Refactor audio effect handling: remove cooldown logic and enhance sound playback functionality

stage/stage.gd

@@ -94,6 +94,7 @@ var g_active_items: Dictionary = {}
 var pending_page: int = -1
 var active_actions_dirty: bool = true
 var active_actions_elapsed: float = 0.0
+var interface_sounds_enabled: bool = false
 
 var owniverse:Owniverse = Owniverse.new()
 var owniverse_items: Dictionary[String, OwniverseItem] = {}
@@ -323,6 +324,11 @@ func _ready() -> void:
     for pa in page_actions:
         page_actions[pa].action_pressed.connect(_page_action_pressed)
         page_actions[pa].page_id = pa
+    _enable_interface_sounds.call_deferred()
+
+
+func _enable_interface_sounds() -> void:
+    interface_sounds_enabled = true
 
 
 ## Starts a fresh universe. Can be connected directly to a button's pressed signal.
@@ -398,10 +404,15 @@ func _process(delta: float) -> void:
 
 
 func _change_speed(delta: int) -> void:
-
+    var previous_speed: int = owniverse.speed
     owniverse.speed = owniverse.speed + delta
 
     var speed: int = owniverse.speed
+    if speed > previous_speed:
+        effects_player.play_effect("time_plus")
+    elif speed < previous_speed:
+        effects_player.play_effect("time_minus")
+
     var ind: int = 1
     for icon in g_speed_icons:
         if ind <= speed:
@@ -421,6 +432,17 @@ func _change_speed(delta: int) -> void:
 
 
 func _on_topmenu_button_pressed(screen_name: String) -> void:
+    var current_screen: String = ""
+    for screen_id in screens:
+        if screens[screen_id].visible:
+            current_screen = screen_id
+            break
+
+    if current_screen == screen_name:
+        return
+
+    if interface_sounds_enabled:
+        effects_player.play_effect("window_close" if screen_name == "World" else "window_open")
 
     for screen_id in screens:
         #print(screen_name, " ←→ ", screen_id)