Group Functions

group Functions

Functions exported by the LeapC library.

Functions

int64_t LeapGetNow(void)

Samples the universal clock used by the system to timestamp image and tracking frames.

The returned counter value is given in microseconds since an epoch time. The clock used for the counter itself is implementation-defined, but generally speaking, it is global, monotonic, and makes use of the most accurate high-performance counter available on the system.

Since

3.0.0

Returns

microseconds since an unspecified epoch.

eLeapRS LeapCreateConnection(const LEAP_CONNECTION_CONFIG *pConfig, LEAP_CONNECTION *phConnection)

Creates a new LEAP_CONNECTION object.

Pass the LEAP_CONNECTION pointer to LeapOpenConnection() to establish a connection to the Ultraleap Tracking Service; and to subsequent operations on the same connection.

Since

3.0.0

Parameters
  • pConfig – The configuration to be used with the newly created connection. If pConfig is null, a connection is created with a default configuration.

  • phConnection[out] Receives a pointer to the connection object, set to invalid on failure

Returns

The operation result code, a member of the eLeapRS enumeration.

eLeapRS LeapOpenConnection(LEAP_CONNECTION hConnection)

Opens a connection to the service.

This routine will not block. A connection to the service will not be established until the first invocation of LeapPollConnection.

Since

3.0.0

Parameters

hConnection – A handle to the connection object, created by LeapCreateConnection().

Returns

The operation result code, a member of the eLeapRS enumeration.

eLeapRS LeapGetConnectionInfo(LEAP_CONNECTION hConnection, LEAP_CONNECTION_INFO *pInfo)

Retrieves status information about the specified connection.

Call LeapCreateConnection() to generate the handle for the connection; call LeapOpenConnection() to establish the connection; then call this function to check the connection status.

Since

3.0.0

Parameters
  • hConnection – The handle of the connection of interest. Created by LeapCreateConnection.

  • pInfo[out] A pointer to a buffer that receives additional connection information. One input, the size field of pInfo is the size of the buffer(i.e. the size of a LEAP_CONNECTION_INFO struct); On output, the size field of pInfo receives the size necessary to hold the entire information block.

Returns

The operation result code, a member of the eLeapRS enumeration.

eLeapRS LeapSetPolicyFlags(LEAP_CONNECTION hConnection, uint64_t set, uint64_t clear)

Sets or clears one or more policy flags.

Changing policies is asynchronous. After you call this function, a subsequent call to LeapPollConnection provides a LEAP_POLICY_EVENT containing the current policies, reflecting any changes.

To get the current policies without changes, specify zero for both the set and clear parameters. When ready, LeapPollConnection() provides the a LEAP_POLICY_EVENT containing the current settings.

The eLeapPolicyFlag enumeration defines the policy flags.

Since

3.0.0

Parameters
  • hConnection – The connection handle created by LeapCreateConnection().

  • set – A bitwise combination of flags to be set. Set to 0 if not setting any flags.

  • clear – A bitwise combination of flags to be cleared. Set to 0 to if not clearing any flags.

Returns

The operation result code, a member of the eLeapRS enumeration.

eLeapRS LeapSetTrackingMode(LEAP_CONNECTION hConnection, eLeapTrackingMode mode)

Requests a tracking mode.

Changing tracking modes is asynchronous. After you call this function, a subsequent call to LeapPollConnection provides a LEAP_POLICY_EVENT containing the current policies, reflecting any changes.

The eLeapTrackingMode enumeration defines the tracking mode.

Since

5.0.0

Parameters
  • hConnection – The connection handle created by LeapCreateConnection().

  • mode – The enum value specifying the requested tracking mode

Returns

The operation result code, a member of the eLeapRS enumeration.

eLeapRS LeapGetTrackingMode(LEAP_CONNECTION hConnection)

Requests the currently set tracking mode.

Requesting the current tracking mode is asynchronous. After you call this function, a subsequent call to LeapPollConnection provides a LEAP_TRACKING_MODE_EVENT containing the current tracking mode, reflecting any changes.

The eLeapTrackingMode enumeration defines the tracking mode.

Since

5.0.0

Parameters

hConnection – The connection handle created by LeapCreateConnection().

