Mastering Multiplayer Networking in Unity

Multiplayer networking allows developers to create interactive online games where players can **connect, interact, and compete**. Unity provides several networking solutions, including **Mirror, FishNet, Photon, and Unity Netcode**. This guide explores the fundamentals of **multiplayer networking** in Unity and how to get started.

Why Use Multiplayer Networking?

Networking is essential for **online gaming**. It allows:

Real-time Player Interaction - Enable players to interact dynamically.
Competitive & Cooperative Modes - Build multiplayer combat or co-op experiences.
Dedicated Server Hosting - Reduce latency and improve stability.
Cross-Platform Play - Connect players across different devices.

Choosing a Networking Solution

Unity supports multiple **networking frameworks**:


1. **Mirror** - Open-source, optimized for performance, recommended for most multiplayer games.
2. **FishNet** - High-performance and feature-rich alternative to Mirror.
3. **Photon** - Cloud-based networking with scalable multiplayer capabilities.
4. **Unity Netcode** - Unity's official multiplayer framework for small-scale projects.

Setting Up Mirror Networking

Mirror is a popular **high-performance networking solution** for Unity.

1. Install Mirror

To install Mirror, add it via **Unity Package Manager**:


1. Open Unity's Package Manager (Window > Package Manager).
2. Click the **+** button and choose "Add package from Git URL."
3. Enter: `https://github.com/MirrorNetworking/Mirror.git`
4. Click "Add" to install Mirror.

2. Create a Network Manager

Mirror requires a **NetworkManager** component to handle player connections.


using Mirror;
using UnityEngine;

public class MyNetworkManager : NetworkManager
{
    public override void OnServerAddPlayer(NetworkConnectionToClient conn)
    {
        GameObject player = Instantiate(playerPrefab);
        NetworkServer.AddPlayerForConnection(conn, player);
    }
}

3. Synchronizing Player Movement

Use Mirror’s **NetworkTransform** to sync player movement.


using Mirror;
using UnityEngine;

public class PlayerMovement : NetworkBehaviour
{
    public float speed = 5f;

    void Update()
    {
        if (!isLocalPlayer) return;

        float moveX = Input.GetAxis("Horizontal");
        float moveY = Input.GetAxis("Vertical");

        transform.Translate(new Vector3(moveX, moveY, 0) * speed * Time.deltaTime);
    }
}

4. Spawning Players

Players need to spawn in the **networked environment**.


using Mirror;
using UnityEngine;

public class PlayerSpawner : NetworkBehaviour
{
    public GameObject playerPrefab;

    public override void OnStartServer()
    {
        GameObject player = Instantiate(playerPrefab, Vector3.zero, Quaternion.identity);
        NetworkServer.Spawn(player);
    }
}

Building & Testing Multiplayer

To test your multiplayer game:


1. Build your game: **File > Build Settings > PC, Mac, Linux**
2. Open multiple instances of the game.
3. Start one as **Host** and others as **Clients**.
4. Watch players sync across the network!

Conclusion

Multiplayer networking in Unity opens up endless possibilities for **online experiences**. Whether using **Mirror, FishNet, or Photon**, the key to successful networking is **optimizing performance and reducing latency**. Start small, test often, and build your dream multiplayer game!

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