make proper setup for VRPN with buttons and trackers

addons/vrpn/scripts/VRPN_Tracker.gd

@@ -0,0 +1,33 @@
+class_name VRPN_Tracker
+extends Node3D
+
+@export var vrpn : VRPN = null
+@export var tracker_name : String = "Tracker0"
+@export var tracker_sensor : int = 0
+@export var tracker_use_position : bool = true
+@export var tracker_use_rotation : bool = true
+@export var register_on_start : bool = true
+
+func _ready() -> void:
+	if vrpn and register_on_start:
+		vrpn.tracker.append(self)
+
+func _on_vrpn(vrpn_data : Dictionary):
+	match vrpn_data['type'] as VRPN.TrackingDataType:
+		VRPN.TrackingDataType.POS_QUAT:
+			if vrpn_data['tracker'] == tracker_name and vrpn_data['sensor'] == tracker_sensor:
+				if tracker_use_position:
+					self.global_position = vrpn_data['position']
+				if tracker_use_rotation:
+					var rotation := vrpn_data['rotation'] as Quaternion
+					self.global_basis =  Basis(rotation)
+		VRPN.TrackingDataType.ACCELERATION:
+			pass
+		VRPN.TrackingDataType.VELOCITY:
+			pass
+		_:
+			push_warning("unknown tracker datatype")
+
+
+func _on_vrpn_connected(s):
+	pass # Replace with function body.