Returns

The operation result code, a member of the eLeapRS enumeration.

eLeapRS LeapSetPause(LEAP_CONNECTION hConnection, bool pause)

Pauses the service.

Attempts to pause or unpause the service depending on the argument. This is treated as a ‘user pause’, as though a user had requested a pause through the Leap Control Panel. The connection must have the AllowPauseResume policy set or it will fail with eLeapRS_InvalidArgument.

Since

4.0.0

Parameters
  • hConnection – The connection handle created by LeapCreateConnection().

  • pause – Set to ‘true’ to pause, or ‘false’ to unpause

Returns

The operation result code, a member of the eLeapRS enumeration.

eLeapRS LeapSetAllocator(LEAP_CONNECTION hConnection, const LEAP_ALLOCATOR *allocator)

Sets the allocator functions to use for a particular connection.

If user-supplied allocator functions are not supplied, the functions that require dynamic memory allocation will not be available.

Since

4.0.0

Parameters
  • hConnection – A handle to the connection object, created by LeapCreateConnection().

  • allocator – A pointer to a structure containing the allocator functions to be called as needed by the library.

eLeapRS LeapSaveConfigValue(LEAP_CONNECTION hConnection, const char *key, const LEAP_VARIANT *value, uint32_t *pRequestID)

Causes the client to commit a configuration change to the Ultraleap Tracking Service.

The change is performed asynchronously and may fail. LeapPollConnection() returns this event structure when the request has been processed. Use the pRequestID value to correlate the response to the originating request.

Since

3.0.0

Parameters
  • hConnection – The connection handle created by LeapCreateConnection().

  • key – The key of the configuration to commit.

  • value – The value of the configuration to commit.

  • pRequestID[out] A pointer to a memory location to which the id for this request is written, or nullptr if this value is not needed.

Returns

The operation result code, a member of the eLeapRS enumeration.

eLeapRS LeapRequestConfigValue(LEAP_CONNECTION hConnection, const char *key, uint32_t *pRequestID)

Requests the current value of a service configuration setting.

The value is fetched asynchronously since it requires a service transaction. LeapPollConnection() returns this event structure when the request has been processed. Use the pRequestID value to correlate the response to the originating request.

Since

3.0.0

Parameters
  • hConnection – The connection handle created by LeapCreateConnection().

  • key – The key of the configuration to request

  • pRequestID[out] A pointer to a memory location to which the id for this request is written.

Returns

The operation result code, a member of the eLeapRS enumeration.

eLeapRS LeapGetDeviceList(LEAP_CONNECTION hConnection, LEAP_DEVICE_REF *pArray, uint32_t *pnArray)

Retrieves a list of Ultraleap Tracking camera devices currently attached to the system.

To get the number of connected devices, call this function with the pArray parameter set to null. The number of devices is written to the memory specified by pnArray. Use the device count to create an array of LEAP_DEVICE_REF structs large enough to hold the number of connected devices. Finally, call LeapGetDeviceList() with this array and known count to get the list of Leap devices. A device must be opened with LeapOpenDevice() before device properties can be queried.

Since

3.0.0

Parameters
  • hConnection – The connection handle created by LeapCreateConnection().

  • pArray[out] A pointer to an array that LeapC fills with the device list.

  • pnArray[inout] On input, set to the number of elements in pArray; on output, LeapC sets this to the number of valid device handles.

Returns

The operation result code, a member of the eLeapRS enumeration.

eLeapRS LeapOpenDevice(LEAP_DEVICE_REF rDevice, LEAP_DEVICE *phDevice)

Opens a device reference and retrieves a handle to the device.

To ensure resources are properly freed, users must call LeapCloseDevice() when finished with the device, even if the retrieved device has problems or cannot stream.

Since

3.0.0

Parameters
  • rDevice – A device reference.

  • phDevice[out] A pointer that receives the opened device handle.

Returns

The operation result code, a member of the eLeapRS enumeration.

eLeapRS LeapGetDeviceInfo(LEAP_DEVICE hDevice, LEAP_DEVICE_INFO *info)

Gets device properties.

