Resolved Error when connecting to Relay as client w/ NGO

Hi all,

In my flow, I'm creating a lobby, player 2 joins and once that happens the lobby host will allocate a relay server and via lobby I'm sharing the joinCode and letting player 2 join the relay server via this joinCode.

All seems to work fine except the client (player 2) is trying to load a scene that's already active:

Exception: Failed to find any loaded scene named GameplayScene!

Now I debugged the code where S*** hits the fan and it seems not all cases are covered, it's throwing an exception in the snippet below in file ```NetworkSceneManager, line 641```.

Code (CSharp):

1. internal Scene GetAndAddNewlyLoadedSceneByName(string sceneName)
2. {
3.     for (int i = 0; i < SceneManager.sceneCount; i++)
4.     {
5.         var sceneLoaded = SceneManager.GetSceneAt(i);
6.         if (sceneLoaded.name == sceneName)
7.         {
8.             if (!ScenesLoaded.ContainsKey(sceneLoaded.handle))
9.             {
10.                 ScenesLoaded.Add(sceneLoaded.handle, sceneLoaded);
11.                 return sceneLoaded;
12.             }
13.         }
14.     }
15.  
16.     throw new Exception($"Failed to find any loaded scene named {sceneName}!");
17. }

I learned that

if (!ScenesLoaded.ContainsKey(sceneLoaded.handle))

will always be

true

in my case. The

ScenesLoaded

dictionary already contains the scene it's trying to load and thus will automatically end up in the exception being thrown.

It seems like a bug to me, if so I'll report it properly. But any way I can work around this? I don't need help loading correct scenes or anything, which this code states to be doing:

/// Since SceneManager.GetSceneByName only returns the first scene that matches the name

/// we must "find" a newly added scene by looking through all loaded scenes and determining

/// which scene with the same name has not yet been loaded.

/// In order to support loading the same additive scene within in-scene placed NetworkObjects,

/// we must do this to be able to soft synchronize the "right version" of the NetworkObject.

To be clear: I'm NOT spawning a PlayerPrefab from the NetworkManager as I'm not looking to do this anyway (might need to change my setup to UDP instead of NGO?). I'm also not sending any RPCs yet or doing any other kind of networked activity yet.

It's kinda blocking me to continue this project. And I'm starting to seriously consider other non-unity networking solutions (I know Relay is in Beta, but I also wanna make progress )

Running this on Unity 2021.2.3f1 and using the following package versions:


Cheers!

 

Hi Kip,

Thanks for the extensive response. Before you posted this I've changed from NGO to UDP as it'd fit my needs better for this specific project anyway. And I'm not running into any issues so far. Lobby and Relay seem to be doing their jobs just fine.

But good to know there's a workaround for the NGO issue I happened to run in to.

Cheers!

P.S. The reason I've posted this here and not started a ticket is because other devs might run in to this same issue. Now the web knows and it's workaround