Overhaul ParatroopersPower:

- Adds support for multiple drop planes.
- Adds support a beacon and camera.
- Prevents the plane from circling if it can’t unload.

OpenRA.Mods.RA/ParaDrop.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2011 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2014 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. For more information,
@@ -8,6 +8,7 @@
  */
 #endregion
 
+using System;
 using System.Collections.Generic;
 using OpenRA.Mods.RA.Activities;
 using OpenRA.Mods.RA.Air;
@@ -16,48 +17,71 @@ using OpenRA.Traits;
 
 namespace OpenRA.Mods.RA
 {
-	public class ParaDropInfo : TraitInfo<ParaDrop>
+	public class ParaDropInfo : ITraitInfo, Requires<CargoInfo>
 	{
-		public readonly int LZRange = 4;
+		[Desc("Distance around the drop-point to unload troops")]
+		public readonly WRange DropRange = WRange.FromCells(4);
+
+		[Desc("Sound to play when dropping")]
 		public readonly string ChuteSound = "chute1.aud";
+
+		public object Create(ActorInitializer init) { return new ParaDrop(init.self, this); }
 	}
 
-	public class ParaDrop : ITick
+	public class ParaDrop : ITick, INotifyRemovedFromWorld
 	{
+		readonly ParaDropInfo info;
+		readonly Actor self;
+		readonly Cargo cargo;
+		readonly HashSet<CPos> droppedAt = new HashSet<CPos>();
+
+		public event Action<Actor> OnRemovedFromWorld = self => { };
+		public event Action<Actor> OnEnteredDropRange = self => { };
+		public event Action<Actor> OnExitedDropRange = self => { };
+
+		[Sync] bool inDropRange;
+		[Sync] Target target;
+
 		bool checkForSuitableCell;
-		readonly List<CPos> droppedAt = new List<CPos>();
-		CPos lz;
+
+		public ParaDrop(Actor self, ParaDropInfo info)
+		{
+			this.info = info;
+			this.self = self;
+			cargo = self.Trait<Cargo>();
+		}
 
 		public void SetLZ(CPos lz, bool checkLandingCell)
 		{
-			this.lz = lz;
 			droppedAt.Clear();
+			target = Target.FromCell(self.World, lz);
 			checkForSuitableCell = checkLandingCell;
 		}
 
 		public void Tick(Actor self)
 		{
-			var info = self.Info.Traits.Get<ParaDropInfo>();
-			var r = info.LZRange;
+			var wasInDropRange = inDropRange;
+			inDropRange = target.IsInRange(self.CenterPosition, info.DropRange);
 
-			if ((self.Location - lz).LengthSquared <= r * r && !droppedAt.Contains(self.Location))
-			{
-				var cargo = self.Trait<Cargo>();
-				if (cargo.IsEmpty(self))
-					FinishedDropping(self);
-				else
-				{
-					if (checkForSuitableCell && !IsSuitableCell(cargo.Peek(self), self.Location))
-						return;
+			if (inDropRange && !wasInDropRange)
+				OnEnteredDropRange(self);
 
-					// unload a dude here
-					droppedAt.Add(self.Location);
+			if (!inDropRange && wasInDropRange)
+				OnExitedDropRange(self);
 
-					var a = cargo.Unload(self);
-					self.World.AddFrameEndTask(w => w.Add(new Parachute(a, self.CenterPosition)));
-					Sound.Play(info.ChuteSound, self.CenterPosition);
-				}
-			}
+			// Are we able to drop the next trooper?
+			if (!inDropRange || cargo.IsEmpty(self))
+				return;
+
+			if (droppedAt.Contains(self.Location) || checkForSuitableCell && !IsSuitableCell(cargo.Peek(self), self.Location))
+				return;
+
+			// unload a dude here
+			droppedAt.Add(self.Location);
+
+			var a = cargo.Unload(self);
+			self.World.AddFrameEndTask(w => w.Add(new Parachute(a, self.CenterPosition)));
+			Sound.Play(info.ChuteSound, self.CenterPosition);
 		}
 
 		static bool IsSuitableCell(Actor actorToDrop, CPos p)
@@ -65,11 +89,9 @@ namespace OpenRA.Mods.RA
 			return actorToDrop.Trait<IPositionable>().CanEnterCell(p);
 		}
 
-		static void FinishedDropping(Actor self)
+		public void RemovedFromWorld(Actor self)
 		{
-			self.CancelActivity();
-			self.QueueActivity(new FlyOffMap());
-			self.QueueActivity(new RemoveSelf());
+			OnRemovedFromWorld(self);
 		}
 	}
 }