Add setting for milliseconds per game tick mode

src/date_type.h

@@ -24,8 +24,8 @@ typedef uint8  Day;   ///< Type for the day of the month, note: 1 based, first d
 /**
  * 1 day is 74 ticks; _date_fract used to be uint16 and incremented by 885. On
  *                    an overflow the new day begun and 65535 / 885 = 74.
- * 1 tick is approximately 30 ms.
- * 1 day is thus about 2 seconds (74 * 30 = 2220) on a machine that can run OpenTTD normally
+ * 1 tick is approximately 27 ms.
+ * 1 day is thus about 2 seconds (74 * 27 = 1998) on a machine that can run OpenTTD normally
  */
 static const int DAY_TICKS         =  74; ///< ticks per day
 static const int DAYS_IN_YEAR      = 365; ///< days per year

src/economy_type.h

@@ -241,4 +241,11 @@ enum CargoPaymentAlgorithm : byte {
 	CPA_END,             ///< Used for iterations and limit testing
 };
 
+enum TickRateMode : byte {
+	TRM_BEGIN = 0,       ///< Used for iterations and limit testing
+	TRM_TRADITIONAL = 0, ///< Traditional value (30ms)
+	TRM_MODERN,          ///< Modern value (27ms)
+	TRM_END,             ///< Used for iterations and limit testing
+};
+
 #endif /* ECONOMY_TYPE_H */

src/framerate_gui.cpp

@@ -183,16 +183,13 @@ namespace {
 		}
 	};
 
-	/** %Game loop rate, cycles per second */
-	static const double GL_RATE = 1000.0 / MILLISECONDS_PER_TICK;
-
 	/**
 	 * Storage for all performance element measurements.
 	 * Elements are initialized with the expected rate in recorded values per second.
 	 * @hideinitializer
 	 */
 	PerformanceData _pf_data[PFE_MAX] = {
-		PerformanceData(GL_RATE),               // PFE_GAMELOOP
+		PerformanceData(1),                     // PFE_GAMELOOP
 		PerformanceData(1),                     // PFE_ACC_GL_ECONOMY
 		PerformanceData(1),                     // PFE_ACC_GL_TRAINS
 		PerformanceData(1),                     // PFE_ACC_GL_ROADVEHS
@@ -479,6 +476,7 @@ struct FramerateWindow : Window {
 
 	void UpdateData()
 	{
+		_pf_data[PFE_GAMELOOP].expected_rate = _ticks_per_second;
 		double gl_rate = _pf_data[PFE_GAMELOOP].GetRate();
 		bool have_script = false;
 		this->rate_gameloop.SetRate(gl_rate, _pf_data[PFE_GAMELOOP].expected_rate);

src/gfx.cpp

@@ -46,6 +46,8 @@ bool _shift_pressed;  ///< Is Shift pressed?
 bool _invert_ctrl;
 bool _invert_shift;
 uint16 _game_speed = 100; ///< Current game-speed; 100 is 1x, 0 is infinite.
+uint8 _milliseconds_per_tick = 27; ///< Milliseconds per tick
+float _ticks_per_second;           ///< Ticks per second
 bool _left_button_down;     ///< Is left mouse button pressed?
 bool _left_button_clicked;  ///< Is left mouse button clicked?
 bool _right_button_down;    ///< Is right mouse button pressed?
@@ -2439,3 +2441,9 @@ void ChangeGameSpeed(bool enable_fast_forward)
 		_game_speed = 100;
 	}
 }
+
+void SetupTickRate()
+{
+	_milliseconds_per_tick = (_settings_game.economy.tick_rate == TRM_MODERN) ? 27 : 30;
+	_ticks_per_second = 1000.0f / _milliseconds_per_tick;
+}

src/gfx_func.h

@@ -56,6 +56,8 @@ extern bool _shift_pressed;  ///< Is Shift pressed?
 extern bool _invert_ctrl;
 extern bool _invert_shift;
 extern uint16 _game_speed;
+extern uint8 _milliseconds_per_tick;
+extern float _ticks_per_second;
 
 extern bool _left_button_down;
 extern bool _left_button_clicked;
@@ -79,6 +81,7 @@ void HandleShiftChanged();
 void HandleMouseEvents();
 void UpdateWindows();
 void ChangeGameSpeed(bool enable_fast_forward);
+void SetupTickRate();
 
 void DrawMouseCursor();
 void ScreenSizeChanged();

src/gfx_type.h

@@ -317,8 +317,12 @@ enum SpriteType : byte {
 	ST_INVALID  = 4,      ///< Pseudosprite or other unusable sprite, used only internally
 };
 
