eyeTracker improvements

[marcobarilari]

• Refactor eyetracking script.
• Clean up should involve closing the eyeTracker

[Remi-Gau]

Other to do

• make the miss_hit linter happy by avoiding lines of more than 100 characters

[marcobarilari]

Optional useful functions to implement in the future:

• Set level of verbosity for error/warning/status messages. ‘level’ optional, new level of verbosity. ‘oldlevel’ is the old level of verbosity. The following levels are supported: 0 = Shut up. 1 = Print errors, 2 = Print also warnings, 3 = Print also some info, 4 = Print more useful info (default), >5 = Be very verbose (mostly for debugging the driver itself).

oldlevel = Eyelink(‘Verbosity’ [,level]);

• Sanity check that ET is set a specific eye that we want, we might forget to check :)

eye_used = Eyelink('EyeAvailable');
switch eye_used
    case el.BINOCULAR
        error('tracker indicates binocular')
    case el.LEFT_EYE
        error('tracker indicates left eye')
    case el.RIGHT_EYE
        disp('tracker indicates right eye')
    case -1
        error('eyeavailable returned -1')
    otherwise
        eye_used
        error('unexpected result from eyeavailable')
end

• Tag the ET data output

Eyelink('command', 'add_file_preamble_text', 'Recorded by EyelinkToolbox demo-experiment');

• Set parser (conservative saccade thresholds)

Eyelink('command', 'saccade_velocity_threshold = 35');
Eyelink('command', 'saccade_acceleration_threshold = 9500');

• Drift correction, do a final check of calibration using drift correction. You have to hit ESC before return.

EyelinkDoDriftCorrection(el);
success = EyelinkDoDriftCorrection(el);
if success~=1
    Eyelink('shutdown');
    cleanUp()
    return;
end

or use [status = ] Eyelink(‘DriftCorrStart’, x, y [,dtype=0][, dodraw=1][, allow_setup=0]); e.g.:

% Perform drift correction: The special flags 1,1,1 request interactive correction with video display:  
result = Eyelink('DriftCorrStart',30,30,1,1,1);

• Tag the recording, in the past caused delays during the presentation so I avoided to use it

Eyelink('message', 'Trial_1');

• EyelinkGazeContingentDemo.m is a nice example on how reading online data from ET and change your stimulaiton accordingly