Multiple Eyetracker Support

[sammaxwellxyz]

Support data configurations from multiple eye trackers, instead of just eyelink for gaze preprocessing.

Currently pspm_convert_pupil_gaze_distance supports the gaze data as extracted from eyelink data, the gaze data is in pixels and orientated such that (0,0) is the bottom-left point on the screen and the maximal x and y coordinates are the top-right of the screen.

Other eye trackers may not have their data calibrated as such, where necessary we should support other formats.

Tobii: https://developer.tobii.com/pc-gaming/unity-sdk/api-overview/#gaze-point-data - returns coordinates between (0,0) and (1,1), (0,0) being bottom left and (1,1) begin top right of the screen. This can be supplemented the width and height gathered from the tobii API https://developer.tobii.com/pc-gaming/unity-sdk/scripting-api/#displayinfo.

Gazepoint 3D: https://www.gazept.com/dl/Gazepoint_API_v2.0.pdf works as fractions using POG as the gaze point in X or Y as a fraction of screen size. (0,0) is top left, (1,1) bottom-right. width and height can also be extracted from the API (in pixels)

Eyetribe https://theeyetribe.com/dev.theeyetribe.com/dev.theeyetribe.com/dev/index.html - Gaze coordinates are the point on screen that the user is currently looking. Gaze coordinates are defined as pixels in a top-left oriented 2D coordinate system and are available in both raw and smoothed forms.

I was unable to find documentation for SMI, Seeing Machines Facelab, or Smart Eye.