Actors will lose targets and AI won't follow indefinitely

OpenRA.Mods.Common/AI/HackyAI.cs

@@ -664,7 +664,7 @@ namespace OpenRA.Mods.Common.AI
 			if (protectSq == null)
 				protectSq = RegisterNewSquad(SquadType.Protection, attacker);
 
-			if (!protectSq.TargetIsValid)
+			if (!protectSq.IsTargetValid)
 				protectSq.TargetActor = attacker;
 
 			if (!protectSq.IsValid)

OpenRA.Mods.Common/AI/Squad.cs

@@ -72,11 +72,16 @@ namespace OpenRA.Mods.Common.AI
 			set { Target = Target.FromActor(value); }
 		}
 
-		public bool TargetIsValid
+		public bool IsTargetValid
 		{
 			get { return Target.IsValidFor(Units.FirstOrDefault()) && !Target.Actor.HasTrait<Husk>(); }
 		}
 
+		public bool IsTargetVisible
+		{
+			get { return Bot.Player.PlayerActor.Owner.CanTargetActor(TargetActor); }
+		}
+
 		public WPos CenterPosition { get { return Units.Select(u => u.CenterPosition).Average(); } }
 	}
 }

OpenRA.Mods.Common/AI/States/AirStates.cs

@@ -185,7 +185,7 @@ namespace OpenRA.Mods.Common.AI
 			if (!owner.IsValid)
 				return;
 
-			if (!owner.TargetIsValid)
+			if (!owner.IsTargetValid)
 			{
 				var a = owner.Units.Random(owner.Random);
 				var closestEnemy = owner.Bot.FindClosestEnemy(a.CenterPosition);

OpenRA.Mods.Common/AI/States/GroundStates.cs

@@ -30,7 +30,7 @@ namespace OpenRA.Mods.Common.AI
 			if (!owner.IsValid)
 				return;
 
-			if (!owner.TargetIsValid)
+			if (!owner.IsTargetValid)
 			{
 				var t = owner.Bot.FindClosestEnemy(owner.Units.FirstOrDefault().CenterPosition);
 				if (t == null) return;
@@ -68,7 +68,7 @@ namespace OpenRA.Mods.Common.AI
 			if (!owner.IsValid)
 				return;
 
-			if (!owner.TargetIsValid)
+			if (!owner.IsTargetValid)
 			{
 				var closestEnemy = owner.Bot.FindClosestEnemy(owner.Units.Random(owner.Random).CenterPosition);
 				if (closestEnemy != null)
@@ -127,7 +127,7 @@ namespace OpenRA.Mods.Common.AI
 			if (!owner.IsValid)
 				return;
 
-			if (!owner.TargetIsValid)
+			if (!owner.IsTargetValid)
 			{
 				var closestEnemy = owner.Bot.FindClosestEnemy(owner.Units.Random(owner.Random).CenterPosition);
 				if (closestEnemy != null)

OpenRA.Mods.Common/AI/States/ProtectionStates.cs

@@ -19,6 +19,9 @@ namespace OpenRA.Mods.Common.AI
 
 	class UnitsForProtectionAttackState : GroundStateBase, IState
 	{
+		public const int BackoffTicks = 4;
+		internal int Backoff = BackoffTicks;
+
 		public void Activate(Squad owner) { }
 
 		public void Tick(Squad owner)
@@ -26,7 +29,7 @@ namespace OpenRA.Mods.Common.AI
 			if (!owner.IsValid)
 				return;
 
-			if (!owner.TargetIsValid)
+			if (!owner.IsTargetValid)
 			{
 				owner.TargetActor = owner.Bot.FindClosestEnemy(owner.CenterPosition, WRange.FromCells(8));
 
@@ -37,8 +40,22 @@ namespace OpenRA.Mods.Common.AI
 				}
 			}
 
-			foreach (var a in owner.Units)
+			if (!owner.IsTargetVisible)
-				owner.World.IssueOrder(new Order("AttackMove", a, false) { TargetLocation = owner.TargetActor.Location });
+			{
+				if (Backoff < 0)
+				{
+					owner.FuzzyStateMachine.ChangeState(owner, new UnitsForProtectionFleeState(), true);
+					Backoff = BackoffTicks;
+					return;
+				}
+
+				Backoff--;
+			}
+			else
+			{
+				foreach (var a in owner.Units)
+					owner.World.IssueOrder(new Order("AttackMove", a, false) { TargetLocation = owner.TargetActor.Location });
+			}
 		}
 
 		public void Deactivate(Squad owner) { }

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

@@ -22,6 +22,7 @@ namespace OpenRA.Mods.Common.Activities
 		readonly Target target;
 		readonly AttackPlane attackPlane;
 		readonly AmmoPool[] ammoPools;
+
 		Activity inner;
 		int ticksUntilTurn;
 