To get the device serial number, you must supply a LEAP_DEVICE_INFO struct whose serial member points to a char array large enough to hold the null-terminated serial number string. To get the required length, call LeapGetDeviceInfo() using a LEAP_DEVICE_INFO struct that has serial set to NULL. LeapC sets serial_length field of the struct to the required length. You can then allocate memory for the string, set the serial field, and call this function again.

Since

3.0.0

Parameters
  • hDevice – A handle to the device to be queried.

  • info[out] The struct to receive the device property data.

Returns

The operation result code, a member of the eLeapRS enumeration.

eLeapRS LeapPollConnection(LEAP_CONNECTION hConnection, uint32_t timeout, LEAP_CONNECTION_MESSAGE *evt)

Polls the connection for a new event.

The specific types of events that may be received are not configurable in this entrypoint. Configure the device or connection object directly to change what events will be received.

Pointers in the retrieved event message structure will be valid until the associated connection or device is closed, or the next call to LeapPollConnection().

Calling this method concurrently will return eLeapRS_ConcurrentPoll.

Since

3.0.0

Parameters
  • hConnection – The connection handle created by LeapCreateConnection().

  • timeout – The maximum amount of time to wait, in milliseconds. If this value is zero, the evt pointer references the next queued message, if there is one, and returns immediately.

  • evt[out] A pointer to a structure that is filled with event information. This structure will be valid as long as the LEAP_CONNECTION object is valid.

Returns

The operation result code, a member of the eLeapRS enumeration. If the operation times out, this method will return eLeapRS_Timeout. The evt pointer will reference a message of type eLeapEventType_None.

eLeapRS LeapGetFrameSize(LEAP_CONNECTION hConnection, int64_t timestamp, uint64_t *pncbEvent)

Retrieves the number of bytes required to allocate an interpolated frame at the specified time.

Use this function to determine the size of the buffer to allocate when calling LeapInterpolateFrame().

Since

3.1.1

Parameters
  • hConnection – The connection handle created by LeapCreateConnection().

  • timestamp – The timestamp of the frame whose size is to be queried.

  • pncbEvent[out] A pointer that receives the number of bytes required to store the specified frame.

Returns

The operation result code, a member of the eLeapRS enumeration.

eLeapRS LeapGetFrameSizeEx(LEAP_CONNECTION hConnection, LEAP_DEVICE hDevice, int64_t timestamp, uint64_t *pncbEvent)

Retrieves the number of bytes required to allocate an interpolated frame at the specified time for a particular device.

Use this function to determine the size of the buffer to allocate when calling LeapInterpolateFrameEx().

Since

4.1.0

Parameters
  • hConnection – The connection handle created by LeapCreateConnection().

  • hDevice – A device handle returned by LeapOpenDevice().

  • timestamp – The timestamp of the frame whose size is to be queried.

  • pncbEvent[out] A pointer that receives the number of bytes required to store the specified frame.

Returns

The operation result code, a member of the eLeapRS enumeration.

eLeapRS LeapInterpolateFrame(LEAP_CONNECTION hConnection, int64_t timestamp, LEAP_TRACKING_EVENT *pEvent, uint64_t ncbEvent)

Constructs a frame at the specified timestamp by interpolating between measured frames.

Caller is responsible for allocating a buffer large enough to hold the data of the frame. Use LeapGetFrameSize() to calculate the minimum size of this buffer.

Use LeapCreateClockRebaser(), LeapUpdateRebase(), and LeapRebaseClock() to synchronize time measurements in the application with time measurements in the Ultraleap Tracking Service. This process is required to achieve accurate, smooth interpolation.

Since

3.1.1

Parameters
  • hConnection – The connection handle created by LeapCreateConnection().

  • timestamp – The timestamp at which to interpolate the frame data.

  • pEvent[out] A pointer to a flat buffer which is filled with an interpolated frame.

  • ncbEvent – The number of bytes pointed to by pEvent.

Returns

The operation result code, a member of the eLeapRS enumeration.

eLeapRS LeapInterpolateFrameEx(LEAP_CONNECTION hConnection, LEAP_DEVICE hDevice, int64_t timestamp, LEAP_TRACKING_EVENT *pEvent, uint64_t ncbEvent)

Constructs a frame at the specified timestamp for a particular device by interpolating between measured frames.

