:warning: **Eye Tracking will only work on Windows right now and only with a Vive Pro Eye** :warning: Just head orientation tracking will always work!
There is a GazeTest map in the [Study Framework Demo](https://git-ce.rwth-aachen.de/vr-vis/VR-Group/study-framework-demo) project.
# Usage
* In the ``StudySetup`` Actor set ``UseGazeTracker`` to ``EyeTracking`` (if you want to use the actual eye tracker) or ``HeadRotationOnly`` (which just approximates the gaze direction by the head's forward direction; it is the fall-back if no eye tracker is found and ``EyeTracking`` is chosen).
* Object's that should be "gazeable" have to have one of the two components:
*``SFGazeTarget``: This has it's own sphere collision which is used for line trace checks (so use this if only part of an actor should be gazeable or even a region greater than the actor itself).
*``SFGazeTargetActor``: The whole actor is used for line trace checks.
* both either use the name specified as ``TargetName`` or if ``USeActorName`` is activated, the name of the actor they are attached to.
* The GazeTracker (e.g. ``USFGameInstance::Get()->GetGazeTracker()``) provides:
*``GetCurrentGazeTarget()``: returning the name (``TargetName`` or actor name) of the currently gaze at target or an empty string if nothing "gazeable" is looked at.
*``LaunchCalibration()`` to launch a calibration from code.
* logs the currently gaze at target name and the gaze direction per frame into a separate file per participant. The participant's gaze tracking logs are located in the StudyLogs/GazeTrackingLogs folder. For head rotation logs, please refer to the [Logging the Position of the Player](https://git-ce.rwth-aachen.de/vr-vis/VR-Group/unreal-development/plugins/unreal-study-framework/-/wikis/Logging#example-logging-the-position-of-the-player-in-vr) section of the wiki.
# Prerequisite
If you just want to use ``HeadRotationOnly`` as tracking mode, the following is not required.
To add eye tracking you have to add the ``SRanipal`` plugin to your project it can be downloaded as part of the SDK [here](https://developer-express.vive.com/resources/vive-sense/eye-and-facial-tracking-sdk/download/latest/)(HTC Vive account required)\
:warning: Make sure that the ``Plugins/SRanipal/Binaries`` folder is commited to your project. In case it is ignored by default do ``git add -f Plugins/SRanipal/Binaries``
Furthermore ``Vive SRAnipal`` needs to be installed. Currently this can be done via Steam installing ``Vive Console``. I had problems starting calibration, since the firmware seemed not to be updated, starting ``Tobii Pro Lab`` automatically started a firmware update.
Also in your project you have to have the ``SRanpial`` plugin activated in the .uproject file
```
"Plugins": [
{
"Name": "SRanipal",
"Enabled": true
}
],
```
# Starting
For any HTC Vive Pro Eye eye tracking to work:
* Steam (VR) for me needed to be started as admin
* SR_Runtime needs to be started (as admin)
* For development potentially also Visual Studio starting Unreal need to be run as admin
* (or maybe just run entirely under the admin profile)
If this is not done, eye calibration is not started correctly.
Some more insights can be found at: [Unreal Eye Tracking Demo Project](https://git-ce.rwth-aachen.de/vr-vis/VR-Group/unreal-eye-tracking)