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

@@ -8,8 +8,8 @@
  */
 #endregion
 
-using System;
 using System.Collections.Generic;
+using System.Drawing;
 using System.Linq;
 using OpenRA.Activities;
 using OpenRA.Mods.Common.Traits;
@@ -19,17 +19,35 @@ namespace OpenRA.Mods.Common.Activities
 {
 	public class HeliAttack : Activity
 	{
-		readonly Target target;
 		readonly Helicopter helicopter;
 		readonly AttackHeli attackHeli;
 		readonly AmmoPool[] ammoPools;
+		readonly bool attackOnlyVisibleTargets;
 
-		public HeliAttack(Actor self, Target target)
+		Target target;
+		bool canHideUnderFog;
+		protected Target Target
 		{
-			this.target = target;
+			get
+			{
+				return target;
+			}
+
+			private set
+			{
+				target = value;
+				if (target.Type == TargetType.Actor)
+					canHideUnderFog = target.Actor.HasTrait<HiddenUnderFog>();
+			}
+		}
+
+		public HeliAttack(Actor self, Target target, bool attackOnlyVisibleTargets = true)
+		{
+			Target = target;
 			helicopter = self.Trait<Helicopter>();
 			attackHeli = self.Trait<AttackHeli>();
 			ammoPools = self.TraitsImplementing<AmmoPool>().ToArray();
+			this.attackOnlyVisibleTargets = attackOnlyVisibleTargets;
 		}
 
 		public override Activity Tick(Actor self)
@@ -37,6 +55,16 @@ namespace OpenRA.Mods.Common.Activities
 			if (IsCanceled || !target.IsValidFor(self))
 				return NextActivity;
 
+			if (attackOnlyVisibleTargets && target.Type == TargetType.Actor && canHideUnderFog
+				&& !self.Owner.CanTargetActor(target.Actor))
+			{
+				var newTarget = Target.FromCell(self.World, self.World.Map.CellContaining(target.CenterPosition));
+
+				self.CancelActivity();
+				self.SetTargetLine(newTarget, Color.Green);
+				return Util.SequenceActivities(new HeliFly(self, newTarget));
+			}
+
 			// If all ammo pools are depleted and none reload automatically, return to helipad to reload and then move to next activity
 			// TODO: This should check whether there is ammo left that is actually suitable for the target
 			if (ammoPools.All(x => !x.Info.SelfReloads && !x.HasAmmo()))

OpenRA.Mods.Common/Activities/Move/MoveAdjacentTo.cs

@@ -10,6 +10,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Drawing;
 using System.Linq;
 using OpenRA.Activities;
 using OpenRA.Mods.Common.Pathfinder;
@@ -27,7 +28,23 @@ namespace OpenRA.Mods.Common.Activities
 		readonly DomainIndex domainIndex;
 		readonly uint movementClass;
 
-		protected Target Target { get; private set; }
+		Target target;
+		bool canHideUnderFog;
+		protected Target Target
+		{
+			get
+			{
+				return target;
+			}
+
+			private set
+			{
+				target = value;
+				if (target.Type == TargetType.Actor)
+					canHideUnderFog = target.Actor.HasTrait<HiddenUnderFog>();
+			}
+		}
+
 		protected CPos targetPosition;
 		Activity inner;
 		bool repath;
@@ -66,6 +83,17 @@ namespace OpenRA.Mods.Common.Activities
 		{
 			var targetIsValid = Target.IsValidFor(self);
 
+			// Target moved under the fog. Move to its last known position.
+			if (Target.Type == TargetType.Actor && canHideUnderFog
+				&& !self.Owner.CanTargetActor(Target.Actor))
+			{
+				if (inner != null)
+					inner.Cancel(self);
+
+				self.SetTargetLine(Target.FromCell(self.World, targetPosition), Color.Green);
+				return Util.RunActivity(self, new AttackMoveActivity(self, mobile.MoveTo(targetPosition, 0)));
+			}
+
 			// Inner move order has completed.
 			if (inner == null)
 			{