Enable use of "custom" palettes per tile Templates

Keep the tileset's palette as default, defined on the tileset, but override it for any tile templates that may want to do so with a palette defined on the template.

OpenRA.Game/Graphics/TerrainRenderer.cs

@@ -9,25 +9,34 @@
 #endregion
 
 using System;
+using System.Collections.Generic;
 using OpenRA.Traits;
 
 namespace OpenRA.Graphics
 {
 	sealed class TerrainRenderer : IDisposable
 	{
-		readonly TerrainSpriteLayer terrain;
+		const string TerrainPalette = "terrain";
+
+		readonly World world;
+		readonly Dictionary<string, TerrainSpriteLayer> spriteLayers = new Dictionary<string, TerrainSpriteLayer>();
 		readonly Theater theater;
 		readonly CellLayer<TerrainTile> mapTiles;
 		readonly CellLayer<byte> mapHeight;
 
 		public TerrainRenderer(World world, WorldRenderer wr)
 		{
+			this.world = world;
 			theater = wr.Theater;
 			mapTiles = world.Map.MapTiles.Value;
 			mapHeight = world.Map.MapHeight.Value;
 
-			terrain = new TerrainSpriteLayer(world, wr, theater.Sheet, BlendMode.Alpha,
-				wr.Palette("terrain"), wr.World.Type != WorldType.Editor);
+			foreach (var template in world.TileSet.Templates)
+			{
+				var palette = template.Value.Palette ?? TerrainPalette;
+				spriteLayers.GetOrAdd(palette, pal =>
+					new TerrainSpriteLayer(world, wr, theater.Sheet, BlendMode.Alpha, wr.Palette(palette), wr.World.Type != WorldType.Editor));
+			}
 
 			foreach (var cell in world.Map.AllCells)
 				UpdateCell(cell);
@@ -38,12 +47,18 @@ namespace OpenRA.Graphics
 
 		public void UpdateCell(CPos cell)
 		{
-			terrain.Update(cell, theater.TileSprite(mapTiles[cell]));
+			var tile = mapTiles[cell];
+			var palette = world.TileSet.Templates[tile.Type].Palette ?? TerrainPalette;
+			var sprite = theater.TileSprite(tile);
+			foreach (var kv in spriteLayers)
+				kv.Value.Update(cell, palette == kv.Key ? sprite : null);
 		}
 
 		public void Draw(WorldRenderer wr, Viewport viewport)
 		{
-			terrain.Draw(viewport);
+			foreach (var kv in spriteLayers.Values)
+				kv.Draw(wr.Viewport);
+
 			foreach (var r in wr.World.WorldActor.TraitsImplementing<IRenderOverlay>())
 				r.Render(wr);
 		}
@@ -52,7 +67,9 @@ namespace OpenRA.Graphics
 		{
 			mapTiles.CellEntryChanged -= UpdateCell;
 			mapHeight.CellEntryChanged -= UpdateCell;
-			terrain.Dispose();
+
+			foreach (var kv in spriteLayers.Values)
+				kv.Dispose();
 		}
 	}
 }

OpenRA.Game/Map/TileSet.cs

@@ -73,6 +73,7 @@ namespace OpenRA
 		public readonly int2 Size;
 		public readonly bool PickAny;
 		public readonly string Category;
+		public readonly string Palette;
 
 		readonly TerrainTileInfo[] tileInfo;