diff --git a/OpenRA.FileFormats/Map/TileSet.cs b/OpenRA.FileFormats/Map/TileSet.cs
index e6d973b09d..621a47bd26 100644
--- a/OpenRA.FileFormats/Map/TileSet.cs
+++ b/OpenRA.FileFormats/Map/TileSet.cs
@@ -39,17 +39,17 @@ namespace OpenRA.FileFormats
 		public bool PickAny;
 		public string Category;
 
-		[FieldLoader.LoadUsing( "LoadTiles" )]
+		[FieldLoader.LoadUsing("LoadTiles")]
 		public Dictionary<byte, string> Tiles = new Dictionary<byte, string>();
 
 		public TileTemplate() {}
-		public TileTemplate(MiniYaml my) { FieldLoader.Load( this, my ); }
+		public TileTemplate(MiniYaml my) { FieldLoader.Load(this, my); }
 
-		static object LoadTiles( MiniYaml y )
+		static object LoadTiles(MiniYaml y)
 		{
 			return y.NodesDict["Tiles"].NodesDict.ToDictionary(
 				t => byte.Parse(t.Key),
-				t => t.Value.Value );
+				t => t.Value.Value);
 		}
 
 		static readonly string[] Fields = { "Id", "Image", "Size", "PickAny" };
@@ -60,12 +60,14 @@ namespace OpenRA.FileFormats
 			foreach (var field in Fields)
 			{
 				FieldInfo f = this.GetType().GetField(field);
-				if (f.GetValue(this) == null) continue;
-				root.Add( new MiniYamlNode( field, FieldSaver.FormatValue( this, f ) ) );
+				if (f.GetValue(this) == null)
+					continue;
+
+				root.Add(new MiniYamlNode(field, FieldSaver.FormatValue(this, f)));
 			}
 
-			root.Add( new MiniYamlNode( "Tiles", null,
-				Tiles.Select( x => new MiniYamlNode( x.Key.ToString(), x.Value ) ).ToList() ) );
+			root.Add(new MiniYamlNode("Tiles", null,
+				Tiles.Select(x => new MiniYamlNode(x.Key.ToString(), x.Value)).ToList()));
 
 			return new MiniYaml(null, root);
 		}
@@ -90,9 +92,9 @@ namespace OpenRA.FileFormats
 
 		public TileSet() {}
 
-		public TileSet( string filepath )
+		public TileSet(string filepath)
 		{
-			var yaml = MiniYaml.DictFromFile( filepath );
+			var yaml = MiniYaml.DictFromFile(filepath);
 
 			// General info
 			FieldLoader.Load(this, yaml["General"]);
@@ -110,7 +112,7 @@ namespace OpenRA.FileFormats
 		{
 			foreach (var t in Templates)
 				if (t.Value.Data == null)
-					using( var s = FileSystem.OpenWithExts(t.Value.Image, Extensions) )
+					using (var s = FileSystem.OpenWithExts(t.Value.Image, Extensions))
 						t.Value.Data = new Terrain(s, TileSize);
 		}
 
@@ -122,33 +124,35 @@ namespace OpenRA.FileFormats
 			foreach (var field in fields)
 			{
 				FieldInfo f = this.GetType().GetField(field);
-				if (f.GetValue(this) == null) continue;
-				gen.Add( new MiniYamlNode( field, FieldSaver.FormatValue( this, f ) ) );
+				if (f.GetValue(this) == null)
+					continue;
+
+				gen.Add(new MiniYamlNode(field, FieldSaver.FormatValue(this, f)));
 			}
 
-			root.Add( new MiniYamlNode( "General", null, gen ) );
+			root.Add(new MiniYamlNode("General", null, gen));
 
-			root.Add( new MiniYamlNode( "Terrain", null,
-				Terrain.Select( t => new MiniYamlNode(
-					"TerrainType@{0}".F( t.Value.Type ),
-					t.Value.Save() ) ).ToList() ) );
+			root.Add(new MiniYamlNode( "Terrain", null,
+				Terrain.Select(t => new MiniYamlNode(
+					"TerrainType@{0}".F(t.Value.Type),
+					t.Value.Save())).ToList()));
 
