Add WVec.HorizontalLengthSquared to simplify range checks.

OpenRA.FileFormats/WVec.cs

@@ -38,6 +38,7 @@ namespace OpenRA
 		public static int Dot(WVec a, WVec b) { return a.X * b.X + a.Y * b.Y + a.Z * b.Z; }
 		public long LengthSquared { get { return (long)X * X + (long)Y * Y + (long)Z * Z; } }
 		public int Length { get { return (int)Math.Sqrt(LengthSquared); } }
+		public long HorizontalLengthSquared { get { return (long)X * X + (long)Y * Y; } }
 
 		public WVec Rotate(WRot rot)
 		{

OpenRA.Game/Traits/Target.cs

@@ -91,12 +91,7 @@ namespace OpenRA.Traits
 
 			// Target ranges are calculated in 2D, so ignore height differences
 			var rangeSquared = range.Range*range.Range;
-			return Positions.Any(t =>
-			{
-				var dx = (long)(t.X - origin.X);
-				var dy = (long)(t.Y - origin.Y);
-				return dx*dx + dy*dy <= rangeSquared;
-			});
+			return Positions.Any(t => (t - origin).HorizontalLengthSquared <= rangeSquared);
 		}
 
 	}

OpenRA.Mods.RA/Air/Land.cs

@@ -25,13 +25,19 @@ namespace OpenRA.Mods.RA.Air
 			if (!Target.IsValid)
 				Cancel(self);
 
-			if (IsCanceled) return NextActivity;
-
-			var d = Target.CenterPosition - self.CenterPosition;
-			if (d.LengthSquared < 256*256) // close enough (1/4 cell)
+			if (IsCanceled)
 				return NextActivity;
 
 			var aircraft = self.Trait<Aircraft>();
+			var d = Target.CenterPosition - self.CenterPosition;
+
+			// close enough (1/16 cell)
+			// TODO: TickMove may overshoot if the aircraft speed is too high
+			if (d.HorizontalLengthSquared < 4096)
+			{
+				aircraft.SetPxPosition(self, PPos.FromWPos(Target.CenterPosition));
+				return NextActivity;
+			}
 
 			if (aircraft.Altitude > 0)
 				--aircraft.Altitude;