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

project/aircraft/aircraft.tscn

@@ -71,5 +71,6 @@ transform = Transform3D(-0.5, -1.27582e-08, 7.43353e-08, 4.33325e-10, 0.4923, 0.
 
 [connection signal="use_fallback" from="." to="AttitudeRoot/PilotEyes" method="_on_aircraft_use_fallback"]
 [connection signal="timeout" from="AttitudeRoot/PilotEyes/PilotFloor/XROrigin3D/RecentTracking" to="." method="_on_recent_tracking_timeout"]
+[connection signal="fog_density_changed" from="MarshConnector" to="." method="_on_marsh_connector_fog_density_changed"]
 
 [editable path="Mi-2"]

project/fog_controller.gd

@@ -0,0 +1,8 @@
+extends WorldEnvironment
+
+func _on_fog_density_changed(new_density: float) -> void:
+	if new_density == 0.0 or not is_finite(new_density):
+		environment.fog_enabled = false
+	else:
+		environment.fog_enabled = true
+		environment.fog_density = 10 ** new_density

project/fog_controller.gd.uid

@@ -0,0 +1 @@
+uid://6g3b2ohwbkyv

project/main.tscn

@@ -1,7 +1,8 @@
-[gd_scene load_steps=7 format=3 uid="uid://crq3o0eu4y8ya"]
+[gd_scene load_steps=8 format=3 uid="uid://crq3o0eu4y8ya"]
 
 [ext_resource type="Script" uid="uid://dfcjdxesyn3l0" path="res://start_vr.gd" id="1_ig7tw"]
 [ext_resource type="PackedScene" uid="uid://bj1s0g7ixjw71" path="res://aircraft/aircraft.tscn" id="2_0xm2m"]
+[ext_resource type="Script" uid="uid://6g3b2ohwbkyv" path="res://fog_controller.gd" id="3_1bvp3"]
 [ext_resource type="PackedScene" uid="uid://bchcr54i3piaw" path="res://ads33-terrain/Cones_scene_terrain.tscn" id="3_h2yge"]
 
 [sub_resource type="ProceduralSkyMaterial" id="ProceduralSkyMaterial_7dm0k"]
@@ -12,6 +13,10 @@ sky_material = SubResource("ProceduralSkyMaterial_7dm0k")
 [sub_resource type="Environment" id="Environment_0xm2m"]
 background_mode = 2
 sky = SubResource("Sky_ig7tw")
+fog_enabled = true
+fog_sun_scatter = 0.5
+fog_density = 0.0
+fog_depth_end = 80.0
 
 [node name="Main" type="Node3D"]
 
@@ -21,6 +26,7 @@ sky = SubResource("Sky_ig7tw")
 
 [node name="WorldEnvironment" type="WorldEnvironment" parent="."]
 environment = SubResource("Environment_0xm2m")
+script = ExtResource("3_1bvp3")
 
 [node name="DirectionalLight3D" type="DirectionalLight3D" parent="."]
 transform = Transform3D(0.866025, 0.433013, 0.25, 0, -0.5, 0.866025, 0.5, -0.75, -0.433013, -5, 5, -5)
@@ -29,4 +35,5 @@ shadow_enabled = true
 [node name="StartVR" type="Node3D" parent="."]
 script = ExtResource("1_ig7tw")
 
+[connection signal="fog_density_changed" from="Aircraft" to="WorldEnvironment" method="_on_fog_density_changed"]
 [connection signal="setup_failed" from="StartVR" to="Aircraft" method="_on_vr_setup_failed"]

project/project.godot

@@ -62,6 +62,11 @@ pov_reset={
 "events": [Object(InputEventKey,"resource_local_to_scene":false,"resource_name":"","device":-1,"window_id":0,"alt_pressed":false,"shift_pressed":false,"ctrl_pressed":false,"meta_pressed":false,"pressed":false,"keycode":0,"physical_keycode":81,"key_label":0,"unicode":113,"location":0,"echo":false,"script":null)
 ]
 }
+fog_cycle={
+"deadzone": 0.2,
+"events": [Object(InputEventKey,"resource_local_to_scene":false,"resource_name":"","device":-1,"window_id":0,"alt_pressed":false,"shift_pressed":false,"ctrl_pressed":false,"meta_pressed":false,"pressed":false,"keycode":0,"physical_keycode":70,"key_label":0,"unicode":102,"location":0,"echo":false,"script":null)
+]
+}
 
