diff --git a/src/screen.c b/src/screen.c
index 9d36eee39..744523dab 100644
--- a/src/screen.c
+++ b/src/screen.c
@@ -217,7 +217,7 @@ void SCR_SetMode(void)
 
 	// Set the video mode in the video interface.
 	if (setmodeneeded)
-		VID_SetMode(--setmodeneeded);
+		VID_SetMode(setmodeneeded - 1);
 
 	V_SetPalette(0);