Unlock the Power of Multiplayer Games with Colyseus

Building a multiplayer game can be a daunting task, especially when it comes to networking and state synchronization. But what if you could focus solely on creating an amazing gaming experience, without worrying about the underlying infrastructure? Enter Colyseus, a revolutionary framework designed to simplify the process of building online multiplayer games.

Getting Started with Colyseus

To demonstrate the capabilities of Colyseus, we’ll build a multiplayer Tetris clone, dubbed Tetrolyseus. We’ll use Colyseus’ npm-init initializer to set up our project, which automates the creation of new projects and generates the necessary files. Our project will consist of two main files: index.ts and MyRoom.ts.

npx colyseus init tetrolyseus

Understanding Colyseus Rooms

In Colyseus, a room is the central piece of our game, responsible for handling client connections and storing the game’s state. A room is defined by its unique name, which clients use to connect to it. We can attach lifecycle events to a Colyseus room, such as onCreate, onJoin, onLeave, and onDispose, to manage our game logic.

import { Room } from 'colyseus';

class MyRoom extends Room {
  onCreate() {
    // Initialize game state
  }

  onJoin(client: Client) {
    // Handle client joining the room
  }

  onLeave(client: Client) {
    // Handle client leaving the room
  }

  onDispose() {
    // Clean up game state
  }
}

Modeling Game State

Every game requires a well-structured state to function properly. Colyseus provides a simple and type-safe way to enable synchronization and nested child schema, allowing us to break down our state into reusable components. We’ll create a GameState class that consists of several child schema properties, including Position, Board, and Tetrolyso.

import { Schema } from 'colyseus';

class Position extends Schema {
  @type('number') x: number;
  @type('number') y: number;
}

class Board extends Schema {
  @type('array') cells: number[][];
}

class Tetrolyso extends Schema {
  @type('number') score: number;
  @type('number') level: number;
}

class GameState extends Schema {
  @type('Position') position: Position;
  @type('Board') board: Board;
  @type('Tetrolyso') tetrolyso: Tetrolyso;
}

Working with Game State: Frontend

To visualize our game state, we’ll build a frontend using plain HTML, CSS, and TypeScript. We’ll use NES.css and Parcel.js to create a simple layout, and establish a connection to our backend using Colyseus’ JavaScript client. Once connected, we can join or create a game room and access our GameState instance.

<div id="game-container"></div>

import { Client } from 'colyseus';

const client = new Client('ws://localhost:2567');
const room = client.joinOrCreate('my_room');
const gameState = room.state;

Game Rendering and State Updates

We’ll render our UI using CSS Grid and our Board state, and display the current Tetrolyso. To get our game moving, we’ll attach a callback to the onStateChange handler, which will rerender our UI whenever the state changes. We’ll also handle player input by sending messages to our backend, which will update the game state accordingly.

room.onStateChange((state) => {
  // Rerender UI based on updated state
});

Working with Game State: Backend

In our backend, we’ll extend our TetrolyseusRoom to initialize our state, compute scores, detect collisions, and implement game logic. We’ll use a Delayed instance to create a game loop, which will perform all the necessary steps to update our game state.

class TetrolyseusRoom extends Room {
  onCreate() {
    // Initialize game state
  }

  update() {
    // Compute scores, detect collisions, and update game state
  }
}

Making it Multiplayer

To add multiplayer functionality, we’ll introduce a ReadyState message type and update our GameState to include a running flag. We’ll also assign player roles (MOVER or ROTATOR) randomly, and limit player actions based on their roles.

class ReadyState extends Schema {
  @type('boolean') isReady: boolean;
}

class GameState extends Schema {
  @type('ReadyState') readyState: ReadyState;
  //...
}

Ready to Ship?

Finally, we’ll create an application bundle for easier shipping by extending our package.json and adding additional scripts. With Colyseus, building a multiplayer game has never been easier. Focus on creating an amazing gaming experience, and let Colyseus handle the rest.

{
  "scripts": {
    "build": "parcel build index.html",
    "start": "parcel serve index.html"
  }
}