-			root.Add( new MiniYamlNode( "Templates", null,
-				Templates.Select( t => new MiniYamlNode(
-					"Template@{0}".F( t.Value.Id ),
-					t.Value.Save() ) ).ToList() ) );
+			root.Add(new MiniYamlNode("Templates", null,
+				Templates.Select(t => new MiniYamlNode(
+					"Template@{0}".F(t.Value.Id),
+					t.Value.Save())).ToList()));
 			root.WriteToFile(filepath);
 		}
 
 		public byte[] GetBytes(TileReference<ushort,byte> r)
 		{
 			TileTemplate tile;
-			if( Templates.TryGetValue( r.type, out tile ) )
-				return tile.Data.TileBitmapBytes[ r.index ];
+			if (Templates.TryGetValue(r.type, out tile))
+				return tile.Data.TileBitmapBytes[r.index];
 
-			byte[] missingTile = new byte[ TileSize * TileSize ];
-			for( int i = 0 ; i < missingTile.Length ; i++ )
-				missingTile[ i ] = 0x36;
+			byte[] missingTile = new byte[TileSize*TileSize];
+			for (var i = 0; i < missingTile.Length; i++)
+				missingTile[i] = 0x36;
 
 			return missingTile;
 		}
@@ -159,6 +163,7 @@ namespace OpenRA.FileFormats
 			string ret;
 			if (!tt.TryGetValue(r.index, out ret))
 				return "Clear"; // Default walkable
+
 			return ret;
 		}
 
diff --git a/OpenRA.Game/Graphics/Animation.cs b/OpenRA.Game/Graphics/Animation.cs
index d614fa82cf..99fa370093 100644
--- a/OpenRA.Game/Graphics/Animation.cs
+++ b/OpenRA.Game/Graphics/Animation.cs
@@ -24,15 +24,13 @@ namespace OpenRA.Graphics
 
 		public string Name { get { return name; } }
 
-		public Animation( string name )
-			: this( name, () => 0 )
-		{
-		}
+		public Animation(string name)
+			: this(name, () => 0)	{}
 
-		public Animation( string name, Func<int> facingFunc )
+		public Animation(string name, Func<int> facingFunc)
 		{
 			this.name = name.ToLowerInvariant();
-			this.tickFunc = () => { };
+			this.tickFunc = () => {};
 			this.facingFunc = facingFunc;
 		}
 
@@ -46,12 +44,12 @@ namespace OpenRA.Graphics
 			}
 		}
 
-		public void Play( string sequenceName )
+		public void Play(string sequenceName)
 		{
 			PlayThen(sequenceName, null);
 		}
 
-		public void PlayRepeating( string sequenceName )
+		public void PlayRepeating(string sequenceName)
 		{
 			backwards = false;
 			tickAlways = false;
@@ -75,16 +73,16 @@ namespace OpenRA.Graphics
 			return true;
 		}
 
-		public void PlayThen( string sequenceName, Action after )
+		public void PlayThen(string sequenceName, Action after)
 		{
 			backwards = false;
 			tickAlways = false;
-			CurrentSequence = SequenceProvider.GetSequence( name, sequenceName );
+			CurrentSequence = SequenceProvider.GetSequence(name, sequenceName);
 			frame = 0;
 			tickFunc = () =>
 			{
 				++frame;
-				if( frame >= CurrentSequence.Length )
+				if (frame >= CurrentSequence.Length)
 				{
 					frame = CurrentSequence.Length - 1;
 					tickFunc = () => { };
@@ -99,11 +97,11 @@ namespace OpenRA.Graphics
 			backwards = true;
 		}
 
-		public void PlayFetchIndex( string sequenceName, Func<int> func )
+		public void PlayFetchIndex(string sequenceName, Func<int> func)
 		{
 			backwards = false;
 			tickAlways = true;
-			CurrentSequence = SequenceProvider.GetSequence( name, sequenceName );
+			CurrentSequence = SequenceProvider.GetSequence(name, sequenceName);
 			frame = func();
 			tickFunc = () => frame = func();
 		}
@@ -113,19 +111,19 @@ namespace OpenRA.Graphics
 
 		public void Tick()
 		{
-			Tick( 40 ); // tick one frame
+			Tick(40); // tick one frame
 		}
 