-/** The number of milliseconds per game tick. */
-static const uint MILLISECONDS_PER_TICK = 30;
+/**
+ * The number of milliseconds per game tick.
+ * The value 27 together with a day length of 74 ticks makes one day 1998 milliseconds, almost exactly 2 seconds.
+ * With a 2 second day, one standard month is 1 minute, and one standard year is slightly over 12 minutes.
+ */
+#define MILLISECONDS_PER_TICK ((uint)_milliseconds_per_tick)
 
 /** Information about the currently used palette. */
 struct Palette {

src/lang/extra/english.txt

@@ -599,6 +599,11 @@ STR_CONFIG_SETTING_CARGO_PAYMENT_ALGORITHM_HELPTEXT             :The algorithm t
 STR_CONFIG_SETTING_CARGO_PAYMENT_ALGORITHM_TRADITIONAL          :Traditional
 STR_CONFIG_SETTING_CARGO_PAYMENT_ALGORITHM_MODERN               :Modern
 
+STR_CONFIG_SETTING_TICK_RATE                                    :Game tick rate: {STRING2}
+STR_CONFIG_SETTING_TICK_RATE_HELPTEXT                           :Number of milliseconds per game tick.
+STR_CONFIG_SETTING_TICK_RATE_TRADITIONAL                        :30 ms/tick (traditional)
+STR_CONFIG_SETTING_TICK_RATE_MODERN                             :27 ms/tick (modern)
+
 STR_CONFIG_SETTING_TOWN_MIN_DISTANCE                            :Minimum distance between towns: {STRING2}
 STR_CONFIG_SETTING_TOWN_MIN_DISTANCE_HELPTEXT                   :Set the minimum distance in tiles between towns for map generation and random founding
 

src/openttd.cpp

@@ -568,6 +568,8 @@ void MakeNewgameSettingsLive()
 	if (_settings_newgame.game_config != nullptr) {
 		_settings_game.game_config = new GameConfig(_settings_newgame.game_config);
 	}
+
+	SetupTickRate();
 }
 
 void OpenBrowser(const char *url)
@@ -2027,7 +2029,7 @@ void StateGameLoop()
 		_scaled_date_ticks++;   // This must update in lock-step with _tick_skip_counter, such that it always matches what SetScaledTickVariables would return.
 
 		if (_settings_client.gui.autosave == 6 && !(_game_mode == GM_MENU || _game_mode == GM_BOOTSTRAP) &&
-				(_scaled_date_ticks % (_settings_client.gui.autosave_custom_minutes * (60000 / MILLISECONDS_PER_TICK))) == 0) {
+				(_scaled_date_ticks % (_settings_client.gui.autosave_custom_minutes * (_settings_game.economy.tick_rate == TRM_MODERN ? (60000 / 27) : (60000 / 30)))) == 0) {
 			_do_autosave = true;
 			_check_special_modes = true;
 			SetWindowDirty(WC_STATUS_BAR, 0);

src/saveload/afterload.cpp

@@ -4191,6 +4191,10 @@ bool AfterLoadGame()
 		_settings_game.economy.payment_algorithm = IsSavegameVersionBefore(SLV_MORE_CARGO_AGE) ? CPA_TRADITIONAL : CPA_MODERN;
 	}
 
+	if (SlXvIsFeatureMissing(XSLFI_VARIABLE_TICK_RATE)) {
+		_settings_game.economy.tick_rate = IsSavegameVersionUntil(SLV_MORE_CARGO_AGE) ? TRM_TRADITIONAL : TRM_MODERN;
+	}
+
 	InitializeRoadGUI();
 
 	/* This needs to be done after conversion. */
@@ -4207,6 +4211,8 @@ bool AfterLoadGame()
 
 	GamelogPrintDebug(1);
 
