Add CellRegion and CellLayer classes to simplify map overlays.

OpenRA.Game/Map/CellLayer.cs

@@ -0,0 +1,105 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2014 The OpenRA Developers (see AUTHORS)
+ * This file is part of OpenRA, which is free software. It is made
+ * available to you under the terms of the GNU General Public License
+ * as published by the Free Software Foundation. For more information,
+ * see COPYING.
+ */
+#endregion
+
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Drawing;
+using OpenRA.Graphics;
+
+namespace OpenRA
+{
+	// Represents a layer of "something" that covers the map
+	public class CellLayer<T> : IEnumerable<T>
+	{
+		public readonly Size Size;
+		T[] entries;
+
+		public CellLayer(Map map)
+			: this(new Size(map.MapSize.X, map.MapSize.Y)) { }
+
+		public CellLayer(Size size)
+		{
+			Size = size;
+			entries = new T[size.Width * size.Height];
+		}
+
+		// Resolve an array index from cell coordinates
+		int Index(CPos cell)
+		{
+			// This will eventually define a distinct case for diagonal cell grids
+			return cell.Y * Size.Width + cell.X;
+		}
+
+		/// <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;
+			}
+		}
+
+		/// <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;
+			}
+		}
+
+		/// <summary>Clears the layer contents with a known value</summary>
+		public void Clear(T clearValue)
+		{
+			for (var i = 0; i < entries.Length; i++)
+				entries[i] = clearValue;
+		}
+
+		public IEnumerator<T> GetEnumerator()
+		{
+			return (IEnumerator<T>)entries.GetEnumerator();
+		}
+
+		IEnumerator IEnumerable.GetEnumerator()
+		{
+			return GetEnumerator();
+		}
+	}
+
+	// Helper functions
+	public static class CellLayer
+	{
+		/// <summary>Create a new layer by resizing another layer.  New cells are filled with defaultValue.</summary>
+		public static CellLayer<T> Resize<T>(CellLayer<T> layer, Size newSize, T defaultValue)
+		{
+			var result = new CellLayer<T>(newSize);
+			var width = Math.Min(layer.Size.Width, newSize.Width);
+			var height = Math.Min(layer.Size.Height, newSize.Height);
+
+			result.Clear(defaultValue);
+			for (var j = 0; j < height; j++)
+				for (var i = 0; i < width; i++)
+					result[i, j] = layer[i, j];
+
+			return result;
+		}
+	}
+}