Resolved [XR Management] Controlling the used XRLoader Manually

What is the proper way to manually control the XR loader at start-up using XR Management?

I currently have XR Management configured to not initialize on start-up and include the Oculus and OpenVR loaders. In my start-up code I set the loader to use by removing the inappropriate one from the XRGeneralSettings.Instance.Manager.loaders collection based on the platform configuration of the application. After setting the loaders collection I then run the Manager's InitializeLoader and StartSubsystems functions. This seems to work properly in editor and the appropriate XRLoader is used; however, since the Manager is a ScriptableObject (XRManagerSettings instance) the modifications to the loaders collection actually change the XR Management configuration in the project which makes me think I am not doing this correctly.

Based on this post it sounds like there is a better way to handle the manual control of XRLoaders to use but I cannot seem to find another post or any documentation to indicate what that would be. Should I just be creating an instance of the OpenVRLoader or OculusLoader and calling Initialize and Start on them manually? That also feels wrong as it doesn't seem the loader would get the configuration values set via the XR Management UI.

Here is my current project setup:
Unity 2019.4.16
XR Plugin Management 3.2.17
Oculus XR Plugin 1.6.1
OpenVR XR Plugin 1.0.1

 

Thanks, @joejo. Seems odd that such an action is unsupported at runtime. Feels like the API should expose that as a read-only collection then.

Does that mean pulling the specific loader from the global XR Plug-in Management state loader and just calling Initialize followed by Start on it directly?

Also, do I need to call Stop and Deinitialize manually during application quit?

My current code looks something like this:

Code (CSharp):

1. Type targetLoaderType = null;
2.  
3. switch (platformType)
4. {
5.     case PlatformType.SteamVR:
6.         targetLoaderType = typeof(OpenVRLoader);
7.         break;
8.     case PlatformType.Oculus:
9.         targetLoaderType = typeof(OculusLoader);
10.         break;
11. }
12.  
13. if (targetLoaderType != null)
14. {
15.     List<XRLoader> loaders = XRGeneralSettings.Instance.Manager.loaders;
16.  
17.     for (int loaderIndex = loaders.Count - 1; loaderIndex >= 0; --loaderIndex)
18.     {
19.         XRLoader loader = loaders[loaderIndex];
20.  
21.         if (loader.GetType() != targetLoaderType)
22.         {
23.             loaders.RemoveAt(loaderIndex);
24.         }
25.     }
26. }
27. else
28. {
29.     Debug.LogError($"No known loader type available for current platform! Platform: {platformType}");
30. }
31.  
32. yield return XRGeneralSettings.Instance.Manager.InitializeLoader();
33.  
34. if (XRGeneralSettings.Instance.Manager.activeLoader != null)
35. {
36.     XRGeneralSettings.Instance.Manager.StartSubsystems();
37.     yield return null;
38. }
39. else
40. {
41.     Debug.LogError("Failed to initialize XR loader!");
42. }

Would I need to maintain any of that or would I just replace the InitializeLoader and StartSubsystems calls with the direct XRLoader equivalents?

 

Thanks for the help on this @joejo. I was able to get a solution implemented that works in editor and builds.

Unfortunately, I have run into a heap corruption issue from the Valve OpenVR XR Plugin that causes the Unity Editor to just close without resulting in caught crash. I've submitted a pull request to get the plugin fixed but it is currently preventing me from rolling the XR Management implementation out to the rest of my team.