Timestamp and Frame data for Eye Tracking

[Justine]

Hello! 🙂

I am trying to extract eye data using the following code:

using System.Collections;
using System.Runtime.InteropServices;
using UnityEngine;
using System;
using System.IO;
using ViveSR.anipal.Eye;
using ViveSR.anipal;
using ViveSR;

/// <summary>
/// Example usage for eye tracking callback
/// Note: Callback runs on a separate thread to report at ~120hz.
/// Unity is not threadsafe and cannot call any UnityEngine api from within callback thread.
/// </summary>
public class EyeTrackingRecordData : MonoBehaviour
{
    // ********************************************************************************************************************
    //
    //  Define user ID information.
    //  - The developers can define the user ID format such as "ABC_001". The ID is used for the name of text file 
    //    that records the measured eye movement data.
    // 
    // ********************************************************************************************************************
    public static int UserID = 2; // Always change Participant Number for every participant
    public static int scenario = 00; // Always change Scenario Number for every scenario
    //public string UserID;       // Definte ID number such as 001, ABC001, etc.
    public string Path = Directory.GetCurrentDirectory();
    //string File_Path = Directory.GetCurrentDirectory() + "\\video_" + UserID + ".txt";
    public string File_Path = Directory.GetCurrentDirectory() + "P" + UserID + "_" + "S" + scenario + ".txt";


    // ********************************************************************************************************************
    //
    //  Parameters for time-related information.
    //
    // ********************************************************************************************************************
    public static int cnt_callback = 0;
    public int cnt_saccade = 0, Endbuffer = 3, SaccadeTimer = 30;
    float Timeout = 1.0f, InitialTimer = 0.0f;
    private static long SaccadeEndTime = 0;
    private static long MeasureTime, CurrentTime, MeasureEndTime = 0;
    private static float time_stamp;
    private static int frame;

    // ********************************************************************************************************************
    //
    //  Parameters for eye data.
    //
    // ********************************************************************************************************************
    private static EyeData_v2 eyeData = new EyeData_v2();
    public EyeParameter eye_parameter = new EyeParameter();
    public GazeRayParameter gaze = new GazeRayParameter();
    private static bool eye_callback_registered = false;
    private static UInt64 eye_valid_L, eye_valid_R;                 // The bits explaining the validity of eye data.
    private static float openness_L, openness_R;                    // The level of eye openness.
    private static float pupil_diameter_L, pupil_diameter_R;        // Diameter of pupil dilation.
    private static Vector2 pos_sensor_L, pos_sensor_R;              // Positions of pupils.
    private static Vector3 gaze_origin_L, gaze_origin_R;            // Position of gaze origin.
    private static Vector3 gaze_direct_L, gaze_direct_R;            // Direction of gaze ray.
    private static float frown_L, frown_R;                          // The level of user's frown.
    private static float squeeze_L, squeeze_R;                      // The level to show how the eye is closed tightly.
    private static float wide_L, wide_R;                            // The level to show how the eye is open widely.
    private static double gaze_sensitive;                           // The sensitive factor of gaze ray.
    private static float distance_C;                                // Distance from the central point of right and left eyes.
    private static bool distance_valid_C;                           // Validity of combined data of right and left eyes.
    public bool cal_need;                                           // Calibration judge.
    public bool result_cal;                                         // Result of calibration.
    private static int track_imp_cnt = 0;
    private static TrackingImprovement[] track_imp_item;

    //private static EyeData eyeData = new EyeData();
    //private static bool eye_callback_registered = false;

    //public Text uiText;
    private float updateSpeed = 0;
    private static float lastTime, currentTime;


    // ********************************************************************************************************************
    //
    //  Start is called before the first frame update. The Start() function is performed only one time.
    //
    // ********************************************************************************************************************
    void Start()
    {
        //File_Path = Directory.GetCurrentDirectory() + "\\Assets" + UserID + ".txt";
        InputUserID();                              // Check if the file with the same ID exists.
        //Invoke("SystemCheck", 0.5f);                // System check.
        //SRanipal_Eye_v2.LaunchEyeCalibration();     // Perform calibration for eye tracking.
        //Calibration();
        //TargetPosition();                           // Implement the targets on the VR view.
        //Invoke("Measurement", 0.5f);                // Start the measurement of ocular movements in a separate callback function.  
    }


