Unity Multiplayer Starter Game

A code along project to get familiar with Unity multiplayer game setups.

Unity Version and Packages

• Unity 6 Beta (6000.0.2f1)
• VContainer - A lightweight Unity dependency injection solution
• SceneReference - An inspector scene reference tool
• Mirror - A Unity network solution continued by the community.
• PlayFab Unity3D SDK - A Microsoft game backend solution.
• PlayFab Unity Editor Extension - A Unity editor extension for setting up PlayFab.

Art Assets

• Low Poly Models made by @Zsky_01
• RPG Monster Duo PBR Polyart

Prerequisites

• It would be nice to look at official tutorial resources

  1. Hello World
  2. Gold Path Module One
  3. Golden Path Module Two

• Kart models: download from Low Poly Models, use .blend files under BLEND folder. Make sure install Blender for Unity to convert them into assets.

• Input settings can be configured as scriptable objects, a good trick to use and define InputAction behaviour before creating them as reusable configurations.

• Useful command line helpers and use cases link: Here.

• For Unity 2023.1.x or later, Multiplayer Play Mode is a better option for testing out server, host and client.

• For Unity 2022.x.x or earilier, using command lines with log output for debug purposes.

  1. Log Server

  <Path to Project>\<Game>.exe -logfile log-server.txt -mode server

  2. Log Client

  <Path to Project>\<Game>.exe -logfile log-client.txt -mode client

The Debugging logs on NetworkVariableTest works and outputs server uptime information. A DebugHelper outputs debugging logs on the screen as well.

How To Use

1. Add HelloWorldScene to File->Build Settings.
2. Go to the built executable location. Run console commands for both server and client from cmd or Powershell.
3. If server is started first, it has nothing in the scene. Once a client starts, a player object will spawn in both games.
4. Install Multiplayer Tools from Unity Package Manager Registry. Not mandatory, but very helpful for debugging and monitoring network traffic.
   • Profiler can be accessed from Window->Analysis->Profiler, and scrolldown to NGO Messages and NGO Objects sections.
   • Create an empty object in the scene and attach RuntimeNetstatsMonitor component for runtime data monitoring.

Network Behaviour Notes

• NetworkObject carrier should not be in the scene. Network prefabs handles all NetworkObject instances.
• Any MonoBehaviour implementing a NetworkBehaviour component can override the Netcode method OnNetworkSpawn(). The OnNetworkSpawn() method fires in response to the NetworkObject spawning.
• Having authority capability mapped with IsServer or IsClient flag will help sync with the rest of the code about which side has authority.

bool HasAuthority => isServer; // can be set for your whole class or even project
// ...
if (HasAuthority)
    { 
        // take an authoritative decision
        // ...
    }
if (!HasAuthority)
    {
        // ...
    }

• NetworkVariable take Generics and serialize them intelligently. If using a constum data structure as NetworkVariable type, it should implement INetworkSerializable and its NetworkSerialize method.

public struct CustomData : INetworkSerializable{
    public int Id;
    public bool IsOwner;
    
    public void NetworkSerialize<T>(BufferSerializer<T> serializer) where T: IReaderWriter{
        serializer.SerializeValue(ref Id);
        serializer.SerializeValue(ref IsOwner);
    }
}

• [ServerRpc] attribute marks events being sent to the server. The method is forced to have ServerRpc suffix, otherwise it won't compile.
• [ClientRpc] attribute marks events executed by the server and being sent to the client. he method is forced to have ClientRpc suffix, otherwise it won't compile.

Credits

• Multiplayer Kart made by adammyhre