Test and Implement VR Recentering ("Teleporting")

[bastianilso]

Often when people enter VR, they are not perfectly centered at world position 0.0, 0.0, 0.0. This leads to a number of issues:

• Our data analysis requires we can compare peoples performance. If people are positioned at different coordinates in the world, this makes comparing their head- and controller movement harder compare.
• People standing/sitting off-center, leads to ergonomical issues with motorspaces and discoverability issues (e.g. the visual indication could end up behind you).

According to Hamzah and Steffen, it should be possible to re-center VR through the XR Framework's API (see code below). This way, we can transport people back to 0.0, 0.0, 0.0 regardless of where they are. I can see several ways we can do this:

1) When a Whack-A-Mole game starts (after countdown), automatically recenter and calibrate the current position to be 0.0, 0.0, 0.0 . This design is simple and should be quick to implement. (e0003a39e86dfaca61b60d03627186a4399e833a)

2) If we eventually move to an interaction paradigm where no therapist is facilitating, we could have a preliminary calibration stage , we could consider showing a preliminary calibration screen, which requests the player to sit down and get ready to play. The player confirms by pressing any button on the VR controller or on the keyboard. Alternatively, we wait for participant movements to become stable (indicating that they sit still).

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.XR;

public class Constraint : MonoBehaviour
{
    public Camera Cam;
    public bool constrain;
    // Start is called before the first frame update

    // Update is called once per frame
    void Update()
    {
        if (constrain == true)
        {
            InputTracking.Recenter();
        }
        if (Input.GetKeyDown(KeyCode.C))
        {
            constrain = false;
        }
    }
}