Add a SubCell field to UIM. Allow UIM to query for units by subcell.

OpenRA.Game/Traits/TraitsInterfaces.cs

@@ -81,11 +81,21 @@ namespace OpenRA.Traits
 	{
 		int2 PxPosition { get; }
 	}
+	
+	public enum SubCell
+	{
+		FullCell,
+		TopLeft,
+		TopRight,
+		Center,
+		BottomLeft,
+		BottomRight
+	}
 
 	public interface IOccupySpace : IHasLocation
 	{
 		int2 TopLeft { get; }
-		IEnumerable<int2> OccupiedCells();
+		IEnumerable<Pair<int2, SubCell>> OccupiedCells();
 	}
 	
 	public static class IOccupySpaceExts
@@ -96,10 +106,10 @@ namespace OpenRA.Traits
 			var nearestDistance = int.MaxValue;
 			foreach( var cell in ios.OccupiedCells() )
 			{
-				var dist = ( other - cell ).LengthSquared;
+				var dist = ( other - cell.First ).LengthSquared;
 				if( dist < nearestDistance )
 				{
-					nearest = cell;
+					nearest = cell.First;
 					nearestDistance = dist;
 				}
 			}

OpenRA.Game/Traits/World/Shroud.cs

@@ -136,7 +136,7 @@ namespace OpenRA.Traits
 			if (ios != null)
 			{
 				var cells = ios.OccupiedCells();
-				if (cells.Any()) return cells;
+				if (cells.Any()) return cells.Select(c => c.First);
 			}
 
 			return new[] { a.CenterLocation / Game.CellSize };

OpenRA.Game/Traits/World/UnitInfluence.cs

@@ -26,9 +26,10 @@ namespace OpenRA.Traits
 		class InfluenceNode
 		{
 			public InfluenceNode next;
+			public SubCell subCell;
 			public Actor actor;
 		}
-
+	
 		InfluenceNode[,] influence;
 		Map map;
 
@@ -51,21 +52,32 @@ namespace OpenRA.Traits
 
 		public bool AnyUnitsAt(int2 a)
 		{
-			return /*map.IsInMap(a) && */influence[ a.X, a.Y ] != null;
+			return influence[ a.X, a.Y ] != null;
+		}
+		
+		public bool AnyUnitsAt(int2 a, SubCell sub)
+		{		
+			var node = influence[ a.X, a.Y ];
+			while (node != null)
+			{
+				if (node.subCell == sub) return true;
+				node = node.next;
+			}
+			return false;
 		}
 
 		public void Add( Actor self, IOccupySpace unit )
 		{
 			if (unit != null)
 				foreach( var c in unit.OccupiedCells() )
-					influence[ c.X, c.Y ] = new InfluenceNode { next = influence[ c.X, c.Y ], actor = self };
+					influence[ c.First.X, c.First.Y ] = new InfluenceNode { next = influence[ c.First.X, c.First.Y ], subCell = c.Second, actor = self };
 		}
 
 		public void Remove( Actor self, IOccupySpace unit )
 		{
 			if (unit != null)
 				foreach (var c in unit.OccupiedCells())
-					RemoveInner( ref influence[ c.X, c.Y ], self );
+					RemoveInner( ref influence[ c.First.X, c.First.Y ], self );
 		}
 
 		void RemoveInner( ref InfluenceNode influenceNode, Actor toRemove )