Merge pull request #5851 from RoosterDragon/shroud-perf

Speed up shroud checks

OpenRA.Game/Map/CellLayer.cs

@@ -12,7 +12,6 @@ using System;
 using System.Collections;
 using System.Collections.Generic;
 using System.Drawing;
-using OpenRA.Graphics;
 
 namespace OpenRA
 {
@@ -21,7 +20,7 @@ namespace OpenRA
 	{
 		public readonly Size Size;
 		public readonly TileShape Shape;
-		T[] entries;
+		readonly T[] entries;
 
 		public CellLayer(Map map)
 			: this(map.TileShape, new Size(map.MapSize.X, map.MapSize.Y)) { }
@@ -37,35 +36,27 @@ namespace OpenRA
 		int Index(CPos cell)
 		{
 			var uv = Map.CellToMap(Shape, cell);
-			return uv.Y * Size.Width + uv.X;
+			return Index(uv.X, uv.Y);
+		}
+
+		// Resolve an array index from map coordinates
+		int Index(int u, int v)
+		{
+			return v * Size.Width + u;
 		}
 
 		/// <summary>Gets or sets the <see cref="OpenRA.CellLayer"/> using cell coordinates</summary>
 		public T this[CPos cell]
 		{
-			get
-			{
-				return entries[Index(cell)];
-			}
-
-			set
-			{
-				entries[Index(cell)] = value;
-			}
+			get { return entries[Index(cell)]; }
+			set { entries[Index(cell)] = value; }
 		}
 
 		/// <summary>Gets or sets the layer contents using raw map coordinates (not CPos!)</summary>
 		public T this[int u, int v]
 		{
-			get
-			{
-				return entries[v * Size.Width + u];
-			}
-
-			set
-			{
-				entries[v * Size.Width + u] = value;
-			}
+			get { return entries[Index(u, v)]; }
+			set { entries[Index(u, v)] = value; }
 		}
 
 		/// <summary>Clears the layer contents with a known value</summary>

OpenRA.Game/Map/CellRegion.cs

@@ -11,8 +11,7 @@
 using System;
 using System.Collections;
 using System.Collections.Generic;
-using System.Drawing;
-using OpenRA.Graphics;
+using System.Linq;
 
 namespace OpenRA
 {
@@ -50,29 +49,69 @@ namespace OpenRA
 			return new CellRegion(region.shape, tl, br);
 		}
 
+		/// <summary>Returns the minimal region that covers at least the specified cells.</summary>
+		public static CellRegion BoundingRegion(TileShape shape, IEnumerable<CPos> cells)
+		{
+			if (cells == null || !cells.Any())
+				throw new ArgumentException("cells must not be null or empty.", "cells");
+
+			var minX = int.MaxValue;
+			var minY = int.MaxValue;
+			var maxX = int.MinValue;
+			var maxY = int.MinValue;
+			foreach (var cell in cells)
+			{
+				if (minX > cell.X)
+					minX = cell.X;
+				if (maxX < cell.X)
+					maxX = cell.X;
+				if (minY > cell.Y)
+					minY = cell.Y;
+				if (maxY < cell.Y)
+					maxY = cell.Y;
+			}
+
+			return new CellRegion(shape, new CPos(minX, minY), new CPos(maxX, maxY));
+		}
+
+		public bool Contains(CellRegion region)
+		{
+			return
+				TopLeft.X <= region.TopLeft.X && TopLeft.Y <= region.TopLeft.Y &&
+				BottomRight.X >= region.BottomRight.X && BottomRight.Y >= region.BottomRight.Y;
+		}
+
 		public bool Contains(CPos cell)
 		{
 			var uv = Map.CellToMap(shape, cell);
 			return uv.X >= mapTopLeft.X && uv.X <= mapBottomRight.X && uv.Y >= mapTopLeft.Y && uv.Y <= mapBottomRight.Y;
 		}
 
-		public IEnumerator<CPos> GetEnumerator()
+		public CellRegionEnumerator GetEnumerator()
 		{
 			return new CellRegionEnumerator(this);
 		}
 
+		IEnumerator<CPos> IEnumerable<CPos>.GetEnumerator()
+		{
+			return GetEnumerator();
+		}
+
 		IEnumerator IEnumerable.GetEnumerator()
 		{
 			return GetEnumerator();
 		}
 
-		class CellRegionEnumerator : IEnumerator<CPos>
+		public class CellRegionEnumerator : IEnumerator<CPos>
 		{
 			readonly CellRegion r;
 
 			// Current position, in map coordinates
 			int u, v;
 
+			// Current position, in cell coordinates
+			CPos current;
+
 			public CellRegionEnumerator(CellRegion region)
 			{
 				r = region;
@@ -94,6 +133,7 @@ namespace OpenRA
 						return false;
 				}
 
+				current = Map.MapToCell(r.shape, new CPos(u, v));
 				return true;
 			}
 
@@ -104,7 +144,7 @@ namespace OpenRA
 				v = r.mapTopLeft.Y;
 			}
 
-			public CPos Current { get { return Map.MapToCell(r.shape, new CPos(u, v)); } }
+			public CPos Current { get { return current; } }
 			object IEnumerator.Current { get { return Current; } }
 			public void Dispose() { }
 		}