XR Trackable Items

A trackable is something that can be tracked during application execution. This is, and object which changes on its position and orientation can be detected. Then, you can use that information to add 3D elements assoiciated to those trackables. While a trackable is detected, its world transform matrix is updated depending on real-world object changes. There are different types of trackables that can be detected by Evergine: planes, images and faces. They all extend XRTrackableItem as base class.

Supported Devices

Currently in Evergine, the following devices has Trackable Items support:

Device	XR Platform
Android	ARCore

XRTrackableItem

This base class holds information that is common to any trackable element.

Properties and Methods

Property	Description
ID	Gets trackable identifier. This is internally generated by Evergine and will be unique for all detected trackables.
Transform	Stores position and orientation information for the detected trackable. Will be continuously updated while application is running with real-world object information.

XRPlaneTrackable

This class represents plane detection. Depending on XR platform implementation you can use XRPlaneDetectionType to detect just vertical or horizontal planes, or even enable both types of plane detection.

Properties and Methods

Property	Description
BoundaryPolygon	Holds information of vertices for an approximation of polygon boundaries for a detected plane. Values are relative to XZ plane that should be transformed by trackable transform information to get boundaries in world-relative coordinates.
Size	Estimated width and length of the plane.
Type	Type of detected plane: horizontal with upward or downward facing, or vertical plane.

XRImageTrackable

Trackable for images, no matter they are static or in movement.

Properties and Methods

Property	Description
DatabaseIndex	Indicates index of the image in the internal images database.
Name	Indicates name of the image in the internal images database.
Size	Size of detected image.
TrackingMethod	Depending on tracking state: if image is not being tracked, is tracked by last pose information or full tracking.

XRFaceTrackable

This class is used to face tracking. A single face at the same time would be detected.

Properties and Methods

Property	Description
MeshVerticesPointer	Pointer to native face mesh vertices buffer.
MeshVerticesCount	Number of face mesh vertices.
MeshTextureCoordinatesPointer	Pointer to native face texture coordinates buffer.
MeshTextureCoordinatesCount	Number of texture coordinates.
MeshNormalsPointer	Pointer to native face mesh normals buffer.
MeshNormalsCount	Number of normals.
MeshTriangleIndicesPointer	Pointer to native mesh index buffer.
MeshTriangleIndicesCount	Number indexes.
LeftForeheadPose	Pose for the left forehead.
RightForeheadPose	Pose for the right forehead.
NosePose	Pose for the nose.