Refactor Leap attack logic

OpenRA.Mods.Cnc/Activities/LeapAttack.cs

@@ -0,0 +1,104 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2018 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;
+using System.Linq;
+using OpenRA.Activities;
+using OpenRA.Mods.Cnc.Traits;
+using OpenRA.Mods.Common.Activities;
+using OpenRA.Mods.Common.Traits;
+using OpenRA.Traits;
+
+namespace OpenRA.Mods.Cnc.Activities
+{
+	public class LeapAttack : Activity
+	{
+		readonly Target target;
+		readonly AttackLeapInfo info;
+		readonly AttackLeap attack;
+		readonly Mobile mobile, targetMobile;
+		readonly EdibleByLeap edible;
+		readonly bool allowMovement;
+		readonly IFacing facing;
+
+		public LeapAttack(Actor self, Target target, bool allowMovement, AttackLeap attack, AttackLeapInfo info)
+		{
+			this.target = target;
+			this.info = info;
+			this.attack = attack;
+			this.allowMovement = allowMovement;
+
+			mobile = self.Trait<Mobile>();
+			facing = self.TraitOrDefault<IFacing>();
+
+			if (target.Type == TargetType.Actor)
+			{
+				targetMobile = target.Actor.TraitOrDefault<Mobile>();
+				edible = target.Actor.TraitOrDefault<EdibleByLeap>();
+			}
+
+			attack.IsAiming = true;
+		}
+
+		public override Activity Tick(Actor self)
+		{
+			if (IsCanceled || edible == null)
+				return NextActivity;
+
+			// Run this even if the target became invalid to avoid visual glitches
+			if (ChildActivity != null)
+			{
+				ChildActivity = ActivityUtils.RunActivity(self, ChildActivity);
+				return this;
+			}
+
+			if (target.Type != TargetType.Actor || !edible.CanLeap(self) || !target.IsValidFor(self) || !attack.HasAnyValidWeapons(target))
+				return NextActivity;
+
+			var minRange = attack.GetMinimumRangeVersusTarget(target);
+			var maxRange = attack.GetMaximumRangeVersusTarget(target);
+			if (!target.IsInRange(self.CenterPosition, maxRange) || target.IsInRange(self.CenterPosition, minRange))
+			{
+				if (!allowMovement)
+					return NextActivity;
+
+				QueueChild(new MoveWithinRange(self, target, minRange, maxRange));
+				return this;
+			}
+
+			if (attack.Armaments.All(a => a.IsReloading))
+				return this;
+
+			// Use CenterOfSubCell with ToSubCell instead of target.Centerposition
+			// to avoid continuous facing adjustments as the target moves
+			var targetSubcell = targetMobile != null ? targetMobile.ToSubCell : SubCell.Any;
+			var destination = self.World.Map.CenterOfSubCell(target.Actor.Location, targetSubcell);
+			var origin = self.World.Map.CenterOfSubCell(self.Location, mobile.FromSubCell);
+			var desiredFacing = (destination - origin).Yaw.Facing;
+			if (facing != null && facing.Facing != desiredFacing)
+			{
+				QueueChild(new Turn(self, desiredFacing));
+				return this;
+			}
+
+			QueueChild(new Leap(self, target, mobile, targetMobile, info.Speed.Length, attack, edible));
+
+			// Re-queue the child activities to kill the target if it didn't die in one go
+			return this;
+		}
+
+		protected override void OnLastRun(Actor self)
+		{
+			attack.IsAiming = false;
+			base.OnLastRun(self);
+		}
+	}
+}