add rain sound

dynamic-sky/scripts/weather_vfx.gd

@@ -19,6 +19,11 @@ extends Node3D
 @export var lightning_color: Color = Color(0.9, 0.9, 1.0)
 @export var lightning_flash_duration: float = 0.15
 
+@export_group("Rain Audio")
+@export var rain_audio_enabled: bool = true
+@export var rain_volume_db_max: float = 0.0
+@export var rain_crossfade_threshold: float = 0.5
+
 @export_group("Thunder")
 @export var thunder_enabled: bool = true
 @export var thunder_min_delay: float = 1.0
@@ -42,6 +47,8 @@ var _lightning_light: DirectionalLight3D
 var _thunder_player: AudioStreamPlayer
 var _thunder_pending: bool = false
 var _thunder_delay_timer: float = 0.0
+var _rain_light_player: AudioStreamPlayer
+var _rain_hard_player: AudioStreamPlayer
 
 
 func _ready() -> void:
@@ -49,6 +56,7 @@ func _ready() -> void:
 	_create_snow_system()
 	_create_lightning_light()
 	_create_thunder_player()
+	_create_rain_audio_players()
 
 
 func _process(delta: float) -> void:
@@ -67,6 +75,7 @@ func _process(delta: float) -> void:
 	
 	_process_lightning(delta)
 	_process_thunder(delta)
+	_process_rain_audio()
 	_follow_camera()
 
 
@@ -130,6 +139,66 @@ func _create_thunder_player() -> void:
 	add_child(_thunder_player)
 
 
+func _create_rain_audio_players() -> void:
+	_rain_light_player = AudioStreamPlayer.new()
+	_rain_light_player.name = "RainLightPlayer"
+	_rain_light_player.volume_db = -80.0
+	_rain_light_player.bus = "Master"
+	_rain_light_player.stream = load("res://resources/rain_light.mp3")
+	add_child(_rain_light_player)
+	
+	_rain_hard_player = AudioStreamPlayer.new()
+	_rain_hard_player.name = "RainHardPlayer"
+	_rain_hard_player.volume_db = -80.0
+	_rain_hard_player.bus = "Master"
+	_rain_hard_player.stream = load("res://resources/rain_gentle.mp3")
+	add_child(_rain_hard_player)
+
+
+func _process_rain_audio() -> void:
+	if not rain_audio_enabled:
+		if _rain_light_player.playing:
+			_rain_light_player.stop()
+		if _rain_hard_player.playing:
+			_rain_hard_player.stop()
+		return
+	
+	if _current_rain < 0.01:
+		if _rain_light_player.playing:
+			_rain_light_player.stop()
+		if _rain_hard_player.playing:
+			_rain_hard_player.stop()
+		return
+	
+	# Below threshold: only light rain plays, volume scales linearly 0 → max
+	# Above threshold: light rain fades out, hard rain fades in
+	if _current_rain <= rain_crossfade_threshold:
+		# Light rain: volume from 0 to max based on percentage within the range
+		var light_vol := _current_rain / rain_crossfade_threshold
+		_set_rain_player(_rain_light_player, light_vol)
+		_stop_rain_player(_rain_hard_player)
+	else:
+		# Crossfade zone: light fades out, hard fades in
+		var t := (_current_rain - rain_crossfade_threshold) / (1.0 - rain_crossfade_threshold)
+		_set_rain_player(_rain_light_player, 1.0 - t)
+		_set_rain_player(_rain_hard_player, t)
+
+
+func _set_rain_player(player: AudioStreamPlayer, weight: float) -> void:
+	if weight < 0.001:
+		_stop_rain_player(player)
+		return
+	if not player.playing:
+		player.volume_db = -80.0
+		player.play()
+	player.volume_db = lerpf(-80.0, rain_volume_db_max, weight)
+
+
+func _stop_rain_player(player: AudioStreamPlayer) -> void:
+	if player.playing:
+		player.stop()
+
+
 func _create_lightning_light() -> void:
 	_lightning_light = DirectionalLight3D.new()
 	_lightning_light.name = "LightningFlash"