Opaque-display-only environment/room

[Zee2]

Overview

Requires #11035 to be merged first!

Adds an optional prefab to display a simple (highly optimized) environment when running on opaque displays. Very useful for gauging floor height, testing locomotion, etc.

Changes

• Adds demo script OnlyDisplayIfOpaque, which does exactly what you'd expect it to
• Adds sample assets for VR environment
• Adds environment prefab to HandInteractionExample, but no other scenes (yet)

[keveleigh]

@Zee2 Looks like this branch might need a rebase: I think it contains some commits from #11035

[AMollis]

We appreciate your contribution and thank you for the pull request.

Microsoft Mixed Reality Toolkit version 2 (MRTK2) is currently in limited support. This means that Microsoft is only fixing high priority issues. Unfortunately, this pull request does not meet the necessary priority and will be closed. If you strongly feel that this change deserves more attention, please open a new pull request and explain why it is important.

Microsoft recommends that all new HoloLens 2 Unity applications use MRTK3 instead of MRTK2.

Please note that MRTK3 was released in August 2023. It features an all-new architecture for developing rich mixed reality experiences and has a minimum requirement of Unity 2021.3 LTS. For more information about MRTK3, please visit https://www.mixedrealitytoolkit.org.

Thank you for your continued support of the Mixed Reality Toolkit!