ArTrackable

Something that can be tracked and that anchors can be attached to.

Summary

Enumerations

ArTrackableType{   AR_TRACKABLE_BASE_TRACKABLE = 0x41520100,   AR_TRACKABLE_PLANE = 0x41520101,   AR_TRACKABLE_POINT = 0x41520102,   AR_TRACKABLE_AUGMENTED_IMAGE = 0x41520104,   AR_TRACKABLE_FACE = 0x41520105,   AR_TRACKABLE_STREETSCAPE_GEOMETRY = 0x41520103,   AR_TRACKABLE_EARTH = 0x41520109,   AR_TRACKABLE_DEPTH_POINT = 0x41520111,   AR_TRACKABLE_INSTANT_PLACEMENT_POINT = 0x41520112,   AR_TRACKABLE_NOT_VALID = 0 }

enum Object types for heterogeneous query/update lists.

Typedefs
ArTrackable	typedef struct ArTrackable_ Trackable base type (reference type, long-lived).
ArTrackableList	typedef struct ArTrackableList_ A list of ArTrackable's (value type).

Functions
ArTrackableList_acquireItem(const ArSession *session, const ArTrackableList *trackable_list, int32_t index, ArTrackable **out_trackable)	void Acquires a reference to an indexed entry in the list.
ArTrackableList_create(const ArSession *session, ArTrackableList **out_trackable_list)	void Creates a trackable list object.
ArTrackableList_destroy(ArTrackableList *trackable_list)	void Releases the memory used by a trackable list object, along with all the anchor references it holds.
ArTrackableList_getSize(const ArSession *session, const ArTrackableList *trackable_list, int32_t *out_size)	void Retrieves the number of trackables in this list.
ArTrackable_acquireNewAnchor(ArSession *session, ArTrackable *trackable, ArPose *pose, ArAnchor **out_anchor)	ArStatus Creates an Anchor at the given pose in the world coordinate space, attached to this Trackable, and acquires a reference to it.
ArTrackable_getAnchors(const ArSession *session, const ArTrackable *trackable, ArAnchorList *out_anchor_list)	void Gets the set of anchors attached to this trackable.
ArTrackable_getTrackingState(const ArSession *session, const ArTrackable *trackable, ArTrackingState *out_tracking_state)	void Retrieves the current state of ARCore's knowledge of the pose of this trackable.
ArTrackable_getType(const ArSession *session, const ArTrackable *trackable, ArTrackableType *out_trackable_type)	void Retrieves the type of the trackable.
ArTrackable_release(ArTrackable *trackable)	void Releases a reference to a trackable.

Enumerations

ArTrackableType

 ArTrackableType

Object types for heterogeneous query/update lists.

Properties
AR_TRACKABLE_AUGMENTED_IMAGE	The ArAugmentedImage subtype of Trackable.
AR_TRACKABLE_BASE_TRACKABLE	The base Trackable type. Can be passed to ArSession_getAllTrackables and ArFrame_getUpdatedTrackables as the filter_type to get all/updated Trackables of all types.
AR_TRACKABLE_DEPTH_POINT	On supported devices, trackable type for depth image based hit results returned by ArFrame_hitTest when ArConfig_setDepthMode has been set to AR_DEPTH_MODE_AUTOMATIC.
AR_TRACKABLE_EARTH	Trackable type for ArEarth.
AR_TRACKABLE_FACE	Trackable type for faces.
AR_TRACKABLE_INSTANT_PLACEMENT_POINT	Trackable type for results retrieved from ArFrame_hitTestInstantPlacement. This trackable type is only available when when ArConfig_setInstantPlacementMode is AR_INSTANT_PLACEMENT_MODE_LOCAL_Y_UP.
AR_TRACKABLE_NOT_VALID	An invalid Trackable type.
AR_TRACKABLE_PLANE	The ArPlane subtype of Trackable.
AR_TRACKABLE_POINT	The ArPoint subtype of Trackable.
AR_TRACKABLE_STREETSCAPE_GEOMETRY	Trackable type for Streetscape Geometry.

Typedefs

ArTrackable

struct ArTrackable_ ArTrackable

Trackable base type (reference type, long-lived).

ArTrackableList

struct ArTrackableList_ ArTrackableList

A list of ArTrackable's (value type).

• Create with: ArTrackableList_create
• Release with: ArTrackableList_destroy

Functions

ArTrackableList_acquireItem

void ArTrackableList_acquireItem(
  const ArSession *session,
  const ArTrackableList *trackable_list,
  int32_t index,
  ArTrackable **out_trackable
)

Acquires a reference to an indexed entry in the list.

This call must eventually be matched with a call to ArTrackable_release.

ArTrackableList_create

void ArTrackableList_create(
  const ArSession *session,
  ArTrackableList **out_trackable_list
)

Creates a trackable list object.

ArTrackableList_destroy

void ArTrackableList_destroy(
  ArTrackableList *trackable_list
)

Releases the memory used by a trackable list object, along with all the anchor references it holds.

ArTrackableList_getSize

void ArTrackableList_getSize(
  const ArSession *session,
  const ArTrackableList *trackable_list,
  int32_t *out_size
)

Retrieves the number of trackables in this list.

ArTrackable_acquireNewAnchor

ArStatus ArTrackable_acquireNewAnchor(
  ArSession *session,
  ArTrackable *trackable,
  ArPose *pose,
  ArAnchor **out_anchor
)

Creates an Anchor at the given pose in the world coordinate space, attached to this Trackable, and acquires a reference to it.

The type of Trackable will determine the semantics of attachment and how the Anchor's pose will be updated to maintain this relationship. Note that the relative offset between the pose of multiple Anchors attached to a Trackable may adjust slightly over time as ARCore updates its model of the world.

Details
Returns	AR_SUCCESS or any of: AR_ERROR_NOT_TRACKING if the trackable's tracking state was not AR_TRACKING_STATE_TRACKING AR_ERROR_SESSION_PAUSED if the session was paused AR_ERROR_RESOURCE_EXHAUSTED if too many anchors exist AR_ERROR_ILLEGAL_STATE if this trackable doesn't support anchors

ArTrackable_getAnchors

void ArTrackable_getAnchors(
  const ArSession *session,
  const ArTrackable *trackable,
  ArAnchorList *out_anchor_list
)

Gets the set of anchors attached to this trackable.

Details
Parameters	session The ARCore session trackable The trackable to query the anchors of. out_anchor_list The list to fill. This list must have already been allocated with ArAnchorList_create. If previously used, the list will first be cleared.

ArTrackable_getTrackingState

void ArTrackable_getTrackingState(
  const ArSession *session,
  const ArTrackable *trackable,
  ArTrackingState *out_tracking_state
)

Retrieves the current state of ARCore's knowledge of the pose of this trackable.

Note: Starting in ARCore 1.12, changing the active camera config using ArSession_setCameraConfig may cause the tracking state on certain devices to become permanently AR_TRACKING_STATE_PAUSED. For consistent behavior across all supported devices, release any previously created trackables when setting a new camera config.

ArTrackable_getType

void ArTrackable_getType(
  const ArSession *session,
  const ArTrackable *trackable,
  ArTrackableType *out_trackable_type
)

Retrieves the type of the trackable.

See ArTrackableType for valid types.

ArTrackable_release

void ArTrackable_release(
  ArTrackable *trackable
)

Releases a reference to a trackable.

This does not mean that the trackable will necessarily stop tracking. The same trackable may still be included in from other calls, for example ArSession_getAllTrackables.

This function may safely be called with NULL - it will do nothing.