            [0, 0],
            [0, 0]
        ];
        do {
            cx = 1 + 2 * Math.floor(RNG.getUniform() * (width - 1) / 2);
            cy = 1 + 2 * Math.floor(RNG.getUniform() * (height - 1) / 2);
            if (!done) {
                map[cx][cy] = 0;
            }
            if (!map[cx][cy]) {
                this._randomize(dirs);
                do {
                    if (Math.floor(RNG.getUniform() * (this._regularity + 1)) == 0) {
                        this._randomize(dirs);
                    }
                    blocked = true;
                    for (let i = 0; i < 4; i++) {
                        nx = cx + dirs[i][0] * 2;
                        ny = cy + dirs[i][1] * 2;
                        if (this._isFree(map, nx, ny, width, height)) {
                            map[nx][ny] = 0;
                            map[cx + dirs[i][0]][cy + dirs[i][1]] = 0;
                            cx = nx;
                            cy = ny;
                            blocked = false;
                            done++;
                            break;
                        }
                    }
                } while (!blocked);
            }
        } while (done + 1 < width * height / 4);
        for (let i = 0; i < this._width; i++) {
            for (let j = 0; j < this._height; j++) {
                callback(i, j, map[i][j]);
            }
        }
        this._map = [];
        return this;
    }
    _randomize(dirs) {
        for (let i = 0; i < 4; i++) {
            dirs[i][0] = 0;
            dirs[i][1] = 0;
        }
        switch (Math.floor(RNG.getUniform() * 4)) {
            case 0:
                dirs[0][0] = -1;
                dirs[1][0] = 1;
                dirs[2][1] = -1;
                dirs[3][1] = 1;
                break;
            case 1:
                dirs[3][0] = -1;
                dirs[2][0] = 1;
                dirs[1][1] = -1;
                dirs[0][1] = 1;
                break;
            case 2:
                dirs[2][0] = -1;
                dirs[3][0] = 1;
                dirs[0][1] = -1;
                dirs[1][1] = 1;
                break;
            case 3:
                dirs[1][0] = -1;
                dirs[0][0] = 1;
                dirs[3][1] = -1;
                dirs[2][1] = 1;
                break;
        }
    }
    _isFree(map, x, y, width, height) {
        if (x < 1 || y < 1 || x >= width || y >= height) {
            return false;
        }
        return map[x][y];
    }
}