is there a gaze only (as opposed to click/button input) mode in unity3d google vr sdk?

Question

I am using the google VR SDK (for cardboard) in unity3d but the cardboard i have does not have buttons. Is there a way to enable gaze only mode that treats extended gaze (a few seconds) as a button click? ( i guy in a tutorial video said "you can enable gaze only mode" but did not explain anything afterwards) is this a feature built in or do i have to code the gaze interaction from scratch to accomplish this?

I have searched everywhere for the code to enable this not only the public props that appear on the editor on the different prefabs available from the demo scenes.

Answer 1

I don't know how or if there is a built-in method for this. But you can easily build extending the button:

using UnityEngine.UI;
#if UNITY_EDITOR
using UnityEditor;
using UnityEditor.UI;
#endif

public class DwellTimeButton : Button
{
    public float dwellTime = 0.5f;

    public override void OnPointerEnter(PointerEventData pointerEventData)
    {
        base.OnPointerEnter(pointerEventData);

        StartCoroutine (DwellTimeRoutine());
    }

    public override void OnPointerExit (PointerEventData pointerEventData)
    {
        base.OnPointerExit(pointerEventData);

        StopAllCoroutines ();
    }

    private IEnumerator DwellTimeRoutine ()
    {
        yield return new WaitForSeconds (dwellTime);

        onClick.Invoke();
    }

#if UNITY_EDITOR
    [CustomEditor (typeof (DwellTimeButton)]
    private class DwellTimeButtonEditor : ButtonEditor
    {
        SerializedProperty dwellTime;

        protected override void OnEnable()
        {
            base.OnEnable();

            dwellTime = serializedObject.FindProperty("dwellTime");
        }

        public override void OnInspectorGUI()
        {
            base.OnInspectorGUI();

            serializedObject.Update();

            EditorGUILayout.PropertyField(dwellTime);

            serializedObject.ApplyModifiedProperties();
        }
    }
#endif
}

Replace a normal Unity Button with this component and set the desired dwellTime. It will then automatically invoke the onClick event after staying focused for the dwellTime.

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As alternative without having to replace the Button everywhere you can simply attach this component additionally on every button:

using System.Collections;
using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.UI;

[RequireComponent(typeof(Button))]
public class DwellTimeButton : MonoBehaviour, IPointerEnterHandler, IPointerExitHandler
{
    [SerializeField] private Button button;

    public float dwellTime = 0.5f;

    private void Awake()
    {
        if (!button) button = GetComponent<Button>();
    }

    public  void OnPointerEnter(PointerEventData pointerEventData)
    {
        button.OnPointerEnter(pointerEventData);

        StartCoroutine(DwellTimeRoutine());
    }

    public  void OnPointerExit(PointerEventData pointerEventData)
    {
        button.OnPointerExit(pointerEventData);

        StopAllCoroutines();
    }

    private IEnumerator DwellTimeRoutine()
    {
        yield return new WaitForSeconds(dwellTime);

        button.onClick.Invoke();
    }
}

This does basically the same but invokes the onClick and other events of the Button component instead.

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note: typed on smartphone but I hope the idea gets clear