fix black screen when starting level with warp or map in opengl rende…

…r, with startscreen and screenblocks > 10

It's an hack It doesn't really fix the problem but it works

src/d_main.cpp

@@ -1004,6 +1004,8 @@ void D_Display ()
 		twod->Begin(screen->GetWidth(), screen->GetHeight());
 		if (!hud_toggled)
 		{
+			static int saved_screenblocks = screenblocks;
+			//if (gametic == 1) screenblocks = 10;
 			V_DrawBlend(viewsec);
 			if (automapactive)
 			{
@@ -1042,6 +1044,7 @@ void D_Display ()
 				StatusBar->CallDraw (HUD_StatusBar, vp.TicFrac);
 				StatusBar->DrawTopStuff (HUD_StatusBar);
 			}
+			//if (gametic == 1) screenblocks = saved_screenblocks;
 			//stb.Unclock();
 			//Printf("Stbar = %f\n", stb.TimeMS());
 		}