Open a specific device with Nite2.UserTracker(device)

[llynch]

using this version of openni and nite:

OniVersion(major = 2, minor = 2, maintenance = 0, build = 30)
NiteVersion(major = 2, minor = 2, maintenance = 0, build = 10)

consider this code:

devices = openni2.Device.open_all()
userTracker = nite2.UserTracker(devices[1]) # warning will always fail with device use None

I have found a fix. In fact it is the python DevStruct that does not match the one in c++.
I have made a work around here, note that sensors_info is not affected so some improvement could be done there.
line 186 in nite2.py

class _NiteDevStruct(ctypes.Structure):
    """
    PlaybackControl* m_pPlaybackControl;

    OniDeviceHandle m_device;
    DeviceInfo m_deviceInfo;
    SensorInfo m_aSensorInfo[ONI_MAX_SENSORS];

    bool m_isOwner;
    """

    _fields_ = [
        ("pPlaybackControl", ctypes.c_void_p),
        ("device", openni2.c_api.OniDeviceHandle),

        ("device_info", openni2.c_api.OniDeviceInfo),
        ("sensor_info", openni2.c_api.OniSensorInfo * 10),

        ("is_owner", ctypes.c_bool)
    ]

class UserTracker(HandleObject):
    def __init__(self, device):
        handle = c_api.NiteUserTrackerHandle()
        if not device:
            c_api.niteInitializeUserTracker(ctypes.byref(handle))
        else:
            self._devstruct = _NiteDevStruct()
            self._devstruct.pPlaybackControl = None
            self._devstruct.device = device._handle
            self._devstruct.device_info = device.get_device_info()
            #self._devstruct.sensor_info = device.get_sensor_infos(sensor_type)
            self._devstruct.is_owner = True

            c_api.niteInitializeUserTrackerByDevice(ctypes.byref(self._devstruct), ctypes.byref(handle))

        HandleObject.__init__(self, handle)
        _registered_user_trackers.add(self)