Make the legacy editor more robust against invalid templates.

OpenRA.Editor/BrushTool.cs

@@ -41,7 +41,7 @@ namespace OpenRA.Editor
 					if (surface.Map.Contains(cell))
 					{
 						var z = u + v * template.Size.X;
-						if (tile[z].Length > 0)
+						if (tile != null && tile[z].Length > 0)
 						{
 							var index = template.PickAny ? (byte)((u + pos.X) % 4 + ((v + pos.Y) % 4) * 4) : (byte)z;
 							surface.Map.MapTiles.Value[cell] = new TerrainTile(brushTemplate.N, index);

OpenRA.Editor/Surface.cs

@@ -275,6 +275,9 @@ namespace OpenRA.Editor
 						var vj = v * ChunkSize + j;
 						var tr = Map.MapTiles.Value[ui, vj];
 						var tile = TileSetRenderer.Data(tr.Type);
+						if (tile == null)
+							continue;
+
 						var index = (tr.Index < tile.Length) ? tr.Index : (byte)0;
 						var rawImage = tile[index];
 						for (var x = 0; x < TileSetRenderer.TileSize; x++)

OpenRA.Editor/TileSetRenderer.cs

@@ -104,7 +104,14 @@ namespace OpenRA.Editor
 
 		public byte[][] Data(ushort id)
 		{
-			return templates[id];
+			byte[][] template;
+			if (!templates.TryGetValue(id, out template))
+			{
+				Console.WriteLine("warning: Unknown tile template {0}", id);
+				return null;
+			}
+
+			return template;
 		}
 	}
 }