Caller is responsible for allocating a buffer large enough to hold the data of the frame. Use LeapGetFrameSizeEx() to calculate the minimum size of this buffer.

Use LeapCreateClockRebaser(), LeapUpdateRebase(), and LeapRebaseClock() to synchronize time measurements in the application with time measurements in the Ultraleap Tracking Service. This process is required to achieve accurate, smooth interpolation.

Since

4.1.0

Parameters
  • hConnection – The connection handle created by LeapCreateConnection().

  • hDevice – A device handle returned by LeapOpenDevice().

  • timestamp – The timestamp at which to interpolate the frame data.

  • pEvent[out] A pointer to a flat buffer which is filled with an interpolated frame.

  • ncbEvent – The number of bytes pointed to by pEvent.

Returns

The operation result code, a member of the eLeapRS enumeration.

eLeapRS LeapInterpolateFrameFromTime(LEAP_CONNECTION hConnection, int64_t timestamp, int64_t sourceTimestamp, LEAP_TRACKING_EVENT *pEvent, uint64_t ncbEvent)

Constructs a frame at the specified timestamp by interpolating between a frame near the timestamp and a frame near the sourceTimestamp.

Caller is responsible for allocating a buffer large enough to hold the data of the frame. Use LeapGetFrameSize() to calculate the minimum size of this buffer.

Use LeapCreateClockRebaser(), LeapUpdateRebase(), and LeapRebaseClock() to synchronize time measurements in the application with time measurements in the Ultraleap Tracking Service. This process is required to achieve accurate, smooth interpolation.

Since

3.1.1

Parameters
  • hConnection – The connection handle created by LeapCreateConnection().

  • timestamp – The timestamp to which to interpolate the frame data.

  • sourceTimestamp – The timestamp of the beginning frame from which to interpolate the frame data.

  • pEvent[out] A pointer to a flat buffer which is filled with an interpolated frame.

  • ncbEvent – The number of bytes pointed to by pEvent.

Returns

The operation result code, a member of the eLeapRS enumeration.

eLeapRS LeapInterpolateFrameFromTimeEx(LEAP_CONNECTION hConnection, LEAP_DEVICE hDevice, int64_t timestamp, int64_t sourceTimestamp, LEAP_TRACKING_EVENT *pEvent, uint64_t ncbEvent)

Constructs a frame at the specified timestamp for a particular device by interpolating between a frame near the timestamp and a frame near the sourceTimestamp.

Caller is responsible for allocating a buffer large enough to hold the data of the frame. Use LeapGetFrameSizeEx() to calculate the minimum size of this buffer.

Use LeapCreateClockRebaser(), LeapUpdateRebase(), and LeapRebaseClock() to synchronize time measurements in the application with time measurements in the Ultraleap Tracking Service. This process is required to achieve accurate, smooth interpolation.

Since

4.1.0

Parameters
  • hConnection – The connection handle created by LeapCreateConnection().

  • hDevice – A device handle returned by LeapOpenDevice().

  • timestamp – The timestamp to which to interpolate the frame data.

  • sourceTimestamp – The timestamp of the beginning frame from which to interpolate the frame data.

  • pEvent[out] A pointer to a flat buffer which is filled with an interpolated frame.

  • ncbEvent – The number of bytes pointed to by pEvent.

Returns

The operation result code, a member of the eLeapRS enumeration.

void LeapCloseDevice(LEAP_DEVICE hDevice)

Closes a device handle previously opened with LeapOpenDevice.

Since

3.0.0

Parameters

hDevice – The device handle to close.

void LeapCloseConnection(LEAP_CONNECTION hConnection)

Closes a previously opened connection.

This method closes the specified connection object if it is opened

This method never fails.

Since

4.0.0

Parameters

hConnection – A handle to the connection object to be closed.

void LeapDestroyConnection(LEAP_CONNECTION hConnection)

Destroys a previously opened connection.

This method closes the specified connection object if it is opened, destroys the underlying object, and releases all resources associated with it.

This method never fails.

Be sure that no other functions are accessing the connection when this function is called.

Since

3.0.0

Parameters

hConnection – A handle to the connection object to be destroyed.

eLeapRS LeapCreateClockRebaser(LEAP_CLOCK_REBASER *phClockRebaser)

Initializes a new Leap clock-rebaser handle object.

