Package org.lwjgl.openxr

Class VARJOMarkerTracking

java.lang.Object

org.lwjgl.openxr.VARJOMarkerTracking

public class VARJOMarkerTracking
extends Object

The XR_VARJO_marker_tracking extension.

Varjo Markers are physical markers tracked by the video cameras of the HMD. Different types of markers can be used for different purposes. As an example, Varjo Markers can be used as cheap replacements for electronic trackers. The cost per printed tracker is significantly lower and the markers require no power to function.

This extension provides the tracking interface to a set of marker types and sizes. Markers can be printed out from the PDF documents and instructions freely available at https://developer.varjo.com/docs/get-started/varjo-markers#printing-varjo-markers. Note that the printed marker must have the exact physical size for its ID.

Object markers are used to track static or dynamic objects in the user environment. You may use object markers in both XR and VR applications. Each marker has a unique ID, and you must not use the same physical marker more than once in any given environment. For added precision, an application may use multiple markers to track a single object. For example, you could track a monitor by placing a marker in each corner.

There is a set of marker IDs recognized by runtime and if the application uses ID which is not in the set then runtime must return ERROR_MARKER_ID_INVALID_VARJO.

Field Summary

Fields

Modifier and Type	Field	Description
static final int	XR_ERROR_MARKER_ID_INVALID_VARJO	Extends XrResult.
static final int	XR_ERROR_MARKER_NOT_TRACKED_VARJO	Extends XrResult.
static final int	XR_TYPE_EVENT_DATA_MARKER_TRACKING_UPDATE_VARJO	Extends XrStructureType.
static final int	XR_TYPE_MARKER_SPACE_CREATE_INFO_VARJO	Extends XrStructureType.
static final int	XR_TYPE_SYSTEM_MARKER_TRACKING_PROPERTIES_VARJO	Extends XrStructureType.
static final String	XR_VARJO_MARKER_TRACKING_EXTENSION_NAME	The extension name.
static final int	XR_VARJO_marker_tracking_SPEC_VERSION	The extension specification version.

Method Summary

Modifier and Type	Method	Description
static int	nxrCreateMarkerSpaceVARJO(XrSession session, long createInfo, long space)	Unsafe version of: CreateMarkerSpaceVARJO
static int	nxrGetMarkerSizeVARJO(XrSession session, long markerId, long size)	Unsafe version of: GetMarkerSizeVARJO
static int	xrCreateMarkerSpaceVARJO(XrSession session, XrMarkerSpaceCreateInfoVARJO createInfo, org.lwjgl.PointerBuffer space)	Creates marker space.
static int	xrGetMarkerSizeVARJO(XrSession session, long markerId, XrExtent2Df size)	Gets physical size of marker.
static int	xrSetMarkerTrackingPredictionVARJO(XrSession session, long markerId, boolean enable)	Sets marker tracking with prediction.
static int	xrSetMarkerTrackingTimeoutVARJO(XrSession session, long markerId, long timeout)	Sets marker lifetime duration.
static int	xrSetMarkerTrackingVARJO(XrSession session, boolean enabled)	Enables marker tracking.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

XR_VARJO_marker_tracking_SPEC_VERSION

public static final int XR_VARJO_marker_tracking_SPEC_VERSION

The extension specification version.

See Also:

• Constant Field Values

XR_VARJO_MARKER_TRACKING_EXTENSION_NAME

public static final String XR_VARJO_MARKER_TRACKING_EXTENSION_NAME

The extension name.

See Also:

• Constant Field Values

XR_TYPE_SYSTEM_MARKER_TRACKING_PROPERTIES_VARJO

public static final int XR_TYPE_SYSTEM_MARKER_TRACKING_PROPERTIES_VARJO

Extends XrStructureType.

Enum values:

• TYPE_SYSTEM_MARKER_TRACKING_PROPERTIES_VARJO
• TYPE_EVENT_DATA_MARKER_TRACKING_UPDATE_VARJO
• TYPE_MARKER_SPACE_CREATE_INFO_VARJO

See Also:

• Constant Field Values

XR_TYPE_EVENT_DATA_MARKER_TRACKING_UPDATE_VARJO

public static final int XR_TYPE_EVENT_DATA_MARKER_TRACKING_UPDATE_VARJO

Extends XrStructureType.

Enum values:

• TYPE_SYSTEM_MARKER_TRACKING_PROPERTIES_VARJO
• TYPE_EVENT_DATA_MARKER_TRACKING_UPDATE_VARJO
• TYPE_MARKER_SPACE_CREATE_INFO_VARJO

See Also:

• Constant Field Values

XR_TYPE_MARKER_SPACE_CREATE_INFO_VARJO

public static final int XR_TYPE_MARKER_SPACE_CREATE_INFO_VARJO

Extends XrStructureType.

