OpenXR Passthrough not working (Unity)

[MichalSun]

Hi!

I've been building my app in unity (2021.3.33f1) and bumped into an error log:

"CompositionLayerPassthroughAPI HTC_Passthrough feature instance not found."

Passthrough worked in previous version of the app. Now I just get black background. I'm using "VIVE OpenXR Plugin 2.2.0" with enabled Composition layer and Passthrough features in the XR Plugin Management. I'm also starting the passthrough with:

void OnEnable()
    {
        ID = CompositionLayerPassthroughAPI.CreatePlanarPassthrough(LayerType.Underlay);
    }

What might be an issue there? Please help!

[pmanakhov]

The same here. I followed all the steps from https://developer.vive.com/resources/openxr/unity/tutorials/passthrough/ one-to-one. I even tried downgrading OpenXR Plugin from 2.3.0 to 2.0.0. No luck.

I'm using Unity 2021.3.8f1 with HTC Vive XR Elite.

[VIVE_chengnay]

Hi @MichalSun @pmanakhov,

Could you double check again if Composition Layer and Passthrough is checked?

If it is checked, could you try unchecked and checked again?

And, will it work using our sample scenes under "Assets\Samples\VIVE OpenXR Plugin\<version>\VIVE OpenXR Samples\Samples\Passthrough\Scenes" folder?

[pmanakhov]

Alright, I've just recreated the Unity project following the same steps on another machine and, surprisingly, it worked. I'll leave the link to my Unity project on GitHub here as a template (https://github.com/pmanakhov/VivePassthroughTemplate) if anyone needs it in the future

[jboss]

I ran into the same problem. The sample scene worked fine, so I looked at the differences. and found that I had to change the camera settings.

You need to set Clear Flags to Solid Color and then background to a color with 0 opacity.

I think it would be good to mention this in the explanation at
https://developer.vive.com/resources/openxr/unity/tutorials/passthrough/

It now only describes that you should copy the gameobjects from the sample scene, but if you already have a camerarig in your scene you don't want to do this.