moved Follow to ra

OpenRA.Mods.RA/Activities/Follow.cs

@@ -0,0 +1,57 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007,2009,2010 Chris Forbes, Robert Pepperell, Matthew Bowra-Dean, Paul Chote, Alli Witheford.
+ * This file is part of OpenRA.
+ * 
+ *  OpenRA is free software: you can redistribute it and/or modify
+ *  it 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.
+ * 
+ *  OpenRA is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ * 
+ *  You should have received a copy of the GNU General Public License
+ *  along with OpenRA.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#endregion
+
+using OpenRA.Traits;
+using OpenRA.Traits.Activities;
+
+namespace OpenRA.Mods.RA.Activities
+{
+	public class Follow : IActivity
+	{
+		Actor Target;
+		int Range;
+
+		public Follow(Actor target, int range)
+		{
+			Target = target;
+			Range = range;
+		}
+
+		public IActivity NextActivity { get; set; }
+
+		public IActivity Tick( Actor self )
+		{
+			if (Target == null || Target.IsDead)
+				return NextActivity;
+
+			var inRange = ( Target.Location - self.Location ).LengthSquared < Range * Range;
+
+			if( !inRange )
+				return new Move( Target, Range ) { NextActivity = this };
+
+			return this;
+		}
+
+		public void Cancel(Actor self)
+		{
+			Target = null;
+		}
+	}
+}