reinstate range circles; IRenderSelection allows arb. plugging in of these things

OpenRA.Mods.RA/DetectCloaked.cs

@@ -0,0 +1,47 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2010 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,
+ * see LICENSE.
+ */
+#endregion
+
+using System.Linq;
+using OpenRA.Traits;
+
+namespace OpenRA.Mods.RA
+{
+	class DetectCloakedInfo : TraitInfo<DetectCloaked>
+	{
+		public readonly int Interval = 12;		// ~.5s
+		public readonly float DecloakTime = 2f;	// 2s
+		public readonly int Range = 5;
+		public readonly bool AffectOwnUnits = true;
+	}
+
+	class DetectCloaked : ITick
+	{
+		[Sync]
+		int ticks;
+
+		public void Tick(Actor self)
+		{
+			if (--ticks <= 0)
+			{
+				var info = self.Info.Traits.Get<DetectCloakedInfo>();
+				ticks = info.Interval;
+
+				var toDecloak = self.World.FindUnitsInCircle(self.CenterLocation, info.Range * Game.CellSize)
+					.Where(a => a.traits.Contains<Cloak>());
+
+				if (!info.AffectOwnUnits)
+					toDecloak = toDecloak.Where(a => self.Owner.Stances[a.Owner] != Stance.Ally);
+
+				foreach (var a in toDecloak)
+					a.traits.Get<Cloak>().Decloak((int)(25 * info.DecloakTime));
+			}
+		}
+	}
+}