API Reference

Components

All the functions declared in the components are available in both C++ and blueprint.

class UViveHandTrackingComponent : public UActorComponent

This is a the component class used for hand detection. It provides functions to start/stop detection and get results.

ViveHandTrackingMode StartDetection(ViveHandTrackingMode ChoosedMode)

Start detection with choosed mode. Return value is the actual mode used in detection, since not all modes are supported on the device.

void StopDetection()

Stop the detection. Blocking call until the pipeline is actually stopped.

const FViveHandTrackingResult &GetLeftHand() const

Get detection result of left hand. Use FViveHandTrackingResult::isValid to check if hand is valid.

const FViveHandTrackingResult &GetRightHand() const

Get detection result of right hand. Use FViveHandTrackingResult::isValid to check if hand is valid.

const ViveHandTrackingStatus &GetStatus() const

Returns running status of hand detection.

const ViveHandTrackingFailure &GetError() const

Returns detailed error if GetStatus() is ViveHandTrackingStatus::Error.

const ViveHandTrackingMode &GetMode() const

Current running mode for detection, value is only valid if GetStatus() is ViveHandTrackingStatus::Starting or ViveHandTrackingStatus::Running.

const bool UpdatedInThisFrame() const

Returns true if GetLeftHand() and GetRightHand() are updated in this frame. This can be useful for calculating states that only depends on hand result. Since Vive Hand Tracking SDK normally have slower FPS than VR rendering, it saves computation power if these states are only updated when hand results change.

Always return false if detection is not running.

const int GetLastIndex() const

Returns the frame index, which can be used to indicate detection status. Negative means stopped or error, 0 means starting, positive means up and running.

Structs

class FViveHandTrackingResult

Struct containing detection result for one hand.

bool isValid

Returns if this hand is valid (visible in camera) or not.

TArray<FVector> SpawnPoints

Returns position of the hand. The meaning of this field is different based on actual ViveHandTrackingMode.

  • ViveHandTrackingMode::Point2D

    Size is 1, which indicates the 2D position of hand. The position is always 0.25m in front of camera.

  • ViveHandTrackingMode::Point3D

    Size is 1, which indicates the 3D position of hand.

  • ViveHandTrackingMode::Skeleton

    Size is 21 with all the keypoints of the hand. See Hand Positions (Modes) for order of the keypoints.

    Note

    Some keypoints may be missing due to occulusion from other objects or hand itself. In such cases, a place-holder position is returned which cannot be used as real position. Use x == 0 && y == 0 && z == 0 to check if a keypoint is valid.

ViveHandTrackingType gestureType

Returns pre-defined gesture type.

Enums

enum class ViveHandTrackingMode : uint8

Enum for detection mode. Larger mode return more info, but runs more slowly. If a mode is not supported on a device, will fallback to previous supported mode.

See also

See Hand Positions (Modes) section for detailed modes description.

enumerator Point2D = 0

Fastest mode, return one 2d point for hand.

enumerator Point3D = 1

Return one 3d point for hand, supported on Vive Pro and Focus.

enumerator Skeleton = 2

Return skeleton (21 points) for hand, supported on Vive and Vive Pro.

enum class ViveHandTrackingType : uint8

Enum for predefined gesture classification.

See also

See Pre-defined gesture classification section for detailed gesture description.

enumerator Unknown = 0

All other gestures not in predefined set.

enumerator Point = 1
enumerator Fist = 2
enumerator OK = 3
enumerator Like = 4
enumerator Five = 5
enum class ViveHandTrackingStatus : uint8

Enum for possible status in hand detection.

enumerator NotStarted = 0

Detection is not started or stopped.

enumerator Starting = 1

Detection is started, but first result is not returned yet.

enumerator Running = 2

Detection is running and updates result regularly.

enumerator Error = 3

Detection failed to start, or error occured during detection.

enum class ViveHandTrackingFailure : uint8

Enum for possible errors in hand detection.

enumerator None = 0

No error occurs.

enumerator OpenCL = 1

(Only on Windows) OpenCL is not supported on the machine.

See also

See Notes for Windows for possible solutions.

enumerator Camera = 2

Start camera failed. This happens if Vive Hand Tracking SDK failed to get camera frames.

  • Windows: See Camera Setup in SteamVR for possible solutions.
  • Android phone & WaveVR: Make sure camera permission is granted before start detection.
    • Some phones does not support NDK Camera2 API (or return no cameras in API).
    • Most WaveVR devices other than Vive Focus does not support camera API yet.
enumerator Internal = 10

Internal errors.

enumerator CPUOnPC = 11

CPU backend is not supported on Windows. Please use different backend when you start detection.