function glMatrices():pointer;
  var funcSystemTime:uInt32;
  begin
    if (funcSystemTime:=getSystemTime())-oglMatricesTimeLast>oglCacheTime then
      begin
        if (result:=glxMatrices())<>nil then
          begin
            oglMatrices:=result;
            oglMatricesTimeLast:=funcSystemTime;
          end;
      end
    else
      result:=oglMatrices;
   exit(result);
  end;