SteamVR, OpenXR & OpenVR

Foveated Rendering

• Eye-TrackedFoveated Rendering via Quad Views
  for OpenXR games, e.g. DCS and Pavlov VR
• Variable Rate Shading and Foveated Rendering
• PimaxMagic4All:  use Pimax' Foveated Rendering feature
  with other headsets for SteamVR games
  Dynamic Foveated Rendering currently for
  HP Reverb G2 Omnicept Edition, Quest Pro, Varjo;
  Fixed Foveated Rendering for most others.

Fixed Foveated Rendering for WMR HMDs in Assetto Corsa

• For Glare setting under Video settings is Medium or lower,
  Assetto Corsa, an OpenVR application,
  can use OpenXR Toolkit through OpenComposite.
• Content Manager interactions with OpenXR toolkit

Graphics Settings Guide

from Into the Radius VR

image sharpening (impacts performance)

CAS (Contrast Adaptive Sharpening) vs NIS (Nvidia Image Scaling)

Microsoft Store OpenXR Tools for Windows Mixed Reality

Nvidia Deep Learning SuperSampling (DLSS)

based on Temporal (instead of MultiSample) AntiAliasing.

OpenKneeboard supports one or 2 overlays for OpenXR.

Virtual Desktop OpenXR (VDXR) also works for Oculus, not WMR.
OpenKneeboard's Fred Emmott diagrammed SteamVR flow:

OpenComposite

Play SteamVR games with OpenXR instead of OpenVR

on GitLab:  download from AppVeyor > Platform: x64 > Artifacts > OpenComposite.zip
Replace openvr_api.dll in the game:

$ find . -name openvr_api.dll -print
./Steam/bin/cef/cef.win7x64/openvr_api.dll
./Steam/openvr_api.dll
./Steam/steamapps/common/Aircar/Engine/Binaries/ThirdParty/OpenVR/OpenVRv1_0_16/Win64/openvr_api.dll
./Steam/steamapps/common/Aircar/Engine/Plugins/Marketplace/SteamVRInput/Source/ThirdParty/OpenVRSDK/bin/win64/openvr_api.dll
./Steam/steamapps/common/assettocorsa/system/x64/openvr_api.dll
./Steam/steamapps/common/assettocorsa/system/x86/openvr_api.dll
./Steam/steamapps/common/Bigscreen/Bigscreen_Data/Plugins/x86_64/openvr_api.dll
./Steam/steamapps/common/fpsVR/openvr_api.dll
./Steam/steamapps/common/MixedRealityVRDriver/bin/win32/openvr_api.dll
./Steam/steamapps/common/MixedRealityVRDriver/bin/win64/openvr_api.dll
./Steam/steamapps/common/OpenVR Benchmark/cyubeVR/Tools/openvr_api.dll
./Steam/steamapps/common/OpenVR Benchmark/Engine/Binaries/ThirdParty/OpenVR/OpenVRv1_0_10/win32/openvr_api.dll
./Steam/steamapps/common/OpenVR Benchmark/Engine/Binaries/ThirdParty/OpenVR/OpenVRv1_0_10/win64/openvr_api.dll
./Steam/steamapps/common/OpenVR Benchmark/Engine/Binaries/ThirdParty/OpenVR/OpenVRv1_0_15/Win64/openvr_api.dll
./Steam/steamapps/common/OpenVR Benchmark/Engine/Binaries/ThirdParty/OpenVR/OpenVRv1_0_16/Win64/openvr_api.dll
./Steam/steamapps/common/OVRdrop/OVRdrop_Data/Plugins/openvr_api.dll
./Steam/steamapps/common/SteamVR/bin/vrwebhelper/win64/openvr_api.dll
./Steam/steamapps/common/SteamVR/bin/win32/openvr_api.dll
./Steam/steamapps/common/SteamVR/bin/win64/openvr_api.dll
./Steam/steamapps/common/SteamVR/tools/steamvr_desktop_game_theater/win64/steamvr_desktop_game_theater_Data/Plugins/openvr_api.dll
./Steam/steamapps/common/SteamVR/tools/steamvr_environments/game/bin/win64/openvr_api.dll
./Steam/steamapps/common/SteamVR/tools/steamvr_media_player/win64/steamvr_media_player_Data/Plugins/openvr_api.dll
./Steam/steamapps/common/SteamVR/tools/steamvr_room_setup/win64/steamvr_room_setup_Data/Plugins/openvr_api.dll
./Steam/steamapps/common/SteamVR/tools/steamvr_tutorial/win64/steamvr_tutorial_Data/Plugins/openvr_api.dll

Make sure to turn off option to automatically start SteamVR in WMR Settings;
disabling hardware-accelerated GPU scheduling (HAGS).

OpenXR vs OpenVR

OpenVR:  required for controllers;    OpenVR Benchmark

OpenXR:  supports Foveated Rendering for multiple headsets

OpenXR ToolKit on GitHub

tweak OpenXR features and settings on e.g. DCS and MSFS 2020
via OpenComposite, works with e.g. Assetto Corsa, Project Cars 2

OpenXR for Windows Mixed Reality headsets

- Automagically installed for WMR on Windows >= 20H2

14 Apr 2023 settings   experiment with HAGS

SteamVR

with OpenComposite, supports both OpenVR and OpenXR

OpenVR ToolKit works with OpenVR,
but reportedly works with e.g. Reverb G2, which now uses OpenXR..?
WMR headsets are driven by Windows Holographic API -> WMR runtime,
but that API may be driven:

• directly from games or game engines (but none of interest)
  Matthieu Bucchianeri recommends Unreal over Unity,
  with UE5.3 adding VRS (Variable Rate Shading) with eye gaze,
      but Nvidia VRSS2 is only on DX11;  "UE5 is all in on DX12"
• from SteamVR, provoking performance issues
• using a special version of OpenXR, which may be driven by games,
  game engines or OpenComposite from OpenVR.
  This last is most performant for games of interest.

Windows Mixed Reality Passthrough for OpenXR

Works with HP Reverb (not G2) cameras and e.g. StereoKit apps.

Win 11 performance hacks

virtual monitor pre-allocation, Xbox overlay, OpenXR Explorer
Use OpenXR Loader Specs instead of registry key
Settings > System > Display > Graphics Default settings
Change default graphics settings   (HAGS)