Split fixed-wing attack and strafe attack types.

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

@@ -25,6 +25,7 @@ namespace OpenRA.Mods.Common.Activities
 		readonly Rearmable rearmable;
 		readonly bool forceAttack;
 		readonly Color? targetLineColor;
+		readonly WDist strafeDistance;
 
 		Target target;
 		Target lastVisibleTarget;
@@ -45,6 +46,8 @@ namespace OpenRA.Mods.Common.Activities
 			attackAircraft = self.Trait<AttackAircraft>();
 			rearmable = self.TraitOrDefault<Rearmable>();
 
+			strafeDistance = attackAircraft.Info.StrafeRunLength;
+
 			// 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
 			if ((target.Type == TargetType.Actor && target.Actor.CanBeViewedByPlayer(self.Owner))
@@ -151,7 +154,9 @@ namespace OpenRA.Mods.Common.Activities
 				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)
+			else if (attackAircraft.Info.AttackType == AirAttackType.Strafe)
+				QueueChild(new StrafeAttackRun(self, attackAircraft, target, strafeDistance != WDist.Zero ? strafeDistance : lastVisibleMaximumRange));
+			else if (attackAircraft.Info.AttackType == AirAttackType.Default && !aircraft.Info.CanHover)
 				QueueChild(new FlyAttackRun(self, target, lastVisibleMaximumRange));
 
 			// Turn to face the target if required.
@@ -228,4 +233,41 @@ namespace OpenRA.Mods.Common.Activities
 			return false;
 		}
 	}
+
+	class StrafeAttackRun : Activity
+	{
+		Target target;
+		WDist exitRange;
+		readonly AttackAircraft attackAircraft;
+
+		public StrafeAttackRun(Actor self, AttackAircraft attackAircraft, Target t, WDist exitRange)
+		{
+			ChildHasPriority = false;
+
+			target = t;
+			this.attackAircraft = attackAircraft;
+			this.exitRange = exitRange;
+		}
+
+		protected override void OnFirstRun(Actor self)
+		{
+			QueueChild(new Fly(self, target, target.CenterPosition));
+			QueueChild(new Fly(self, target, exitRange, WDist.MaxValue, target.CenterPosition));
+		}
+
+		public override bool Tick(Actor self)
+		{
+			if (TickChild(self) || IsCanceling)
+				return true;
+
+			// Strafe attacks target the ground below the original target
+			// Update the position if we seen the target move; keep the previous one if it dies or disappears
+			bool targetIsHiddenActor;
+			target = target.Recalculate(self.Owner, out targetIsHiddenActor);
+			if (!targetIsHiddenActor && target.Type == TargetType.Actor)
+				attackAircraft.SetRequestedTarget(self, Target.FromTargetPositions(target), true);
+
+			return false;
+		}
+	}
 }

OpenRA.Mods.Common/Traits/Air/AttackAircraft.cs

@@ -17,13 +17,18 @@ using OpenRA.Traits;
 namespace OpenRA.Mods.Common.Traits
 {
 	// TODO: Add CurleyShuffle (TD, TS), Circle (Generals Gunship-style)
-	public enum AirAttackType { Hover, Strafe }
+	public enum AirAttackType { Default, Hover, Strafe }
 
 	public class AttackAircraftInfo : AttackFollowInfo, Requires<AircraftInfo>
 	{
-		[Desc("Attack behavior. Currently supported types are Strafe (default) and Hover.")]
-		public readonly AirAttackType AttackType = AirAttackType.Strafe;
+		[Desc("Attack behavior. Currently supported types are:",
+			"Default: Attack while following the default movement rules.",
+			"Hover: Hover, even if the Aircraft can't hover while idle.",
+			"Strafe: Perform a fixed-length attack run on the target.")]
+		public readonly AirAttackType AttackType = AirAttackType.Default;
 
+		[Desc("Distance the strafing aircraft makes to a target before turning for another pass. When set to WDist.Zero this defaults to the maximum armament range.")]
+		public readonly WDist StrafeRunLength = WDist.Zero;
 
 		[Desc("Does this actor cancel its attack activity when it needs to resupply? Setting this to 'false' will make the actor resume attack after reloading.")]
 		public readonly bool AbortOnResupply = true;

OpenRA.Mods.Common/UpdateRules/Rules/20191117/ReplaceAttackTypeStrafe.cs

@@ -0,0 +1,48 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+ * This file is part of OpenRA, which is free software. It is made
+ * available to you under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, either version 3 of
+ * the License, or (at your option) any later version. For more
+ * information, see COPYING.
+ */
+#endregion
+
+using System.Collections.Generic;
+using OpenRA.Mods.Common.Traits;
+
+namespace OpenRA.Mods.Common.UpdateRules.Rules
+{
+	public class ReplaceAttackTypeStrafe : UpdateRule
+	{
+		public override string Name { get { return "Replaced AttackAircraft AttackType: Strafe logic."; } }
+		public override string Description
+		{
+			get
+			{
+				return "The AttackType: Strafe behaviour on AttackAircraft has been renamed to Default,\n"
+					+ "and AttackTurnDelay has been removed. A new AttackType: Strafe has been added, with a\n"
+					+ "new StrafeRunLength parameter, designed for use with the FirstBurstTargetOffset and\n"
+					+ "FollowingBurstTargetOffset weapon parameters.";
+			}
+		}
+
+		public override IEnumerable<string> UpdateActorNode(ModData modData, MiniYamlNode actorNode)
+		{
+			var aircraft = actorNode.LastChildMatching("Aircraft");
+			if (aircraft != null)
+			{
+				var attackAircraft = actorNode.LastChildMatching("AttackAircraft");
+				if (attackAircraft == null)
+					yield break;
+
+				var attackType = attackAircraft.LastChildMatching("AttackType");
+				if (attackType.NodeValue<AirAttackType>() == AirAttackType.Strafe)
+					attackAircraft.RemoveNode(attackType);
+
+				attackAircraft.RemoveNodes("AttackTurnDelay");
+			}
+		}
+	}
+}

OpenRA.Mods.Common/UpdateRules/UpdatePath.cs

@@ -144,6 +144,7 @@ namespace OpenRA.Mods.Common.UpdateRules
 				new RemoveInitialFacingHardcoding(),
 				new RemoveAirdropActorTypeDefault(),
 				new RenameProneTime(),
+				new ReplaceAttackTypeStrafe(),
 			})
 		};
 

mods/ra/rules/aircraft.yaml

@@ -112,7 +112,6 @@ MIG:
 	AttackAircraft:
 		FacingTolerance: 20
 		PersistentTargeting: false
-		AttackTurnDelay: 30
 	Aircraft:
 		CruiseAltitude: 2560
 		InitialFacing: 192