96 lines
3.3 KiB
GDScript
96 lines
3.3 KiB
GDScript
class_name Sfx
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extends RefCounted
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# Forgejo #146: the three things that happen to something and should be
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# heard - a shot leaving a gun, a vessel dying, a structure coming down.
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#
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# The sounds themselves are synthesised (see audio/make_sfx.py) rather than
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# downloaded. The ticket asked for free sources and the good ones are in its
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# comments, but a generated sound has no licence to track, no attribution to
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# keep, and no binary in the repository whose provenance nobody can check
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# later. Swapping in a file from one of those packs is a matter of replacing
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# the .wav - nothing here knows or cares which it is.
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#
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# Parented to the tree root for the same reason Music is: a sound started by
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# something that is about to be freed - which is every one of these, a dying
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# ship being the obvious case - cannot live on the thing that started it.
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#
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# A POOL rather than one player, because these overlap constantly: a fleet
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# firing is several shots inside one shot's length. The oldest is recycled
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# when they are all busy, which is the right thing to lose.
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const NODE_NAME: String = "SfxPlayers"
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const VOICES: int = 12
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const SHOT: String = "shot"
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const SHIP_DEATH: String = "ship_death"
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const BUILDING_DEATH: String = "building_death"
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const SOUNDS: Dictionary = {
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SHOT: "res://audio/sfx_shot.wav",
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SHIP_DEATH: "res://audio/sfx_ship_death.wav",
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BUILDING_DEATH: "res://audio/sfx_building_death.wav",
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}
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# Per-sound level. A shot is fired constantly and a death happens once, so
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# they cannot share a volume and stay in proportion.
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const LEVELS: Dictionary = {
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SHOT: -26.0,
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SHIP_DEATH: -23.0,
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BUILDING_DEATH: -23.0,
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}
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# Shots vary a little in pitch so a stream of them does not turn into one
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# flat machine-gun note. The deaths do not: they are events, and a wobbling
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# explosion sounds broken rather than varied.
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const SHOT_PITCH_SPREAD: float = 0.12
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static func _pool(tree: SceneTree) -> Node:
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var existing: Node = tree.root.get_node_or_null(NODE_NAME)
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if existing != null:
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return existing
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var pool := Node.new()
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pool.name = NODE_NAME
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# #128 stops the tree for dialogs. A sound already in flight should
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# finish rather than freeze mid-bang.
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pool.process_mode = Node.PROCESS_MODE_ALWAYS
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tree.root.add_child(pool)
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for i in range(VOICES):
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var voice := AudioStreamPlayer.new()
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voice.process_mode = Node.PROCESS_MODE_ALWAYS
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pool.add_child(voice)
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return pool
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# Plays one sound. Safe from a node on its way out of the tree, and safe to
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# call far more often than there are voices.
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static func play(tree: SceneTree, id: String) -> void:
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if tree == null or not SOUNDS.has(id):
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return
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var stream: AudioStream = load(String(SOUNDS[id]))
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if stream == null:
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return
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var pool: Node = _pool(tree)
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var voice: AudioStreamPlayer = null
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for child in pool.get_children():
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if not (child as AudioStreamPlayer).playing:
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voice = child
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break
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if voice == null:
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# All busy. The oldest is the one furthest through its own sound, so
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# it is the one with the least left to lose.
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var most: float = -1.0
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for child in pool.get_children():
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var at: float = (child as AudioStreamPlayer).get_playback_position()
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if at > most:
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most = at
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voice = child
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if voice == null:
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return
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voice.stream = stream
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voice.volume_db = float(LEVELS.get(id, -10.0))
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voice.pitch_scale = 1.0
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if id == SHOT:
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voice.pitch_scale = 1.0 + randf_range(-SHOT_PITCH_SPREAD, SHOT_PITCH_SPREAD)
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voice.play()
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