    // ********************************************************************************************************************
    //
    //  Checks if the filename with the same user ID already exists. If so, you need to change the name of UserID.
    //
    // ********************************************************************************************************************
    void InputUserID()
    {
        Debug.Log(File_Path);

        if (File.Exists(File_Path))
        {
            Debug.Log("File with the same UserID already exists. Please change the UserID in the C# code.");

            //  When the same file name is found, we stop playing Unity.

            if (UnityEditor.EditorApplication.isPlaying)
            {
                UnityEditor.EditorApplication.isPlaying = false;
            }
        }
        else
        {
            Data_txt();
        }
    }


    // ********************************************************************************************************************
    //
    //  Check if the system works properly.
    //
    // ********************************************************************************************************************
    void SystemCheck()
    {
        if (SRanipal_Eye_API.GetEyeData_v2(ref eyeData) == ViveSR.Error.WORK)
        {
            Debug.Log("Device is working properly.");
        }

        if (SRanipal_Eye_API.GetEyeParameter(ref eye_parameter) == ViveSR.Error.WORK)
        {
            Debug.Log("Eye parameters are measured.");
        }

        //  Check again if the initialisation of eye tracking functions successfully. If not, we stop playing Unity.
        Error result_eye_init = SRanipal_API.Initial(SRanipal_Eye_v2.ANIPAL_TYPE_EYE_V2, IntPtr.Zero);

        if (result_eye_init == Error.WORK)
        {
            Debug.Log("[SRanipal] Initial Eye v2: " + result_eye_init);
        }
        else
        {
            Debug.LogError("[SRanipal] Initial Eye v2: " + result_eye_init);

            if (UnityEditor.EditorApplication.isPlaying)
            {
                UnityEditor.EditorApplication.isPlaying = false;    // Stops Unity editor.
            }
        }
    }

    // ********************************************************************************************************************
    //
    //  Calibration is performed if the calibration is necessary.
    //
    // ********************************************************************************************************************
    void Calibration()
    {
        SRanipal_Eye_API.IsUserNeedCalibration(ref cal_need);           // Check the calibration status. If needed, we perform the calibration.

        if (cal_need == true)
        {
            result_cal = SRanipal_Eye_v2.LaunchEyeCalibration();

            if (result_cal == true)
            {
                Debug.Log("Calibration is done successfully.");
            }

            else
            {
                Debug.Log("Calibration is failed.");
                if (UnityEditor.EditorApplication.isPlaying)
                {
                    UnityEditor.EditorApplication.isPlaying = false;    // Stops Unity editor if the calibration if failed.
                }
            }
        }

        if (cal_need == false)
        {
            Debug.Log("Calibration is not necessary");
        }
    }

    // ********************************************************************************************************************
    //
    //  Create a text file and header names of each column to store the measured data of eye movements.
    //
    // ********************************************************************************************************************
    void Data_txt()
    {
        string variable =
        "time(100ns)" + "," +
        "time_stamp(ms)" + "," +
        "frame" + "," +
        "eye_valid_L" + "," +
        "eye_valid_R" + "," +
        "openness_L" + "," +
        "openness_R" + "," +
        "pupil_diameter_L(mm)" + "," +
        "pupil_diameter_R(mm)" + "," +
        "pos_sensor_L.x" + "," +
        "pos_sensor_L.y" + "," +
        "pos_sensor_R.x" + "," +
        "pos_sensor_R.y" + "," +
        "gaze_origin_L.x(mm)" + "," +
        "gaze_origin_L.y(mm)" + "," +
        "gaze_origin_L.z(mm)" + "," +
        "gaze_origin_R.x(mm)" + "," +
        "gaze_origin_R.y(mm)" + "," +
        "gaze_origin_R.z(mm)" + "," +
        "gaze_direct_L.x" + "," +
        "gaze_direct_L.y" + "," +
        "gaze_direct_L.z" + "," +
        "gaze_direct_R.x" + "," +
        "gaze_direct_R.y" + "," +
        "gaze_direct_R.z" + "," +
        "gaze_sensitive" + "," +
        "frown_L" + "," +
        "frown_R" + "," +
        "squeeze_L" + "," +
        "squeeze_R" + "," +
        "wide_L" + "," +
        "wide_R" + "," +
        "distance_valid_C" + "," +
        "distance_C(mm)" + "," +
        "track_imp_cnt" +
        Environment.NewLine;

