doom2df old renderer speed question for ketmar

// old algo (alas, no visible set)
procedure g_Map_DrawPanels (PanelType: Word; hasAmbient: Boolean; constref ambColor: TDFColor);

  procedure DrawGeneral (constref panels: TPanelArray); inline;
  var
    i: Integer;
  begin
    if panels <> nil then
    begin
      for i := 0 to High(panels) do
        if not panels[i].Door then panels[i].Draw(hasAmbient, ambColor);
    end;
  end;

  procedure DrawDoors (constref panels: TPanelArray); inline;
  var
    i: Integer;
  begin
    if panels <> nil then
    begin
      for i := 0 to High(panels) do
        if panels[i].Enabled then panels[i].Draw(hasAmbient, ambColor);
    end;
  end;

begin
  case PanelType of
    PANEL_WALL:       DrawGeneral(gWalls);
    PANEL_CLOSEDOOR:  DrawDoors(gWalls);
    PANEL_BACK:       DrawGeneral(gRenderBackgrounds);
    PANEL_FORE:       DrawGeneral(gRenderForegrounds);
    PANEL_WATER:      DrawGeneral(gWater);
    PANEL_ACID1:      DrawGeneral(gAcid1);
    PANEL_ACID2:      DrawGeneral(gAcid2);
    PANEL_STEP:       DrawGeneral(gSteps);
  end;
end;