Aircraft - Drone "Follow Unit" Waypoint Action

addons/aircraft/functions/fnc_droneAddActions.sqf

@@ -22,7 +22,7 @@ if (!alive _vehicle) exitWith {};
 if (_vehicle getVariable [QGVAR(droneActionsAdded), false]) exitWith {};
 _vehicle setVariable [QGVAR(droneActionsAdded), true];
 
-// move to location
+// Move to location
 private _condition = {
     params ["_vehicle"];
     (missionNamespace getVariable [QGVAR(droneWaypoints), true]) && {waypointsEnabledUAV _vehicle} && {(ACE_controlledUAV select 2) isEqualTo [0]}
@@ -37,14 +37,63 @@ private _action = [QGVAR(droneSetWaypointMove), localize "$STR_AC_MOVE",
     "\a3\3DEN\Data\CfgWaypoints\Move_ca.paa", _statement, _condition] call EFUNC(interact_menu,createAction);
 [_vehicle, 1, ["ACE_SelfActions"], _action] call EFUNC(interact_menu,addActionToObject);
 
+// Follow unit/vehicle at turret location
+_condition = {
+    params ["_vehicle"];
+    private _target = cursorTarget;
+    (missionNamespace getVariable [QGVAR(droneWaypoints), true]) && {waypointsEnabledUAV _vehicle} && {(ACE_controlledUAV select 2) isEqualTo [0]} && {!isNull _target} && {["CAManBase", "LandVehicle", "Ship"] findIf {_target isKindOf _x} != -1}
+};
+_statement = {
+    params ["_vehicle"];
+    private _group = group driver _vehicle;
+    private _pos = ([_vehicle, [0]] call FUNC(droneGetTurretTargetPos)) select 0;
+    [QGVAR(droneSetWaypoint), [_vehicle, _group, _pos, "FOLLOW", cursorTarget], _group] call CBA_fnc_targetEvent;
+    private _followDistance = _vehicle getVariable [QGVAR(wpFollowDistance), 0];
+    [[LLSTRING(DroneFollowHint), _followDistance], 3] call EFUNC(common,displayTextStructured);
+};
+_action = [QGVAR(droneSetWaypointFollow), localize "$STR_AC_FOLLOW", "\a3\3DEN\Data\CfgWaypoints\Follow_ca.paa", _statement, _condition] call EFUNC(interact_menu,createAction);
+[_vehicle, 1, ["ACE_SelfActions"], _action] call EFUNC(interact_menu,addActionToObject);
+
+// Set drone follow distance
+_condition = {
+    params ["_vehicle"];
+    private _group = group driver _vehicle;
+    private _index = (currentWaypoint _group) min count waypoints _group;
+    private _waypoint = [_group, _index];
+    (missionNamespace getVariable [QGVAR(droneWaypoints), true]) && {waypointsEnabledUAV _vehicle} && {(ACE_controlledUAV select 2) isEqualTo [0]} && {(waypointType _waypoint) == "HOLD"}
+};
+_statement = {
+    params ["_vehicle", "", "_value"];
+    _vehicle setVariable [QGVAR(wpFollowDistance), _value];
+    [[LLSTRING(DroneFollowHint), _value], 3] call EFUNC(common,displayTextStructured);
+};
+_action = [QGVAR(droneSetFollowDistance), LLSTRING(DroneFollowDistance), "", {}, _condition] call EFUNC(interact_menu,createAction);
+private _base = [_vehicle, 1, ["ACE_SelfActions"], _action] call EFUNC(interact_menu,addActionToObject);
+private _followDistances = if (_vehicle isKindOf "Car_F") then {
+    [0, 25, 50, 100, 200]
+} else {
+    [0, 100, 200, 300, 400, 500]
+};
+{
+    _action = [
+        QGVAR(droneSetFollowDistance_) + str _x,
+        str _x,
+        "",
+        _statement,
+        {true},
+        {},
+        _x
+    ] call EFUNC(interact_menu,createAction);
+    [_vehicle, 1, _base, _action] call EFUNC(interact_menu,addActionToObject);
+} forEach _followDistances;
 
 if (_vehicle isKindOf "Air") then {
-    // loiter at location
+    // Loiter at location
     _condition = {
         params ["_vehicle"];
         (missionNamespace getVariable [QGVAR(droneWaypoints), true]) && {waypointsEnabledUAV _vehicle} && {(ACE_controlledUAV select 2) isEqualTo [0]}
     };
-    _statement = {        
+    _statement = {
         params ["_vehicle"];
         private _group = group driver _vehicle;
         private _pos = ([_vehicle, [0]] call FUNC(droneGetTurretTargetPos)) select 0;
@@ -55,7 +104,7 @@ if (_vehicle isKindOf "Air") then {
     [_vehicle, 1, ["ACE_SelfActions"], _action] call EFUNC(interact_menu,addActionToObject);
 