        File.AppendAllText("eyedata_" + "P" + UserID + "_" + "S" + scenario + ".txt", variable);
    }


    void Update()
    {
        if (SRanipal_Eye_Framework.Status != SRanipal_Eye_Framework.FrameworkStatus.WORKING) return;


        if (SRanipal_Eye_Framework.Instance.EnableEyeDataCallback == true && eye_callback_registered == false)
        {
            SRanipal_Eye_v2.WrapperRegisterEyeDataCallback(Marshal.GetFunctionPointerForDelegate((SRanipal_Eye_v2.CallbackBasic)EyeCallback));
            eye_callback_registered = true;
        }
        else if (SRanipal_Eye_Framework.Instance.EnableEyeDataCallback == false && eye_callback_registered == true)
        {
            SRanipal_Eye_v2.WrapperUnRegisterEyeDataCallback(Marshal.GetFunctionPointerForDelegate((SRanipal_Eye_v2.CallbackBasic)EyeCallback));
            eye_callback_registered = false;
        }

        float timeNow = Time.realtimeSinceStartup;
    }


    private void OnDisable()
    {
        Release();
    }

    void OnApplicationQuit()
    {
        Release();
    }

    /// <summary>
    /// Release callback thread when disabled or quit
    /// </summary>
    private static void Release()
    {
        if (eye_callback_registered == true)
        {
            SRanipal_Eye.WrapperUnRegisterEyeDataCallback(Marshal.GetFunctionPointerForDelegate((SRanipal_Eye_v2.CallbackBasic)EyeCallback));
            eye_callback_registered = false;
        }
    }

    /// <summary>
    /// Required class for IL2CPP scripting backend support
    /// </summary>
    internal class MonoPInvokeCallbackAttribute : System.Attribute
    {
        public MonoPInvokeCallbackAttribute() { }
    }

    /// <summary>
    /// Eye tracking data callback thread.
    /// Reports data at ~120hz
    /// MonoPInvokeCallback attribute required for IL2CPP scripting backend
    /// </summary>
    /// <param name="eye_data">Reference to latest eye_data</param>
    [MonoPInvokeCallback]
    private static void EyeCallback(ref EyeData_v2 eye_data)
    {
        EyeParameter eye_parameter = new EyeParameter();
        SRanipal_Eye_API.GetEyeParameter(ref eye_parameter);

        eyeData = eye_data;
        // do stuff with eyeData...

        //lastTime = currentTime;
        //currentTime = eyeData.timestamp;

