Bug (Case 1407649) OpenXR - Device disconnected events not firing?

This seems to have been an issue for over 2 years now, when using Unity OpenXR package 1.3.1 currently, when using InputDevices.deviceDisconnected, nothing fires when XR devices are disconnected during play mode. When using InputDevices.deviceConnected, despite the connected events all firing at start of play mode for all known devices, the connected events fire perfectly in play mode when devices are connected thereafter. Similarly, in Window > Analysis > Input Debugger, you can see the OpenXR controller devices stay active there too and don't disconnect properly.

To clarify, I am using SteamVR for OpenXR and testing with a lighthouse setup of Vive Cosmos + Faceplate + Vive Controller + Base Station

Tiny repro project: https://drive.google.com/file/d/1MvNI6q0sJupliWSFgLZwZlEvKSrylxUl/view?usp=sharing

Sample code to easily see this:

Code (CSharp):

1. using System.Collections.Generic;
2. using UnityEngine;
3. using UnityEngine.XR;
4.  
5. public class Test : MonoBehaviour
6. {
7.     void OnEnable()
8.     {
9.         List<InputDevice> allDevices = new List<InputDevice>();
10.         InputDevices.GetDevices(allDevices);
11.         foreach (InputDevice device in allDevices)
12.         {
13.             InputDevices_deviceConnected(device);
14.         }
15.  
16.         InputDevices.deviceConnected += InputDevices_deviceConnected;
17.         InputDevices.deviceDisconnected += InputDevices_deviceDisconnected;
18.     }
19.     private void InputDevices_deviceConnected(InputDevice device)
20.     {
21.         Debug.Log("Device Connected: " + device.name);
22.     }
23.     private void OnDisable()
24.     {
25.         InputDevices.deviceConnected -= InputDevices_deviceConnected;
26.         InputDevices.deviceDisconnected -= InputDevices_deviceDisconnected;
27.     }
28.     private void InputDevices_deviceDisconnected(InputDevice device)
29.     {
30.         Debug.Log("Device disconnected: " + device.name);
31.     }
32.  
33. }
34.  

I made a vid of it here:

 

Makes sense, I made a rudimentary setup using those already and waiting a few seconds to register a device as disconnected myself.

 

Same behaviour in my projects when having OpenXR checked inside the "XR Plugin Management" section. Yet, I think it's still a bit confusing because talking about e.g. the Unity VarjoOpenXR SDK, the connected/disconnected state works as mentioned (when turning the controller on/off). I know this is not the right forum to address vendor behaviour but I wanted to add it for completion sake.

Anyway: Is there possibly another way to check the "turning on/off" event of Input Devices without the need to use "isActive" as it would require a constant check in the Update() method?

 

Sounds promising - thank you for sticking with this topic!

 

I'm not sure to what extent this would involve short interruptions, like controllers being lost from view, but I would always want to get a consistent notification of what happened when tracking is lost at least.

One thing I decided early on was that my game's inputs (runtime provided info) should always visually match-up with the game view. So that player can always knows what the runtime (or hardware) is doing/seeing/or is failing to do depending on the context; basically always providing some kind of correct visual matchup for the player's proprioception. Knowing when the controllers drop out, or are not tracked, especially for very temporary occurrence (like when the controller was held back too far and wasn't visible from headset-based cameras) is a key part of that for me. To me it seemed less jarring to have the controller disappear then reappear rather than suddenly be held still at it's last known location (half a second ago).

Pausing the app isn't always a possibility, especially with multiplayer. I'm not sure I would want an externally mandated game-pause to suddenly stop the core action of my game, like to the point of no longer feeding the still tracked telemetry -- e.g. stopping all of my player's movements from being mirrored out to their networked avatars.

 

In my use case this is for the use of Vive trackers, if one disconnects during a session where someone uses 6+ vive trackers, it is a bit of a problem. Also, for general VR controllers, if we don't know the controller has disconnected, we can't pause the game or show a warning.

 

Unless anything changed in the OpenXR Package in Packman or the Vive Tracker extension has been added to it in Unity which it hasn't, I still don't get any controller disconnect events for the Vive trackers through OpenXR - I even released an Asset Store asset I've been working on for ages which really could use it - https://assetstore.unity.com/packages/tools/animation/openxr-vr-motion-capture-r1tools-214497

 

As mentioned by @thep3000 using the Unity InputSystem InputActions isTrackedProperty for each controller has worked for me.



Then assign function calls to the input actions performed and canceled events respectively to handle controllers being tracked and untracked. If you still need to get controller information, you can still run
InputDevices.GetDeviceAtXRNode to poll the controller in the left and right hands respectively.

Code (CSharp):

1.        
2.  
3.         [SerializeField] InputAction m_leftControllerTracked = new InputAction();
4.         [SerializeField] InputAction m_rightControllerTracked = new InputAction();
5.  
6.         private void Start()
7.         {
8.             m_leftControllerTracked.performed += LeftControllerStateUpdate;
9.             m_leftControllerTracked.canceled += LeftControllerStateUpdate;
10.  
11.             m_rightControllerTracked.performed += RightControllerStateUpdate;
12.             m_rightControllerTracked.canceled += RightControllerStateUpdate;
13.  
14.             m_leftControllerTracked.Enable();
15.             m_rightControllerTracked.Enable();
16.         }