Enum values:

• TYPE_SYSTEM_MARKER_TRACKING_PROPERTIES_VARJO
• TYPE_EVENT_DATA_MARKER_TRACKING_UPDATE_VARJO
• TYPE_MARKER_SPACE_CREATE_INFO_VARJO

See Also:

• Constant Field Values

XR_ERROR_MARKER_NOT_TRACKED_VARJO

public static final int XR_ERROR_MARKER_NOT_TRACKED_VARJO

Extends XrResult.

Enum values:

• ERROR_MARKER_NOT_TRACKED_VARJO
• ERROR_MARKER_ID_INVALID_VARJO

See Also:

• Constant Field Values

XR_ERROR_MARKER_ID_INVALID_VARJO

public static final int XR_ERROR_MARKER_ID_INVALID_VARJO

Extends XrResult.

Enum values:

• ERROR_MARKER_NOT_TRACKED_VARJO
• ERROR_MARKER_ID_INVALID_VARJO

See Also:

• Constant Field Values

Method Details

xrSetMarkerTrackingVARJO

public static int xrSetMarkerTrackingVARJO(XrSession session,
 boolean enabled)

Enables marker tracking.

C Specification

The SetMarkerTrackingVARJO function is defined as:

 XrResult  xrSetMarkerTrackingVARJO(
     XrSession                                   session,
     XrBool32                                    enabled);

Description

The SetMarkerTrackingVARJO function enables or disables marker tracking functionality. As soon as feature is become disabled all trackable markers become inactive and corresponding events will be generated. An application may call any of the functions in this extension regardless if the marker tracking functionality is enabled or disabled.

Valid Usage (Implicit)

• The XR_VARJO_marker_tracking extension must be enabled prior to calling SetMarkerTrackingVARJO
• session must be a valid XrSession handle

Return Codes

On success, this command returns

• SUCCESS
• SESSION_LOSS_PENDING

On failure, this command returns

• ERROR_FUNCTION_UNSUPPORTED
• ERROR_RUNTIME_FAILURE
• ERROR_HANDLE_INVALID
• ERROR_INSTANCE_LOST
• ERROR_SESSION_LOST
• ERROR_FEATURE_UNSUPPORTED

Parameters:

session - an XrSession handle previously created with CreateSession.

enabled - the flag to enable or disable marker tracking.

xrSetMarkerTrackingTimeoutVARJO

public static int xrSetMarkerTrackingTimeoutVARJO(XrSession session,
 long markerId,
 long timeout)

Sets marker lifetime duration.

C Specification

The SetMarkerTrackingTimeoutVARJO function is defined as:

 XrResult xrSetMarkerTrackingTimeoutVARJO(
     XrSession                                   session,
     uint64_t                                    markerId,
     XrDuration                                  timeout);

Description

The SetMarkerTrackingTimeoutVARJO function sets a desired lifetime duration for a specified marker. The default value is NO_DURATION. Negative value will be clamped to NO_DURATION. It defines the time period during which the runtime must keep returning poses of previously tracked markers. The tracking may be lost if the marker went outside of the trackable field of view. In this case the runtime still will try to predict marker’s pose for the timeout period. The runtime must return ERROR_MARKER_ID_INVALID_VARJO if the supplied markerId is invalid.

Valid Usage (Implicit)

• The XR_VARJO_marker_tracking extension must be enabled prior to calling SetMarkerTrackingTimeoutVARJO
• session must be a valid XrSession handle

Return Codes

On success, this command returns

• SUCCESS
• SESSION_LOSS_PENDING

On failure, this command returns

• ERROR_FUNCTION_UNSUPPORTED
• ERROR_RUNTIME_FAILURE
• ERROR_HANDLE_INVALID
• ERROR_INSTANCE_LOST
• ERROR_SESSION_LOST
• ERROR_MARKER_ID_INVALID_VARJO
• ERROR_FEATURE_UNSUPPORTED

Parameters:

session - an XrSession handle previously created with CreateSession.

markerId - the unique identifier of the marker for which the timeout will be updated.

timeout - the desired lifetime duration for a specified marker.

xrSetMarkerTrackingPredictionVARJO

public static int xrSetMarkerTrackingPredictionVARJO(XrSession session,
 long markerId,
 boolean enable)

Sets marker tracking with prediction.

C Specification

The SetMarkerTrackingPredictionVARJO function is defined as:

 XrResult xrSetMarkerTrackingPredictionVARJO(
     XrSession                                   session,
     uint64_t                                    markerId,
     XrBool32                                    enable);

Description

The SetMarkerTrackingPredictionVARJO function enables or disables the prediction feature for a specified marker. By default, markers are created with disabled prediction. This works well for markers that are supposed to be stationary. The prediction can be used to improve tracking of movable markers. The runtime must return ERROR_MARKER_ID_INVALID_VARJO if the supplied markerId is invalid.

