Add CellRegion and CellLayer classes to simplify map overlays.

OpenRA.Game/Map/CellRegion.cs

@@ -0,0 +1,101 @@
+#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 (on-screen) rectangular collection of tiles.
+	// TopLeft and BottomRight are inclusive
+	public class CellRegion : IEnumerable<CPos>
+	{
+		// Corners of the region
+		public readonly CPos TopLeft;
+		public readonly CPos BottomRight;
+
+		// Corners in map coordinates
+		// Defined for forward compatibility with diagonal cell grids
+		readonly CPos mapTopLeft;
+		readonly CPos mapBottomRight;
+
+		public CellRegion(CPos topLeft, CPos bottomRight)
+		{
+			TopLeft = topLeft;
+			BottomRight = bottomRight;
+
+			mapTopLeft = TopLeft;
+			mapBottomRight = BottomRight;
+		}
+
+		public bool Contains(CPos cell)
+		{
+			// Defined for forward compatibility with diagonal cell grids
+			var uv = cell;
+			return uv.X >= mapTopLeft.X && uv.X <= mapBottomRight.X && uv.Y >= mapTopLeft.Y && uv.Y <= mapBottomRight.Y;
+		}
+
+		public IEnumerator<CPos> GetEnumerator()
+		{
+			return new CellRegionEnumerator(this);
+		}
+
+		IEnumerator IEnumerable.GetEnumerator()
+		{
+			return GetEnumerator();
+		}
+
+		class CellRegionEnumerator : IEnumerator<CPos>
+		{
+			readonly CellRegion r;
+
+			// Current position, in map coordinates
+			int u, v;
+
+			public CellRegionEnumerator(CellRegion region)
+			{
+				r = region;
+				Reset();
+			}
+
+			public bool MoveNext()
+			{
+				u += 1;
+
+				// Check for column overflow
+				if (u > r.mapBottomRight.X)
+				{
+					v += 1;
+					u = r.mapTopLeft.X;
+
+					// Check for row overflow
+					if (v > r.mapBottomRight.Y)
+						return false;
+				}
+
+				return true;
+			}
+
+			public void Reset()
+			{
+				// Enumerator starts *before* the first element in the sequence.
+				u = r.mapTopLeft.X - 1;
+				v = r.mapTopLeft.Y;
+			}
+
+			public CPos Current { get { return new CPos(u, v); } }
+			object IEnumerator.Current { get { return Current; } }
+			public void Dispose() { }
+		}
+	}
+}