C Specification

The XrEventDataUserPresenceChangedEXT structure is defined as:

// Provided by XR_EXT_user_presence
typedef struct XrEventDataUserPresenceChangedEXT {
    XrStructureType    type;
    const void*        next;
    XrSession          session;
    XrBool32           isUserPresent;
} XrEventDataUserPresenceChangedEXT;

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 or this extension.

  • session is the XrSession that is receiving the notification.

  • isUserPresent is an XrBool32 value for new state of user presence after the change.

Description

The XrEventDataUserPresenceChangedEXT event is queued for retrieval using xrPollEvent when the user presence is changed, as well as when a session starts running.

Receiving XrEventDataUserPresenceChangedEXT with the isUserPresent is XR_TRUE indicates that the system has detected the presence of a user in the XR experience. For example, this may indicate that the user has put on the headset, or has entered the tracking area of a non-head-worn XR system.

Receiving XrEventDataUserPresenceChangedEXT with the isUserPresent is XR_FALSE indicates that the system has detected the absence of a user in the XR experience. For example, this may indicate that the user has removed the headset or has stepped away from the tracking area of a non-head-worn XR system.

The runtime must queue this event upon a successful call to the xrBeginSession function, regardless of the value of isUserPresent, so that the application can be in sync on the state when a session begins running.

The runtime must return a valid XrSession handle for a running session.

After the application calls xrEndSession, a running session is ended and the runtime must not enqueue any more user presence events. Therefore, the application will no longer observe any changes of the isUserPresent until another running session.

Note

This extension does not require any specific correlation between user presence state and session state except that the XrEventDataUserPresenceChangedEXT event can not be observed without a running session. A runtime may choose to correlate the two states or keep them independent.

Valid Usage (Implicit)

See Also

XR_EXT_user_presence, XrBool32, XrSession, XrStructureType

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.