OpenXR support

[arturoc]

PR Details

Adds support for OpenXR using DX11

Description

Port of https://github.com/anotherdevguy/stride/tree/openxr to work with DX11 instead of Vulkan. Supports the same functionality as currently supported by OpenVR except for the recenter function which is not supported by OpenXR itself and should be done manually from the engine.

Motivation and Context

OpenXR superseeds OpenVR and supports many more features and devices.

Types of changes

• [ ] Docs change / refactoring / dependency upgrade
• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• [ ] My change requires a change to the documentation.
• [ ] I have added tests to cover my changes.
• [ ] All new and existing tests passed.

[CLAassistant]

All committers have signed the CLA.

[xen2]

Probably we should target master rather than master-4.0?

[joreg]

@xen2 ideally we could have this in a 4.0 branch release so we can ship it with current versions of vvvv. or would this be too big a hassle on your end?

[xen2]

@xen2 ideally we could have this in a 4.0 branch release so we can ship it with current versions of vvvv. or would this be too big a hassle on your end?

If this works and no apparent regression, I'm happy to give it a try (build system changed quite a lot so not sure how CI will behave -- worst case I should be able to compile/publish it locally since it's a one time thing).

[joreg]

if you could give that a shot it would be amazing! if it is too big a hassle, we've also added the same here already #1483

[xen2]

FYI I had to revert because various platforms were broken (it might be difficult because older Xamarin platforms don't have proper Span support). I will focus on master for now.