wired up so it actually works

OpenRa.Game/Traits/AttackHeli.cs

@@ -0,0 +1,35 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using OpenRa.Game.Traits.Activities;
+
+namespace OpenRa.Game.Traits
+{
+	class AttackHeli : AttackBase
+	{
+		public AttackHeli(Actor self) : base(self) { }
+
+		const int facingTolerance = 20;
+		public override void Tick(Actor self)
+		{
+			base.Tick(self);
+
+			if (target == null) return;
+
+			var unit = self.traits.Get<Unit>();
+			var facingToTarget = Util.GetFacing(target.CenterLocation - self.CenterLocation, unit.Facing);
+
+			if (Math.Abs(facingToTarget - unit.Facing) % 256 < facingTolerance)
+				DoAttack(self);
+		}
+
+		protected override void QueueAttack(Actor self, Order order)
+		{
+			self.CancelActivity();
+			self.QueueActivity(new HeliAttack(order.TargetActor));
+			target = order.TargetActor;
+			// todo: fly home
+		}
+	}
+}