How to fix the front-facing camera not showing up.

This guide will help you troubleshoot and solve Vive's cam not working with FragmentVR.

Reasons and Workarounds

There are two very probable reasons you can't see the camera in your HMD the way you should:

1. Your camera is already in use!
This wasn't the case for me, but it's a common issue with webcams. You just can't access the camera from multiple places, which is dumb, I know, but you have to know this limitation and accept it and work around it. The best you can do is to just not load your camera from any other program. Alternatively, once Fragment supports any camera source, you could have a virtual camera. Fragment does not yet support alternative camera sources.

2. You're in SteamVR Home or a beta branch of SteamVR.
I'm not sure why, but the beta breaks things like the webcam, and it's not really Fragment's fault. I end up not being able to use the Vive's cam at all when I'm in SteamVR Home. Disable that feature. Make sure you're not on a beta branch. Then, restart VR.

If all else fails, you can uninstall the VR drivers completely, unplug the devices, restart Windows, and plug the devices back in and reinstall the drivers.