Add exponential fog controllable with keyboard and MARSH parameter

project/aircraft/aircraft.gd

@@ -1,15 +1,18 @@
 extends Node3D
 
 signal use_fallback(active: bool)
+signal fog_density_changed(new_density: float)
 
 ## Rotation of cyclic stick model for full control deflection, in degrees
 @export var range_cyclic: float = 30
 ## Main rotor speed, in revolutions per minute
 @export var rotor_rpm: float = 500
 @export var track_platform: bool = false
+@export var fog_values: Array[float] = [0.0, -1.0, -2.0, -3.0, -4.0]
 
 ## Current angle of rotor rotation
 var _rotor_azimuth: float = 0
+var fog_index: int = 0
 
 @onready var connector: MarshConnector = $MarshConnector
 @onready var skeleton: Skeleton3D = $"Mi-2/Armature/Skeleton3D"
@@ -65,6 +68,14 @@ func _process(delta: float) -> void:
 		xr_origin.transform = tracker_mount.transform * tracker.transform.affine_inverse()
 		recent_tracking.start()
 
+func _input(event):
+	if event.is_action_pressed("fog_cycle"):
+		var step = 1
+		if event is InputEventWithModifiers and event.shift_pressed:
+			step = -1
+		# The index is updated in the signal callback to handle parameter changes
+		connector.fog_density = fog_values[(fog_index + step) % len(fog_values)]
+
 # Only reset the position when tracking is lost for some time
 func _on_recent_tracking_timeout() -> void:
 	xr_origin.transform = Transform3D.IDENTITY
@@ -72,3 +83,14 @@ func _on_recent_tracking_timeout() -> void:
 func _on_vr_setup_failed() -> void:
 	xr_camera.current = false
 	use_fallback.emit(true)
+
+func _on_marsh_connector_fog_density_changed(new_density: float) -> void:
+	# Forward to parent
+	fog_density_changed.emit(new_density)
+
+	# Round down to nearest defined value or assign the last one (so it will disable on next cycle)
+	# Example: -1.5 should select -2 and on next cycle it will be -3
+	var new_index = fog_values.find_custom(func (d): return d <= new_density)
+	if new_index == -1:
+		new_index = len(fog_values) - 1
+	fog_index = new_index