        MeasureTime = DateTime.Now.Ticks;
        time_stamp = eyeData.timestamp;
        frame = eyeData.frame_sequence;
        eye_valid_L = eyeData.verbose_data.left.eye_data_validata_bit_mask;
        eye_valid_R = eyeData.verbose_data.right.eye_data_validata_bit_mask;
        openness_L = eyeData.verbose_data.left.eye_openness;
        openness_R = eyeData.verbose_data.right.eye_openness;
        pupil_diameter_L = eyeData.verbose_data.left.pupil_diameter_mm;
        pupil_diameter_R = eyeData.verbose_data.right.pupil_diameter_mm;
        pos_sensor_L = eyeData.verbose_data.left.pupil_position_in_sensor_area;
        pos_sensor_R = eyeData.verbose_data.right.pupil_position_in_sensor_area;
        gaze_origin_L = eyeData.verbose_data.left.gaze_origin_mm;
        gaze_origin_R = eyeData.verbose_data.right.gaze_origin_mm;
        gaze_direct_L = eyeData.verbose_data.left.gaze_direction_normalized;
        gaze_direct_R = eyeData.verbose_data.right.gaze_direction_normalized;
        gaze_sensitive = eye_parameter.gaze_ray_parameter.sensitive_factor;
        frown_L = eyeData.expression_data.left.eye_frown;
        frown_R = eyeData.expression_data.right.eye_frown;
        squeeze_L = eyeData.expression_data.left.eye_squeeze;
        squeeze_R = eyeData.expression_data.right.eye_squeeze;
        wide_L = eyeData.expression_data.left.eye_wide;
        wide_R = eyeData.expression_data.right.eye_wide;
        distance_valid_C = eyeData.verbose_data.combined.convergence_distance_validity;
        distance_C = eyeData.verbose_data.combined.convergence_distance_mm;
        track_imp_cnt = eyeData.verbose_data.tracking_improvements.count;
        //track_imp_item = eyeData.verbose_data.tracking_improvements.items;

        //  Convert the measured data to string data to write in a text file.
        string value =
            MeasureTime.ToString() + "," +
            time_stamp.ToString() + "," +
            frame.ToString() + "," +
            eye_valid_L.ToString() + "," +
            eye_valid_R.ToString() + "," +
            openness_L.ToString() + "," +
            openness_R.ToString() + "," +
            pupil_diameter_L.ToString() + "," +
            pupil_diameter_R.ToString() + "," +
            pos_sensor_L.x.ToString() + "," +
            pos_sensor_L.y.ToString() + "," +
            pos_sensor_R.x.ToString() + "," +
            pos_sensor_R.y.ToString() + "," +
            gaze_origin_L.x.ToString() + "," +
            gaze_origin_L.y.ToString() + "," +
            gaze_origin_L.z.ToString() + "," +
            gaze_origin_R.x.ToString() + "," +
            gaze_origin_R.y.ToString() + "," +
            gaze_origin_R.z.ToString() + "," +
            gaze_direct_L.x.ToString() + "," +
            gaze_direct_L.y.ToString() + "," +
            gaze_direct_L.z.ToString() + "," +
            gaze_direct_R.x.ToString() + "," +
            gaze_direct_R.y.ToString() + "," +
            gaze_direct_R.z.ToString() + "," +
            gaze_sensitive.ToString() + "," +
            frown_L.ToString() + "," +
            frown_R.ToString() + "," +
            squeeze_L.ToString() + "," +
            squeeze_R.ToString() + "," +
            wide_L.ToString() + "," +
            wide_R.ToString() + "," +
            distance_valid_C.ToString() + "," +
            distance_C.ToString() + "," +
            track_imp_cnt.ToString() +
            //track_imp_item.ToString() +
            Environment.NewLine;

        File.AppendAllText("eyedata_" + "P" + UserID + "_" + "S" + scenario + ".txt", value);


    }
}

An example of the data extracted is also attached:

eyedata_P2_S0.txt

The data looks great, however, it is important for my experiment to collect eye data with respect to unix time. The main reason I want to collect eye data with respect to unix time is because I have another script that collects the HMD's motion (position and rotation). The data collected using this script starts from frame 1,2,3 and so on. In order for me to compare and analyze the motion of the HMD with eye data is to compare the data with respect to time. Therefore, I want to collect eye data stating from frame 1, 2, 3, 4 and so on as soon as I enter play mode. If anyone can help me regarding this, I would be highly grateful!

Thank you. 🙂

Note: I am using SRanipal Runtime Version 1.3.2.0

 

 

[VIVE_chengnay]

Hi @Justine,

You can use Time.frameCount instead.

[Justine]

Hi @chengnay,

Which variable should I assign Time.frameCount?

Because I assigned it to MeasureTime, time_stamp, and frame in three separate tests, however, the editor crashes and no eye data is collected. 

Hope to hear from you soon. Thank you.

[VIVE_chengnay]

Hi @Justine,

Could you add another varaiable? For example, int frameCount.

