C Specification

The XrEventDataReferenceSpaceChangePending event is sent to the application to notify it that the origin (and perhaps the bounds) of a reference space is changing. This may occur due to the user recentering the space explicitly, or the runtime otherwise switching to a different space definition.

The reference space change must only take effect for xrLocateSpace or xrLocateViews calls whose XrTime parameter is greater than or equal to the changeTime provided in that event. Runtimes should provide a changeTime to applications that allows for a deep render pipeline to present frames that are already in flight using the previous definition of the space. Runtimes should choose a changeTime that is midway between the XrFrameState::predictedDisplayTime of future frames to avoid threshold issues with applications that calculate future frame times using XrFrameState::predictedDisplayPeriod.

The poseInPreviousSpace provided here must only describe the change in the natural origin of the reference space and must not incorporate any origin offsets specified by the application during calls to xrCreateReferenceSpace. If the runtime does not know the location of the space’s new origin relative to its previous origin, poseValid must be false, and the position and orientation of poseInPreviousSpace are undefined.

// Provided by XR_VERSION_1_0
typedef struct XrEventDataReferenceSpaceChangePending {
    XrStructureType         type;
    const void*             next;
    XrSession               session;
    XrReferenceSpaceType    referenceSpaceType;
    XrTime                  changeTime;
    XrBool32                poseValid;
    XrPosef                 poseInPreviousSpace;
} XrEventDataReferenceSpaceChangePending;

Members

Member Descriptions

  • type is the XrStructureType of this structure.

  • next is NULL or a pointer to the next structure in a structure chain. No such structures are defined in core OpenXR.

  • session is the XrSession for which the reference space is changing.

  • referenceSpaceType is the XrReferenceSpaceType that is changing.

  • changeTime is the target XrTime after which xrLocateSpace or xrLocateViews will return values that respect this change.

  • poseValid is true if the runtime can determine the poseInPreviousSpace of the new space in the previous space before the change.

  • poseInPreviousSpace is an XrPosef defining the position and orientation of the new reference space’s natural origin within the natural reference frame of its previous space.

Description

Valid Usage (Implicit)

See Also

XR_VERSION_1_0, XrBool32, XrPosef, XrReferenceSpaceType, XrSession, XrStructureType, XrTime, xrCreateReferenceSpace

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 2014-2024, The Khronos Group Inc.

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