Pass the filled-in LEAP_CLOCK_REBASER object to calls to LeapUpdateRebase(), LeapRebaseClock(), and LeapDestroyClockRebaser().

Since

3.1.2

Parameters

phClockRebaser[out] The pointer to the clock-rebaser object to be initialized.

Returns

The operation result code, a member of the eLeapRS enumeration.

eLeapRS LeapUpdateRebase(LEAP_CLOCK_REBASER hClockRebaser, int64_t userClock, int64_t leapClock)

Updates the relationship between the Ultraleap Tracking Service clock and the user clock.

When using LeapInterpolateFrame(), call this function for every graphics frame rendered by your application. The function should be called as close to the actual point of rendering as possible.

The relationship between the application clock and the Ultraleap Tracking Service clock is neither fixed nor stable. Simulation restarts can cause user clock values to change instantaneously. Certain systems simulate slow motion, or respond to heavy load, by reducing the tick rate of the user clock. As a result, the LeapUpdateRebase() function must be called for every rendered frame.

Since

3.1.2

Parameters
  • hClockRebaser – The handle to a rebaser object created by LeapCreateClockRebaser().

  • userClock – A clock value supplied by the application, sampled at about the same time as LeapGetNow() was sampled.

  • leapClock – The Ultraleap Tracking Service clock value sampled by a call to LeapGetNow().

Returns

The operation result code, a member of the eLeapRS enumeration.

eLeapRS LeapRebaseClock(LEAP_CLOCK_REBASER hClockRebaser, int64_t userClock, int64_t *pLeapClock)

Computes the Ultraleap Tracking Service clock corresponding to a specified application clock value.

Use this function to translate your application clock to the Ultraleap Tracking Service clock when interpolating frames. LeapUpdateRebase() must be called for every rendered frame for the relationship between the two clocks to remain synchronized.

Since

3.1.2

Parameters
  • hClockRebaser – The handle to a rebaser object created by LeapCreateClockRebaser().

  • userClock – The clock in microseconds referenced to the application clock.

  • pLeapClock[out] The corresponding Ultraleap Tracking Service clock value.

Returns

The operation result code, a member of the eLeapRS enumeration.

void LeapDestroyClockRebaser(LEAP_CLOCK_REBASER hClockRebaser)

Destroys a previously created clock-rebaser object.

This method destroys the specified clock-rebaser object, and releases all resources associated with it.

Since

3.1.2

Parameters

hClockRebaser – A handle to the clock-rebaser object to be destroyed.

LEAP_VECTOR LeapPixelToRectilinear(LEAP_CONNECTION hConnection, eLeapPerspectiveType camera, LEAP_VECTOR pixel)

Provides the corrected camera ray intercepting the specified point on the image.

Given a point on the image, LeapPixelToRectilinear() corrects for camera distortion and returns the true direction from the camera to the source of that image point within the Ultraleap Tracking camera field of view.

This direction vector has an x and y component [x, y, 1], with the third element always 1. Note that this vector uses the 2D camera coordinate system where the x-axis parallels the longer (typically horizontal) dimension and the y-axis parallels the shorter (vertical) dimension. The camera coordinate system does not correlate to the 3D Ultraleap Tracking coordinate system.

Since

3.1.3

Parameters
  • hConnection – The connection handle created by LeapCreateConnection().

  • camera – The camera to use, a member of the eLeapPerspectiveType enumeration

  • pixel – A Vector containing the position of a pixel in the image.

Returns

A Vector containing the ray direction (the z-component of the vector is always 1).

LEAP_VECTOR LeapPixelToRectilinearEx(LEAP_CONNECTION hConnection, LEAP_DEVICE hDevice, eLeapPerspectiveType camera, eLeapCameraCalibrationType calibrationType, LEAP_VECTOR pixel)

Provides the corrected camera ray intercepting the specified point on the image for a particular device.

Given a point on the image, LeapPixelToRectilinearEx() corrects for camera distortion and returns the true direction from the camera to the source of that image point within the Devices field of view.