[Justine]

Hi @chengnay,

Thank you for your reply!

So then I should add it inside this method?

private static void EyeCallback(ref EyeData_v2 eye_data)

[VIVE_chengnay]

Hi @Justine,

I think you can just add it under "Parameters for time-related information".

[Justine]

Hi @chengnay,

So I added a new variable under "Parameters for time-related information". Then I added the variable to Data_txt() and EyeCallback(ref EyeData_v2 eye_data) methods. However, no data is being extracted.

Please find below code for your reference:

using System.Collections;
using System.Runtime.InteropServices;
using UnityEngine;
using System;
using System.IO;
using ViveSR.anipal.Eye;
using ViveSR.anipal;
using ViveSR;

/// <summary>
/// Example usage for eye tracking callback
/// Note: Callback runs on a separate thread to report at ~120hz.
/// Unity is not threadsafe and cannot call any UnityEngine api from within callback thread.
/// </summary>
public class EyeTrackingRecordData : MonoBehaviour
{
    // ********************************************************************************************************************
    //
    //  Define user ID information.
    //  - The developers can define the user ID format such as "ABC_001". The ID is used for the name of text file 
    //    that records the measured eye movement data.
    // 
    // ********************************************************************************************************************
    public static int UserID = 3; // Always change Participant Number for every participant
    public static int scenario = 0; // Always change Scenario Number for every scenario
    //public string UserID;       // Definte ID number such as 001, ABC001, etc.
    public string Path = Directory.GetCurrentDirectory();
    //string File_Path = Directory.GetCurrentDirectory() + "\\video_" + UserID + ".txt";
    public string File_Path = Directory.GetCurrentDirectory() + "P" + UserID + "_" + "S" + scenario + ".txt";


    // ********************************************************************************************************************
    //
    //  Parameters for time-related information.
    //
    // ********************************************************************************************************************
    public static int cnt_callback = 0;
    public int cnt_saccade = 0, Endbuffer = 3, SaccadeTimer = 30;
    float Timeout = 1.0f, InitialTimer = 0.0f;
    private static long SaccadeEndTime = 0;
    private static long MeasureTime, CurrentTime, MeasureEndTime = 0;
    private static float time_stamp;
    private static int frame;
    private static int frameCount;

    // ********************************************************************************************************************
    //
    //  Parameters for eye data.
    //
    // ********************************************************************************************************************
    private static EyeData_v2 eyeData = new EyeData_v2();
    public EyeParameter eye_parameter = new EyeParameter();
    public GazeRayParameter gaze = new GazeRayParameter();
    private static bool eye_callback_registered = false;
    private static UInt64 eye_valid_L, eye_valid_R;                 // The bits explaining the validity of eye data.
    private static float openness_L, openness_R;                    // The level of eye openness.
    private static float pupil_diameter_L, pupil_diameter_R;        // Diameter of pupil dilation.
    private static Vector2 pos_sensor_L, pos_sensor_R;              // Positions of pupils.
    private static Vector3 gaze_origin_L, gaze_origin_R;            // Position of gaze origin.
    private static Vector3 gaze_direct_L, gaze_direct_R;            // Direction of gaze ray.
    private static float frown_L, frown_R;                          // The level of user's frown.
    private static float squeeze_L, squeeze_R;                      // The level to show how the eye is closed tightly.
    private static float wide_L, wide_R;                            // The level to show how the eye is open widely.
    private static double gaze_sensitive;                           // The sensitive factor of gaze ray.
    private static float distance_C;                                // Distance from the central point of right and left eyes.
    private static bool distance_valid_C;                           // Validity of combined data of right and left eyes.
    public bool cal_need;                                           // Calibration judge.
    public bool result_cal;                                         // Result of calibration.
    private static int track_imp_cnt = 0;
    private static TrackingImprovement[] track_imp_item;

    //private static EyeData eyeData = new EyeData();
    //private static bool eye_callback_registered = false;

    //public Text uiText;
    private float updateSpeed = 0;
    private static float lastTime, currentTime;


