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Getting Started with Boss Room

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Boss Room is a fully functional co-op multiplayer RPG made with Unity Netcode. it's an educational sample designed to showcase typical netcode patterns that are often featured in similar multiplayer games.

PLEASE NOTE: Boss Room is compatible with the latest Unity Long Term Support (LTS) editor version, currently 2021 LTS. Please include standalone support for Windows/Mac in your installation.

Download the project files

  1. Go to the Multiplayer Samples Co-Op Latest Release on GitHub.
  2. Click on to automatically start downloading the folder.
  3. Unzip the Project zip file. It unzips a folder named<version>.
    Windows users

    Using Windows' built-in extracting tool may generate an "Error 0x80010135: Path too long" error window which can invalidate the extraction process. As a workaround, shorten the zip file to a single character (for example and move it to the shortest path on your computer (such as in root C:) and retry. If that solution fails, another workaround is to extract the downloaded zip file using an application like 7zip.

  4. You may choose to move your unzipped folder to a new location. My default location is my Downloads folder that I regularly clean out, so I moved the folder to my desktop.
  5. You can now add the Boss Room project to your Unity Hub.

Boss Room has been developed and tested on the following platforms:

  • Windows

  • Mac

  • iOS

  • Android Boss Room's min spec devices are:

  • iPhone 6S

  • Samsung Galaxy J2 Core

Add the project with Unity Hub

  1. Open your Unity Hub.
  2. Click the dropdown arrow next to Open, then select Add project from disk.
  3. Select the root folder of the downloaded project. For example,<version>.

The first time you open the project, Unity will import all assets, which will take longer than usual - this is normal. The Unity Netcode for GameObjects package will also be installed with Boss Room.

Issues with importing due to parental control software: If you have issues with importing you may want to check your DNS settings as some ISP parental controls may block GitHub access. For example, see this information on WebSafe.

Register the project with Unity Gaming Services (UGS)

This project leverages several services from UGS to ease connectivity between players. To use these services inside your project, you must first create an organization inside the Unity Dashboard, and enable both the Relay and Lobby services.

Open the project

To open the project for the first time:

  1. In your Unity Hub, double-click the project.
  2. Navigate to the Editor window.
  3. Then under the Project tab, go to Assets > Boss Room > Scenes and double-click on the Startup scene.
  4. Click Play. The Boss Room menu scene loads.

Test multiplayer

To see the multiplayer functionality in action, you can either run multiple instances of the game locally on your computer or choose to connect through the internet.

Local multiplayer setup

For a local multiplayer setup, you must build an executable and launch several instances of this executable to both host and join a game.

  1. With the Boss Room project open in your Unity editor, click File > Build Settings > Build.
  2. Save the binary as Boss Room.

After the build has completed, you can launch several instances of the built executable to both host and join a game.

Mac Users

To run multiple instances of the same app, you need to use the command line:

  1. First, change your directory to the folder where you saved the Boss Room executable. For example, cd Desktop/<version>.
  2. Run the command Open -n If you saved the app as BossRoom, your command is Open -n However, if you saved your app as Boss Room with a space, your command needs to include quotation marks ("") around the executable name: Open -n "".

Multiplayer over internet

In contrast to running a local setup, when playing over internet we don't necessarily need a built executable. You can run the game in editor.

Running the game over internet currently requires using Port Forwarding or Integrating Boss Room with Unity Gaming Services.

Port Forwarding

The Portforward Site has guides on how to enable port forwarding on a huge number of routers. Boss Room uses UDP and needs a 9998 external port to be open.

Integrating Boss Room with Unity Gaming Services

With the release of Boss Room 1.1.0, Boss Room integrated with Unity Gaming Services (UGS): Authentication, Relay, and Lobby. These services make it easy for players to host and join games that are playable over the internet, without the need for port forwarding or out-of-game coordination.


To interact with the rest of UGS, the user must be authenticated. Therefore, authentication is kicked off as soon as the game launches and the main menu scene loads.


The Authentication service supports anonymous sign-in and doesn't require any additional input from the player.

The Authentication API doesn't distinguish multiple instances of the same project running on the same machine and logs in the same user in all those different instances. Both ParrelSync clones and actual game builds are affected and can mess up testing the game locally.

However, Authentication supports Profiles that allows different users existing on the same physical machine. To test locally, we need both builds and editor players to be able to switch to different Profiles.

