if (Input.touchCount > 0 && Input.GetTouch(0).phase == TouchPhase.Moved) {
// Get movement of the finger since last frame
Vector2 touchDeltaPosition = Input.GetTouch(0).deltaPosition;
// Move object across XY plane
transform.Translate(-touchDeltaPosition.x * speed, -touchDeltaPosition.y * speed, 0);
}