add CashTrickler trait, to support oil derricks, etc

OpenRA.Mods.RA/CashTrickler.cs

@@ -0,0 +1,36 @@
+#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 OpenRA.Traits;
+
+namespace OpenRA.Mods.RA
+{
+	class CashTricklerInfo : TraitInfo<CashTrickler>
+	{
+		public readonly int Period = 10;
+		public readonly int Amount = 3;
+	}
+
+	class CashTrickler : ITick
+	{
+		[Sync]
+		int ticks;
+
+		public void Tick(Actor self)
+		{
+			if (--ticks < 0)
+			{
+				var info = self.Info.Traits.Get<CashTricklerInfo>();
+				self.Owner.PlayerActor.Trait<PlayerResources>().GiveCash(info.Amount);
+				ticks = info.Period;
+			}
+		}
+	}
+}