-		public bool HasSequence(string seq) { return SequenceProvider.HasSequence( name, seq ); }
+		public bool HasSequence(string seq) { return SequenceProvider.HasSequence(name, seq); }
 
-		public void Tick( int t )
+		public void Tick(int t)
 		{
-			if( tickAlways )
+			if (tickAlways)
 				tickFunc();
 			else
 			{
 				timeUntilNextFrame -= t;
-				while( timeUntilNextFrame <= 0 )
+				while (timeUntilNextFrame <= 0)
 				{
 					tickFunc();
 					timeUntilNextFrame += CurrentSequence != null ? CurrentSequence.Tick : 40; // 25 fps == 40 ms
@@ -145,9 +143,9 @@ namespace OpenRA.Graphics
 			}
 		}
 
-		public Sequence GetSequence( string sequenceName )
+		public Sequence GetSequence(string sequenceName)
 		{
-			return SequenceProvider.GetSequence( name, sequenceName );
+			return SequenceProvider.GetSequence(name, sequenceName);
 		}
 	}
 }
diff --git a/OpenRA.Game/Graphics/Sheet.cs b/OpenRA.Game/Graphics/Sheet.cs
index 2e7277f580..a390d218be 100644
--- a/OpenRA.Game/Graphics/Sheet.cs
+++ b/OpenRA.Game/Graphics/Sheet.cs
@@ -9,6 +9,7 @@
 #endregion
 
 using System.Drawing;
+using System.Drawing.Imaging;
 using OpenRA.FileFormats;
 using OpenRA.FileFormats.Graphics;
 
@@ -16,21 +17,44 @@ namespace OpenRA.Graphics
 {
 	public class Sheet
 	{
-		Bitmap bitmap;
 		ITexture texture;
 		bool dirty;
-		byte[] data;
+		public byte[] Data { get; private set; }
 		public readonly Size Size;
 
 		public Sheet(Size size)
 		{
 			Size = size;
+			Data = new byte[4*Size.Width*Size.Height];
 		}
 
 		public Sheet(string filename)
 		{
-			bitmap = (Bitmap)Image.FromStream(FileSystem.Open(filename));
+			var bitmap = (Bitmap)Image.FromStream(FileSystem.Open(filename));
 			Size = bitmap.Size;
+
+			Data = new byte[4*Size.Width*Size.Height];
+			var b = bitmap.LockBits(bitmap.Bounds(),
+				ImageLockMode.ReadOnly, PixelFormat.Format32bppArgb);
+
+			unsafe
+			{
+				int* c = (int*)b.Scan0;
+
+				for (var x = 0; x < Size.Width; x++)
+					for (var y = 0; y < Size.Height; y++)
+				{
+					var i = 4*Size.Width*y + 4*x;
+
+					// Convert argb to bgra
+					var argb = *(c + (y * b.Stride >> 2) + x);
+					Data[i++] = (byte)(argb >> 0);
+					Data[i++] = (byte)(argb >> 8);
+					Data[i++] = (byte)(argb >> 16);
+					Data[i++] = (byte)(argb >> 24);
+				}
+			}
+			bitmap.UnlockBits(b);
 		}
 
 		public ITexture Texture
@@ -45,23 +69,61 @@ namespace OpenRA.Graphics
 
 				if (dirty)
 				{
-					if (data != null)
-					{
-						texture.SetData(data, Size.Width, Size.Height);
-						dirty = false;
-					}
-					else if (bitmap != null)
-					{
-						texture.SetData(bitmap);
-						dirty = false;
-					}
+					texture.SetData(Data, Size.Width, Size.Height);
+					dirty = false;
 				}
 
