/// <summary>
/// If new data is available, updates <see cref="LatestPose"/>.
/// </summary>
/// <remarks>
/// If the client "connection" was interrupted, this call will automatically attempt to reconnect. If
/// something goes wrong during that process, it's possible that the call could throw an exception.
/// </remarks>
/// <returns>True if new data was available, false otherwise.</returns>
public bool UpdatePose()
{
if (m_bPendingReconnect)
{
// Note: This call could throw.
if (InternalConnect())
{
// Successfully reconnected; clear the flag and continue normally.
m_bPendingReconnect = false;
}
else
{
// Failed to reconnect; don't go any further, but try to reconnect again next time.
return(false);
}
}
NPResult getDataResult = m_clientLib.NP_GetData(ref m_trackirData, 0, 0);
if (getDataResult == NPResult.OK)
{
if (m_trackirData.FrameSignature != m_latestFrameSignature)
{
// We got fresh data, so update the latest cached/transformed pose.
const float kEncodedRangeMinMax = 16383.0f;
const float kDecodedTranslationMinMaxMeters = 0.5f; // +/- 50 cm
const float kDecodedRotationMinMaxRadians = (float)Math.PI; // +/- 180 deg
// Negate right-hand rule rotations to be consistent with left-handed coordinate basis.
// See remarks in the comments for the TrackIRData struct for more information.
float rollRad = (-m_trackirData.Roll / kEncodedRangeMinMax) * kDecodedRotationMinMaxRadians;
float pitchRad = (-m_trackirData.Pitch / kEncodedRangeMinMax) * kDecodedRotationMinMaxRadians;
float yawRad = (-m_trackirData.Yaw / kEncodedRangeMinMax) * kDecodedRotationMinMaxRadians;
float xMeters = (m_trackirData.X / kEncodedRangeMinMax) * kDecodedTranslationMinMaxMeters;
float yMeters = (m_trackirData.Y / kEncodedRangeMinMax) * kDecodedTranslationMinMaxMeters;
float zMeters = (m_trackirData.Z / kEncodedRangeMinMax) * kDecodedTranslationMinMaxMeters;
m_latestPose.Orientation = Pose.Quaternion.FromTaitBryanIntrinsicZYX(rollRad, yawRad, pitchRad);
m_latestPose.PositionMeters = new Pose.Vector3(xMeters, yMeters, zMeters);
m_latestFrameSignature = m_trackirData.FrameSignature;
// Successfully retrieved a new pose.
return(true);
}
else
{
// No error, but no new data available.
return(false);
}
}
else
{
// Got an unexpected return code from the NP_GetData call.
m_latestFrameSignature = -1;
m_bPendingReconnect = true;
return(false);
}
}
/// <summary>
/// Stops data transmission and unregisters the application's window handle.
/// </summary>
public void Disconnect()
{
if (m_bDataTransmitting)
{
NPResult stopDataResult = m_clientLib.NP_StopDataTransmission();
if (stopDataResult != NPResult.OK)
{
Console.WriteLine("WARNING: NP_StopDataTransmission returned " + stopDataResult.ToString() + ".");
}
m_bDataTransmitting = false;
}
if (m_bRegisteredWindowHandle)
{
NPResult unregisterResult = m_clientLib.NP_UnregisterWindowHandle();
if (unregisterResult != NPResult.OK)
{
Console.WriteLine("WARNING: NP_UnregisterWindowHandle returned " + unregisterResult.ToString() + ".");
}
m_bRegisteredWindowHandle = false;
}
}
/// <summary>
/// Uses the cached appId and hwnd to initialize the TrackIR API.
/// </summary>
/// <returns>
/// True if initialization completed successfully, false if the API returned the code
/// <see cref="NPResult.ERR_DEVICE_NOT_PRESENT"/>. Any other failure condition throws an exception.
/// </returns>
private bool InternalConnect()
{
// Clear this flag. Most exit paths from this function represent errors we can't recover from, and we
// shouldn't keep trying repeatedly; the only exception is waiting for ERR_DEVICE_NOT_PRESENT to resolve.
m_bPendingReconnect = false;
// Retrieve host software version.
UInt16 version;
NPResult queryVersionResult = m_clientLib.NP_QueryVersion(out version);
if (queryVersionResult == NPResult.ERR_DEVICE_NOT_PRESENT)
{
// Don't go any further; we'll try to connect again next time UpdatePose is called.
m_bPendingReconnect = true;
return(false);
}
else if (queryVersionResult != NPResult.OK)
{
Console.WriteLine("WARNING: NP_QueryVersion returned " + queryVersionResult.ToString() + ".");
}
HostSoftwareVersionMajor = (version >> 8);
HostSoftwareVersionMinor = (version & 0x00FF);
// Retrieve signature object and validate that signature strings match expected values.
TrackIRSignature signature = new TrackIRSignature();
NPResult getSignatureResult = m_clientLib.NP_GetSignature(ref signature);
if (getSignatureResult != NPResult.OK)
{
throw new TrackIRException("NP_GetSignature returned " + getSignatureResult.ToString() + ".");
}
const string kExpectedAppSignature = "hardware camera\n software processing data\n track user movement\n\n Copyright EyeControl Technologies";
const string kExpectedDllSignature = "precise head tracking\n put your head into the game\n now go look around\n\n Copyright EyeControl Technologies";
if (signature.AppSignature != kExpectedAppSignature || signature.DllSignature != kExpectedDllSignature)
{
throw new TrackIRException("Unable to verify TrackIR Enhanced signature values.");
}
// Register the application window for liveness checks. This allows the TrackIR software to
// detect situations where e.g. your application crashes and fails to shut down cleanly.
NPResult registerHwndResult = m_clientLib.NP_RegisterWindowHandle(m_appHwnd);
if (registerHwndResult == NPResult.OK)
{
m_bRegisteredWindowHandle = true;
}
else
{
throw new TrackIRException("NP_RegisterWindowHandle returned " + registerHwndResult.ToString() + ".");
}
// Register the application by its NaturalPoint-assigned ID.
NPResult registerIdResult = m_clientLib.NP_RegisterProgramProfileID(m_appId);
if (registerIdResult != NPResult.OK)
{
throw new TrackIRException("NP_RegisterProgramProfileID returned " + registerIdResult.ToString() + ".");
}
// Signal that we want to start receiving tracking data.
NPResult startDataResult = m_clientLib.NP_StartDataTransmission();
if (startDataResult == NPResult.OK)
{
m_bDataTransmitting = true;
}
else
{
throw new TrackIRException("NP_StartDataTransmission returned " + startDataResult.ToString() + ".");
}
return(true);
}
