From c02846e2cb5da4b3d1b8955f6b776c5b37766f03 Mon Sep 17 00:00:00 2001
From: Paul Chote <pchote@users.noreply.github.com>
Date: Mon, 14 Dec 2020 17:52:57 +0000
Subject: [PATCH] Replace invalid tiles on map load.

---
 OpenRA.Game/Map/Map.cs     | 16 ++++++++++------
 OpenRA.Game/Map/TileSet.cs | 14 ++++++++++++++
 2 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/OpenRA.Game/Map/Map.cs b/OpenRA.Game/Map/Map.cs
index 49350da418..cffcfa1f8f 100644
--- a/OpenRA.Game/Map/Map.cs
+++ b/OpenRA.Game/Map/Map.cs
@@ -287,7 +287,6 @@ namespace OpenRA
 			this.modData = modData;
 			var size = new Size(width, height);
 			Grid = modData.Manifest.Get<MapGrid>();
-			var tileRef = new TerrainTile(tileset.Templates.First().Key, 0);
 
 			Title = "Name your map here";
 			Author = "Your name here";
@@ -310,7 +309,7 @@ namespace OpenRA
 				Tiles.CellEntryChanged += UpdateRamp;
 			}
 
-			Tiles.Clear(tileRef);
+			Tiles.Clear(tileset.DefaultTerrainTile);
 
 			PostInit();
 		}
@@ -430,12 +429,17 @@ namespace OpenRA
 			foreach (var uv in AllCells.MapCoords)
 				CustomTerrain[uv] = byte.MaxValue;
 
-			// Cache initial ramp state
+			// Replace invalid tiles and cache ramp state
 			var tileset = Rules.TileSet;
-			foreach (var uv in AllCells)
+			foreach (var uv in AllCells.MapCoords)
 			{
-				var tile = tileset.GetTileInfo(Tiles[uv]);
-				Ramp[uv] = tile != null ? tile.RampType : (byte)0;
+				if (!tileset.TryGetTileInfo(Tiles[uv], out var info))
+				{
+					Tiles[uv] = tileset.DefaultTerrainTile;
+					info = tileset.GetTileInfo(tileset.DefaultTerrainTile);
+				}
+
+				Ramp[uv] = info.RampType;
 			}
 
 			AllEdgeCells = UpdateEdgeCells();
diff --git a/OpenRA.Game/Map/TileSet.cs b/OpenRA.Game/Map/TileSet.cs
index a1ac55ac46..eb8e9ade42 100644
--- a/OpenRA.Game/Map/TileSet.cs
+++ b/OpenRA.Game/Map/TileSet.cs
@@ -241,5 +241,19 @@ namespace OpenRA
 
 			return tpl.Contains(r.Index) ? tpl[r.Index] : null;
 		}
+
+		public bool TryGetTileInfo(TerrainTile r, out TerrainTileInfo info)
+		{
+			if (!Templates.TryGetValue(r.Type, out var tpl) || !tpl.Contains(r.Index))
+			{
+				info = null;
+				return false;
+			}
+
+			info = tpl[r.Index];
+			return info != null;
+		}
+
+		public TerrainTile DefaultTerrainTile { get { return new TerrainTile(Templates.First().Key, 0); } }
 	}
 }