 				return texture;
 			}
 		}
 
-		public byte[] Data { get { if (data == null) data = new byte[4 * Size.Width * Size.Height]; return data; } }
+		public Bitmap AsBitmap()
+		{
+			var b = new Bitmap(Size.Width, Size.Height);
+			var output = b.LockBits(new Rectangle(0, 0, Size.Width, Size.Height),
+				ImageLockMode.WriteOnly, PixelFormat.Format32bppArgb);
+
+			unsafe
+			{
+				int* c = (int*)output.Scan0;
+
+				for (var x = 0; x < Size.Width; x++)
+					for (var y = 0; y < Size.Height; y++)
+					{
+						var i = 4*Size.Width*y + 4*x;
+
+						// Convert bgra to argb
+						var argb = (Data[i+3] << 24) | (Data[i+2] << 16) | (Data[i+1] << 8) | Data[i];
+						*(c + (y * output.Stride >> 2) + x) = argb;
+					}
+			}
+			b.UnlockBits(output);
+
+			return b;
+		}
+
+		public Bitmap AsBitmap(TextureChannel channel, Palette pal)
+		{
+			var b = new Bitmap(Size.Width, Size.Height);
+			var output = b.LockBits(new Rectangle(0, 0, Size.Width, Size.Height),
+				ImageLockMode.WriteOnly, PixelFormat.Format32bppArgb);
+
+			unsafe
+			{
+				int* c = (int*)output.Scan0;
+
+				for (var x = 0; x < Size.Width; x++)
+					for (var y = 0; y < Size.Height; y++)
+				{
+					var index = Data[4*Size.Width*y + 4*x + (int)channel];
+					*(c + (y * output.Stride >> 2) + x) = pal.GetColor(index).ToArgb();
+				}
+			}
+			b.UnlockBits(output);
+
+			return b;
+		}
+
 		public void MakeDirty() { dirty = true; }
 	}
 }
diff --git a/OpenRA.Game/Graphics/SheetBuilder.cs b/OpenRA.Game/Graphics/SheetBuilder.cs
index 1340e501ce..74c57f92a2 100644
--- a/OpenRA.Game/Graphics/SheetBuilder.cs
+++ b/OpenRA.Game/Graphics/SheetBuilder.cs
@@ -8,68 +8,69 @@
  */
 #endregion
 
+using System;
 using System.Drawing;
 
 namespace OpenRA.Graphics
 {
+	public class SheetOverflowException : Exception
+	{
+		public SheetOverflowException()
+			: base("Sprite sequence spans multiple sheets.\n"+
+				"This should be considered as a bug, but you "+
+				"can increase the Graphics.SheetSize setting "+
+				"to temporarily avoid the problem.") {}
+	}
+
+	public enum SheetType
+	{
+		Indexed = 1,
+		DualIndexed = 2,
+		BGRA = 4,
+	}
+
 	public class SheetBuilder
 	{
-		internal SheetBuilder(TextureChannel ch)
+		Sheet current;
+		TextureChannel channel;
+		SheetType type;
+		int rowHeight = 0;
+		Point p;
+
+		internal SheetBuilder(SheetType t)
 		{
-			current = null;
-			rowHeight = 0;
-			channel = null;
-			initialChannel = ch;
+			current = new Sheet(new Size(Renderer.SheetSize, Renderer.SheetSize));;
+			channel = TextureChannel.Red;
+			type = t;
 		}
 
-		public Sprite Add(byte[] src, Size size)
+		public Sprite Add(byte[] src, Size size, bool allowSheetOverflow)
 		{
-			Sprite rect = Allocate(size);
+			var rect = Allocate(size, allowSheetOverflow);
 			Util.FastCopyIntoChannel(rect, src);
 			return rect;
 		}
 
-		public Sprite Add(Size size, byte paletteIndex)
+		public Sprite Add(Size size, byte paletteIndex, bool allowSheetOverflow)
 		{
-			byte[] data = new byte[size.Width * size.Height];
-			for (int i = 0; i < data.Length; i++)
+			var data = new byte[size.Width * size.Height];
+			for (var i = 0; i < data.Length; i++)
 				data[i] = paletteIndex;
 
-			return Add(data, size);
+			return Add(data, size, allowSheetOverflow);
 		}
 
-		Sheet NewSheet() { return new Sheet(new Size( Renderer.SheetSize, Renderer.SheetSize ) ); }
-
-		Sheet current = null;
-		int rowHeight = 0;
-		Point p;
-		TextureChannel? channel = null;
-		TextureChannel initialChannel;
-
-		TextureChannel? NextChannel(TextureChannel? t)
+		TextureChannel? NextChannel(TextureChannel t)
 		{
-			if (t == null)
-				return initialChannel;
+			var nextChannel = (int)t + (int)type;
+			if (nextChannel > (int)TextureChannel.Alpha)
+				return null;
 