This direction vector has an x and y component [x, y, 1], with the third element always 1. Note that this vector uses the 2D camera coordinate system where the x-axis parallels the longer (typically horizontal) dimension and the y-axis parallels the shorter (vertical) dimension. The camera coordinate system does not correlate to the 3D Ultraleap coordinate system.

Since

4.1.0

Parameters
  • hConnection – The connection handle created by LeapCreateConnection().

  • hDevice – A device handle returned by LeapOpenDevice().

  • camera – The camera to use, a member of the eLeapPerspectiveType enumeration

  • calibrationType – The type of camera calibration to use

  • pixel – A Vector containing the position of a pixel in the image.

Returns

A Vector containing the ray direction (the z-component of the vector is always 1).

LEAP_VECTOR LeapRectilinearToPixel(LEAP_CONNECTION hConnection, eLeapPerspectiveType camera, LEAP_VECTOR rectilinear)

Provides the point in the image corresponding to a ray projecting from the camera.

Given a ray projected from the camera in the specified direction, LeapRectilinearToPixel() corrects for camera distortion and returns the corresponding pixel coordinates in the image.

The ray direction is specified in relationship to the camera. The first vector element is the tangent of the “horizontal” view angle; the second element is the tangent of the “vertical” view angle.

The LeapRectilinearToPixel() function returns pixel coordinates outside of the image bounds if you project a ray toward a point for which there is no recorded data.

LeapRectilinearToPixel() is typically not fast enough for realtime distortion correction. For better performance, use a shader program executed on a GPU.

Since

3.1.3

Parameters
  • hConnection – The connection handle created by LeapCreateConnection().

  • camera – The camera to use, a member of the eLeapPerspectiveType enumeration

  • rectilinear – A Vector containing the ray direction.

Returns

A Vector containing the pixel coordinates [x, y, 1] (with z always 1).

LEAP_VECTOR LeapRectilinearToPixelEx(LEAP_CONNECTION hConnection, LEAP_DEVICE hDevice, eLeapPerspectiveType camera, eLeapCameraCalibrationType calibrationType, LEAP_VECTOR rectilinear)

Provides the point in the image corresponding to a ray projecting from the camera for a particular device.

Given a ray projected from the camera in the specified direction, LeapRectilinearToPixelEx() corrects for camera distortion and returns the corresponding pixel coordinates in the image.

The ray direction is specified in relationship to the camera. The first vector element is the tangent of the “horizontal” view angle; the second element is the tangent of the “vertical” view angle.

The LeapRectilinearToPixelEx() function returns pixel coordinates outside of the image bounds if you project a ray toward a point for which there is no recorded data.

LeapRectilinearToPixelEx() is typically not fast enough for realtime distortion correction. For better performance, use a shader program executed on a GPU.

Since

4.1.0

Parameters
  • hConnection – The connection handle created by LeapCreateConnection().

  • hDevice – A device handle returned by LeapOpenDevice().

  • camera – The camera to use, a member of the eLeapPerspectiveType enumeration

  • calibrationType – The type of camera calibration to use

  • rectilinear – A Vector containing the ray direction.

Returns

A Vector containing the pixel coordinates [x, y, 1] (with z always 1).

void LeapCameraMatrix(LEAP_CONNECTION hConnection, eLeapPerspectiveType camera, float *dest)

Returns an OpenCV-compatible camera matrix.

Since

3.2.1

Parameters
  • hConnection – The connection handle created by LeapCreateConnection().

  • camera – The camera to use, a member of the eLeapPerspectiveType enumeration

  • dest[out] A pointer to a single-precision float array of size 9

void LeapCameraMatrixEx(LEAP_CONNECTION hConnection, LEAP_DEVICE hDevice, eLeapPerspectiveType camera, float *dest)

Returns an OpenCV-compatible camera matrix for a particular device.

Since

4.1.0

Parameters
  • hConnection – The connection handle created by LeapCreateConnection().

  • hDevice – A device handle returned by LeapOpenDevice().

  • camera – The camera to use, a member of the eLeapPerspectiveType enumeration

  • dest[out] A pointer to a single-precision float array of size 9

void LeapExtrinsicCameraMatrix(LEAP_CONNECTION hConnection, eLeapPerspectiveType camera, float *dest)

This finds the default device and returns the result LeapExtrinsicCameraMatrixEx()

Since

5.1.0

Parameters
  • hConnection – The connection handle created by LeapCreateConnection().

