gd: added menu template

addons/maaacks_game_template/base/scripts/music_controller.gd

@@ -0,0 +1,184 @@
+class_name MusicController
+extends Node
+## Controller for music playback across scenes.
+##
+## This node persistently checks for stream players added to the scene tree.
+## It detects stream players that match the audio bus and have autoplay on.
+## It then reparents the stream players to itself, and handles blending.
+## The expected use-case is to attach this script to an autoloaded scene.
+
+const BLEND_BUS_PREFIX : String = "Blend"
+const MAX_DEPTH = 16
+const MINIMUM_VOLUME_DB = -80
+
+## Detect stream players with matching audio bus.
+@export var audio_bus : StringName = &"Music"
+
+@export_group("Blending")
+@export var fade_out_duration : float = 0.0 :
+	set(value):
+		fade_out_duration = value
+		if fade_out_duration < 0:
+			fade_out_duration = 0
+			
+@export var fade_in_duration : float = 0.0 :
+	set(value):
+		fade_in_duration = value
+		if fade_in_duration < 0:
+			fade_in_duration = 0
+
+## Matched stream players with no stream set will stop current playback.
+@export var empty_streams_stop_player : bool = true
+
+var music_stream_player : AudioStreamPlayer
+var blend_audio_bus : StringName
+var blend_audio_bus_idx : int
+
+func fade_out(duration : float = 0.0) -> Tween:
+	if is_zero_approx(duration): return
+	music_stream_player.bus = audio_bus
+	var tween = create_tween()
+	tween.tween_property(music_stream_player, "volume_db", MINIMUM_VOLUME_DB, duration)
+	return tween
+
+func _set_sub_audio_volume_db(sub_volume_db : float) -> void:
+	AudioServer.set_bus_volume_db(blend_audio_bus_idx, sub_volume_db)
+
+func fade_in(duration : float = 0.0) -> Tween:
+	if is_zero_approx(duration): return
+	music_stream_player.bus = blend_audio_bus
+	AudioServer.set_bus_volume_db(blend_audio_bus_idx, MINIMUM_VOLUME_DB)
+	var tween = create_tween()
+	tween.tween_method(_set_sub_audio_volume_db, MINIMUM_VOLUME_DB, 0, duration)
+	return tween
+
+func blend_to(target_volume_db : float, duration : float = 0.0) -> Tween:
+	if not is_zero_approx(duration):
+		var tween = create_tween()
+		tween.tween_property(music_stream_player, "volume_db", target_volume_db, duration)
+		return tween
+	music_stream_player.volume_db = target_volume_db
+	return
+
+func stop() -> void:
+	if not is_instance_valid(music_stream_player):
+		return
+	music_stream_player.stop()
+
+func play(playback_position : float = 0.0) -> void:
+	if not is_instance_valid(music_stream_player):
+		return
+	if is_zero_approx(playback_position) and not music_stream_player.playing:
+		music_stream_player.play()
+	else:
+		music_stream_player.play(playback_position)
+
+func _fade_out_and_free() -> void:
+	if not is_instance_valid(music_stream_player):
+		return
+	var stream_player = music_stream_player
+	var tween = fade_out(fade_out_duration)
+	if tween != null:
+		await(tween.finished)
+	stream_player.queue_free()
+
+func _play_and_fade_in() -> void:
+	play()
+	fade_in( fade_in_duration )
+
+func _is_matching_stream(stream_player : AudioStreamPlayer) -> bool:
+	if stream_player.bus != audio_bus:
+		return false
+	if not is_instance_valid(music_stream_player):
+		return false
+	return music_stream_player.stream == stream_player.stream
+
+func _connect_stream_on_tree_exiting(stream_player : AudioStreamPlayer) -> void:
+	if not stream_player.tree_exiting.is_connected(_on_removed_music_player.bind(stream_player)):
+		stream_player.tree_exiting.connect(_on_removed_music_player.bind(stream_player))
+
+func _blend_and_remove_stream_player(stream_player : AudioStreamPlayer) -> void:
