OpenXR and an Introduction to the Khronos Group

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The Khronos Group (Khronos) is consortium of over 150 hardware and software companies who help define standards for various compute, graphics, and media APIs. For example, if you've worked with computer graphics, then you've probably already come across one of their more familiar specifications, OpenGL, the cross-platform 2D/3D graphics API. But the work of the Khronos Group goes well beyond graphics to include OpenXR, OpenCL, and several other active standards.

Creating open standards and specifications (i.e., cross-platform APIs) requires a breadth of knowledge to ensure they provide a rich set of functionality while allowing for future innovations. Thus, the importance of having a consortium with such a large number of members cannot be understated. There are different categories of members including Promoter Members like Qualcomm Technologies, Inc. (QTI), who have full working group participation, voting rights, and the right to designate a director to the Khronos Board, and Contributor Members who have full working group participation and voting rights, and several other categories.

While the Khronos Group is focused on standards and specifications, Khronos doesn't provide implementations. Rather they provide the specifications, as well as header files on their GitHub site, for the various standards which organizations can implement. However, some of the standards pages on the Khronos website (e.g., https://www.khronos.org/openxr/) do provide links to implementations by Khronos members.

In addition to defining interfaces for operations, Khronos' API specifications may also support one or more of the following API extension types:

• Vendor extensions: vendor-specific extensions related to that vendor's specific hardware or software.
• Experimental vendor extensions: vendor-specific extensions available for experimenting with on developer devices only; these are removed once the implementation has been finalized.
• Cross-vendor extensions: extensions introduced and implemented by groups of Khronos members.
• Official Khronos extensions: ratified extensions that have been included into the core specification of an API.

Implementing Khronos APIs can be done royalty free (i.e., the standards and specifications can be freely implemented), but conformance is enforced through Khronos' API Adopters Program. Not only does this help to ensure that implementations fulfill the specifications, but those implementors who do conform receive additional benefits such as access to a suite of conformance tests, usage of the API standard's logo and trademark, and other marketing opportunities through Khronos.

OpenXR and Recent Announcements

OpenXR is an API specification by Khronos for developing high-performance, cross-platform VR applications. Its design features a rich interface that abstracts the common cross-reality (XR) functionality found in today's XR devices.

Recently Khronos made a few exciting announcements in regards to OpenXR. First, the Adopters Program for OpenXR 1.0 has been launched and includes a comprehensive test suite to help ensure implementations conform to the cross-platform API specification. In addition, one of the first conformant implementations of OpenXR is the OpenXR Mobile SDK runtime for the Android-based Oculus Quest powered by the Snapdragon® mobile platform.

The OpenXR 1.0 specification also now includes new advanced cross-vender extensions for eye and hand tracking. As Hiren Bhinde, director of product management, Qualcomm Technologies, Inc. said of this announcement: "This is an important milestone and validates industry-wide adoption of the OpenXR standard. The new OpenXR extensions for eye tracking and hand tracking are key in pushing the technology envelope forward and enabling immersive user experiences."

Here at QDN we couldn't agree more as we're seeing all sorts of use cases for XR ranging from gaming and entertainment to healthcare and education. These use cases will be further enhanced by the convergence with other technologies including 5G and AI which are supported in the latest generation of XR platforms like the Snapdragon XR2 5G Platform.

Additional Resources

If you're interested in learning more be sure to check out the following resources:

• Khronos Group Developer Resource Hub: contains links to all of the Khronos Group's standards.
• Oculus OpenXR Mobile SDK: the download page for Oculus' conformant implementation of OpenXR 1.0.
• OpenXR SDK Project: the header files for implementing OpenXR in C.

Also, be sure to check out some of our recent blogs on XR:

• Optimized XR Tools and Hardware Highlighted at Facebook Connect
• XR User Interfaces and Perception Technologies

Snapdragon is a product of Qualcomm Technologies, Inc. and/or its subsidiaries.