The OpenXR standard is a consortium of dozens of companies in the XR industry, across platforms, headsets, chipsets, and game engines. Orchestrated by the Khronos Group the consortium consists of some of the biggest names in the industry. The OpenXR 1.0 spec was finally ratified last year in July 2019. Now, Khronos is providing an update to the industry to show how much the standard has grown since ratification. While I wish that OpenXR had come out sooner, considering the growth in AR and VR over the past few years, I believe that OpenXR will be fundamental to the continued growth of these technologies—especially as they try to support more applications.
There is now a list of devices that are certified as OpenXR conformant. While this list is admittedly quite short, it includes a considerable number of XR headsets already in market. This telegraphs that OpenXR is at least being taken seriously by two of the biggest players in the market: Facebook and Microsoft. Right now, Facebook’s Oculus Rift S and Oculus Quest are both certified as OpenXR conformant devices. The Quest has been very successful in the market, which makes me think that its OpenXR certification will incentivize more developers to target OpenXR.
Microsoft’s Hololens 2 and Windows Mixed Reality headsets are also conformant with OpenXR. Microsoft’s involvement is fascinating because it includes both AR and VR. Windows Mixed Reality has a broad array of headsets, including the much-anticipated, premium HP Reverb G2. Something worth considering as well is the fact that Qualcomm is a big component of supporting OpenXR with its chipsets since both the Oculus Quest and Microsoft Hololens 2 are both running on its processors.
Notably missing from this list of conformant hardware vendors are HTC, Magic Leap, Valve and Varjo, all of whom are OpenXR members. That said, Valve and Varjo have OpenXR 1.0 Developer previews, so they must be close to getting their respective software stacks and headsets compatible with OpenXR. Another major development is Valve’s announcement that it is building the next generation of the SteamVR platform on top of OpenXR, instead of its own in-house OpenVR platform. SteamVR support for OpenXR means that more developers and headset makers will release products that work with OpenXR, making cross-platform and application compatibility much better.
User experience with OpenXR
OpenXR also standardizes user experiences, which is one of the key components of enabling key cross-platform compatibility. Hand tracking and eye tracking will both eventually be standard in the XR headsets of the future, so it makes sense that OpenXR is standardizing around them now. There are OpenXR API layers that allow cross-vendor and cross-platform UI experiences, with a standard set of features for both hand and eye tracking. Hand tracking compliance in OpenXR requires 26 unique joints per hand, for fully articulated movement. Microsoft’s Hololens 2 meets this criterion, and Ultraleap has a developer preview available as well. This means that it is awfully close to being OpenXR conformant.
Khronos OpenXR also supports eye tracking, with the help of Tobii and Microsoft. In fact, Microsoft’s Hololens 2 standalone AR headset has a working eye tracking solution. I have experienced it personally many times and can say that its calibration and authentication process is fantastic. Tobii was pivotal in helping OpenXR develop the eye-tracking component of the conformance tests and will likely be the go-to 3rdparty solution for most XR headsets moving forward (if a company doesn’t develop its own solution). Tobii’s eye tracking technology is currently in StarVR, HTC Vive Pro Eye and Pico Neo 2 Eye, all of which still need to pass the OpenXR conformance tests. Tobii and Microsoft’s support is key—developers need to know that enough headsets support OpenXR and its standard for eye tracking, that their applications will be supported if they design them for conformance.
In addition to growing hardware and platform support, OpenXR is also gaining traction with software developers. Microsoft, which now owns Mojang (the developer of Minecraft), announced that the rendering engine for a new game called Render Dragon will be built with desktop VR support using OpenXR. Additionally, Microsoft is giving mixed reality developers access to open source OpenXR samples to see how it can be used to access the full potential of the Hololens 2. Microsoft is clearly taking a leadership role in OpenXR in ways that other vendors simply are not—it seems to understand how important open standards are for industry growth. While Microsoft’s software contributions are significant, thankfully they are not alone; Google’s Chromium 81 (the core technology that drives Chrome) is utilizing OpenXR as the default backend for WebXR. With Chromium used in both Microsoft Edge and Google Chrome, most web users are now using an OpenXR compatible browser. Even the 3D rendering application Blender now integrates OpenXR, and will deliver a native VR scene inspection capability in version 2.83 of the app.
OpenXR is also important to the vision of running XR applications in the 5G edge cloud. For compliance, AR applications must communicate with extremely low latency sensor data to the renderer on the MEC server. The rendered images can then stream over a low latency 5G connection and show them on the headset with minimal overhead. OpenXR’s role in this process is setting a standard for how sensors handle data and communicate it quickly and reliably to the edge. Additionally, it standardizes display composition, which ensures a proper scene render based on where the user is looking at that time.
As you can see from the developments over the last year, OpenXR has gained a considerable amount of momentum in both hardware and software deployments. I think the fact that Khronos and OpenXR can already show conformant hardware and software solutions less than a year after ratification is especially important. With this momentum, especially from Facebook and Microsoft, I believe that OpenXR has an incredibly good road ahead of it—especially as network operators and HMD manufacturers look for ways to standardize software and hardware across multiple vendors. The industry without a doubt needs open standards like OpenXR that encourage cross-platform and cross-vendor compatibility. This will make it easier to build applications and ensure their broadest reach possible. Right now, developers are targeting a very small set of headsets, but this selectivity makes things harder. Standardizing around OpenXR will make things easier and hopefully speed up adoption.