Mirror networking
- Game Development course
- Advanced
- Lesson 15/71
- 4 min
Learn SyncVar and Command structure with Mirror.
Mirror Networking and NetworkBehaviour
Mirror is an open-source, high-performance Client-Server networking library for Unity. Instead of standard MonoBehaviour, classes inherit from NetworkBehaviour.
using Mirror;
public class PlayerController : NetworkBehaviour {
[SyncVar]
public int health = 100;
}When the server updates a variable tagged with the [SyncVar] attribute, Mirror automatically synchronizes the new value across all connected clients.
Client-to-Server Calls with [Command]
In an authoritative setup, clients cannot mutate game state directly. For a client to request an action on the server, a method tagged with the [Command] attribute is called.
// Called by client, executed strictly on the server
[Command]
public void CmdFireWeapon(Vector3 direction) {
SpawnBulletOnServer(direction);
}Command methods must begin with the Cmd prefix to make it immediately evident that a client request is being dispatched to the server.
Practice Print synchronized health value
Define a Start method. Inside, declare int health = 100; and print "Oyuncu cani senkron: " + health to the console using Debug.Log.
Starter code
using UnityEngine;
public class MirrorPlayer : MonoBehaviour
{
// Start icinde can ve SyncVar bilgisini yazdir
}Sample solution
using UnityEngine;
public class MirrorPlayer : MonoBehaviour
{
void Start()
{
int health = 100;
Debug.Log("Oyuncu cani senkron: " + health);
}
}Expected output
Oyuncu cani senkron: 100
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 Which attribute in the Mirror library automatically synchronizes a variable's server value across all clients?
- [SyncVar] Correct answer
- [ClientRpc]
- [TargetRpc]
- [Command]
Explanation: [SyncVar] (Synchronized Variable) automatically syncs server-side value changes to each client's local copy.
2 Declare SyncVar
[____] public int health = 100;[SyncVar] public int health = 100;Explanation: In Mirror, the '[SyncVar]' attribute is used for variable synchronization.
3 Mirror concepts
| Term | Meaning |
|---|---|
NetworkBehaviour |
Base class for networked components |
[SyncVar] |
Variable synced from server to clients |
[Command] |
Method run by client on the server |
CmdOnEk |
Mandatory prefix for Command functions |