UPDATE: For demos built with SDK 0.4.1 or newer, this is all *less* of a problem, but the below checklist is a great fallback. There are still quite a few demos that do things differently, so I would like to recommend the "Unofficial VR Game Manager/Launcher by Bilago", which can be found here. It can be a great help to experiment with what makes a demo tick, and then remember those settings for next time.
So after some trial and error, below is the checklist I go by now.
Note that this checklist assumes the following:
- You are using Windows 8 (though it may apply to other Windows versions),
- The Unity demo you are trying to run was built with DirectX11 turned off,
- You're using a single monitor + your DK2 (known issue that multi-monitor config results in judder).
1. Rift Display Mode: "Extended Desktop to the HMD" (via Oculus Runtime in your system tray)
2. Turn your DK2 *ON*.
4. Main monitor: Primary, i.e. "This is your main display" (via Screen Resolution window, by right clicking on an empty area of your desktop)
5. DK2 monitor: Not primary, Landscape orientation. (Most users with a simple monitor set up like mine will need to use Landscape, but others have reported needing to use Portrait or Landscape (Flipped), etc. Whatever works for you -- the point is to feel free to change Orientation.) Make sure the Rift display in this window is light blue like your main monitor. If it's small and dark, it usually means you didn't set your desktop to "Extend". If you did set your desktop to Extend and you're still seeing this, switch back to "PC Screen Only" and then back to "Extend", and then it should pick it up.
6. To run a Unity demo, use the DirectToRift executable that hopefully came with the demo in question. The demo should then pop right up onto the DK2. If you get any judder, get out of the demo, turn the Rift off and back on, then try again.
If anyone finds that this checklist doesn't hold true in all cases, please let me know.