Re: [Flightgear-devel] VR Options Menu Is Not Available In Daily Build

[James H. <ja...@al...>]

On Wednesday, 10 August 2022 19:49:30 BST James Hogan via Flightgear-devel 
wrote:
> On Tuesday, 9 August 2022 10:46:01 BST SV001R wrote:
> > I downloaded daily build and connected the device and also installed and
> > executed "OpenXR for Windows Mixed Reality" app from Microsoft Store.
> > 
> > But in FlightGear, "VR options" in view menu is in grey color and not
> > available. (no response for any click on it)
> 
> There are two issues here:
> 
> 1) The windows nightly builds don't build with VR enabled. The only
> component missing I think is the OpenXR loader which needs to be built for
> flightgear build to find it. I've tested this once on a family member's PC
> with a dummy/ virtual headset. I'd love for this to be fixed to allow more
> people to try it, but it isn't something I can easily test (though I may
> get a chance soon).

I want to get my head around this so I have something to test. The main 
options I can see to get OpenXR loader included in the windows builds are:

1) Add https://github.com/KhronosGroup/OpenXR-SDK to flightgear/3rdparty. Not 
ideal IMO as the cmake stuff assumes a top level project, so it'd need 
modifying, and on Linux at least it should very much be a distro thing.
2) Add OpenXR-SDK as an external project to flightgear, so it fetches it 
automatically (or possibly from 3rdparty - if that can work). Also not ideal 
IMO, and none of the other dependencies do that yet.
3) Add OpenXR-SDK as a git submodule of fgmeta and ensure it gets built before 
flightgear is configured for windows, so flightgear cmake can pick up the openxr 
loader static library and enable VR.

Option 3 seems best to me. I can see from the following log:
http://build.flightgear.org:8080/job/Windows-nightly/4461/console
That various submodules of fgmeta are updated, then it goes on to run the 
build_release_windows.bat script.

Does the nightly build use fgmeta/CMakeLists.txt at all, or is that just 
another way of doing the same thing as the build_release_windows.bat script?
I don't see any mention of building OSG in build_release_windows.bat...
Should openxr loader be built separately somehow like osg is, since it isn't 
going to need regular rebuilding?

Thanks
James (Hogan)