added AutoTarget trait

OpenRa.Game/Game.cs

@@ -239,7 +239,6 @@ namespace OpenRa.Game
 				.FirstOrDefault();
 		}
 
-
 		public static Random SharedRandom = new Random(0);		/* for things that require sync */
 		public static Random CosmeticRandom = new Random();		/* for things that are just fluff */
 

OpenRa.Game/OpenRa.Game.csproj

@@ -157,6 +157,7 @@
     <Compile Include="Traits\Activities\Turn.cs" />
     <Compile Include="Traits\AttackBase.cs" />
     <Compile Include="Traits\AttackTurreted.cs" />
+    <Compile Include="Traits\AutoTarget.cs" />
     <Compile Include="Traits\Building.cs" />
     <Compile Include="Traits\Harvester.cs" />
     <Compile Include="Traits\Helicopter.cs" />

OpenRa.Game/Traits/AutoTarget.cs

@@ -0,0 +1,30 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace OpenRa.Game.Traits
+{
+	class AutoTarget : ITick
+	{
+		public AutoTarget(Actor self) {}
+
+		public void Tick(Actor self)
+		{
+			var attack = self.traits.WithInterface<AttackBase>().First();
+			
+			if (attack.target == null)
+				attack.target = ChooseTarget(self, 
+					Rules.WeaponInfo[self.Info.Primary].Range);
+		}
+
+		Actor ChooseTarget(Actor self, float range)
+		{
+			var inRange = Game.FindUnitsInCircle(self.CenterLocation, Game.CellSize * range);
+
+			return inRange.Where(a => a.Owner != self.Owner)	/* todo: one day deal with friendly players */
+				.OrderBy(a => (a.Location - self.Location).LengthSquared)
+				.FirstOrDefault();
+		}
+	}
+}

units.ini

@@ -278,7 +278,7 @@ Footprint=_ x
 SelectionPriority=3
 [GUN]
 Description=Turret
-Traits=Building, Turreted, RenderBuildingTurreted, AttackTurreted
+Traits=Building, Turreted, RenderBuildingTurreted, AttackTurreted, AutoTarget
 Dimensions=1,1
 Footprint=x
 SelectionPriority=3