    // ********************************************************************************************************************
    //
    //  Start is called before the first frame update. The Start() function is performed only one time.
    //
    // ********************************************************************************************************************
    void Start()
    {
        //File_Path = Directory.GetCurrentDirectory() + "\\Assets" + UserID + ".txt";
        InputUserID();                              // Check if the file with the same ID exists.
        //Invoke("SystemCheck", 0.5f);                // System check.
        //SRanipal_Eye_v2.LaunchEyeCalibration();     // Perform calibration for eye tracking.
        //Calibration();
        //TargetPosition();                           // Implement the targets on the VR view.
        //Invoke("Measurement", 0.5f);                // Start the measurement of ocular movements in a separate callback function.  
    }


    // ********************************************************************************************************************
    //
    //  Checks if the filename with the same user ID already exists. If so, you need to change the name of UserID.
    //
    // ********************************************************************************************************************
    void InputUserID()
    {
        Debug.Log(File_Path);

        if (File.Exists(File_Path))
        {
            Debug.Log("File with the same UserID already exists. Please change the UserID in the C# code.");

            //  When the same file name is found, we stop playing Unity.

            if (UnityEditor.EditorApplication.isPlaying)
            {
                UnityEditor.EditorApplication.isPlaying = false;
            }
        }
        else
        {
            Data_txt();
        }
    }


    // ********************************************************************************************************************
    //
    //  Check if the system works properly.
    //
    // ********************************************************************************************************************
    void SystemCheck()
    {
        if (SRanipal_Eye_API.GetEyeData_v2(ref eyeData) == ViveSR.Error.WORK)
        {
            Debug.Log("Device is working properly.");
        }

        if (SRanipal_Eye_API.GetEyeParameter(ref eye_parameter) == ViveSR.Error.WORK)
        {
            Debug.Log("Eye parameters are measured.");
        }

        //  Check again if the initialisation of eye tracking functions successfully. If not, we stop playing Unity.
        Error result_eye_init = SRanipal_API.Initial(SRanipal_Eye_v2.ANIPAL_TYPE_EYE_V2, IntPtr.Zero);

        if (result_eye_init == Error.WORK)
        {
            Debug.Log("[SRanipal] Initial Eye v2: " + result_eye_init);
        }
        else
        {
            Debug.LogError("[SRanipal] Initial Eye v2: " + result_eye_init);

            if (UnityEditor.EditorApplication.isPlaying)
            {
                UnityEditor.EditorApplication.isPlaying = false;    // Stops Unity editor.
            }
        }
    }

    // ********************************************************************************************************************
    //
    //  Calibration is performed if the calibration is necessary.
    //
    // ********************************************************************************************************************
    void Calibration()
    {
        SRanipal_Eye_API.IsUserNeedCalibration(ref cal_need);           // Check the calibration status. If needed, we perform the calibration.

        if (cal_need == true)
        {
            result_cal = SRanipal_Eye_v2.LaunchEyeCalibration();

            if (result_cal == true)
            {
                Debug.Log("Calibration is done successfully.");
            }

            else
            {
                Debug.Log("Calibration is failed.");
                if (UnityEditor.EditorApplication.isPlaying)
                {
                    UnityEditor.EditorApplication.isPlaying = false;    // Stops Unity editor if the calibration if failed.
                }
            }
        }

        if (cal_need == false)
        {
            Debug.Log("Calibration is not necessary");
        }
    }

