diff --git a/source/glbackend/glbackend.h b/source/glbackend/glbackend.h
index 5c44220cf..b5301bf4c 100644
--- a/source/glbackend/glbackend.h
+++ b/source/glbackend/glbackend.h
@@ -373,7 +373,7 @@ public:
 
 	void SetFadeDisable(bool yes)
 	{
-		if (!yes) renderState.Flags |= RF_FogDisabled;
+		if (yes) renderState.Flags |= RF_FogDisabled;
 		else renderState.Flags &= ~RF_FogDisabled;
 	}