Initial commit: OpenRA game engine

Fork from OpenRA/OpenRA with one-click launch script (start-ra.cmd)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

OpenRA.Game/Map/ProjectedCellRegion.cs

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+#region Copyright & License Information
+/*
+ * Copyright (c) The OpenRA Developers and Contributors
+ * 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, either version 3 of
+ * the License, or (at your option) any later version. For more
+ * information, see COPYING.
+ */
+#endregion
+
+using System.Collections;
+using System.Collections.Generic;
+
+namespace OpenRA
+{
+	// Represents a (on-screen) rectangular collection of tiles.
+	// TopLeft and BottomRight are inclusive
+	public class ProjectedCellRegion : IEnumerable<PPos>
+	{
+		// Corners of the region
+		public readonly PPos TopLeft;
+		public readonly PPos BottomRight;
+
+		// Corners of the bounding map region that contains all the cells that
+		// may be projected within this region.
+		readonly MPos mapTopLeft;
+		readonly MPos mapBottomRight;
+
+		public ProjectedCellRegion(Map map, PPos topLeft, PPos bottomRight)
+		{
+			TopLeft = topLeft;
+			BottomRight = bottomRight;
+
+			// The projection from MPos -> PPos cannot produce a larger V coordinate
+			// so the top edge of the MPos region is the same as the PPos region.
+			// (in fact the cells are identical if height == 0)
+			mapTopLeft = (MPos)topLeft;
+
+			// The bottom edge is trickier: cells at MPos.V > bottomRight.V may have
+			// been projected into this region if they have height > 0.
+			// Each height step is equivalent to 512 WDist units, which is one MPos
+			// step for isometric cells, but only half a MPos step for classic cells. Doh!
+			var maxHeight = map.Grid.MaximumTerrainHeight;
+			var heightOffset = map.Grid.Type == MapGridType.RectangularIsometric ? maxHeight : maxHeight / 2;
+
+			// Use the map Height data array to clamp the bottom coordinate so it doesn't overflow the map
+			mapBottomRight = map.Height.Clamp(new MPos(bottomRight.U, bottomRight.V + heightOffset));
+		}
+
+		public bool Contains(PPos puv)
+		{
+			return puv.U >= TopLeft.U && puv.U <= BottomRight.U && puv.V >= TopLeft.V && puv.V <= BottomRight.V;
+		}
+
+		/// <summary>
+		/// The region in map coordinates that contains all the cells that
+		/// may be projected inside this region.  For increased performance,
+		/// this does not validate whether individual map cells are actually
+		/// projected inside the region.
+		/// </summary>
+		public MapCoordsRegion CandidateMapCoords => new(mapTopLeft, mapBottomRight);
+
+		public ProjectedCellRegionEnumerator GetEnumerator()
+		{
+			return new ProjectedCellRegionEnumerator(this);
+		}
+
+		IEnumerator<PPos> IEnumerable<PPos>.GetEnumerator()
+		{
+			return GetEnumerator();
+		}
+
+		IEnumerator IEnumerable.GetEnumerator()
+		{
+			return GetEnumerator();
+		}
+
+		public struct ProjectedCellRegionEnumerator : IEnumerator<PPos>
+		{
+			readonly ProjectedCellRegion r;
+
+			// Current position, in projected map coordinates
+			int u, v;
+
+			public ProjectedCellRegionEnumerator(ProjectedCellRegion region)
+				: this()
+			{
+				r = region;
+				Reset();
+				Current = new PPos(u, v);
+			}
+
+			public bool MoveNext()
+			{
+				u++;
+
+				// Check for column overflow
+				if (u > r.BottomRight.U)
+				{
+					v++;
+					u = r.TopLeft.U;
+
+					// Check for row overflow
+					if (v > r.BottomRight.V)
+						return false;
+				}
+
+				Current = new PPos(u, v);
+				return true;
+			}
+
+			public void Reset()
+			{
+				// Enumerator starts *before* the first element in the sequence.
+				u = r.TopLeft.U - 1;
+				v = r.TopLeft.V;
+			}
+
+			public PPos Current { get; private set; }
+			readonly object IEnumerator.Current => Current;
+			public readonly void Dispose() { }
+		}
+	}
+}