Split tileset artwork loading out of TileSet.

This simplifies terrain loading and allows for
non-square tiles in game.

The editor still relies on the old code for now.

OpenRA.Game/Graphics/TerrainRenderer.cs

@@ -18,7 +18,6 @@ namespace OpenRA.Graphics
 {
 	class TerrainRenderer
 	{
-		SheetBuilder sheetBuilder;
 		IVertexBuffer<Vertex> vertexBuffer;
 
 		World world;
@@ -29,23 +28,6 @@ namespace OpenRA.Graphics
 			this.world = world;
 			this.map = world.Map;
 
-			var allocated = false;
-			Func<Sheet> allocate = () =>
-			{
-				if (allocated)
-					throw new SheetOverflowException("Terrain sheet overflow");
-				allocated = true;
-
-				// TODO: Use a fixed sheet size specified in the tileset yaml
-				return SheetBuilder.AllocateSheet();
-			};
-
-			sheetBuilder = new SheetBuilder(SheetType.Indexed, allocate);
-
-			var tileSize = new Size(Game.CellSize, Game.CellSize);
-			var tileMapping = new Cache<TileReference<ushort,byte>, Sprite>(
-				x => sheetBuilder.Add(world.TileSet.GetBytes(x), tileSize));
-
 			var terrainPalette = wr.Palette("terrain").Index;
 			var vertices = new Vertex[4 * map.Bounds.Height * map.Bounds.Width];
 			int nv = 0;
@@ -53,7 +35,7 @@ namespace OpenRA.Graphics
 			for (var j = map.Bounds.Top; j < map.Bounds.Bottom; j++)
 				for (var i = map.Bounds.Left; i < map.Bounds.Right; i++)
 				{
-					var tile = tileMapping[map.MapTiles.Value[i, j]];
+					var tile = wr.Theater.TileSprite(map.MapTiles.Value[i, j]);
 					Util.FastCreateQuad(vertices, Game.CellSize * new float2(i, j), tile, terrainPalette, nv, tile.size);
 					nv += 4;
 				}
@@ -96,7 +78,7 @@ namespace OpenRA.Graphics
 
 			Game.Renderer.WorldSpriteRenderer.DrawVertexBuffer(
 				vertexBuffer, verticesPerRow * firstRow, verticesPerRow * (lastRow - firstRow),
-				PrimitiveType.QuadList, sheetBuilder.Current);
+				PrimitiveType.QuadList, wr.Theater.Sheet);
 
 			foreach (var r in world.WorldActor.TraitsImplementing<IRenderOverlay>())
 				r.Render(wr);