README.md | Explore in Territory

# VR

_For a more thorough/high level overview of the entire WebXR stack, please refer to
[components/webxr](https://source.chromium.org/chromium/chromium/src/+/main:components/webxr/README.md)_

`device/vr` abstracts [WebXR](https://immersive-web.github.io/webxr/) features
across multiple platforms. Note that in some instances, necessary extension
points or potential layering violations will require the creation of an
interface in this directory, and an implementation in `components/webxr`.

Although the directory is named "vr" both VR and AR features are implemented
here. The name is an artifact from the time when it was associated with the now
deprecated WebVR API.

When other code in Chrome refers to a device or vr "Runtime" they are usually
referring to the implementations in the subfolders here; though it is perhaps
better to think of this as Chrome's runtime *integration* and the actual code
that talks to the headset on the platform side as the "Runtime" or "Driver".

## Platform support

Windows and Android are the primary supported platforms, largely because they're
the only platforms with significant XR device traction at this point. OpenXR
could theoretically provide support on Linux/Mac, but at this time we have not
ensured that the code can build nor implemented any necessary loader/other
features to enable OpenXr on those platforms.

| API                   | OS       | Supports | Enabled by Default |
|-----------------------|:--------:|:--------:|:------------------:|
| ARCore                | Android  | AR       | Yes                |
| Google Cardboard SDK  | Android  | VR       | Yes                |
| OpenXR                | Windows  | VR       | Yes*               |
| OpenXR                | Windows  | AR       | No                 |
| OpenXR                | Android  | VR       | No                 |
| OpenXR                | Android  | AR       | No                 |

 - \* OpenXR runtimes are only enabled on Windows if they implement the
   "[XR_EXT_win32_appcontainer_compatible](https://www.khronos.org/registry/OpenXR/specs/1.0/html/xrspec.html#XR_EXT_win32_appcontainer_compatible)"
   extension.

Integrations with some APIs (such as AR Core) are partially locaed in
chrome/browser/vr due to architectural and historical limitations. In the future
those will ideally be migrated to this directory as well.

Full documentation for OpenXr may be found [here](openxr/README.md).

## Windows Build setup
On Windows, the device code runs in a sandboxed utility process. The Chrome
installers (e.g. mini_installer) and test setup scripts, will ensure that the
appropriate permissions (ACLs) are set on the install directory to run in the
sandbox. However, if you wish to build and run the code from your local out
directory directly, you will need to either disable the sandbox (not recommended
as it could lead to an accidental compat issue) or manually set these
permissions. The permissions will persist, so the commands need only be run once
per out-directory.

To set the appropriate ACLs run:
```
icacls <chromium out directory> /grant *S-1-15-3-1024-3424233489-972189580-2057154623-747635277-1604371224-316187997-3786583170-1043257646:(OI)(CI)(RX)
icacls <chromium out directory> /grant *S-1-15-3-1024-2302894289-466761758-1166120688-1039016420-2430351297-4240214049-4028510897-3317428798:(OI)(CI)(RX)
```

## Testing
See [XR Browser Tests documentation](../../chrome/vr/test/xr_browser_tests.md).
chromium/device/vr/README.md