    // ********************************************************************************************************************
    //
    //  Create a text file and header names of each column to store the measured data of eye movements.
    //
    // ********************************************************************************************************************
    void Data_txt()
    {
        string variable =
        "time(100ns)" + "," +
        "time_stamp(ms)" + "," +
        "frame" + "," +
        "frame_Count" + "," +
        "eye_valid_L" + "," +
        "eye_valid_R" + "," +
        "openness_L" + "," +
        "openness_R" + "," +
        "pupil_diameter_L(mm)" + "," +
        "pupil_diameter_R(mm)" + "," +
        "pos_sensor_L.x" + "," +
        "pos_sensor_L.y" + "," +
        "pos_sensor_R.x" + "," +
        "pos_sensor_R.y" + "," +
        "gaze_origin_L.x(mm)" + "," +
        "gaze_origin_L.y(mm)" + "," +
        "gaze_origin_L.z(mm)" + "," +
        "gaze_origin_R.x(mm)" + "," +
        "gaze_origin_R.y(mm)" + "," +
        "gaze_origin_R.z(mm)" + "," +
        "gaze_direct_L.x" + "," +
        "gaze_direct_L.y" + "," +
        "gaze_direct_L.z" + "," +
        "gaze_direct_R.x" + "," +
        "gaze_direct_R.y" + "," +
        "gaze_direct_R.z" + "," +
        "gaze_sensitive" + "," +
        "frown_L" + "," +
        "frown_R" + "," +
        "squeeze_L" + "," +
        "squeeze_R" + "," +
        "wide_L" + "," +
        "wide_R" + "," +
        "distance_valid_C" + "," +
        "distance_C(mm)" + "," +
        "track_imp_cnt" +
        Environment.NewLine;

        File.AppendAllText("eyedata_" + "P" + UserID + "_" + "S" + scenario + ".txt", variable);
    }


    void Update()
    {
        if (SRanipal_Eye_Framework.Status != SRanipal_Eye_Framework.FrameworkStatus.WORKING) return;


        if (SRanipal_Eye_Framework.Instance.EnableEyeDataCallback == true && eye_callback_registered == false)
        {
            SRanipal_Eye_v2.WrapperRegisterEyeDataCallback(Marshal.GetFunctionPointerForDelegate((SRanipal_Eye_v2.CallbackBasic)EyeCallback));
            eye_callback_registered = true;
        }
        else if (SRanipal_Eye_Framework.Instance.EnableEyeDataCallback == false && eye_callback_registered == true)
        {
            SRanipal_Eye_v2.WrapperUnRegisterEyeDataCallback(Marshal.GetFunctionPointerForDelegate((SRanipal_Eye_v2.CallbackBasic)EyeCallback));
            eye_callback_registered = false;
        }

        float timeNow = Time.realtimeSinceStartup;
    }


    private void OnDisable()
    {
        Release();
    }

    void OnApplicationQuit()
    {
        Release();
    }

    /// <summary>
    /// Release callback thread when disabled or quit
    /// </summary>
    private static void Release()
    {
        if (eye_callback_registered == true)
        {
            SRanipal_Eye.WrapperUnRegisterEyeDataCallback(Marshal.GetFunctionPointerForDelegate((SRanipal_Eye_v2.CallbackBasic)EyeCallback));
            eye_callback_registered = false;
        }
    }

    /// <summary>
    /// Required class for IL2CPP scripting backend support
    /// </summary>
    internal class MonoPInvokeCallbackAttribute : System.Attribute
    {
        public MonoPInvokeCallbackAttribute() { }
    }

    /// <summary>
    /// Eye tracking data callback thread.
    /// Reports data at ~120hz
    /// MonoPInvokeCallback attribute required for IL2CPP scripting backend
    /// </summary>
    /// <param name="eye_data">Reference to latest eye_data</param>
    [MonoPInvokeCallback]
    private static void EyeCallback(ref EyeData_v2 eye_data)
    {
        EyeParameter eye_parameter = new EyeParameter();
        SRanipal_Eye_API.GetEyeParameter(ref eye_parameter);

        eyeData = eye_data;
        // do stuff with eyeData...

