More detailed controller information are currently not accessible. State information of the thumbstick or touchpad are stored in gamepad property of an XRInputSource. An input source is currently a hidden property which can’t be accessed over the respective instance of WebXRController. However, it is of course technically possible to expose it in some way.
@mrdoob Do you already have something in mind for exposing inputSource.gamepad? Right now, an instance of WebXRController receives its inputSource in the updated method called by WebXRManager. Meaning the controller has no permanent reference to its input source. That makes it a bit more complicate to provide access to it…
Related standard: WebXR Gamepads Module - Level 1