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.Mods.Common/Pathfinder/SparsePathGraph.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;
+using System.Collections.Generic;
+
+namespace OpenRA.Mods.Common.Pathfinder
+{
+	/// <summary>
+	/// A sparse pathfinding graph that supports a search over provided cells.
+	/// This is a classic graph that supports an arbitrary graph of nodes and edges,
+	/// and does not require a dense grid of cells.
+	/// Costs and any desired connections to a <see cref="Traits.ICustomMovementLayer"/>
+	/// must be provided as input.
+	/// </summary>
+	sealed class SparsePathGraph : IPathGraph
+	{
+		readonly Func<CPos, List<GraphConnection>> edges;
+		readonly Dictionary<CPos, CellInfo> info;
+
+		public SparsePathGraph(Func<CPos, List<GraphConnection>> edges, int estimatedSearchSize = 0)
+		{
+			this.edges = edges;
+			info = new Dictionary<CPos, CellInfo>(estimatedSearchSize);
+		}
+
+		public List<GraphConnection> GetConnections(CPos position, Func<CPos, bool> targetPredicate)
+		{
+			return edges(position) ?? [];
+		}
+
+		public CellInfo this[CPos pos]
+		{
+			get
+			{
+				if (info.TryGetValue(pos, out var cellInfo))
+					return cellInfo;
+				return default;
+			}
+			set => info[pos] = value;
+		}
+
+		public void Dispose() { }
+	}
+}