  • camera – The camera to use, a member of the eLeapPerspectiveType enumeration

  • dest[out] A pointer to a single-precision float array of size 16, containing the coefficients of the 4x4 matrix in Column Major order

void LeapExtrinsicCameraMatrixEx(LEAP_CONNECTION hConnection, LEAP_DEVICE hDevice, eLeapPerspectiveType camera, float *dest)

Returns a transformation matrix from 3D Leap coordinate space to the coordinate system of the requested camera This is composed of a 4 x 4 matrix of the form:

R, t

0, 1

R is a 3 x 3 rotation matrix

t is a 3 x 1 translation vector

Since

5.1.0

Parameters
  • hConnection – The connection handle created by LeapCreateConnection().

  • hDevice – A device handle returned by LeapOpenDevice().

  • camera – The camera to use, a member of the eLeapPerspectiveType enumeration

  • dest[out] A pointer to a single-precision float array of size 16, containing the coefficients of the 4x4 matrix in Column Major order

void LeapDistortionCoeffs(LEAP_CONNECTION hConnection, eLeapPerspectiveType camera, float *dest)

Returns an OpenCV-compatible lens distortion using the 8-parameter rational model.

The order of the returned array is: [k1, k2, p1, p2, k3, k4, k5, k6]

Since

3.2.1

Parameters
  • hConnection – The connection handle created by LeapCreateConnection().

  • camera – The camera to use, a member of the eLeapPerspectiveType enumeration

  • dest[out] A pointer to a single-precision float array of size 8.

void LeapDistortionCoeffsEx(LEAP_CONNECTION hConnection, LEAP_DEVICE hDevice, eLeapPerspectiveType camera, float *dest)

Returns an OpenCV-compatible lens distortion for a particular device, using the 8-parameter rational model.

The order of the returned array is: [k1, k2, p1, p2, k3, k4, k5, k6]

Since

4.1.0

Parameters
  • hConnection – The connection handle created by LeapCreateConnection().

  • hDevice – A device handle returned by LeapOpenDevice().

  • camera – The camera to use, a member of the eLeapPerspectiveType enumeration

  • dest[out] A pointer to a single-precision float array of size 8.

const char *LeapDevicePIDToString(eLeapDevicePID pid)

Provides the human-readable canonical name of the specified device model.

This method is guaranteed to never return null for the LEAP_DEVICE_INFO.pid field returned by a successful call to LeapGetDeviceInfo

Parameters

pid – The pid of the device

Returns

The string name of the device model, or null if the device type string is invalid.

eLeapRS LeapRecordingOpen(LEAP_RECORDING *ppRecording, const char *filePath, LEAP_RECORDING_PARAMETERS params)

Opens or creates a LEAP_RECORDING.

Pass the LEAP_RECORDING pointer to LeapRecordingOpen() to initiate reading from or writing to a recording. The recording path is relative to the “user path” which is the SD card on Android.

Since

3.2.0

Parameters
  • ppRecording – The recording being opened.

  • filePath – The file path. This will be passed directly to the OS without modification. An “.lmt” suffix is suggested.

  • params – The LEAP_RECORDING_PARAMETERS describing what operations are requested.

Returns

The operation result code, a member of the eLeapRS enumeration.

eLeapRS LeapRecordingClose(LEAP_RECORDING *ppRecording)

Closes a LEAP_RECORDING.

Since

3.2.0

Parameters

ppRecording[out] The recording being closed. Will modify *ppRecording to be null.

Returns

The operation result code, a member of the eLeapRS enumeration.

eLeapRS LeapRecordingGetStatus(LEAP_RECORDING pRecording, LEAP_RECORDING_STATUS *pstatus)

Fills in a LEAP_RECORDING_STATUS struct for an open recording.

This struct provides the applicable eLeapRecordingFlags.

Since

3.2.0

Parameters
  • pRecording – The open recording.

  • pstatus[out] A LEAP_RECORDING_STATUS struct to receive the recording status.

