diff --git a/OpenRA.Game/Graphics/Sprite.cs b/OpenRA.Game/Graphics/Sprite.cs
index 4608e5cb75..103c1192ab 100644
--- a/OpenRA.Game/Graphics/Sprite.cs
+++ b/OpenRA.Game/Graphics/Sprite.cs
@@ -48,6 +48,24 @@ namespace OpenRA.Graphics
 		}
 	}
 
+	public class SpriteWithSecondaryData : Sprite
+	{
+		public readonly Rectangle SecondaryBounds;
+		public readonly TextureChannel SecondaryChannel;
+		public readonly float SecondaryTop, SecondaryLeft, SecondaryBottom, SecondaryRight;
+
+		public SpriteWithSecondaryData(Sprite s, Rectangle secondaryBounds, TextureChannel secondaryChannel)
+			: base(s.Sheet, s.Bounds, s.ZRamp, s.Offset, s.Channel, s.BlendMode)
+		{
+			SecondaryBounds = secondaryBounds;
+			SecondaryChannel = secondaryChannel;
+			SecondaryLeft = (float)Math.Min(secondaryBounds.Left, secondaryBounds.Right) / s.Sheet.Size.Width;
+			SecondaryTop = (float)Math.Min(secondaryBounds.Top, secondaryBounds.Bottom) / s.Sheet.Size.Height;
+			SecondaryRight = (float)Math.Max(secondaryBounds.Left, secondaryBounds.Right) / s.Sheet.Size.Width;
+			SecondaryBottom = (float)Math.Max(secondaryBounds.Top, secondaryBounds.Bottom) / s.Sheet.Size.Height;
+		}
+	}
+
 	public enum TextureChannel : byte
 	{
 		Red = 0,
diff --git a/OpenRA.Game/Graphics/Theater.cs b/OpenRA.Game/Graphics/Theater.cs
index f98ba533a6..543fe7762c 100644
--- a/OpenRA.Game/Graphics/Theater.cs
+++ b/OpenRA.Game/Graphics/Theater.cs
@@ -43,7 +43,6 @@ namespace OpenRA.Graphics
 		{
 			this.tileset = tileset;
 			var allocated = false;
-			var type = tileset.EnableDepth ? SheetType.DualIndexed : SheetType.Indexed;
 
 			Func<Sheet> allocate = () =>
 			{
@@ -51,10 +50,10 @@ namespace OpenRA.Graphics
 					throw new SheetOverflowException("Terrain sheet overflow. Try increasing the tileset SheetSize parameter.");
 				allocated = true;
 
-				return new Sheet(type, new Size(tileset.SheetSize, tileset.SheetSize));
+				return new Sheet(SheetType.Indexed, new Size(tileset.SheetSize, tileset.SheetSize));
 			};
 
-			sheetBuilder = new SheetBuilder(type, allocate);
+			sheetBuilder = new SheetBuilder(SheetType.Indexed, allocate);
 			random = new MersenneTwister();
 
 			var frameCache = new FrameCache(Game.ModData.DefaultFileSystem, Game.ModData.SpriteLoaders);
@@ -71,10 +70,17 @@ namespace OpenRA.Graphics
 					{
 						var f = allFrames[j];
 						var s = sheetBuilder.Allocate(f.Size, f.Offset);
-						Util.FastCopyIntoChannel(s, 0, f.Data);
+						Util.FastCopyIntoChannel(s, f.Data);
 
 						if (tileset.EnableDepth)
-							Util.FastCopyIntoChannel(s, 1, allFrames[j + frameCount].Data);
+						{
+							var ss = sheetBuilder.Allocate(f.Size, f.Offset);
+							Util.FastCopyIntoChannel(ss, allFrames[j + frameCount].Data);
+
+							// s and ss are guaranteed to use the same sheet
+							// because of the custom terrain sheet allocation
+							s = new SpriteWithSecondaryData(s, ss.Bounds, ss.Channel);
+						}
 
 						return s;
 					}).ToArray());
diff --git a/OpenRA.Game/Graphics/Util.cs b/OpenRA.Game/Graphics/Util.cs
index 90b28c856d..85e66a1747 100644
--- a/OpenRA.Game/Graphics/Util.cs
+++ b/OpenRA.Game/Graphics/Util.cs
@@ -31,16 +31,28 @@ namespace OpenRA.Graphics
 
 		public static void FastCreateQuad(Vertex[] vertices, float3 a, float3 b, float3 c, float3 d, Sprite r, float paletteTextureIndex, int nv)
 		{
+			float sl = 0;
+			float st = 0;
+			float sr = 0;
+			float sb = 0;
 			var attribC = ChannelSelect[(int)r.Channel];
-			if (r.Sheet.Type == SheetType.DualIndexed)
-				attribC *= -1;
 
