src/timer/timer_game_calendar.h

   1 /*
   2  * This file is part of OpenTTD.
   3  * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
   4  * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
   5  * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
   6  */
   7
   8 /** @file timer_game_calendar.h Definition of the game-calendar-timer */
   9
  10 #ifndef TIMER_GAME_CALENDAR_H
  11 #define TIMER_GAME_CALENDAR_H
  12
  13 #include "../stdafx.h"
  14 #include "../core/strong_typedef_type.hpp"
  15 #include "timer_game_common.h"
  16
  17 /**
  18  * Timer that is increased every 27ms, and counts towards ticks / days / months / years.
  19  *
  20  * The amount of days in a month depends on the month and year (leap-years).
  21  * There are always 74 ticks in a day (and with 27ms, this makes 1 day 1.998 seconds).
  22  *
  23  * Calendar time is used for technology and time-of-year changes, including:
  24  * - Vehicle, airport, station, object introduction and obsolescence
  25  * - NewGRF variables for visual styles or behavior based on year or time of year (e.g. variable snow line)
  26  * - Inflation, since it is tied to original game years. One interpretation of inflation is that it compensates for faster and higher capacity vehicles,
  27  *   another is that it compensates for more established companies. Each of these point to a different choice of calendar versus economy time, but we have to pick one
  28  *   so we follow a previous decision to tie inflation to original TTD game years.
  29  */
  30 class TimerGameCalendar : public TimerGame<struct Calendar> {
  31 public:
  32         static Year year; ///< Current year, starting at 0.
  33         static Month month; ///< Current month (0..11).
  34         static Date date; ///< Current date in days (day counter).
  35         static DateFract date_fract; ///< Fractional part of the day.
  36         static uint16_t sub_date_fract; ///< Subpart of date_fract that we use when calendar days are slower than economy days.
  37
  38         static YearMonthDay ConvertDateToYMD(Date date);
  39         static Date ConvertYMDToDate(Year year, Month month, Day day);
  40         static void SetDate(Date date, DateFract fract);
  41 };
  42
  43 /**
  44  * Storage class for Calendar time constants.
  45  */
  46 class CalendarTime : public TimerGameConst<struct Calendar> {
  47 public:
  48         static constexpr int DEF_MINUTES_PER_YEAR = 12;
  49         static constexpr int FROZEN_MINUTES_PER_YEAR = 0;
  50         static constexpr int MAX_MINUTES_PER_YEAR = 10080; // One week of real time. The actual max that doesn't overflow TimerGameCalendar::sub_date_fract is 10627, but this is neater.
  51 };
  52
  53 #endif /* TIMER_GAME_CALENDAR_H */