Don't hardcode implementations in interfaces.

OpenRA.Mods.Common/Terrain/DefaultTileCache.cs

@@ -21,9 +21,9 @@ namespace OpenRA.Mods.Common.Terrain
 {
 	public record TheaterTemplate(Sprite[] Sprites, int Stride, int Variants);
 
-	public sealed class DefaultTileCache : IDisposable
+	public sealed class DefaultTileCache : ITileCache, IDisposable
 	{
-		public readonly Cache<SheetType, SheetBuilder> SheetBuilders;
+		readonly Cache<SheetType, SheetBuilder> sheetBuilders;
 		readonly Dictionary<ushort, TheaterTemplate> templates = [];
 		readonly MersenneTwister random;
 
@@ -31,7 +31,7 @@ namespace OpenRA.Mods.Common.Terrain
 
 		public DefaultTileCache(DefaultTerrain terrainInfo, Action<uint, string> onMissingImage = null)
 		{
-			SheetBuilders = new Cache<SheetType, SheetBuilder>(t => new SheetBuilder(t, terrainInfo.SheetSize));
+			sheetBuilders = new Cache<SheetType, SheetBuilder>(t => new SheetBuilder(t, terrainInfo.SheetSize));
 
 			random = new MersenneTwister();
 
@@ -101,14 +101,14 @@ namespace OpenRA.Mods.Common.Terrain
 						var offset = new float3(f.Offset, zOffset);
 						var type = SheetBuilder.FrameTypeToSheetType(f.Type);
 
-						var s = SheetBuilders[type].Allocate(f.Size, zRamp, offset);
+						var s = sheetBuilders[type].Allocate(f.Size, zRamp, offset);
 						OpenRA.Graphics.Util.FastCopyIntoChannel(s, f.Data, f.Type);
 
 						if (terrainInfo.EnableDepth)
 						{
 							var depthFrame = depthFrames != null ? depthFrames[j] : allFrames[j + frameCount];
 							var depthType = SheetBuilder.FrameTypeToSheetType(depthFrame.Type);
-							var ss = SheetBuilders[depthType].Allocate(depthFrame.Size, zRamp, offset);
+							var ss = sheetBuilders[depthType].Allocate(depthFrame.Size, zRamp, offset);
 							OpenRA.Graphics.Util.FastCopyIntoChannel(ss, depthFrame.Data, depthFrame.Type);
 							s = new SpriteWithSecondaryData(s, ss.Sheet, ss.Bounds, ss.Channel);
 						}
@@ -135,7 +135,7 @@ namespace OpenRA.Mods.Common.Terrain
 			var missingSheetType = SheetType.Indexed;
 
 			// Avoid creating an indexed sheet if all tiles are BGRA
-			var missing = SheetBuilders.FirstOrDefault();
+			var missing = sheetBuilders.FirstOrDefault();
 			if (missing.Value != null && missing.Key == SheetType.BGRA)
 			{
 				missingDataLength = 4;
@@ -143,8 +143,8 @@ namespace OpenRA.Mods.Common.Terrain
 				missingSheetType = SheetType.BGRA;
 			}
 
-			MissingTile = SheetBuilders[missingSheetType].Add(new byte[missingDataLength], missingFrameType, new Size(1, 1));
+			MissingTile = sheetBuilders[missingSheetType].Add(new byte[missingDataLength], missingFrameType, new Size(1, 1));
-			foreach (var sb in SheetBuilders.Values)
+			foreach (var sb in sheetBuilders.Values)
 				sb.Current?.ReleaseBuffer();
 		}
 
@@ -165,9 +165,14 @@ namespace OpenRA.Mods.Common.Terrain
 			return template.Sprites[start * template.Stride + r.Index];
 		}
 
+		public SheetBuilder GetSheetBuilder(SheetType sheetType)
+		{
+			return sheetBuilders[sheetType];
+		}
+
 		public void Dispose()
 		{
-			foreach (var sb in SheetBuilders.Values)
+			foreach (var sb in sheetBuilders.Values)
 				sb.Dispose();
 		}
 	}

OpenRA.Mods.Common/Terrain/TileCache.cs

@@ -0,0 +1,22 @@
+#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 OpenRA.Graphics;
+
+namespace OpenRA
+{
+	public interface ITileCache
+	{
+		bool HasTileSprite(TerrainTile r, int? variant = null);
+		Sprite TileSprite(TerrainTile r, int? variant = null);
+		SheetBuilder GetSheetBuilder(SheetType sheetType);
+	}
+}

OpenRA.Mods.Common/Traits/World/TerrainRenderer.cs

@@ -22,7 +22,7 @@ namespace OpenRA.Mods.Common.Traits
 	[TraitLocation(SystemActors.World | SystemActors.EditorWorld)]
 	public class TerrainRendererInfo : TraitInfo, ITiledTerrainRendererInfo
 	{
-		bool ITiledTerrainRendererInfo.ValidateTileSprites(ITemplatedTerrainInfo terrainInfo, Action<string> onError, out DefaultTileCache tileCache)
+		bool ITiledTerrainRendererInfo.ValidateTileSprites(ITemplatedTerrainInfo terrainInfo, Action<string> onError, out ITileCache tileCache)
 		{
 			var missingImages = new HashSet<string>();
 			var failed = false;

OpenRA.Mods.Common/TraitsInterfaces.cs

@@ -783,7 +783,7 @@ namespace OpenRA.Mods.Common.Traits
 	[RequireExplicitImplementation]
 	public interface ITiledTerrainRendererInfo : ITraitInfoInterface
 	{
-		bool ValidateTileSprites(ITemplatedTerrainInfo terrainInfo, Action<string> onError, out DefaultTileCache tileCache);
+		bool ValidateTileSprites(ITemplatedTerrainInfo terrainInfo, Action<string> onError, out ITileCache tileCache);
 	}
 
 	[RequireExplicitImplementation]

OpenRA.Mods.Common/UtilityCommands/DumpSequenceSheetsCommand.cs

@@ -94,11 +94,11 @@ namespace OpenRA.Mods.Common.UtilityCommands
 					{
 						if (!ttr.ValidateTileSprites(templatedTerrainInfo, Console.WriteLine, out var tileCache))
 						{
-							sb = tileCache.SheetBuilders[SheetType.Indexed];
+							sb = tileCache.GetSheetBuilder(SheetType.Indexed);
 							foreach (var s in sb.AllSheets)
 								CommitSheet(sb, s, terrainName, palette, ref sheetCount);
 
-							foreach (var s in tileCache.SheetBuilders[SheetType.BGRA].AllSheets)
+							foreach (var s in tileCache.GetSheetBuilder(SheetType.BGRA).AllSheets)
 								CommitSheet(null, s, terrainName, palette, ref sheetCount);
 						}
 					}