Unity Websocket: The Ultimate Guide to Building Real-time Multiplayer Games

Unity is a popular game development engine that allows developers to create games for multiple platforms. One of the most exciting features of Unity is its ability to support real-time multiplayer games. In this guide, we will explore how to use Unity Websocket to build real-time multiplayer games. We will cover everything from setting up a server to handling data transfer between clients. So, let’s get started.

What is Unity Websocket?

Websockets are a communication protocol that allows for real-time data transfer between clients and servers. Unity Websocket is a library that allows Unity developers to implement websockets in their projects. It provides an easy-to-use API for sending and receiving data over a websocket connection.

Websockets are ideal for real-time multiplayer games because they offer low latency and high reliability. This means that players can interact with each other in real-time, without any noticeable delay. Additionally, websockets are highly scalable, making them suitable for games with a large number of players.

Setting Up a Websocket Server

The first step in building a real-time multiplayer game with Unity Websocket is to set up a server. There are several options for setting up a websocket server, including using a third-party service or building your own from scratch. However, for the purposes of this guide, we will use Node.js and the Socket.io library to create a simple websocket server.

1. Install Node.js on your computer.
2. Create a new directory for your server files.
3. In the directory, create a new file called server.js.
4. In server.js, add the following code:

const io = require(‘socket.io’)(3000);

io.on(‘connection’, (socket) => {console.log(‘a user connected’);

socket.on(‘disconnect’, () => {console.log(‘user disconnected’);});

socket.on(‘chat message’, (msg) => {console.log(‘message: ‘ + msg);io.emit(‘chat message’, msg);});});

This code sets up a websocket server that listens for connections on port 3000. When a user connects, the server logs a message to the console. When the user disconnects, the server logs another message. Finally, when the server receives a ‘chat message’ event, it broadcasts the message to all connected clients.

Connecting to the Websocket Server

Now that we have a websocket server set up, we need to connect to it from our Unity game. To do this, we will use the Unity Websocket library.

1. Download the Unity Websocket library from the Unity Asset Store.
2. Import the library into your Unity project.
3. Create a new script called ‘WebSocketManager’.
4. In the script, add the following code:

using UnityEngine;using UnityWebSocket;

public class WebSocketManager : MonoBehaviour{WebSocket webSocket;

void Start(){webSocket = new WebSocket(“ws://localhost:3000”);webSocket.OnMessage += OnMessage;webSocket.Connect();}

void OnDestroy(){webSocket.Close();webSocket = null;}

void OnMessage(object sender, MessageEventArgs args){Debug.Log(args.Data);}}

This code creates a new websocket connection to the server, listens for incoming messages, and logs them to the Unity console. Note that we are connecting to the server at ‘ws://localhost:3000’, which is the address of our websocket server.

Sending Data over the Websocket

Now that we have a websocket connection set up, we can start sending data between the client and server. To do this, we will use the Send method provided by the Unity Websocket library.

1. Add the following code to your WebSocketManager script:

void Update(){if (Input.GetKeyDown(KeyCode.Space)){webSocket.Send(“Hello, server!”);}}

This code listens for the spacebar to be pressed and sends a message to the server when it is. The message we are sending is simply “Hello, server!”.

Receiving Data from the Websocket

Now that we can send data to the server, we need to be able to receive data from it. To do this, we will use the OnMessage event provided by the Unity Websocket library.

Let’s modify our WebSocketManager script to handle incoming messages:

void OnMessage(object sender, MessageEventArgs args){Debug.Log(args.Data);}

This code simply logs the incoming message to the Unity console. You can modify this code to handle incoming messages in any way you like.

Handling Multiple Clients

So far, we have only looked at how to set up a websocket connection between a single client and server. However, in a real-time multiplayer game, we will have multiple clients connecting to the server at the same time. To handle multiple clients, we need to modify our server code.

Let’s update our server.js file to handle multiple clients:

const io = require(‘socket.io’)(3000);

let players = {};

io.on(‘connection’, (socket) => {console.log(‘a user connected’);

socket.on(‘disconnect’, () => {console.log(‘user disconnected’);delete players[socket.id];io.emit(‘player disconnected’, socket.id);});

socket.on(‘new player’, () => {players[socket.id] = {x: 0,y: 0};io.emit(‘player connected’, socket.id);io.emit(‘update players’, players);});

socket.on(‘move player’, (data) => {players[socket.id].x = data.x;players[socket.id].y = data.y;io.emit(‘update players’, players);});});

This code maintains a list of all connected players and their positions. When a new player connects, the server adds them to the player list and broadcasts a ‘player connected’ event to all connected clients. When a player moves, the server updates their position in the player list and broadcasts an ‘update players’ event to all connected clients.

To handle multiple clients in our Unity game, we simply need to modify our WebSocketManager script to send and receive data for each connected client:

using UnityEngine;using UnityWebSocket;

public class WebSocketManager : MonoBehaviour{WebSocket webSocket;string clientId;

void Start(){webSocket = new WebSocket(“ws://localhost:3000”);webSocket.OnMessage += OnMessage;webSocket.OnOpen += OnOpen;webSocket.Connect();}

void OnDestroy(){webSocket.Close();webSocket = null;}

void OnOpen(object sender, System.EventArgs e){webSocket.Send(“new player”);}

void OnMessage(object sender, MessageEventArgs args){if (args.Data.StartsWith(“clientId:”)){clientId = args.Data.Split(‘:’)[1];}else{// Handle incoming player data here}}

void Update(){if (!string.IsNullOrEmpty(clientId)){// Send player data here}}}

This code sends a ‘new player’ message to the server when the websocket connection is opened. When the server responds with the client ID, the Unity game stores it for future use. The Update method is used to send player data to the server and handle incoming player data.

Conclusion

Unity Websocket is a powerful tool for building real-time multiplayer games. By using websockets, we can create games that feel responsive and engaging, even with a large number of players. With the information presented in this guide, you should be well on your way to building your own real-time multiplayer game using Unity Websocket.

What is a websocket?

A websocket is a communication protocol that allows for real-time data transfer between clients and servers. It is ideal for real-time multiplayer games because it offers low latency and high reliability.

What is Unity Websocket?

Unity Websocket is a library that allows Unity developers to implement websockets in their projects. It provides an easy-to-use API for sending and receiving data over a websocket connection.

How do I set up a websocket server?

There are several options for setting up a websocket server, including using a third-party service or building your own from scratch. For this guide, we used Node.js and the Socket.io library to create a simple websocket server.

How do I handle multiple clients in a real-time multiplayer game?

To handle multiple clients, you need to modify your server code to maintain a list of all connected players and their positions. When a new player connects, add them to the player list and broadcast a ‘player connected’ event to all connected clients. When a player moves, update their position in the player list and broadcast an ‘update players’ event to all connected clients.