diff --git a/OpenRA.FileFormats/Graphics/IGraphicsDevice.cs b/OpenRA.FileFormats/Graphics/IGraphicsDevice.cs
index 9be4681fc8..efd2bb6cfb 100755
--- a/OpenRA.FileFormats/Graphics/IGraphicsDevice.cs
+++ b/OpenRA.FileFormats/Graphics/IGraphicsDevice.cs
@@ -32,7 +32,7 @@ namespace OpenRA.FileFormats.Graphics
 		IGraphicsDevice Create( Size size, WindowMode windowMode );
 	}
 
-	public enum BlendMode { None, Alpha, Additive }
+	public enum BlendMode { None, Alpha, Additive, Subtractive }
 
 	public interface IGraphicsDevice
 	{
diff --git a/OpenRA.Renderer.SdlCommon/SdlGraphics.cs b/OpenRA.Renderer.SdlCommon/SdlGraphics.cs
index f8ab2ecde7..8c8de209e3 100644
--- a/OpenRA.Renderer.SdlCommon/SdlGraphics.cs
+++ b/OpenRA.Renderer.SdlCommon/SdlGraphics.cs
@@ -154,6 +154,9 @@ namespace OpenRA.Renderer.SdlCommon
 
 		public void SetBlendMode(BlendMode mode)
 		{
+			Gl.glBlendEquation(Gl.GL_FUNC_ADD);
+			ErrorHandler.CheckGlError();
+
 			switch (mode)
 			{
 				case BlendMode.None:
@@ -169,6 +172,13 @@ namespace OpenRA.Renderer.SdlCommon
 					ErrorHandler.CheckGlError();
 					Gl.glBlendFunc(Gl.GL_ONE, Gl.GL_ONE);
 					break;
+				case BlendMode.Subtractive:
+					Gl.glEnable(Gl.GL_BLEND);
+					ErrorHandler.CheckGlError();
+					Gl.glBlendFunc(Gl.GL_ONE, Gl.GL_ONE);
+					ErrorHandler.CheckGlError();
+					Gl.glBlendEquation(Gl.GL_FUNC_REVERSE_SUBTRACT);
+					break;
 			}
 			ErrorHandler.CheckGlError();
 		}