XRDevice.isPresent with XRManagement on Quest

Hey,

It seems like XRDevice.isPresent always returns false on 2019.3.0f6 with the new XR Management system on Oculus Quest. Is that expected?

 

Please report a bug.

 

Submitted a bug report. Case: 1215467

Thanks for the advice @Claytonious

 

Thank you for doing that, but don't link to your bug reports on Fogbugz - that exposes *all* of your bug reports to the public, including future ones where you might attach some files or links or info that you don't want to share with the world. Just post the case number itself (in this case, 1215467).

But thanks again, let's hope it gets fixed now!

 

I was under the impression that CommonUsage.userPresence is a replacement for XRDevice.userPresence which tells me if the user is wearing the headset or not. However, XRDevice.isPresent told me if an HMD was connected or not. Is there anything like that with the InputDevice API?

 

So, what ... the API call XRDevice.isPresent ... is now obsolete, and shouldn't be used at all? If so, shouldn't that be documented???

 

This still seems to be broken or undocumented behaviour. @StayTalm_Unity

 

Please note that the current "undocumented" situation is downright dangerous.

I just spent two full days debugging total weirdness of one of our applications, and it turns out that with XRManagement active, XRDevice.refreshRate returns 0, while with "Legacy VR" it returns 72. Case 1240243

Also @ash_at_unity3d it doesn't seem like refresh rate is part of the new xr_input API, or is it just not documented? How do I get the device refresh rate in XR Management? This is important to get frame-perfect physics, smooth animations, ...

 

Are there any Updates on this. I want to detect if a VR-Headset is connected.
On unity 2019.4.9f1 i have a WindowsMR Headset connected but both

Code (CSharp):

1. List<InputDevice> devices = new List<InputDevice>();
2. InputDevices.GetDevicesWithCharacteristics(InputDeviceCharacteristics.HeadMounted, devices);
3. bool isPresent = devices.Count > 0;

and

Code (CSharp):

1. XRDevice.isPresent

is always false.

 

XRDevice.isPresent is still not marked as deprecated in Unity, so it took me an hour to find this. Are you intending to update.

Also, I'd just like to voice some concern here. The massive part of the idea of Unity is to be *simple* for users.However according to the docs, the need to call XRDevice.isPresent has been replaced with the need to write the code:

Code (CSharp):

1.     public static bool isPresent()
2.     {
3.         var xrDisplaySubsystems = new List<XRDisplaySubsystem>();
4.         SubsystemManager.GetInstances<XRDisplaySubsystem>(xrDisplaySubsystems);
5.         foreach (var xrDisplay in xrDisplaySubsystems)
6.         {
7.             if (xrDisplay.running)
8.             {
9.                 return true;
10.             }
11.         }
12.         return false;
13.     }

Not to mention the fact that the whole concept of sub systems is totally undocumented.

Does this not seem like a step backwards?

 

XR on unity is a mess!

 

With Oculus Quest 2 (Oculus Link), it's the opposite for me. it's always true even when i put down the headset

 

I do not understand.
I make a new Project using the VR default Template
My VR device (Samsung Odyssey) is working fine with Unity 2019.4.18 LTS.
But

Code (CSharp):

1. UnityEngine.XR.XRDevice.isPresent

is always "false" as if there is no device.

 

Working in Unity 2020.1.11f1 the following code works to detect user presence on the Oculus Rift S, but always returns false on Quest 2:

Code (CSharp):

1.  
2. if (!_headset.isValid) _headset = InputDevices.GetDeviceAtXRNode(XRNode.CenterEye);
3. _headset.TryGetFeatureValue(CommonUsages.userPresence, out bool present);

As far as the new XR api goes, I'm quite happy with this approach. But the code presented in earlier posts by @StayTalm_Unity and @hrgchris would not be appropriate to be called every frame as it involves instantiating a list of devices. Is there any other efficient and reliable way to check for user presence?

 

Thanks for the reply. I simply want to pause the game while the user isn't wearing the headset. So, onDeviceConnected isn't really useful, unfortunately.

 

The suggested replacements for XRDevice.isPresent above don't always work in Awake(). Moving them to Start() fixes them.

 

I'm not loving awake vs start race conditions when interacting with engine systems they shouldn't exist.

 

The code on the documentation page, that is supposed to be used instead of XRDevice.isPresent is not working. It always return true, for Oculus Quest 2 at least.

 

Same as you, always returning true on a Vive Focus.

 

Ok, so at least for Oculus Quest I found a consistent way of tracking user presence, and many other session state changes.
First, I needed to use OpenXR instead of Oculus. Good riddance, as I found a range of wierd bugs with Oculus especially using Oculus Link. OpenXR works consistently well, unless you need some very specific Quest features like passthrough features which I did not test.
So, first switch from Oculus to OpenXR:
Project Settings > XR Plugin In Management do not use Oculus, use OpenXR instead.
Caveat: If you use default XR rig, by default the controllers will not be tracked, but it's easily fixed:
In Project Settings > XR Plugin In Management>OpenXR under Interaction Profiles add a Oculus Touch Controller profile.

Now to track state changes you want to use OpenXRFeatures which is a bit obscure functionality that I discovered by accident. However there is a very good post describing how to use it:

https://forum.unity.com/threads/how-do-you-implement-openxr-focus-management-in-unity-2020.1117141/

TLDR:
The code is below.
In order for code to work you need to enable the new feature in:
Project Settings > XR Plugin In Management>OpenXR>OpenXR Feature Groups where you will now see a new feature group called VR State Tracking (or whatever you deide to call the feature, in UiName variable):

Code (CSharp):

1.  
2. using UnityEditor;
3. using UnityEngine;
4. using UnityEngine.XR.OpenXR.Features;
5. #if UNITY_EDITOR
6. [UnityEditor.XR.OpenXR.Features.OpenXRFeature(UiName = "VR State Tracking",
7.     BuildTargetGroups = new[] { BuildTargetGroup.WSA, BuildTargetGroup.Standalone, BuildTargetGroup.Android },
8.     Company = "Your Company",
9.     Desc = "Tracks state changes.",
10.     Version = "0.0.1",
11.     FeatureId = featureId)]
12. #endif
13.  
14.  
15. public class MyOwnXRFeature : OpenXRFeature
16. {
17.     public const string featureId = "com.yourcompany.features.statetracking";
18.  
19.  
20.     // This is to change a number of state changes in a very granular way:
21.     protected override void OnSessionStateChange(int oldState, int newState)
22.     {
23.         Debug.Log($"OnSessionStateChange: {oldState} -> {newState}");
24.     }
25.  
26.     // This will happen when headset put on:
27.     protected override void OnSessionBegin(ulong xrSession)
28.     {
29.         Debug.Log($"Feature OnSessionBegin: {xrSession}");
30.     }
31.  
32.     // This will happen when headset taken off:
33.     protected override void OnSessionEnd(ulong xrSession)
34.     {
35.         Debug.Log($"eatureOnSessionEnd: {xrSession}");
36.     }
37.  
38. }

 

Hi

I know this is a post from a while back but I still hope you can help. This might be a really stupid question as well but it's something I've never managed to get my head around. Basically The script works but I don't know how to access the information. As it doesn't derive from MonoBehaviour I can't stick it on an object. It does send info to the console when the headset is removed and put back on but I don't know how to read from a script like this or get this script to set something I can read with other scripts in the project.

I feel like I'm missing a really obvious thing here. I hope you can point me in the right direction.

All the best

Phil

 

Where that script currently calls Debug.Log(), call into your own classes or scripts. For example, call a static method in your own class, it raise an event from a static class that your own scripts subscribe to, or whatever you like.