diff --git a/renderer/RenderSystem.h b/renderer/RenderSystem.h
index 253b9eb..b57aad9 100644
--- a/renderer/RenderSystem.h
+++ b/renderer/RenderSystem.h
@@ -59,7 +59,7 @@ typedef struct glconfig_s {
 	int					maxTextureImageUnits;
 	float				maxTextureAnisotropy;
 
-	int					colorBits, depthBits, stencilBits;
+	int					colorBits, alphabits, depthBits, stencilBits;
 
 	bool				multitextureAvailable;
 	bool				textureCompressionAvailable;
@@ -88,6 +88,10 @@ typedef struct glconfig_s {
 	bool				allowARB2Path;
 
 	bool				isInitialized;
+
+	// DG: current video backend is known to need opaque default framebuffer
+	//     used if r_fillWindowAlphaChan == -1
+	bool				shouldFillWindowAlpha;
 } glconfig_t;