player.cs

bool handlingInput = false;

void Update ()
{
    if(!handlingInput)
        if (Input.touchCount > 0 && Input.GetTouch(0).phase == TouchPhase.Began)
        {
            handlingInput = true;
            StartCoroutine(HandleTouch());
        }
}

IEnumerator HandleTouch()
{
    Touch touch = Input.GetTouch(0);

    while (touch.phase != TouchPhase.Ended && touch.phase != TouchPhase.Canceled)
    {
        if(touch.phase == TouchPhase.Moved)
        {
            Vector3 cameraRelativeDeltaPosition = screenXY2CameraXZ(touch.deltaPosition);
            playerOffset.x = playerOffset.x - cameraRelativeDeltaPosition.x;
            playerOffset.z = playerOffset.z - cameraRelativeDeltaPosition.z;
        }

        yield return new WaitForEndOfFrame();
        touch = Input.GetTouch(0);
    }

    handlingInput = false;
    yield return 0;
}