Master client-server architecture, Photon Unity Networking, and build multiplayer games
Multiplayer games let players interact in the same game world, even when they're on different computers! It's one of the most exciting (and challenging) aspects of game development. From co-op adventures to competitive shooters, multiplayer creates unforgettable experiences!
Multiplayer Networking is synchronizing game state across multiple devices. When one player moves, everyone else sees it. When someone shoots, everyone hears it. It's like magic, but it's actually clever programming!
Multiplayer challenges:
• Synchronizing game state
• Handling network lag
• Preventing cheating
• Managing connections
• Scaling to many players
Player Engagement
Multiplayer games have higher retention and replayability
Social Experience
Playing with friends creates memorable moments
Competitive Scene
Esports and competitive gaming are huge industries
Valuable Skill
Networking knowledge applies beyond games
Most multiplayer games use client-server architecture. The server is the authority - it decides what's real. Clients (players) send inputs to the server, and the server sends back the game state. This prevents cheating and keeps everyone synchronized!
Pros: Secure, prevents cheating, scalable
Cons: Requires server hosting, more complex
Best for: Competitive games, MMOs, shooters
Pros: No server needed, lower latency
Cons: Vulnerable to cheating, harder to scale
Best for: Co-op games, small player counts
1. Client sends input: "I pressed W key"
2. Server processes: "Player moved forward 5 units"
3. Server broadcasts: "Player 1 is now at position (10, 0, 5)"
4. All clients update: Show Player 1 at new position
This happens 20-60 times per second!
Photon is the most popular networking solution for Unity! It handles the complex networking code, provides free hosting for small games, and has excellent documentation. Perfect for beginners and professionals alike!
Step 1: Get Photon
1. Go to photonengine.com
2. Create free account
3. Create new PUN app, copy App ID
4. In Unity: Window → Asset Store → Search "PUN 2 FREE"
5. Download and import
6. Paste App ID when prompted
// NetworkManager.cs - Connect to Photon
using Photon.Pun;
using Photon.Realtime;
public class NetworkManager : MonoBehaviourPunCallbacks
{
void Start()
{
// Connect to Photon servers
PhotonNetwork.ConnectUsingSettings();
}
public override void OnConnectedToMaster()
{
Debug.Log("Connected to Photon!");
PhotonNetwork.JoinLobby();
}
public override void OnJoinedLobby()
{
Debug.Log("Joined lobby!");
}
public void CreateRoom()
{
RoomOptions options = new RoomOptions();
options.MaxPlayers = 4;
PhotonNetwork.CreateRoom("MyRoom", options);
}
public void JoinRoom()
{
PhotonNetwork.JoinRoom("MyRoom");
}
public override void OnJoinedRoom()
{
Debug.Log("Joined room!");
// Spawn player
PhotonNetwork.Instantiate("PlayerPrefab", Vector3.zero, Quaternion.identity);
}
}
// PlayerController.cs - Networked player
using Photon.Pun;
public class PlayerController : MonoBehaviourPun
{
public float speed = 5f;
void Update()
{
// Only control YOUR player
if (!photonView.IsMine) return;
float h = Input.GetAxis("Horizontal");
float v = Input.GetAxis("Vertical");
Vector3 movement = new Vector3(h, 0, v) * speed * Time.deltaTime;
transform.Translate(movement);
}
// Call this to sync an action
public void Shoot()
{
if (!photonView.IsMine) return;
// Call RPC on all clients
photonView.RPC("ShootRPC", RpcTarget.All);
}
[PunRPC]
void ShootRPC()
{
// This runs on ALL clients
Debug.Log("Player shot!");
// Play shoot animation, sound, etc.
}
}
Netcode is the code that handles networking. Good netcode makes multiplayer feel smooth even with lag. Let's learn the key concepts!
Call a function on other players' games. Perfect for events like shooting, jumping, or chatting. Use sparingly - too many RPCs can lag the game!
Automatically sync variables across network. Position, health, score - mark them for sync and Photon handles the rest! Use PhotonTransformView for position/rotation.
Each networked object has an owner. Only the owner can control it. Check photonView.IsMine before accepting input!
Use PhotonNetwork.Instantiate() instead of Instantiate(). This spawns the object on all clients. Prefabs must be in Resources folder!
Network lag is inevitable - data takes time to travel! Good netcode hides lag through clever techniques. Let's learn how to make multiplayer feel smooth!
Player moves immediately on their screen, then server confirms. If wrong, snap to correct position. Makes controls feel instant!
Smooth movement between network updates. Instead of teleporting, objects glide smoothly. Essential for other players' movement!
Server rewinds time when checking hits. If you shot where enemy WAS on your screen, it counts! Makes shooting feel fair despite lag.
Predict where objects will be based on velocity. If updates stop, keep moving in last direction. Reduces visible lag!
You now have all the knowledge to build multiplayer games! Start simple - a basic multiplayer movement game. Then add features: shooting, scoring, chat, matchmaking. The possibilities are endless!
You've completed the Game Development course! You now have the skills to create amazing games - from fundamentals to multiplayer. Keep practicing, keep building, and most importantly, keep having fun! The game development journey never ends - there's always something new to learn and create!