-			switch (t.Value)
-			{
-				case TextureChannel.Red: return TextureChannel.Green;
-				case TextureChannel.Green: return TextureChannel.Blue;
-				case TextureChannel.Blue: return TextureChannel.Alpha;
-				case TextureChannel.Alpha: return null;
-
-				default: return null;
-			}
+			return (TextureChannel)nextChannel;
 		}
 
-		public Sprite Allocate(Size imageSize)
+		public Sprite Allocate(Size imageSize, bool allowSheetOverflow)
 		{
-			if (current == null)
-			{
-				current = NewSheet();
-				channel = NextChannel(null);
-			}
-
 			if (imageSize.Width + p.X > current.Size.Width)
 			{
 				p = new Point(0, p.Y + rowHeight);
@@ -81,22 +82,29 @@ namespace OpenRA.Graphics
 
 			if (p.Y + imageSize.Height > current.Size.Height)
 			{
-
-				if (null == (channel = NextChannel(channel)))
+				var next = NextChannel(channel);
+				if (next == null)
 				{
-					current = NewSheet();
-					channel = NextChannel(channel);
+					if (!allowSheetOverflow)
+						throw new SheetOverflowException();
+
+					current = new Sheet(new Size(Renderer.SheetSize, Renderer.SheetSize));
+					channel = TextureChannel.Red;
 				}
+				else
+					channel = next.Value;
 
 				rowHeight = imageSize.Height;
 				p = new Point(0,0);
 			}
 
-			Sprite rect = new Sprite(current, new Rectangle(p, imageSize), channel.Value);
+			var rect = new Sprite(current, new Rectangle(p, imageSize), channel);
 			current.MakeDirty();
 			p.X += imageSize.Width;
 
 			return rect;
 		}
+
+		public Sheet Current { get { return current; } }
 	}
 }
diff --git a/OpenRA.Game/Graphics/Sprite.cs b/OpenRA.Game/Graphics/Sprite.cs
index e62359f828..1ebcb9eaad 100644
--- a/OpenRA.Game/Graphics/Sprite.cs
+++ b/OpenRA.Game/Graphics/Sprite.cs
@@ -17,57 +17,52 @@ namespace OpenRA.Graphics
 		public readonly Rectangle bounds;
 		public readonly Sheet sheet;
 		public readonly TextureChannel channel;
-		public readonly RectangleF uv;
 		public readonly float2 size;
-
-		readonly float2[] uvhax;
+		readonly float2[] textureCoords;
 
 		public Sprite(Sheet sheet, Rectangle bounds, TextureChannel channel)
 		{
 			this.bounds = bounds;
 			this.sheet = sheet;
 			this.channel = channel;
-
-			uv = new RectangleF(
-					(float)(bounds.Left) / sheet.Size.Width,
-					(float)(bounds.Top) / sheet.Size.Height,
-					(float)(bounds.Width) / sheet.Size.Width,
-					(float)(bounds.Height) / sheet.Size.Height);
-
-			uvhax = new float2[]
-			{
-				new float2( uv.Left, uv.Top ),
-				new float2( uv.Right, uv.Top ),
-				new float2( uv.Left, uv.Bottom ),
-				new float2( uv.Right, uv.Bottom ),
-			};
-
 			this.size = new float2(bounds.Size);
+
+			var left = (float)(bounds.Left) / sheet.Size.Width;
+			var top = (float)(bounds.Top) / sheet.Size.Height;
+			var right = (float)(bounds.Right) / sheet.Size.Width;
+			var bottom = (float)(bounds.Bottom) / sheet.Size.Height;
+			textureCoords = new float2[]
+			{
+				new float2(left, top),
+				new float2(right, top),
+				new float2(left, bottom),
+				new float2(right, bottom),
+			};
 		}
 
-		public float2 FastMapTextureCoords( int k )
+		public float2 FastMapTextureCoords(int k)
 		{
-			return uvhax[ k ];
+			return textureCoords[k];
 		}
 
