Refactor FlyAttack to make strafing runs interruptible when target be…

…comes invalid.

OpenRA.Mods.Common/Activities/Air/FlyAttack.cs

@@ -24,7 +24,6 @@ public class FlyAttack : Activity, IActivityNotifyStanceChanged
 		readonly AttackAircraft attackAircraft;
 		readonly Rearmable rearmable;
 		readonly bool forceAttack;
-		readonly int ticksUntilTurn;
 		readonly Color? targetLineColor;
 
 		Target target;
@@ -35,6 +34,7 @@ public class FlyAttack : Activity, IActivityNotifyStanceChanged
 		bool useLastVisibleTarget;
 		bool hasTicked;
 		bool returnToBase;
+		int remainingTicksUntilTurn;
 
 		public FlyAttack(Actor self, Target target, bool forceAttack, Color? targetLineColor)
 		{
@@ -45,7 +45,6 @@ public FlyAttack(Actor self, Target target, bool forceAttack, Color? targetLineC
 			aircraft = self.Trait<Aircraft>();
 			attackAircraft = self.Trait<AttackAircraft>();
 			rearmable = self.TraitOrDefault<Rearmable>();
-			ticksUntilTurn = attackAircraft.Info.AttackTurnDelay;
 
 			// The target may become hidden between the initial order request and the first tick (e.g. if queued)
 			// Moving to any position (even if quite stale) is still better than immediately giving up
@@ -132,28 +131,33 @@ public override bool Tick(Actor self)
 
 			var delta = attackAircraft.GetTargetPosition(pos, target) - pos;
 			var desiredFacing = delta.HorizontalLengthSquared != 0 ? delta.Yaw.Facing : aircraft.Facing;
-			var isAirborne = self.World.Map.DistanceAboveTerrain(pos).Length >= aircraft.Info.MinAirborneAltitude;
 
-			if (!isAirborne)
-				QueueChild(new TakeOff(self));
+			QueueChild(new TakeOff(self));
 
-			if (attackAircraft.Info.AttackType == AirAttackType.Strafe)
-			{
-				if (target.IsInRange(pos, attackAircraft.GetMinimumRange()))
-					QueueChild(new FlyTimed(ticksUntilTurn, self));
+			var minimumRange = attackAircraft.Info.AttackType == AirAttackType.Strafe ? WDist.Zero : attackAircraft.GetMinimumRangeVersusTarget(target);
 
-				QueueChild(new Fly(self, target, target.CenterPosition, Color.Red));
-				QueueChild(new FlyTimed(ticksUntilTurn, self));
+			// When strafing we must move forward for a minimum number of ticks after passing the target.
+			if (remainingTicksUntilTurn > 0)
+			{
+				Fly.FlyTick(self, aircraft, aircraft.Facing, aircraft.Info.CruiseAltitude);
+				remainingTicksUntilTurn--;
 			}
-			else
+
+			// Move into range of the target.
+			else if (!target.IsInRange(pos, lastVisibleMaximumRange) || target.IsInRange(pos, minimumRange))
+				QueueChild(aircraft.MoveWithinRange(target, minimumRange, lastVisibleMaximumRange, target.CenterPosition, Color.Red));
+
+			// The aircraft must keep moving forward even if it is already in an ideal position.
+			else if (!aircraft.Info.CanHover || attackAircraft.Info.AttackType == AirAttackType.Strafe)
 			{
-				var minimumRange = attackAircraft.GetMinimumRangeVersusTarget(target);
-				if (!target.IsInRange(pos, lastVisibleMaximumRange) || target.IsInRange(pos, minimumRange))
-					QueueChild(new Fly(self, target, minimumRange, lastVisibleMaximumRange, target.CenterPosition, Color.Red));
-				else if (isAirborne) // Don't use 'else' to avoid conflict with TakeOff
-					Fly.VerticalTakeOffOrLandTick(self, aircraft, desiredFacing, aircraft.Info.CruiseAltitude);
+				Fly.FlyTick(self, aircraft, aircraft.Facing, aircraft.Info.CruiseAltitude);
+				remainingTicksUntilTurn = attackAircraft.Info.AttackTurnDelay;
 			}
 
+			// Turn to face the target if required.
+			else if (!attackAircraft.TargetInFiringArc(self, target, attackAircraft.Info.FacingTolerance))
+				aircraft.Facing = Util.TickFacing(aircraft.Facing, desiredFacing, aircraft.TurnSpeed);
+
 			return false;
 		}
 

OpenRA.Mods.Common/Activities/Air/TakeOff.cs

@@ -39,6 +39,9 @@ protected override void OnFirstRun(Actor self)
 			if (aircraft.ForceLanding)
 				return;
 
+			if (self.World.Map.DistanceAboveTerrain(aircraft.CenterPosition).Length >= aircraft.Info.MinAirborneAltitude)
+				return;
+
 			// We are taking off, so remove reservation and influence in ground cells.
 			aircraft.UnReserve();
 			aircraft.RemoveInfluence();