Valid Usage (Implicit)

• The XR_VARJO_marker_tracking extension must be enabled prior to calling SetMarkerTrackingPredictionVARJO
• session must be a valid XrSession handle

Return Codes

On success, this command returns

• SUCCESS
• SESSION_LOSS_PENDING

On failure, this command returns

• ERROR_FUNCTION_UNSUPPORTED
• ERROR_RUNTIME_FAILURE
• ERROR_HANDLE_INVALID
• ERROR_INSTANCE_LOST
• ERROR_SESSION_LOST
• ERROR_MARKER_ID_INVALID_VARJO
• ERROR_FEATURE_UNSUPPORTED

Parameters:

session - an XrSession handle previously created with CreateSession.

markerId - the unique identifier of the marker which should be tracked with prediction.

enable - whether to enable the prediction feature.

nxrGetMarkerSizeVARJO

public static int nxrGetMarkerSizeVARJO(XrSession session,
 long markerId,
 long size)

Unsafe version of: GetMarkerSizeVARJO

xrGetMarkerSizeVARJO

public static int xrGetMarkerSizeVARJO(XrSession session,
 long markerId,
 XrExtent2Df size)

Gets physical size of marker.

C Specification

The GetMarkerSizeVARJO function is defined as:

 XrResult xrGetMarkerSizeVARJO(
     XrSession                                   session,
     uint64_t                                    markerId,
     XrExtent2Df*                                size);

Description

The GetMarkerSizeVARJO function retrieves the height and width of an active marker. The runtime must return ERROR_MARKER_NOT_TRACKED_VARJO if marker tracking functionality is disabled or the marker with given markerId is inactive. The runtime must return ERROR_MARKER_ID_INVALID_VARJO if the supplied markerId is invalid.

Valid Usage (Implicit)

• The XR_VARJO_marker_tracking extension must be enabled prior to calling GetMarkerSizeVARJO
• session must be a valid XrSession handle
• size must be a pointer to an XrExtent2Df structure

Return Codes

On success, this command returns

• SUCCESS
• SESSION_LOSS_PENDING

On failure, this command returns

• ERROR_FUNCTION_UNSUPPORTED
• ERROR_RUNTIME_FAILURE
• ERROR_HANDLE_INVALID
• ERROR_INSTANCE_LOST
• ERROR_SESSION_LOST
• ERROR_MARKER_NOT_TRACKED_VARJO
• ERROR_MARKER_ID_INVALID_VARJO
• ERROR_FEATURE_UNSUPPORTED

See Also

XrExtent2Df

Parameters:

session - an XrSession handle previously created with CreateSession.

markerId - the unique identifier of the marker for which size is requested.

size - pointer to the size to populate by the runtime with the physical size of plane marker in meters.

nxrCreateMarkerSpaceVARJO

public static int nxrCreateMarkerSpaceVARJO(XrSession session,
 long createInfo,
 long space)

Unsafe version of: CreateMarkerSpaceVARJO

xrCreateMarkerSpaceVARJO

public static int xrCreateMarkerSpaceVARJO(XrSession session,
 XrMarkerSpaceCreateInfoVARJO createInfo,
 org.lwjgl.PointerBuffer space)

Creates marker space.

C Specification

The CreateMarkerSpaceVARJO function is defined as:

 XrResult xrCreateMarkerSpaceVARJO(
     XrSession                                   session,
     const XrMarkerSpaceCreateInfoVARJO*         createInfo,
     XrSpace*                                    space);

Description

The CreateMarkerSpaceVARJO function creates marker XrSpace for pose relative to the marker specified in XrMarkerSpaceCreateInfoVARJO. The runtime must return ERROR_MARKER_ID_INVALID_VARJO if the supplied XrMarkerSpaceCreateInfoVARJO::markerId is invalid.

Valid Usage (Implicit)

• The XR_VARJO_marker_tracking extension must be enabled prior to calling CreateMarkerSpaceVARJO
• session must be a valid XrSession handle
• createInfo must be a pointer to a valid XrMarkerSpaceCreateInfoVARJO structure
• space must be a pointer to an XrSpace handle

Return Codes

On success, this command returns

• SUCCESS
• SESSION_LOSS_PENDING

On failure, this command returns

• ERROR_FUNCTION_UNSUPPORTED
• ERROR_VALIDATION_FAILURE
• ERROR_HANDLE_INVALID
• ERROR_INSTANCE_LOST
• ERROR_SESSION_LOST
• ERROR_OUT_OF_MEMORY
• ERROR_LIMIT_REACHED
• ERROR_POSE_INVALID
• ERROR_MARKER_ID_INVALID_VARJO
• ERROR_FEATURE_UNSUPPORTED

See Also

XrMarkerSpaceCreateInfoVARJO

Parameters:

session - an XrSession handle previously created with CreateSession.

createInfo - the structure containing information about how to create the space based on marker.

space - a pointer to a handle in which the created XrSpace is returned.