-		public void DrawAt( WorldRenderer wr, float2 location, string palette )
+		public void DrawAt(WorldRenderer wr, float2 location, string palette)
 		{
-			Game.Renderer.WorldSpriteRenderer.DrawSprite( this, location, wr, palette, this.size );
+			Game.Renderer.WorldSpriteRenderer.DrawSprite(this, location, wr, palette, size);
 		}
 
-		public void DrawAt( float2 location, int paletteIndex )
+		public void DrawAt(float2 location, int paletteIndex)
 		{
-			Game.Renderer.WorldSpriteRenderer.DrawSprite( this, location, paletteIndex, this.size );
+			Game.Renderer.WorldSpriteRenderer.DrawSprite(this, location, paletteIndex, size);
 		}
 
 		public void DrawAt(float2 location, int paletteIndex, float scale)
 		{
-			Game.Renderer.WorldSpriteRenderer.DrawSprite(this, location, paletteIndex, this.size * scale);
+			Game.Renderer.WorldSpriteRenderer.DrawSprite(this, location, paletteIndex, size*scale);
 		}
 
-		public void DrawAt( float2 location, int paletteIndex, float2 size )
+		public void DrawAt(float2 location, int paletteIndex, float2 size)
 		{
-			Game.Renderer.WorldSpriteRenderer.DrawSprite( this, location, paletteIndex, size );
+			Game.Renderer.WorldSpriteRenderer.DrawSprite(this, location, paletteIndex, size);
 		}
 	}
 
diff --git a/OpenRA.Game/Graphics/SpriteFont.cs b/OpenRA.Game/Graphics/SpriteFont.cs
index 974792d5dc..f4284b8055 100644
--- a/OpenRA.Game/Graphics/SpriteFont.cs
+++ b/OpenRA.Game/Graphics/SpriteFont.cs
@@ -31,8 +31,10 @@ namespace OpenRA.Graphics
 			glyphs = new Cache<Pair<char, Color>, GlyphInfo>(CreateGlyph, 
 			         Pair<char,Color>.EqualityComparer);
 
-			// setup a 1-channel SheetBuilder for our private use
-			if (builder == null) builder = new SheetBuilder(TextureChannel.Alpha);
+			// setup a SheetBuilder for our private use
+			// TODO: SheetBuilder state is leaked between mod switches
+			if (builder == null)
+				builder = new SheetBuilder(SheetType.BGRA);
 
 			PrecacheColor(Color.White);
 			PrecacheColor(Color.Red);
@@ -46,7 +48,7 @@ namespace OpenRA.Graphics
 					throw new InvalidOperationException();
 		}
 
-		public void DrawText (string text, float2 location, Color c)
+		public void DrawText(string text, float2 location, Color c)
 		{
 			location.Y += size;	// baseline vs top
 
@@ -84,7 +86,7 @@ namespace OpenRA.Graphics
 
 		public int2 Measure(string text)
 		{
-			return new int2((int)text.Split( '\n' ).Max( s => s.Sum(a => glyphs[Pair.New(a, Color.White)].Advance)), text.Split('\n').Count()*size);
+			return new int2((int)text.Split('\n').Max(s => s.Sum(a => glyphs[Pair.New(a, Color.White)].Advance)), text.Split('\n').Count()*size);
 		}
 
 		Cache<Pair<char,Color>, GlyphInfo> glyphs;
@@ -96,9 +98,8 @@ namespace OpenRA.Graphics
 			face.LoadGlyph(index, LoadFlags.Default, LoadTarget.Normal);
 			face.Glyph.RenderGlyph(RenderMode.Normal);
 
