webxr

NOTE: This version of the documentation tracks unstable development happening on A-Frame’s master branch. If you wish to try it out, grab the unstable build. Otherwise, head to the documentation for the current 1.0.0 version

The webxr system configures a scene’s WebXR device setup, specifically the options for the requestSession call.

When modifying these options, please pay attention to the browser console for diagnostic messages such as trying to use features without properly requesting them.

Example

<a-scene webxr="requiredFeatures: hit-test,local-floor;
optionalFeatures: dom-overlay,unbounded;
overlayElement: #overlay;"></a-scene>

Properties

Property Description Default Value
referenceSpaceType The scene’s reference space type for camera and controllers. local-floor
requiredFeatures Required WebXR session features. local-floor
optionalFeatures Optional WebXR session features. bounded-floor
overlayElement Element selector for use as a WebXR DOM Overlay in AR mode. null

NOTE: Once the scene is initialized, these properties may no longer be changed.

referenceSpaceType

Name of the reference space used by default for the scene, must be one of the entries in reference space names.

Name Description
viewer Rigidly attached to the camera and moves/rotates with it
local Origin is an arbitrary point close to the user’s head location at session start.
local-floor Origin is an arbitrary point close to the user’s feet at session start.
bounded-floor Same as local-floor, but supports room-scale tracking with safety bounds.
unbounded Same as local, but supports large-scale movement beyond ~5 meters / 15 feet.

The default ‘local-floor’ should work reasonably well on all systems, but please be aware that the floor position may be a rough estimate for 3DoF VR systems, or for handheld AR. For AR applications that need accurate floor location, it’s recommended to use type ‘local’ along with world hit testing or plane detection.

Make sure the reference space name is included in requiredFeatures. (‘viewer’ and ‘local’ are automatically available, all others must be requested as features.)

Applications are free to use additional reference spaces internally, but it’s important that the viewer (camera) and controllers are consistent.

For consistency when used in components, this name is available as sceneEl.systems.webxr.sessionReferenceSpaceType, and the corresponding reference space object is available during the XR session as sceneEl.systems['tracked-controls-webxr'].referenceSpace.

requiredFeatures

Array (comma-separated list) of WebXR feature names that are required for the application to work correctly. If one of the features is not supported by the system, or if the user doesn’t agree to it being used, the session request will fail.

Currently, the list of available features includes the reference space names, and the following additional features for AR mode:

Feature Description
hit-test https://immersive-web.github.io/hit-test/
dom-overlay https://immersive-web.github.io/dom-overlays/

optionalFeatures

Array (comma-separated list) of WebXR feature names that an application can use, but where the application will still work if they are not supported. The session will be created without these features if they are unavailable or if the user declined their use.

See requiredFeatures for more information of available WebXR feature names.

overlayElement

Selector for a DOM element that should be used as a WebXR DOM Overlay during an AR session. This is currently only supported for handheld AR using Chrome on Android version 82 or newer.

You must request the feature dom-overlay to use this, either as an optional or required feature.

If the feature is available, sceneEl.xrSession.domOverlayMode will have a string value indicating the type of DOM Overlay being used. This is currently screen for handheld AR, but may also be floating or head-locked on a headset. Also, the overlay element will have the :xr-overlay pseudoclass while active, and you can use this in CSS rules to show/hide UI.