Added a dialog box

Controllers/DialogController.gd

@@ -0,0 +1,25 @@
+extends Node
+
+@export var dialogContainer: MarginContainer
+@export var dialogTextLabel: RichTextLabel
+
+const INCREMENT: float = 0.01
+
+func set_dialog(text: String) -> void:
+	dialogTextLabel.text = text
+	dialogTextLabel.visible_ratio = 0
+	var ratio: float = 0
+	
+	if text.length() == 0:
+		dialogContainer.visible = false
+		return
+	else:
+		dialogContainer.visible = true
+	
+	while true:
+		#don't interfere with other timers
+		if dialogTextLabel.visible_ratio < ratio or dialogTextLabel.visible_ratio >= 1:
+			return
+		dialogTextLabel.visible_ratio += INCREMENT
+		ratio = dialogTextLabel.visible_ratio
+		await get_tree().create_timer(INCREMENT).timeout