The ProfileManager class wraps the logic for deciding what Profile you should be using, if any. In builds, the command-line argument -AuthProfile specifies the new profile id. When iterating in the editor, ParrelSync can use its CloneManager custom arguments to decide what user profile to use. Users can also change profile using the in-game menu.

ProfileManager.Profile generates the custom InitializationOptions:

var unityAuthenticationInitOptions = new InitializationOptions();
var profile = ProfileManager.Profile;

if (profile.Length > 0)

The code that executes profile switch and sign-in logic itself is as follows:

async Task TrySignIn(InitializationOptions initializationOptions)
await Unity.Services.Core.UnityServices.InitializeAsync(initializationOptions);

if (!AuthenticationService.Instance.IsSignedIn)
await AuthenticationService.Instance.SignInAnonymouslyAsync();

Next is lobby and relay.

Lobby and Relay

The Lobby Host Flow
  1. The would-be host enters the lobby name, specifies if it's public or private and hits the Create button.
  2. The Lobby creation API call is made. The newly created lobby is locked (i.e prevented from appearing in the list of publicly available, fully set up games that are ready to be joined) until we successfully complete the relay allocation and Netcode startup steps below.
  3. The host requests a relay allocation from the Relay service.
  4. UTP) starts and the host is switches to the character selection scene. The lobby itself is now considered unlocked and is available for other clients to join.
The Lobby Client Flow
  • There are several ways to connect to a lobby:
    • Choose one of the public lobbies regularly fetched from the Lobby service
    • Quickjoin: Randomly selects a public lobby
    • Using a lobby key, shared through out-of-game means. This works for both public and private lobbies.
  • After joining a lobby, the relay join code passes through lobby metadata to connect to the host via UTP Relay transport.
  • The host receives a request to approve the connecting client, and the host would server-authoritatively switch the player to the appropriate scene.

Currently, the Lobby service has to be polled for updates. This isn't ideal for a responsive feel to character selection; however, when there is an option to get real time updates from the Lobby service, it would be a good alternative way to implement something like this.

Disconnection and Reconnection

Handling player disconnections and reconnections is a necessity in a multiplayer game.

Boss Room uses a session management system that ensures when a player disconnects, some data is kept and accurately assigned back to that player if or when they reconnect (see SessionManager.cs – OnClientDisconnect).

The way Boss Room handles restoration of user data on reconnection can be found in SessionManager.cs - SetupConnectingPlayerSessionData, which is called as a part of a connection approval check that is handled by the host (see ServerGameNetPortal.s – ApprovalCheck).


It's important to promptly remove disconnected players from the lobby. Otherwise, the disconnected player can't rejoin the lobby because they're still considered in it.

When a player disconnects from Relay, eventually the Lobby and Relay service integration (necessary before we run UTP connection) kicks out the disconnected players. However, the timeout for disconnect is quite long (~2 minutes), and we don't rely solely on this mechanism.

To make the process of leaving lobby more reliable, there are several additional cleanup mechanisms:

  • The client code has application quit logic (see ApplicationController.cs - OnWantToQuit and LeaveSession) that sends a request to remove the player from the lobby
  • The host has special logic that removes the disconnected player from the lobby as soon as the host knows about it (NetworkManager.OnClientDisconnectCallback). This is helpful when the client has crashed and cann't send a "leave lobby" request.
  • Lastly, the client has checks that determine if the host has left the lobby, and if so, the client leaves the lobby too. The code for this can be found at ClientGameNetPortal.cs - OnDisconnectOrTimeout.


Errors finding Git installation

If you receive an OS or Unity error trying to locate Git after updating or installing Git, you need to fully restart your computer. Restarting only Unity may not fully update system information to correctly locate the install.

Windows Error 0x80010135: Path too long

Using Windows' built-in extracting tool may generate an "Error 0x80010135: Path too long" error window which can invalidate the extraction process. As a workaround, shorten the zip file to a single character (for example and move it to the shortest path on your computer (such as in root C:) and retry. If that solution fails, another workaround is to extract the downloaded zip file using an application like 7zip.

Run builds on Mac OSX gives "unidentified developer"

If you attempt to run a build on OSX and receive a warning dialog mentioning an "unidentified developer", you may need to override your security settings for this application:

  1. In the Finder on your Mac, locate the application you want to open.


    Don't use Launchpad, it does not allow you to access the shortcut menu.

  2. Control-click the app icon, then choose Open from the shortcut menu.

  3. Click Open.

  4. The app is saved as an exception to your security settings. You can open it in the future by double-clicking it just as you can any registered app.

See Apple Support for details.