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name: unity-networking description: Implement multiplayer games with Unity Netcode, Mirror, or Photon. Masters client-server architecture, state synchronization, and lag compensation. Use for multiplayer features, networking issues, or real-time synchronization. requires:

• csharp-plugin:csharp-code-style

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Unity Networking - Multiplayer Game Development

Overview

Multiplayer networking for Unity using Netcode for GameObjects, Mirror, or Photon frameworks.

Foundation Required: unity-csharp-fundamentals (TryGetComponent, FindAnyObjectByType, null-safe coding)

Core Topics:

• Client-server architecture
• State synchronization
• Lag compensation
• RPC (Remote Procedure Calls)
• Network variables
• Matchmaking

Quick Start (Unity Netcode)

using Unity.Netcode;

public class Player : NetworkBehaviour
{
    private NetworkVariable<int> mHealth = new(100);

    public override void OnNetworkSpawn()
    {
        if (IsOwner)
        {
            // Only owner can control
            HandleInput();
        }

        mHealth.OnValueChanged += OnHealthChanged;
    }

    [ServerRpc]
    void TakeDamageServerRpc(int damage)
    {
        mHealth.Value -= damage;
    }

    [ClientRpc]
    void ShowDamageEffectClientRpc()
    {
        // Visual feedback on all clients
    }
}

Network Architecture

• Authoritative Server: Server validates all actions (competitive)
• Client Authority: Clients control own entities (cooperative)
• Relay Servers: NAT traversal for peer-to-peer
• Dedicated Servers: Professional hosting

Synchronization Patterns

• Transform Sync: Position, rotation interpolation
• Network Variables: Automatic state replication
• RPCs: Remote method calls
• Ownership: Who can modify what

Best Practices

1. Server authority: Prevent cheating
2. Client prediction: Smooth movement
3. Interpolation: Handle lag gracefully
4. Bandwidth optimization: Delta compression
5. Test with network simulation: Latency, packet loss