 [physics]
 

src/marshconnector.cpp

@@ -53,6 +53,15 @@ void MarshConnector::_bind_methods() {
   ADD_PROPERTY(PropertyInfo(Variant::STRING, "hostname"), "set_hostname",
                "get_hostname");
 
+  ClassDB::bind_method(D_METHOD("get_fog_density"),
+                       &MarshConnector::get_fog_density);
+  ClassDB::bind_method(D_METHOD("set_fog_density", "p_fog_density"),
+                       &MarshConnector::set_fog_density);
+  ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "fog_density"), "set_fog_density",
+               "get_fog_density");
+  ADD_SIGNAL(MethodInfo("fog_density_changed",
+                        PropertyInfo(Variant::FLOAT, "new_density")));
+
   // Timer callbacks
   ClassDB::bind_method(D_METHOD("send_heartbeat"),
                        &MarshConnector::send_heartbeat);
@@ -262,6 +271,17 @@ Vector4 MarshConnector::get_controls() { return last_controls; }
 
 Vector4 MarshConnector::get_trim() { return last_trim; }
 
+float MarshConnector::get_fog_density() { return parameters[FOG_DENSITY]; }
+
+void MarshConnector::set_fog_density(float density) {
+  if (density == parameters[FOG_DENSITY])
+    return;
+
+  parameters[FOG_DENSITY] = density;
+  emit_signal("fog_density_changed", density);
+  send_param(FOG_DENSITY);
+}
+
 bool MarshConnector::get_manager_connected() { return manager_connected; }
 
 bool MarshConnector::get_model_connected() { return model_connected; }
@@ -417,7 +437,11 @@ void MarshConnector::handle_param(mavlink_message_t message) {
 
   if (param_value.has_value()) {
     // TODO: Verify the value before updating
-    parameters[i] = *param_value;
+    if (i == FOG_DENSITY) {
+      set_fog_density(*param_value);
+    } else {
+      parameters[i] = *param_value;
+    }
   }
   send_param(Parameter{i});
 }

src/marshconnector.h

@@ -51,6 +51,10 @@ public:
   // Get normalized trim position
   Vector4 get_trim();
 
+  // Get current fog density as set in the parameter
+  float get_fog_density();
+  void set_fog_density(float value);
+
   // Is there a connection to MARSH Manager
   bool get_manager_connected();
   // Is receiving data from flight model
@@ -94,7 +98,7 @@ private:
   // Not an enum class on purpose, to make use more convenient, it's scoped
   // inside the class namespace anyway
   enum Parameter : uint16_t {
-    // FOG_DENSITY,
+    FOG_DENSITY,
     NAV_OFS_HDG,
     NAV_OFS_X,
     NAV_OFS_Y,
@@ -102,11 +106,10 @@ private:
     LOCAL_FRAME_LON,
     PARAM_COUNT,
   };
-  float parameters[PARAM_COUNT] = {0.0, 0.0, 0.0, 0.0, 0.0};
+  float parameters[PARAM_COUNT] = {0.0, 0.0, 0.0, 0.0, 0.0, 0.0};
   const String parameter_names[PARAM_COUNT] = {
-      // "FOG_DENSITY",
+      "FOG_DENSITY", "NAV_OFS_HDG",     "NAV_OFS_X",
-      "NAV_OFS_HDG",     "NAV_OFS_X",       "NAV_OFS_Y",
+      "NAV_OFS_Y",   "LOCAL_FRAME_LAT", "LOCAL_FRAME_LON",
-      "LOCAL_FRAME_LAT", "LOCAL_FRAME_LON",
   };
   Error send_param(Parameter index);
   Error subscribe_message(uint8_t manager_system, uint8_t manager_component,