pool CellInfo[,] to save massive amounts of memory (now uses only 512K for CellInfos on default-sized maps)

OpenRA.Mods.RA/Move/PathFinder.cs

@@ -87,9 +87,10 @@ namespace OpenRA.Mods.RA.Move
 		{
 			using (new PerfSample("Pathfinder"))
 			{
+				using(search)
 					while (!search.queue.Empty)
 					{
-					var p = search.Expand( world );
+						var p = search.Expand(world);
 						if (search.heuristic(p) == 0)
 							return MakePath(search.cellInfo, p);
 					}
@@ -123,16 +124,18 @@ namespace OpenRA.Mods.RA.Move
 		{
 			using (new PerfSample("Pathfinder"))
 			{
+				using (fromSrc)
+				using (fromDest)
 					while (!fromSrc.queue.Empty && !fromDest.queue.Empty)
 					{
 						/* make some progress on the first search */
-					var p = fromSrc.Expand( world );
+						var p = fromSrc.Expand(world);
 
 						if (fromDest.cellInfo[p.X, p.Y].Seen && fromDest.cellInfo[p.X, p.Y].MinCost < float.PositiveInfinity)
 							return MakeBidiPath(fromSrc, fromDest, p);
 
 						/* make some progress on the second search */
-					var q = fromDest.Expand( world );
+						var q = fromDest.Expand(world);
 
 						if (fromSrc.cellInfo[q.X, q.Y].Seen && fromSrc.cellInfo[q.X, q.Y].MinCost < float.PositiveInfinity)
 							return MakeBidiPath(fromSrc, fromDest, q);

OpenRA.Mods.RA/Move/PathSearch.cs

@@ -15,7 +15,7 @@ using OpenRA.Traits;
 
 namespace OpenRA.Mods.RA.Move
 {
-	public class PathSearch
+	public class PathSearch : IDisposable
 	{
 		World world;
 		public CellInfo[ , ] cellInfo;
@@ -193,13 +193,45 @@ namespace OpenRA.Mods.RA.Move
 			return search;
 		}
 
+		static readonly Queue<CellInfo[,]> cellInfoPool = new Queue<CellInfo[,]>();
+
+		static CellInfo[,] GetFromPool()
+		{
+			lock (cellInfoPool)
+				return cellInfoPool.Dequeue();
+		}
+
+		static void PutBackIntoPool(CellInfo[,] ci)
+		{
+			lock (cellInfoPool)
+				cellInfoPool.Enqueue(ci);
+		}
+
 		CellInfo[ , ] InitCellInfo()
 		{
-			var cellInfo = new CellInfo[ world.Map.MapSize.X, world.Map.MapSize.Y ];
+			CellInfo[,] result = null;
+			while (cellInfoPool.Count > 0)
+			{
+				var cellInfo = GetFromPool();
+				if (cellInfo.GetUpperBound(0) != world.Map.MapSize.X - 1 ||
+					cellInfo.GetUpperBound(1) != world.Map.MapSize.Y - 1)
+				{
+					Game.Debug("Discarding old pooled CellInfo of wrong size.");
+					continue;
+				}
+
+				result = cellInfo;
+				break;
+			}
+
+			if (result == null)
+				result  = new CellInfo[ world.Map.MapSize.X, world.Map.MapSize.Y ];
+
 			for( int x = 0 ; x < world.Map.MapSize.X ; x++ )
 				for( int y = 0 ; y < world.Map.MapSize.Y ; y++ )
-					cellInfo[ x, y ] = new CellInfo( int.MaxValue, new int2( x, y ), false );
-			return cellInfo;
+					result[ x, y ] = new CellInfo( int.MaxValue, new int2( x, y ), false );
+
+			return result;
 		}
 
 		public static Func<int2, int> DefaultEstimator( int2 destination )
@@ -212,5 +244,19 @@ namespace OpenRA.Mods.RA.Move
 				return (3400 * diag / 24) + (100 * straight);
 			};
 		}
+
+		bool disposed;
+		public void Dispose()
+		{
+			if (disposed)
+				return;
+
+			disposed = true;
+			GC.SuppressFinalize(this);
+			PutBackIntoPool(cellInfo);
+			cellInfo = null;
+		}
+
+		~PathSearch() { Dispose(); }
 	}
 }