-			var s = builder.Allocate(
-				new Size((int)face.Glyph.Metrics.Width >> 6,
-			         (int)face.Glyph.Metrics.Height >> 6));
+			var size = new Size((int)face.Glyph.Metrics.Width >> 6, (int)face.Glyph.Metrics.Height >> 6);
+			var s = builder.Allocate(size, true);
 
 			var g = new GlyphInfo
 			{
diff --git a/OpenRA.Game/Graphics/SpriteLoader.cs b/OpenRA.Game/Graphics/SpriteLoader.cs
index 79cbe5f08a..97134fc646 100644
--- a/OpenRA.Game/Graphics/SpriteLoader.cs
+++ b/OpenRA.Game/Graphics/SpriteLoader.cs
@@ -35,12 +35,12 @@ namespace OpenRA.Graphics
 			if (ImageCount == 0)
 			{
 				var shp = new ShpTSReader(FileSystem.OpenWithExts(filename, exts));
-				return shp.Select(a => Game.modData.SheetBuilder.Add(a.Image, shp.Size)).ToArray();
+				return shp.Select(a => SheetBuilder.Add(a.Image, shp.Size, true)).ToArray();
 			}
 			else
 			{
 				var shp = new ShpReader(FileSystem.OpenWithExts(filename, exts));
-				return shp.Frames.Select(a => SheetBuilder.Add(a.Image, shp.Size)).ToArray();
+				return shp.Frames.Select(a => SheetBuilder.Add(a.Image, shp.Size, true)).ToArray();
 			}
 		}
 
diff --git a/OpenRA.Game/Graphics/TerrainRenderer.cs b/OpenRA.Game/Graphics/TerrainRenderer.cs
index 3231ef4347..c8a43df742 100644
--- a/OpenRA.Game/Graphics/TerrainRenderer.cs
+++ b/OpenRA.Game/Graphics/TerrainRenderer.cs
@@ -18,8 +18,8 @@ namespace OpenRA.Graphics
 {
 	class TerrainRenderer
 	{
+		SheetBuilder sheetBuilder;
 		IVertexBuffer<Vertex> vertexBuffer;
-		Sheet terrainSheet;
 
 		World world;
 		Map map;
@@ -29,37 +29,31 @@ namespace OpenRA.Graphics
 			this.world = world;
 			this.map = world.Map;
 
-			var tileSize = new Size( Game.CellSize, Game.CellSize );
+			// TODO: Use a fixed sheet size specified in the tileset yaml
+			sheetBuilder = new SheetBuilder(SheetType.Indexed);
+			var tileSize = new Size(Game.CellSize, Game.CellSize);
 			var tileMapping = new Cache<TileReference<ushort,byte>, Sprite>(
-				x => Game.modData.SheetBuilder.Add(world.TileSet.GetBytes(x), tileSize));
-
-			var vertices = new Vertex[4 * map.Bounds.Height * map.Bounds.Width];
-
-			terrainSheet = tileMapping[map.MapTiles.Value[map.Bounds.Left, map.Bounds.Top]].sheet;
-
-			int nv = 0;
+				x => sheetBuilder.Add(world.TileSet.GetBytes(x), tileSize, false));
 
 			var terrainPalette = wr.Palette("terrain").Index;
+			var vertices = new Vertex[4 * map.Bounds.Height * map.Bounds.Width];
+			int nv = 0;
 
-			for( int j = map.Bounds.Top; j < map.Bounds.Bottom; j++ )
-				for( int i = map.Bounds.Left; i < map.Bounds.Right; i++ )
+			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]];
-					// TODO: move GetPaletteIndex out of the inner loop.
 					Util.FastCreateQuad(vertices, Game.CellSize * new float2(i, j), tile, terrainPalette, nv, tile.size);
 					nv += 4;
-
-					if (tileMapping[map.MapTiles.Value[i, j]].sheet != terrainSheet)
-						throw new InvalidOperationException("Terrain sprites span multiple sheets. Try increasing Game.Settings.Graphics.SheetSize.");
 				}
 
-			vertexBuffer = Game.Renderer.Device.CreateVertexBuffer( vertices.Length );
-			vertexBuffer.SetData( vertices, nv );
+			vertexBuffer = Game.Renderer.Device.CreateVertexBuffer(vertices.Length);
+			vertexBuffer.SetData(vertices, nv);
 		}
 
-		public void Draw( WorldRenderer wr, Viewport viewport )
+		public void Draw(WorldRenderer wr, Viewport viewport)
 		{
-			int verticesPerRow = map.Bounds.Width * 4;
+			int verticesPerRow = 4*map.Bounds.Width;
 
 			int visibleRows = (int)(viewport.Height * 1f / Game.CellSize / viewport.Zoom + 2);
 
