Home Forums Unreal Engine 4 SDK What parameter can read left eye or right eye closed

  • This topic has 5 replies, 4 voices, and was last updated 2 years ago by faker.
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  • #19012

    What parameter can read left eye or right eye closed? My device is the Tobii eye tracker 4C!

    Grant [Tobii]

    Hi @faker, thank you for your query. I am afraid that the only means by which the left and right eye data are separately exposed for the 4C is through the Tobii Pro SDK which requires the purchase of a special research licence to correctly operate.

    If you are interested in this, please contact the team as provided @ https://developer.tobii.com/license-agreement/

    Do let us know if you require any further information. Best Wishes.

    Hongbin Zou

    Maybe he just wanted to know if left eye or right eye IS CLOSED?
    The tobii_gaze_origin_callback_t can output those states from the tobii stream engine api which is not UE4 related, I think.

    Grant [Tobii]

    Hi @faker, if indeed all you want is the validity of left/right eye found, you could try this snipped from the c++ stream engine API.

    #include <tobii/tobii_streams.h>
    #include <stdio.h>
    #include <assert.h>
    void gaze_origin_callback( tobii_gaze_origin_t const* gaze_origin, void* user_data )
        if( gaze_origin->left_validity == TOBII_VALIDITY_VALID )
            printf( "Left Eye Found" );
        if( gaze_origin->right_validity == TOBII_VALIDITY_VALID )
            printf( "Right Eye Found );
        printf( "\n" );

    Try it out and let us know how you get on. Best wishes.

    Peter Blanchfield

    Not really a reply actually a follow up question. I have the 4C and a 5C. I also have the pro SDK licence. I am developing a medical application that requires us to be able to get the information on where each eye is looking (tracking strabismic patients – people with squints – working on treating their squints). The pro version does not work with the 5C – presumably because of the firmware on the 5C not having the facility. Is this the case? I am ending up needing two different machines to be able to do my development – one for patients who don’t have a strabismus and one for patients who do as I don’t appear to be able to read a 4C and a 5C on one machine (have to uninstall the 5C drivers to use the 4C again) is this the case or am I doing something wrong. I don’t want to run both eye-trackers at the same time just want to do my development on one machine and not need to keep swapping.

    Grant [Tobii]

    Hi @blanchfield, yes I am afraid that the ET5 does not support the Tobii Pro SDK (nor will it) due to a refocusing of the Tobii Tech business. Accordingly, you will need to maintain your current workaround as described. I hope this does not cause you undue inconvenience. Best Wishes.

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