From f01f8d92b3ccc8f556ad5c6fe69ea3c5b3d7b107 Mon Sep 17 00:00:00 2001
From: RoosterDragon <roosterdragon@outlook.com>
Date: Tue, 9 Dec 2014 23:00:48 +0000
Subject: [PATCH] Cache the initial path layer for faster path search startups.

Reinitializing the initial cell info layer for the path search took a fair bit of time. We cache this initial setup so it only has to be done each time the map size changes. A CopyValuesFrom method in CellLayer is provided which copies values between layers by just copying the internal arrays for super speed.

This speeds up InitCellInfo 10x.
---
 OpenRA.Game/Map/CellLayer.cs      | 11 +++++++++++
 OpenRA.Mods.RA/Move/PathSearch.cs | 25 ++++++++++++++++++++-----
 2 files changed, 31 insertions(+), 5 deletions(-)

diff --git a/OpenRA.Game/Map/CellLayer.cs b/OpenRA.Game/Map/CellLayer.cs
index a78d803455..4ff0287aa2 100644
--- a/OpenRA.Game/Map/CellLayer.cs
+++ b/OpenRA.Game/Map/CellLayer.cs
@@ -34,6 +34,17 @@ namespace OpenRA
 			entries = new T[size.Width * size.Height];
 		}
 
+		public void CopyValuesFrom(CellLayer<T> anotherLayer)
+		{
+			if (Size != anotherLayer.Size || Shape != anotherLayer.Shape)
+				throw new ArgumentException(
+					"layers must have a matching size and shape.", "anotherLayer");
+			if (CellEntryChanged != null)
+				throw new InvalidOperationException(
+					"Cannot copy values when there are listeners attached to the CellEntryChanged event.");
+			Array.Copy(anotherLayer.entries, entries, entries.Length);
+		}
+
 		// Resolve an array index from cell coordinates
 		int Index(CPos cell)
 		{
diff --git a/OpenRA.Mods.RA/Move/PathSearch.cs b/OpenRA.Mods.RA/Move/PathSearch.cs
index f8fe07beaa..46e04bb103 100755
--- a/OpenRA.Mods.RA/Move/PathSearch.cs
+++ b/OpenRA.Mods.RA/Move/PathSearch.cs
@@ -285,6 +285,8 @@ namespace OpenRA.Mods.RA.Move
 		}
 
 		static readonly Queue<CellLayer<CellInfo>> CellInfoPool = new Queue<CellLayer<CellInfo>>();
+		static readonly object defaultCellInfoLayerSync = new object();
+		static CellLayer<CellInfo> defaultCellInfoLayer;
 
 		static CellLayer<CellInfo> GetFromPool()
 		{
@@ -301,7 +303,8 @@ namespace OpenRA.Mods.RA.Move
 		CellLayer<CellInfo> InitCellInfo()
 		{
 			CellLayer<CellInfo> result = null;
-			var mapSize = new Size(self.World.Map.MapSize.X, self.World.Map.MapSize.Y);
+			var map = self.World.Map;
+			var mapSize = new Size(map.MapSize.X, map.MapSize.Y);
 
 			// HACK: Uses a static cache so that double-ended searches (which have two PathSearch instances)
 			// can implicitly share data.  The PathFinder should allocate the CellInfo array and pass it
@@ -309,7 +312,7 @@ namespace OpenRA.Mods.RA.Move
 			while (CellInfoPool.Count > 0)
 			{
 				var cellInfo = GetFromPool();
-				if (cellInfo.Size != mapSize || cellInfo.Shape != self.World.Map.TileShape)
+				if (cellInfo.Size != mapSize || cellInfo.Shape != map.TileShape)
 				{
 					Log.Write("debug", "Discarding old pooled CellInfo of wrong size.");
 					continue;
@@ -320,10 +323,22 @@ namespace OpenRA.Mods.RA.Move
 			}
 
 			if (result == null)
-				result = new CellLayer<CellInfo>(self.World.Map);
+				result = new CellLayer<CellInfo>(map);
+
+			lock (defaultCellInfoLayerSync)
+			{
+				if (defaultCellInfoLayer == null ||
+					defaultCellInfoLayer.Size != mapSize ||
+					defaultCellInfoLayer.Shape != map.TileShape)
+				{
+					defaultCellInfoLayer = new CellLayer<CellInfo>(map);
+					foreach (var cell in map.Cells)
+						defaultCellInfoLayer[cell] = new CellInfo(int.MaxValue, cell, false);
+				}
+
+				result.CopyValuesFrom(defaultCellInfoLayer);
+			}
 
-			foreach (var cell in self.World.Map.Cells)
-				result[cell] = new CellInfo(int.MaxValue, cell, false);
 
 			return result;
 		}