Promise<XRReferenceSpace> requestReferenceSpace(XRReferenceSpaceType type);

"position-disabled",

"bounded",

"unbounded"

Each {{XRReferenceSpace}} has a <dfn for="XRReferenceSpace">type</dfn>, which is an {{XRReferenceSpaceType}}.

An {{XRReferenceSpace}} is obtained by calling {{XRSession/requestReferenceSpace()}}, which creates an instance of an {{XRReferenceSpace}} or an interface extending it, determined by the {{XRReferenceSpaceType}} enum value passed into the call. The type indicates the tracking behavior that the reference space will exhibit:

- Passing a type of <dfn enum-value for="XRReferenceSpaceType">identity</dfn> creates an {{XRReferenceSpace}} instance. It represents a reference space where the [=viewer=] is always at the [=native origin=]. Only the {{XRSession/viewerSpace}} and {{XRInputSource/targetRaySpace}}'s of {{XRInputSource}}'s with an {{XRInputSource/targetRayMode}} of {{XRTargetRayMode/screen}} can be spatially related to an {{identity}} reference space.

- Passing a type of <dfn enum-value for="XRReferenceSpaceType">position-disabled</dfn> creates an {{XRReferenceSpace}} instance. It represents a tracking space where orientation is tracked but the [=viewer=]s position is always at the [=native origin=].

- Passing a type of <dfn enum-value for="XRReferenceSpaceType">eye-level</dfn> creates an {{XRReferenceSpace}} instance. It represents a tracking space with a [=native origin=] near the user's head at the time of creation. The exact position and orientation will be initialized based on the conventions of the underlying platform. When using this reference space the user is not expected to move beyond their initial position much, if at all, and tracking is optimized for that purpose. For devices with [=6DoF=] tracking, {{eye-level}} reference spaces should emphasize keeping the origin stable relative to the user's environment.

- Passing a type of <dfn enum-value for="XRReferenceSpaceType">floor-level</dfn> creates an {{XRReferenceSpace}} instance. It represents a tracking space with a [=native origin=] at the floor in a safe position for the user to stand. The `y` axis equals `0` at floor level, with the `x` and `z` position and orientation initialized based on the conventions of the underlying platform. If the floor level isn't known it MUST be estimated. When using this reference space the user is not expected to move beyond their initial position much, if at all, and tracking is optimized for that purpose. For devices with [=6DoF=] tracking, {{floor-level}} reference spaces should emphasize keeping the origin stable relative to the user's environment.

- Passing a type of <dfn enum-value for="XRReferenceSpaceType">bounded</dfn> creates an {{XRBoundedReferenceSpace}} instance if supported by the [=/XR device=] and the {{XRSession}}. It represents a tracking space with it's [=native origin=] at the floor, where the user is expected to move within a pre-established boundary, given as the {{boundsGeometry}}. Tracking in a {{bounded}} reference space is optimized for keeping the [=native origin=] and {{boundsGeometry}} stable relative to the user's environment.

- Passing a type of <dfn enum-value for="XRReferenceSpaceType">unbounded</dfn> creates an {{XRReferenceSpace}} instance if supported by the [=/XR device=] and the {{XRSession}}. It represents a tracking space where the user is expected to move freely around their environment, potentially even long distances from their starting point. Tracking in an {{unbounded}} reference space is optimized for stability around the user's current position, and as such the [=native origin=] may drift over time.

Devices that support any of the following {{XRReferenceSpaceType}}s MUST support all three: {{XRReferenceSpaceType/position-disabled}}, {{XRReferenceSpaceType/eye-level}}, {{XRReferenceSpaceType/floor-level}}. The minimum sensor data necessary for supporting all three reference spaces is the same.

Note: The {{position-disabled}} type is primarily intended for use with pre-rendered media such as panoramic photos or videos. It should not be used for most other media types due to user discomfort associated with the lack of a neck model or full positional tracking.

1. Let |type| be set to the {{XRReferenceSpaceType}} passed to {{requestReferenceSpace()}}.

1. If |type| is {{bounded}}, let |referenceSpace| be a new {{XRBoundedReferenceSpace}}.

1. Else let |referenceSpace| be a new {{XRReferenceSpace}}.

1. Initialize |referenceSpace|'s [=XRReferenceSpace/type=] to be |type|.

{{XRBoundedReferenceSpace}} extends {{XRReferenceSpace}} to include {{boundsGeometry}}, indicating the pre-confingured boundaries of the users space.

Note: Other XR platforms sometimes refer to the type of tracking offered by a {{bounded}} reference space as "room scale" tracking. An {{XRBoundedReferenceSpace}} is not intended to describe multi-room spaces, areas with uneven floor levels, or very large open areas. Content that needs to handle those scenarios should use an {{unbounded}} reference space.