Initial XR support

[AoGao-Kedoka]

Describe your changes

Adding XR support in rendering. Interacting is handled in another PR.

Steps to build and test

1. To build the branch, first clone, build and install the openxr, then build vtk with:
   https://www.kitware.com/using-vtk-with-the-meta-quest/

   To use VTK with XR devices, enable the CMake option VTK_MODULE_ENABLE_VTK_RenderingOpenXR when building VTK, and set the OpenXR_DIR variable to provide the path to the OpenXR SDK install directory.

2. Build F3D with: -DF3D_MODULE_OPENXR=ON
3. Choose between two and run with f3d ../testing/data/<data>.<datatype> --rendering-backend=xr
   1. Attatch a HMD, open steamvr or
   2. • Install monado, recommend installing from source https://monado.freedesktop.org/getting-started.html#installation-from-source
      • Set monado as active openxr runtime and set using simulation mode (script below)
      • use right mouse to move around or change HMD's position/orientation by giving value in the monado UI (see pic)

#!/bin/bash
# set monado as active openxr runtime
rm ~/.config/openxr/1/active_runtime.json
ln -s /usr/share/openxr/1/openxr_monado.json ~/.config/openxr/1/active_runtime.json

# set simulated monado options
export XR_RUNTIME_JSON=/usr/share/openxr/1/openxr_monado.json
export QWERTY_ENABLE=1
export SIMULATED_ENABLE=1
export XRT_DEBUG_GUI=1
export XRT_COMPOSITOR_FORCE_XCB=1

# start service
monado-service

Checklist for finalizing the PR

• I have performed a self-review of my code
• I have added tests for new features and bugfixes
• I have added documentation for new features
• If it is a modifying the libf3d API, I have updated bindings
• If it is a modifying the .github/workflows/versions.json, I have updated docker_timestamp

AI Disclosure

• I did not use AI to generate any of the content of that pull request
• I used AI to generate code in that pull request, if yes please disclose which part of the code was generated and with which model.
  GPT5.5 for Creating the bounding box and align objects to the bounding box. Reviewed and tested carefully.
• ...

Continuous integration

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[github-actions]

You are modifying libf3d public API! ⚠️Please update bindings accordingly⚠️!
You can find them in their respective directories: c, python, java, webassembly.

[mwestphal]

Nice!

[AoGao-Kedoka]

\ci fast

[Meakk]

Here's a first review. I'll try your branch before going more in depth.