+	var playback_position := music_stream_player.get_playback_position() + AudioServer.get_time_since_last_mix()
+	var old_stream_player = music_stream_player
+	music_stream_player = stream_player
+	music_stream_player.bus = blend_audio_bus
+	play(playback_position)
+	old_stream_player.stop()
+	old_stream_player.queue_free()
+	_connect_stream_on_tree_exiting(music_stream_player)
+
+func _blend_and_connect_stream_player(stream_player : AudioStreamPlayer) -> void:
+	stream_player.bus = blend_audio_bus
+	_fade_out_and_free()
+	music_stream_player = stream_player
+	_play_and_fade_in()
+	_connect_stream_on_tree_exiting(music_stream_player)
+
+func play_stream_player(stream_player : AudioStreamPlayer) -> void:
+	if stream_player == music_stream_player : return
+	if stream_player.stream == null and not empty_streams_stop_player:
+			return
+	if _is_matching_stream(stream_player) : 
+		_blend_and_remove_stream_player(stream_player)
+	else:
+		_blend_and_connect_stream_player(stream_player)
+
+func get_stream_player(audio_stream : AudioStream) -> AudioStreamPlayer:
+	var stream_player := AudioStreamPlayer.new()
+	stream_player.stream = audio_stream
+	stream_player.bus = audio_bus
+	add_child(stream_player)
+	return stream_player
+
+func play_stream(audio_stream : AudioStream) -> AudioStreamPlayer:
+	var stream_player := get_stream_player(audio_stream)
+	stream_player.play.call_deferred()
+	play_stream_player( stream_player )
+	return stream_player
+
+func _clone_music_player(stream_player : AudioStreamPlayer) -> void:
+	var playback_position := stream_player.get_playback_position() + AudioServer.get_time_since_last_mix()
+	var audio_stream := stream_player.stream
+	music_stream_player = get_stream_player(audio_stream)
+	music_stream_player.volume_db = stream_player.volume_db
+	music_stream_player.max_polyphony = stream_player.max_polyphony
+	music_stream_player.pitch_scale = stream_player.pitch_scale
+	music_stream_player.play.call_deferred(playback_position)
+
+func _reparent_music_player(stream_player : AudioStreamPlayer) -> void:
+	var playback_position := stream_player.get_playback_position() + AudioServer.get_time_since_last_mix()
+	stream_player.owner = null
+	stream_player.reparent.call_deferred(self)
+	stream_player.play.call_deferred(playback_position)
+
+func _node_matches_checks(node : Node)  -> bool:
+	return node is AudioStreamPlayer and node.autoplay and node.bus == audio_bus
+
+func _on_removed_music_player(node: Node) -> void:
+	if music_stream_player == node:
+		if node.owner == null:
+			_clone_music_player(node)
+		else:
+			_reparent_music_player(node)
+		if node.tree_exiting.is_connected(_on_removed_music_player.bind(node)):
+			node.tree_exiting.disconnect(_on_removed_music_player.bind(node))
+
+func _on_added_music_player(node: Node) -> void:
+	if node == music_stream_player : return
+	if not (_node_matches_checks(node)) : return
+	play_stream_player(node)
+
+func _enter_tree() -> void:
+	AudioServer.add_bus()
+	blend_audio_bus_idx = AudioServer.bus_count - 1
+	blend_audio_bus = AppSettings.SYSTEM_BUS_NAME_PREFIX + BLEND_BUS_PREFIX + audio_bus
+	AudioServer.set_bus_send(blend_audio_bus_idx, audio_bus)
+	AudioServer.set_bus_name(blend_audio_bus_idx, blend_audio_bus)
+	var tree_node = get_tree()
+	if not tree_node.node_added.is_connected(_on_added_music_player):
+		tree_node.node_added.connect(_on_added_music_player)
+
+func _exit_tree() -> void:
+	var tree_node = get_tree()
+	if tree_node.node_added.is_connected(_on_added_music_player):
+		tree_node.node_added.disconnect(_on_added_music_player)