@@ -79,17 +73,22 @@ namespace OpenRA.Graphics
 					firstRow = r.Bottom - map.Bounds.Top;
 			}
 
-			if (firstRow < 0) firstRow = 0;
-			if (lastRow > map.Bounds.Height) lastRow = map.Bounds.Height;
+			// Sanity checking
+			if (firstRow < 0)
+				firstRow = 0;
 
-			if( lastRow < firstRow ) lastRow = firstRow;
+			if (lastRow > map.Bounds.Height)
+				lastRow = map.Bounds.Height;
+
+			if (lastRow < firstRow)
+				lastRow = firstRow;
 
 			Game.Renderer.WorldSpriteRenderer.DrawVertexBuffer(
 				vertexBuffer, verticesPerRow * firstRow, verticesPerRow * (lastRow - firstRow),
-				PrimitiveType.QuadList, terrainSheet);
+				PrimitiveType.QuadList, sheetBuilder.Current);
 
 			foreach (var r in world.WorldActor.TraitsImplementing<IRenderOverlay>())
-				r.Render( wr );
+				r.Render(wr);
 		}
 	}
 }
diff --git a/OpenRA.Game/Graphics/Util.cs b/OpenRA.Game/Graphics/Util.cs
index 20d79f4f0f..d0efeadc3e 100644
--- a/OpenRA.Game/Graphics/Util.cs
+++ b/OpenRA.Game/Graphics/Util.cs
@@ -32,12 +32,13 @@ namespace OpenRA.Graphics
 
 		static readonly int[] channelMasks = { 2, 1, 0, 3 };	// yes, our channel order is nuts.
 
-		public static void FastCopyIntoChannel(Sprite dest, byte[] src)
+		public static void FastCopyIntoChannel(Sprite dest, byte[] src) { FastCopyIntoChannel(dest, 0, src); }
+		public static void FastCopyIntoChannel(Sprite dest, int channelOffset, byte[] src)
 		{
 			var data = dest.sheet.Data;
 			var srcStride = dest.bounds.Width;
 			var destStride = dest.sheet.Size.Width * 4;
-			var destOffset = destStride * dest.bounds.Top + dest.bounds.Left * 4 + channelMasks[(int)dest.channel];
+			var destOffset = destStride * dest.bounds.Top + dest.bounds.Left * 4 + channelMasks[(int)dest.channel + channelOffset];
 			var destSkip = destStride - 4 * srcStride;
 			var height = dest.bounds.Height;
 
diff --git a/OpenRA.Game/ModData.cs b/OpenRA.Game/ModData.cs
index dd456520d4..f5c298d4b7 100755
--- a/OpenRA.Game/ModData.cs
+++ b/OpenRA.Game/ModData.cs
@@ -53,7 +53,7 @@ namespace OpenRA
 
 			ChromeMetrics.Initialize(Manifest.ChromeMetrics);
 			ChromeProvider.Initialize(Manifest.Chrome);
-			SheetBuilder = new SheetBuilder(TextureChannel.Red);
+			SheetBuilder = new SheetBuilder(SheetType.Indexed);
 			SpriteLoader = new SpriteLoader(new string[] { ".shp" }, SheetBuilder);
 			CursorProvider.Initialize(Manifest.Cursors);
 		}
diff --git a/OpenRA.Mods.RA/Bridge.cs b/OpenRA.Mods.RA/Bridge.cs
index 495e006ce6..d7fda56878 100644
--- a/OpenRA.Mods.RA/Bridge.cs
+++ b/OpenRA.Mods.RA/Bridge.cs
@@ -99,9 +99,9 @@ namespace OpenRA.Mods.RA
 			if (cachedTileset != self.World.Map.Tileset)
 			{
 				cachedTileset = self.World.Map.Tileset;
+				var tileSize = new Size(Game.CellSize, Game.CellSize);
 				sprites = new Cache<TileReference<ushort,byte>, Sprite>(
-				x => Game.modData.SheetBuilder.Add(self.World.TileSet.GetBytes(x),
-					new Size(Game.CellSize, Game.CellSize)));
+					x => Game.modData.SheetBuilder.Add(self.World.TileSet.GetBytes(x), tileSize, true));
 			}
 
 			// Cache templates and tiles for the different states