C Specification

The XrReferenceSpaceType enumeration is defined as:

typedef enum XrReferenceSpaceType {
    XR_REFERENCE_SPACE_TYPE_VIEW = 1,
    XR_REFERENCE_SPACE_TYPE_LOCAL = 2,
    XR_REFERENCE_SPACE_TYPE_STAGE = 3,
  // Provided by XR_VERSION_1_1
    XR_REFERENCE_SPACE_TYPE_LOCAL_FLOOR = 1000426000,
  // Provided by XR_MSFT_unbounded_reference_space
    XR_REFERENCE_SPACE_TYPE_UNBOUNDED_MSFT = 1000038000,
  // Provided by XR_VARJO_foveated_rendering
    XR_REFERENCE_SPACE_TYPE_COMBINED_EYE_VARJO = 1000121000,
  // Provided by XR_ML_localization_map
    XR_REFERENCE_SPACE_TYPE_LOCALIZATION_MAP_ML = 1000139000,
  // Provided by XR_EXT_local_floor
    XR_REFERENCE_SPACE_TYPE_LOCAL_FLOOR_EXT = XR_REFERENCE_SPACE_TYPE_LOCAL_FLOOR,
    XR_REFERENCE_SPACE_TYPE_MAX_ENUM = 0x7FFFFFFF
} XrReferenceSpaceType;

Description

Brief introductions to core reference space types follow. Each has full requirements in a subsequent section, linked from these descriptions.

Enumerant Descriptions

  • XR_REFERENCE_SPACE_TYPE_VIEW. The VIEW reference space tracks the view origin used to generate view transforms for the primary viewer (or centroid of view origins if stereo), with +Y up, +X to the right, and -Z forward. This space points in the forward direction for the viewer without incorporating the user’s eye orientation, and is not gravity-aligned.

    Runtimes must support VIEW reference space.

  • XR_REFERENCE_SPACE_TYPE_LOCAL. The LOCAL reference space establishes a world-locked origin, gravity-aligned to exclude pitch and roll, with +Y up, +X to the right, and -Z forward. This space locks in both its initial position and orientation, which the runtime may define to be either the initial position at application launch or some other calibrated zero position.

    Runtimes must support LOCAL reference space.

  • XR_REFERENCE_SPACE_TYPE_STAGE. The STAGE reference space is a runtime-defined flat, rectangular space that is empty and can be walked around on. The origin is on the floor at the center of the rectangle, with +Y up, and the X and Z axes aligned with the rectangle edges. The runtime may not be able to locate spaces relative to the STAGE reference space if the user has not yet defined one within the runtime-specific UI. Applications can use xrGetReferenceSpaceBoundsRect to determine the extents of the STAGE reference space’s XZ bounds rectangle, if defined.

    Support for the STAGE reference space is optional.

  • XR_REFERENCE_SPACE_TYPE_LOCAL_FLOOR. (provided by XR_VERSION_1_1) Similar to LOCAL space, the LOCAL_FLOOR reference space establishes a world-locked origin, gravity-aligned to exclude pitch and roll, with +Y up, +X to the right, and -Z forward. However, the origin of this space is defined to be on an estimate of the floor level.

    Runtimes must support LOCAL_FLOOR reference space.

An XrSpace handle for a reference space is created using xrCreateReferenceSpace, by specifying the chosen reference space type and a pose within the natural reference frame defined for that reference space type.

Runtimes implement well-known reference spaces from XrReferenceSpaceType if they support tracking of that kind. Available reference space types are indicated by xrEnumerateReferenceSpaces. Note that other spaces can be created as well, such as pose action spaces created by xrCreateActionSpace, which are not enumerated by that API.

See Also

XrEventDataReferenceSpaceChangePending, XrReferenceSpaceCreateInfo, xrEnumerateReferenceSpaces, xrGetReferenceSpaceBoundsRect

Document Notes

For more information, see the OpenXR Specification

This page is extracted from the OpenXR Specification. Fixes and changes should be made to the Specification, not directly.

Copyright

Copyright 2014-2025 The Khronos Group Inc.

This work is licensed under a Creative Commons Attribution 4.0 International License.