Returns

The operation result code, a member of the eLeapRS enumeration.

eLeapRS LeapRecordingReadSize(LEAP_RECORDING pRecording, uint64_t *pncbEvent)

Retrieves the number of bytes required to allocate the next frame in a recording.

Use this function to determine the size of the buffer to allocate before calling LeapRecordingRead().

Since

3.2.0

Parameters
  • pRecording – The recording being read from.

  • pncbEvent[out] A pointer that receives the number of bytes required to store the next frame.

Returns

The operation result code, a member of the eLeapRS enumeration.

eLeapRS LeapRecordingRead(LEAP_RECORDING pRecording, LEAP_TRACKING_EVENT *pEvent, uint64_t ncbEvent)

Reads a tracking frame from a LEAP_RECORDING file.

Caller is responsible for allocating a buffer large enough to hold the data of the frame. Use LeapGetFrameSize() to calculate the minimum size of this buffer.

Since

3.2.0

Parameters
  • pRecording – The recording being read from.

  • pEvent[out] A pointer to a flat buffer which is filled with the next recorded frame.

  • ncbEvent – The number of bytes pointed to by pEvent.

Returns

The operation result code, a member of the eLeapRS enumeration.

eLeapRS LeapRecordingWrite(LEAP_RECORDING pRecording, LEAP_TRACKING_EVENT *pEvent, uint64_t *pnBytesWritten)

Writes a tracking frame to a LEAP_RECORDING file.

Since

3.2.0

Parameters
  • pRecording – The recording being written to.

  • pEvent[out] A pointer to a flat buffer which is filled with an interpolated frame.

  • pnBytesWritten – If non-null the number of bytes written.

Returns

The operation result code, a member of the eLeapRS enumeration.

void LeapScaleOffsetMatrix(LEAP_CONNECTION hConnection, eLeapPerspectiveType camera, float *dest)

This finds the default device and returns the result of LeapScaleOffsetMatrixEx()

See

LeapScaleOffsetMatrixEx for additional information

Since

5.x.x

Parameters
  • hConnection – The connection handle created by LeapCreateConnection().

  • camera – The camera to use, a member of the eLeapPerspectiveType enumeration

  • dest[out] A pointer to a single-precision float array of size 16, containing the coefficients of the 4x4 matrix in Column Major order

void LeapScaleOffsetMatrixEx(LEAP_CONNECTION hConnection, LEAP_DEVICE hDevice, eLeapPerspectiveType camera, float *dest)

Returns the appropriate scale and offset coefficients required to project normalised Rectilinear coordinates to image-scale coordinates.

This is composed of a 4 x 4 matrix of the form:

scale_x, 0, 0, offset_x, 0, 1, 0, 0, 0, 0, scale_z, offset_z 0, 0, 0, 1

This matrix is specific to the size of the current image as contained within LEAP_IMAGE.

In practical terms, use this matrix in combination with normalised rays to project 3D points into a rectilinear image space (i.e. to visualise hands on an undistorted image).

The pipeline would be: 1) Take 3D points from hand tracking. 2) Apply an extrinsic transformation to a specific camera’s coordinate system (

These points will now be in the correct coordinate system consistent with the undistorted rectilinear image provided by

LEAP_IMAGE::distortion_matrix.
See

LeapExtrinsicCameraMatrixEx) 3) Apply a perspective division to transform 3D points to rays. 4) Apply the ScaleOffset matrix to these points.

Since

5.x.x

Parameters
  • hConnection – The connection handle created by LeapCreateConnection().

  • hDevice – A device handle returned by LeapOpenDevice().

  • camera – The camera to use, a member of the eLeapPerspectiveType enumeration

  • dest[out] A pointer to a single-precision float array of size 16, containing the coefficients of the 4x4 matrix in Column Major order

eLeapRS LeapGetVersion(LEAP_CONNECTION hConnection, eLeapVersionPart versionPart, LEAP_VERSION *pVersion)

Returns the version of a specified part of the system.

If an invalid connection handle is provided only the version details of the client will be available.

Since

5.2.x

Parameters
  • hConnection – The connection handle created by LeapCreateConnection().

  • versionPart – The version part to return, this will reference one part of the system.

  • pVersion[out] A pointer to a struct used to store the version number.

Returns

The operation result code, a member of the eLeapRS enumeration.