Implemented Mouse Passthrough

Implemented Mouse Passthrough code to handle allowing/dis-allowing mouse
passthrough, and adding exceptions for specific Control nodes.

lib/globals.gd

@@ -3,6 +3,9 @@ extends Node
 var twitcher: TwitcherExtended
 var context: OverlayContext
 var settings: OverlaySettings
+var _pt_except: Array[Control] = []
+var _pt_mouse: bool = false
+var _current_pt_mask: PackedVector2Array = []
 
 # Called when the node enters the scene tree for the first time.
 func _ready() -> void:
@@ -21,3 +24,49 @@ func _exit_tree() -> void:
 
 func save_settings() -> void:
 	ResourceSaver.save(settings, "user://settings.tres")
+
+
+func clear_mouse_passthrough() -> void:
+	DisplayServer.window_set_mouse_passthrough([])
+
+func _update_mouse_passthrough() -> void:
+	var _pt_mask: PackedVector2Array = []
+	for node in _pt_except:
+		var rect := node.get_global_rect()
+		_pt_mask.append_array([
+			rect.position,
+			Vector2(rect.position.x + rect.size.x, rect.position.y),
+			rect.position + rect.size,
+			Vector2(rect.position.x, rect.position.y + rect.size.y)
+		])
+	
+	if _pt_mask == _current_pt_mask:
+		print("No Changed made, returning.")
+		return
+	
+	_current_pt_mask = _pt_mask
+	DisplayServer.window_set_mouse_passthrough(_current_pt_mask)
+
+func add_to_passthrough_exception(control: Control) -> void:
+	if not _pt_except.has(control):
+		_pt_except.append(control)
+		control.item_rect_changed.connect(_update_mouse_passthrough)
+
+func remove_from_passthrough_exceptioon(control: Control) -> void:
+	if _pt_except.has(control):
+		_pt_except.erase(control)
+		control.item_rect_changed.disconnect(_update_mouse_passthrough)
+
+func enable_mouse_passthrough() -> void:
+	if _pt_mouse:
+		return
+	
+	_pt_mouse = true
+	_update_mouse_passthrough()
+
+func disable_mouse_passthrough() -> void:
+	if not _pt_mouse:
+		return
+	
+	_pt_mouse = false
+	clear_mouse_passthrough()