-			vertices[nv] = new Vertex(a, r.Left, r.Top, 0, 0, paletteTextureIndex, attribC);
-			vertices[nv + 1] = new Vertex(b, r.Right, r.Top, 0, 0, paletteTextureIndex, attribC);
-			vertices[nv + 2] = new Vertex(c, r.Right, r.Bottom, 0, 0, paletteTextureIndex, attribC);
-			vertices[nv + 3] = new Vertex(c, r.Right, r.Bottom, 0, 0, paletteTextureIndex, attribC);
-			vertices[nv + 4] = new Vertex(d, r.Left, r.Bottom, 0, 0, paletteTextureIndex, attribC);
-			vertices[nv + 5] = new Vertex(a, r.Left, r.Top, 0, 0, paletteTextureIndex, attribC);
+			var ss = r as SpriteWithSecondaryData;
+			if (ss != null)
+			{
+				sl = ss.SecondaryLeft;
+				st = ss.SecondaryTop;
+				sr = ss.SecondaryRight;
+				sb = ss.SecondaryBottom;
+				attribC = -(attribC + ChannelSelect[(int)ss.Channel] / 10);
+			}
+
+			vertices[nv] = new Vertex(a, r.Left, r.Top, sl, st, paletteTextureIndex, attribC);
+			vertices[nv + 1] = new Vertex(b, r.Right, r.Top, sr, st, paletteTextureIndex, attribC);
+			vertices[nv + 2] = new Vertex(c, r.Right, r.Bottom, sr, sb, paletteTextureIndex, attribC);
+			vertices[nv + 3] = new Vertex(c, r.Right, r.Bottom, sr, sb, paletteTextureIndex, attribC);
+			vertices[nv + 4] = new Vertex(d, r.Left, r.Bottom, sl, sb, paletteTextureIndex, attribC);
+			vertices[nv + 5] = new Vertex(a, r.Left, r.Top, sl, st, paletteTextureIndex, attribC);
 		}
 
 		public static void FastCopyIntoChannel(Sprite dest, byte[] src) { FastCopyIntoChannel(dest, 0, src); }
diff --git a/glsl/shp.frag b/glsl/shp.frag
index 17fba1bb96..b167d55721 100644
--- a/glsl/shp.frag
+++ b/glsl/shp.frag
@@ -21,8 +21,8 @@ void main()
 	float depth = gl_FragCoord.z;
 	if (length(vDepthMask) > 0.0)
 	{
-		// Preview vertex aware depth
-		depth = depth + DepthTextureScale * dot(x, vDepthMask);
+		vec4 y = texture2D(DiffuseTexture, vTexCoord.pq);
+		depth = depth + DepthTextureScale * dot(y, vDepthMask);
 	}
 
 	// Convert to window coords
diff --git a/glsl/shp.vert b/glsl/shp.vert
index bd1cae3d2e..87c0ca1b62 100644
--- a/glsl/shp.vert
+++ b/glsl/shp.vert
@@ -11,36 +11,27 @@ varying vec4 vDepthMask;
 
 vec4 DecodeChannelMask(float x)
 {
-	float y = abs(x);
-	if (y > 0.7)
+	if (x > 0.7)
 		return vec4(0,0,0,1);
-	if (y > 0.5)
+	if (x > 0.5)
 		return vec4(0,0,1,0);
-	if (y > 0.3)
+	if (x > 0.3)
 		return vec4(0,1,0,0);
 	else
 		return vec4(1,0,0,0);
 }
 
-vec4 DecodeDepthChannelMask(float x)
-{
-	if (x > 0.0)
-		return vec4(0,0,0,0);
-	if (x < -0.7)
-		return vec4(1,0,0,0);
-	if (x < -0.5)
-		return vec4(0,0,0,1);
-	if (x < -0.3)
-		return vec4(0,0,1,0);
-	else
-		return vec4(0,1,0,0);
-}
-
 void main()
 {
 	gl_Position = vec4((aVertexPosition.xyz - Scroll.xyz) * r1 + r2, 1);
 	vTexCoord = aVertexTexCoord;
 	vTexMetadata = aVertexTexMetadata;
-	vChannelMask = DecodeChannelMask(aVertexTexMetadata.t);
-	vDepthMask = DecodeDepthChannelMask(aVertexTexMetadata.t);
+	vChannelMask = DecodeChannelMask(abs(aVertexTexMetadata.t));
+	if (aVertexTexMetadata.t < 0.0)
+	{
+		float x = -aVertexTexMetadata.t * 10.0;
+		vDepthMask = DecodeChannelMask(x - floor(x));
+	}
+	else
+		vDepthMask = vec4(0,0,0,0);
 }