Some code improvements and documentation

Translations/Translations.pot

@@ -2251,6 +2251,9 @@ msgstr ""
 msgid "Tilemap"
 msgstr ""
 
+msgid "Audio"
+msgstr ""
+
 msgid "Layers"
 msgstr ""
 

src/Autoload/Global.gd

@@ -1193,6 +1193,6 @@ func _save_to_override_file() -> void:
 	file.store_line("[display]\n")
 	file.store_line("window/subwindows/embed_subwindows=%s" % single_window_mode)
 	file.store_line("window/per_pixel_transparency/allowed=%s" % window_transparency)
-	file.store_line("[audio]\n")
 	if dummy_audio_driver:
+		file.store_line("[audio]\n")
 		file.store_line('driver/driver="Dummy"')

src/Classes/Layers/AudioLayer.gd

@@ -1,18 +1,21 @@
 class_name AudioLayer
 extends BaseLayer
+## A unique type of layer which acts as an audio track for the timeline.
+## Each audio layer has one audio stream, and its starting position can be
+## in any point during the animation.
 
 signal audio_changed
 signal playback_frame_changed
 
-var audio: AudioStream:
+var audio: AudioStream:  ## The audio stream of the layer.
 	set(value):
 		audio = value
 		audio_changed.emit()
-var playback_position := 0.0:  ## Measured in seconds.
+var playback_position := 0.0:  ## The time in seconds where the audio stream starts playing.
 	get():
 		var frame := project.frames[playback_frame]
 		return frame.position_in_seconds(project)
-var playback_frame := 0:
+var playback_frame := 0:  ## The frame where the audio stream starts playing.
 	set(value):
 		playback_frame = value
 		playback_frame_changed.emit()
@@ -23,6 +26,7 @@ func _init(_project: Project, _name := "") -> void:
 	name = _name
 
 
+## Returns the length of the audio stream.
 func get_audio_length() -> float:
 	if is_instance_valid(audio):
 		return audio.get_length()
@@ -30,6 +34,7 @@ func get_audio_length() -> float:
 		return -1.0
 
 
+## Returns the class name of the audio stream. E.g. "AudioStreamMP3".
 func get_audio_type() -> String:
 	if not is_instance_valid(audio):
 		return ""
@@ -61,4 +66,4 @@ func new_empty_cel() -> AudioCel:
 
 
 func set_name_to_default(number: int) -> void:
-	name = tr("Audio track") + " %s" % number
+	name = tr("Audio") + " %s" % number

src/Preferences/PreferencesDialog.tscn

@@ -1156,13 +1156,11 @@ text = "On"
 
 [node name="DummyAudioDriverLabel" type="Label" parent="HSplitContainer/VBoxContainer/ScrollContainer/RightSide/Performance/PerformanceContainer" groups=["DesktopOnly"]]
 layout_mode = 2
-tooltip_text = "If enabled, the application window can become transparent. This affects performance, so keep it off if you don't need it."
 mouse_filter = 0
 text = "Use dummy audio driver"
 
 [node name="DummyAudioDriver" type="CheckBox" parent="HSplitContainer/VBoxContainer/ScrollContainer/RightSide/Performance/PerformanceContainer" groups=["DesktopOnly"]]
 layout_mode = 2
-tooltip_text = "If enabled, the application window can become transparent. This affects performance, so keep it off if you don't need it."
 mouse_default_cursor_shape = 2
 text = "On"