+	SetupTickRate();
+
 	InitializeWindowsAndCaches();
 	/* Restore the signals */
 	ResetSignalHandlers();

src/saveload/extended_ver_sl.cpp

@@ -188,6 +188,7 @@ const SlxiSubChunkInfo _sl_xv_sub_chunk_infos[] = {
 	{ XSLFI_MULTI_CARGO_SHIPS,                XSCF_NULL,                1,   1, "multi_cargo_ships",                nullptr, nullptr, nullptr          },
 	{ XSLFI_REMAIN_NEXT_ORDER_STATION,        XSCF_IGNORABLE_UNKNOWN,   1,   1, "remain_next_order_station",        nullptr, nullptr, nullptr          },
 	{ XSLFI_LABEL_ORDERS,                     XSCF_NULL,                2,   2, "label_orders",                     nullptr, nullptr, nullptr          },
+	{ XSLFI_VARIABLE_TICK_RATE,               XSCF_IGNORABLE_ALL,       1,   1, "variable_tick_rate",               nullptr, nullptr, nullptr          },
 	{ XSLFI_SCRIPT_INT64,                     XSCF_NULL,                1,   1, "script_int64",                     nullptr, nullptr, nullptr          },
 	{ XSLFI_U64_TICK_COUNTER,                 XSCF_NULL,                1,   1, "u64_tick_counter",                 nullptr, nullptr, nullptr          },
 	{ XSLFI_LINKGRAPH_TRAVEL_TIME,            XSCF_NULL,                1,   1, "linkgraph_travel_time",            nullptr, nullptr, nullptr          },

src/saveload/extended_ver_sl.h

@@ -139,6 +139,7 @@ enum SlXvFeatureIndex {
 	XSLFI_MULTI_CARGO_SHIPS,                      ///< Multi-cargo ships
 	XSLFI_REMAIN_NEXT_ORDER_STATION,              ///< Remain in station if next order is for same station
 	XSLFI_LABEL_ORDERS,                           ///< Label orders
+	XSLFI_VARIABLE_TICK_RATE,                     ///< Variable tick rate
 
 	XSLFI_SCRIPT_INT64,                           ///< See: SLV_SCRIPT_INT64
 	XSLFI_U64_TICK_COUNTER,                       ///< See: SLV_U64_TICK_COUNTER

src/settings_gui.cpp

@@ -2295,6 +2295,7 @@ static SettingsContainer &GetSettingsTree()
 			environment->Add(new SettingEntry("station.catchment_increase"));
 			environment->Add(new SettingEntry("station.cargo_class_rating_wait_time"));
 			environment->Add(new SettingEntry("station.station_size_rating_cargo_amount"));
+			environment->Add(new SettingEntry("economy.tick_rate"));
 		}
 
 		SettingsPage *ai = main->Add(new SettingsPage(STR_CONFIG_SETTING_AI));

src/settings_type.h

@@ -706,6 +706,7 @@ struct EconomySettings {
 	uint16 random_road_reconstruction;       ///< chance out of 1000 per tile loop for towns to start random road re-construction
 	bool disable_inflation_newgrf_flag;      ///< Disable NewGRF inflation flag
 	CargoPaymentAlgorithm payment_algorithm; ///< Cargo payment algorithm
+	TickRateMode tick_rate;                  ///< Tick rate mode
 };
 
 struct LinkGraphSettings {

src/table/settings/settings.ini

@@ -3251,6 +3251,21 @@ strval   = STR_CONFIG_SETTING_CARGO_PAYMENT_ALGORITHM_TRADITIONAL
 cat      = SC_BASIC
 patxname = ""economy.payment_algorithm""
 
+[SDT_VAR]
+var      = economy.tick_rate
+type     = SLE_UINT8
+flags    = SF_GUI_DROPDOWN
+def      = TRM_TRADITIONAL
+min      = TRM_BEGIN
+max      = TRM_END - 1
+interval = 1
+str      = STR_CONFIG_SETTING_TICK_RATE
+strhelp  = STR_CONFIG_SETTING_TICK_RATE_HELPTEXT
+strval   = STR_CONFIG_SETTING_TICK_RATE_TRADITIONAL
+cat      = SC_EXPERT
+post_cb  = [](auto) { SetupTickRate(); }
+patxname = ""economy.tick_rate""
+
 ##
 [SDT_VAR]
 var      = pf.wait_for_pbs_path