        //lastTime = currentTime;
        //currentTime = eyeData.timestamp;

        MeasureTime = DateTime.Now.Ticks;
        time_stamp = eyeData.timestamp;
        frame = eyeData.frame_sequence;
        frameCount = Time.frameCount;
        eye_valid_L = eyeData.verbose_data.left.eye_data_validata_bit_mask;
        eye_valid_R = eyeData.verbose_data.right.eye_data_validata_bit_mask;
        openness_L = eyeData.verbose_data.left.eye_openness;
        openness_R = eyeData.verbose_data.right.eye_openness;
        pupil_diameter_L = eyeData.verbose_data.left.pupil_diameter_mm;
        pupil_diameter_R = eyeData.verbose_data.right.pupil_diameter_mm;
        pos_sensor_L = eyeData.verbose_data.left.pupil_position_in_sensor_area;
        pos_sensor_R = eyeData.verbose_data.right.pupil_position_in_sensor_area;
        gaze_origin_L = eyeData.verbose_data.left.gaze_origin_mm;
        gaze_origin_R = eyeData.verbose_data.right.gaze_origin_mm;
        gaze_direct_L = eyeData.verbose_data.left.gaze_direction_normalized;
        gaze_direct_R = eyeData.verbose_data.right.gaze_direction_normalized;
        gaze_sensitive = eye_parameter.gaze_ray_parameter.sensitive_factor;
        frown_L = eyeData.expression_data.left.eye_frown;
        frown_R = eyeData.expression_data.right.eye_frown;
        squeeze_L = eyeData.expression_data.left.eye_squeeze;
        squeeze_R = eyeData.expression_data.right.eye_squeeze;
        wide_L = eyeData.expression_data.left.eye_wide;
        wide_R = eyeData.expression_data.right.eye_wide;
        distance_valid_C = eyeData.verbose_data.combined.convergence_distance_validity;
        distance_C = eyeData.verbose_data.combined.convergence_distance_mm;
        track_imp_cnt = eyeData.verbose_data.tracking_improvements.count;
        //track_imp_item = eyeData.verbose_data.tracking_improvements.items;

        //  Convert the measured data to string data to write in a text file.
        string value =
            MeasureTime.ToString() + "," +
            time_stamp.ToString() + "," +
            frame.ToString() + "," +
            frameCount.ToString() + "," +
            eye_valid_L.ToString() + "," +
            eye_valid_R.ToString() + "," +
            openness_L.ToString() + "," +
            openness_R.ToString() + "," +
            pupil_diameter_L.ToString() + "," +
            pupil_diameter_R.ToString() + "," +
            pos_sensor_L.x.ToString() + "," +
            pos_sensor_L.y.ToString() + "," +
            pos_sensor_R.x.ToString() + "," +
            pos_sensor_R.y.ToString() + "," +
            gaze_origin_L.x.ToString() + "," +
            gaze_origin_L.y.ToString() + "," +
            gaze_origin_L.z.ToString() + "," +
            gaze_origin_R.x.ToString() + "," +
            gaze_origin_R.y.ToString() + "," +
            gaze_origin_R.z.ToString() + "," +
            gaze_direct_L.x.ToString() + "," +
            gaze_direct_L.y.ToString() + "," +
            gaze_direct_L.z.ToString() + "," +
            gaze_direct_R.x.ToString() + "," +
            gaze_direct_R.y.ToString() + "," +
            gaze_direct_R.z.ToString() + "," +
            gaze_sensitive.ToString() + "," +
            frown_L.ToString() + "," +
            frown_R.ToString() + "," +
            squeeze_L.ToString() + "," +
            squeeze_R.ToString() + "," +
            wide_L.ToString() + "," +
            wide_R.ToString() + "," +
            distance_valid_C.ToString() + "," +
            distance_C.ToString() + "," +
            track_imp_cnt.ToString() +
            //track_imp_item.ToString() +
            Environment.NewLine;

        File.AppendAllText("eyedata_" + "P" + UserID + "_" + "S" + scenario + ".txt", value);


    }
}

Can you please let me know what I did wrong? Thank you. Hope to hear from you soon.

[VIVE_chengnay]

Hi @Justine,

A quick question, I just need to attach the script to the scene and hit play?

I just tried attach the script to the EyeSample_v2.unity and hit play, then Unity freezes. 😞

[VIVE_chengnay]

Hi @Justine,

Could you explain the MonoPInvokeCallback part?

I am not sure this is and it should be the root cause to Unity freeze after attach the script to scene.

I tried your first and second script, both will cause Unity freeze.