 
-    // set height
+    // Set height
     _condition = {
         params ["_vehicle"];
         (missionNamespace getVariable [QGVAR(droneWaypoints), true]) && {waypointsEnabledUAV _vehicle} && {(ACE_controlledUAV select 2) isEqualTo [0]}
@@ -74,7 +123,7 @@ if (_vehicle isKindOf "Air") then {
     } forEach [20, 50, 200, 500, 2000];
 
 
-    // set loiter radius
+    // Set loiter radius
     _condition = {
         params ["_vehicle"];
         private _group = group driver _vehicle;
@@ -97,7 +146,7 @@ if (_vehicle isKindOf "Air") then {
     } forEach [500, 750, 1000, 1250, 1500];
 
 
-    // set loiter direction
+    // Set loiter direction
     _condition = {
         params ["_vehicle", "", "_args"];
         private _group = group driver _vehicle;

addons/aircraft/functions/fnc_droneSetWaypoint.sqf

@@ -8,6 +8,7 @@
  * 1: Group <GROUP>
  * 2: Pos 2D <ARRAY>
  * 3: Type <STRING>
+ * 4: Target to follow <OBJECT> (default: objNull)
  *
  * Return Value:
  * None
@@ -18,7 +19,7 @@
  * Public: No
  */
 
-params ["_vehicle", "_group", "_pos", "_type"];
+params ["_vehicle", "_group", "_pos", "_type", ["_target", objNull]];
 TRACE_4("droneSetWaypoint",_vehicle,_group,_pos,_type);
 
 private _index = (currentWaypoint _group) min count waypoints _group;
@@ -34,9 +35,34 @@ _pos set [
     [0, _currentHeight] select (_currentHeight >= 50)
 ];
 
-// [_group] call CBA_fnc_clearWaypoints;
 _waypoint = _group addWaypoint [_pos, 0];
-_waypoint setWaypointType _type;
+// The Vanilla "FOLLOW"-type waypoint is not used directly, due to 2 main issues (as of v2.16):
+// - It does not work at all for UGVs, which is a known issue https://feedback.bistudio.com/T126283;
+// - No clear scripting way was found to mimic the UAV Terminal's "Follow Distance" functionality;
+// Instead, the solution for both UAV and UGV following consists of a CBA PFH that moves a "HOLD"-type Waypoint every 3 seconds.
+// Either on the target itself, or on the Drone's current position if the target is within the desired follow distance.
+if (_type == "FOLLOW" && {["CAManBase", "LandVehicle", "Ship"] findIf {_target isKindOf _x} != -1}) then {
+    _waypoint setWaypointType "HOLD";
+    [{
+        params ["_args", "_handle"];
+        _args params ["_vehicle", "_group", "_waypoint", "_target"];
+
+        if ( // Abort PFH if a new waypoint is created via UAV Terminal or ACE Interaction
+            _waypoint select 1 != currentWaypoint _group ||
+            {!alive _vehicle} || {isNull _target}
+        ) exitWith {
+            deleteWaypoint _waypoint;
+            [_handle] call CBA_fnc_removePerFrameHandler;
+        };
+
+        private _followDistance = _vehicle getVariable [QGVAR(wpFollowDistance), 0];
+        if ((_vehicle distance2D _target) < _followDistance) then {
+            _waypoint setWaypointPosition [getPosASL _vehicle, -1];
+        } else {
+            _waypoint setWaypointPosition [getPosASL _target, -1];
+        };
+    }, 3, [_vehicle, _group, _waypoint, _target]] call CBA_fnc_addPerFrameHandler;
+};
 
 TRACE_3("",_currentHeight,_currentLoiterRadius,_currentLoiterType);
 if (_currentHeight > 1) then { _vehicle flyInHeight _currentHeight; };

addons/aircraft/stringtable.xml

@@ -177,5 +177,15 @@
             <Russian>30мм СБ 5:1</Russian>
             <Korean>30mm CM 5:1</Korean>
         </Key>
+        <Key ID="STR_ACE_Aircraft_DroneFollowDistance">
+            <English>Follow Distance</English>
+            <Italian>Distanza di seguimento</Italian>
+            <German>Folge-Entfernung</German>
+        </Key>
+        <Key ID="STR_ACE_Aircraft_DroneFollowHint">
+            <English>Following unit within %1m</English>
+            <Italian>Seguendo unità entro %1m</Italian>
+            <German>Folgt Einheit bis zu %1m</German>
+        </Key>
     </Package>
 </Project>

addons/logistics_uavbattery/functions/fnc_canRefuelUAV.sqf

@@ -18,4 +18,4 @@
 
 params ["_caller", "_target"];
 
-("ACE_UAVBattery" in (_caller call EFUNC(common,uniqueItems))) && {(fuel _target) < 1} && {(speed _target) < 1} && {!(isEngineOn _target)} && {(_target distance _caller) <= 4}
+(alive _target) && {"ACE_UAVBattery" in (_caller call EFUNC(common,uniqueItems))} && {(fuel _target) < 1} && {(speed _target) < 1} && {!(isEngineOn _target)} && {(_target distance _caller) <= 4}