Long-term ticket to start the discussion about adding support for OpenXR

Major tasks:

• OpenXR support in VTK
• Create abstract VR API in VTK
• Add OpenXR support in SlicerVR

Reason:

• Unity drops Open VR support here
• Valve eventually moving to OpenXR here and some more info here

Benefits:

• More VR devices supported under a single interface

Related issues

• Flying stopped working #88
• Address issues related to integration with VTK 9.1 #91
• Generalize per-platform support introducing PLATFORM_SUPPORTS_VR option #95
• Refactoring to support OpenVR and OpenXR, and streamline reuse in SlicerMixedReality  #121
• Refactor transform tracking to support OpenXR #122
• 3D pinch function is unreliable #124
• Add external project to build vtkRenderingOpenXRRemoting #128
• Document OpenXR capabilities #158
• Add OpenXR support for HTC Vive Trackers #171

Related pull requests

SlicerVirtualReality:

• STYLE: Improve external project consistency #96
• Update integration to support VTK 9.1 #90
• Tweak external project integration #85
• Update build system to support building against VTK9 #84
• Update build system to support building against VTK9 #84
• Update integration to support VTK 9.1 #90
• Fix retrieval of OpenVR last post updating VTK #103
• COMP: Fix build using renamed API to retrieve OpenVR pose #104
• BUG: Add missing vtkVirtualRealityViewInteractorStyle::SetupActions #105
• COMP: Fix not handled transform type warnings in qMRMLVirtualRealityTransformWidget #107
• Fix interaction support renaming VR interactor style callback functions #108
• BUG: Restore complex gesture support #109
• Fix loading of action manifest flles #114
• Fix lookup of manifest files from both install and build trees #117
• COMP: Fix build accounting for vtkVirtualRealityViewInteractor API change #119
• BUG: Fix lookup of manifest file from build tree #120
• BUG: Fix integration with updated Slicer event delegation and VTK OpenVR API #131
• BUG: Do not report "Unrecognized device" if handling complex gesture #135
• ENH: Update interactor style to use runtime-agnostic API to retrieve poses #143
• Decouple update of transform node matrix and attributes #147
• COMP: Update VTKExternalModule to ensure find_dependency macro is always available #153
• COMP: Fix openxr_loader library windows install rule #154
• COMP: Fix linux build explicitly setting lib install dir #155
• COMP: Update OpenXR integration to rely on OpenXR config module #156
• XR Runtime Combobox Enhancements #157
• DOC: Update README and DeveloperGuide to document OpenXR backend support | ⚠️ Last commit removed from master #169

Slicer:

• ENH: Update VTK backporting VR and OpenXR improvements Slicer/Slicer#7516

• ENH: Update VTK to backporting VR, OpenVR and OpenXR improvements Slicer/Slicer#7514

• Improve Event Delegation in qMRMLThreeDView and qMRMLSliceView Slicer/Slicer#7311

  • ENH: Update MRML interactor style to explicitly use the poked renderer Slicer/Slicer#7315
  • BUG: Restore maximization of view on double click event Slicer/Slicer#7442
  • ENH: Update qMRMLThreeDView to retrieve camera node from displayable manager Slicer/Slicer#7316
  • COMP: Update CTK to include build-system fixes Slicer/Slicer#7318
  • ENH: Remove unused API to set/get displayable manager interactor abort flags Slicer/Slicer#7319
  • Remove obsolete OnInteractorStyleEvent Slicer/Slicer#7320
  • Simplify DisplayableManager header includes Slicer/Slicer#7321
  • STYLE: Remove unused ivars from vtkMRMLViewInteractorStyle Slicer/Slicer#7322
  • ENH: Simplify vtkMRMLViewInteractorStyle::SetMouseCursor Slicer/Slicer#7323
  • ENH: Set MRML interactor style camera node observing displayable manager Slicer/Slicer#7324
  • ENH: Allow virtual func to be called during MRML(ThreeD|Slice)View pimpl init Slicer/Slicer#7325

CTK:

• Ensure virtual functions can be called from derived ctkVTK view pimpl commontk/CTK#1153

VTK:

• MR-10789 VR: Resolve "Not rendered" warnings after XR RenderWindow Initialization

• MR-10789 VR: Add SetInteractionState() API to VR interactor style

• MR-10786 VR: Update vtkVRRenderWindowInteractor marking ComplexGesture recognition functions as public

• MR-10785) VR: Declare AddAction() functions as virtual

• MR-10784 VR: Update interactor style API adding GetMappedAction()

• MR-10783 VR: Accommodate separate eye transforms

• MR-10778 BUG: Recognize OpenVR gesture where buttons are pressed consecutively

• MR-10771 BUG: Add missing Elevation3DEvent to vtkCommand::EventHasData()

• MR-10400 ENH: Re-introduce OpenVR API for retrieving last OpenVR pose

• MR-9892 ENH: Re-introduce support for custom logic handling VR complex gesture

• MR-8977 vtkInstallCMakePackageHelpers: add find_package hints for OpenVR

  Added to that are many other updates adding new capabilities along with the refactoring
  of vtkRenderingOpenVR introducing the vtkRenderingVR base module to be used by vtkRenderingOpenXR and vtkRenderingOpenXRRemoting.