The refactoring is intended to help with:

• supporting both OpenVR and OpenXR in the context of this extension (SlicerVirtualReality)
• allowing code reuse within SlicerMixedReality extension

Approach

Similarly to the VTK refactoring introducing vtkRenderingVR common to both vtkRenderingOpenVR and vtkRenderingOpenXR, proposed approach is the following:

• Create vtkMRMLAbstractVRViewNode that will be common ancestor to vtkMRMLVirtualRealityViewNode and vtkMRMLMixedRealityViewNode
• Create vtkSlicerAbstractVRLogic providing generic methods like the following:
  • AddVRViewNode
  • GetVRViewNode
  • GetDefaultVRViewNode
  • GetVRConnected / SetVRConnected(bool connect)¹
  • GetVRActive / SetVRActive(bool activate)
  • SetDefaultReferenceView
  • SetVolumeRenderingLogic
• Create reusable widget qSlicerVRConnectionPropertiesWidget², qSlicerVRDisplayPropertiesWidget (and qSlicerVRAdvancedPropertiesWidget?)
• Create qMRMLAbstractVRView (common to qMRMLVirtualRealityView and qMRMLMixedRealityView)
  • The view will support running using either the OpenVR or OpenXR runtime
  • qMRMLAbstractVRView will provide generic methods like the following:
    • addDisplayableManager / getDisplayableManagers
    • setCamerasLogic / camerasLogic
    • mrmlAbstractVRViewNode
    • renderer / renderWindow / interactor
    • updateViewFromReferenceViewCamera ³
    • isHardwareConnected ⁴
    • setActionManifestPath / actionManifestPath
  • qMRMLAbstractVRViewPrivate will provide generic methods like the following:
    • startVR / stopVR
    • desiredUpdateRate / stillUpdateRate
    • doVR
    • createRenderWindow / destroyRenderWindow
• Create vtkSlicerAbstractVRViewInteractorStyle
  • Include code common to OpenVR, OpenXR
  • Consolidate InteractorStyle integration #123