OpenVR is an API and runtime that allows access to VR hardware from multiple vendors without requiring that applications have specific knowledge of the hardware they are targeting. This repository on GitHub is an SDK that contains the API and samples. The runtime is under SteamVR in the "Tools" library in the Steam client.
Documentation for the API is available on the OpenVR GitHub Wiki
More information on OpenVR and SteamVR can be found at http://steamvr.com
SteamVR implements OpenVR and is natively supported by Unreal Engine 4, and is also natively supported in Unity version 5.4+.
You can find the SteamVR plugin on the Unity Asset Store
Hardware device makers can develop OpenVR drivers to easily enable support for VR content on Steam
. Steam is one of the largest digital distribution platforms worldwide, with thousands of games available.
Once you have created an Open VR driver, you may distribute it yourself or directly on Steam to users.
You can read more about making an OpenVR driver here