Ananas aus Caracas: rot.js tutorial part 2

by rotjs

HTML

<!doctype html>
<html>
    <head>
        <title>Ananas aus Caracas: rot.js tutorial game</title>
        <script src="https://cdn.jsdelivr.net/npm/rot-js@2/dist/rot.js"></script>
    </head>
    <body>
        <h1>Ananas aus Caracas</h1>
    </body>
</html>

JavaScript

var Game = {
    display: null,
    map: {},
    engine: null,
    player: null,
    
    init: function() {
        this.display = new ROT.Display();
        document.body.appendChild(this.display.getContainer());
        
        this._generateMap();
        
        var scheduler = new ROT.Scheduler.Simple();
        scheduler.add(this.player, true);

        this.engine = new ROT.Engine(scheduler);
        this.engine.start();
    },
    
    _generateMap: function() {
        var digger = new ROT.Map.Digger();
        var freeCells = [];
        
        var digCallback = function(x, y, value) {
            if (value) { return; }
            
            var key = x+","+y;
            this.map[key] = ".";
            freeCells.push(key);
        }
        digger.create(digCallback.bind(this));
        
        this._generateBoxes(freeCells);
        this._drawWholeMap();
        this._createPlayer(freeCells);
    },
    
    _createPlayer: function(freeCells) {
        var index = Math.floor(ROT.RNG.getUniform() * freeCells.length);
        var key = freeCells.splice(index, 1)[0];
        var parts = key.split(",");
        var x = parseInt(parts[0]);
        var y = parseInt(parts[1]);
        this.player = new Player(x, y);
    },
    
    _generateBoxes: function(freeCells) {
        for (var i=0;i<10;i++) {
            var index = Math.floor(ROT.RNG.getUniform() * freeCells.length);
            var key = freeCells.splice(index, 1)[0];
            this.map[key] = "*";
        }
    },
    
    _drawWholeMap: function() {
        for (var key in this.map) {
            var parts = key.split(",");
            var x = parseInt(parts[0]);
            var y = parseInt(parts[1]);
            this.display.draw(x, y, this.map[key]);
        }
    }
};

var Player = function(x, y) {
    this._x = x;
    this._y = y;
    this._draw();
}
    
Player.prototype.act = function() {
    Game.engine.lock();
    window.addEventListener("keydown", this);
}
   ...