Feature: [NewGRF] Allow higher max speeds for ships

src/engine.cpp

@@ -87,6 +87,8 @@ Engine::Engine(VehicleType type, EngineID base)
 		if (type == VEH_ROAD) this->u.road.tractive_effort = 0x4C;
 		/* Aircraft must have INVALID_CARGO as default, as there is no property */
 		if (type == VEH_AIRCRAFT) this->info.cargo_type = INVALID_CARGO;
+		/* Ships must have a non-zero acceleration. */
+		if (type == VEH_SHIP) this->u.ship.acceleration = 1;
 		/* Set visual effect to the default value */
 		switch (type) {
 			case VEH_TRAIN: this->u.rail.visual_effect = VE_DEFAULT; break;

src/engine_type.h

@@ -67,6 +67,7 @@ struct RailVehicleInfo {
 struct ShipVehicleInfo {
 	byte image_index;
 	byte cost_factor;
+	uint8_t acceleration;    ///< Acceleration (1 unit = 1/3.2 mph per tick = 0.5 km-ish/h per tick)
 	uint16_t max_speed;      ///< Maximum speed (1 unit = 1/3.2 mph = 0.5 km-ish/h)
 	uint16_t capacity;
 	byte running_cost;

src/newgrf.cpp

@@ -1586,7 +1586,7 @@ static ChangeInfoResult ShipVehicleChangeInfo(uint engine, int numinfo, int prop
 				svi->cost_factor = buf->ReadByte();
 				break;
 
-			case PROP_SHIP_SPEED: // 0x0B Speed (1 unit is 0.5 km-ish/h)
+			case PROP_SHIP_SPEED: // 0x0B Speed (1 unit is 0.5 km-ish/h). Use 0x23 to achieve higher speeds.
 				svi->max_speed = buf->ReadByte();
 				break;
 
@@ -1714,6 +1714,14 @@ static ChangeInfoResult ShipVehicleChangeInfo(uint engine, int numinfo, int prop
 				SB(ei->callback_mask, 8, 8, buf->ReadByte());
 				break;
 
+			case 0x23: // Speed (1 unit is 0.5 km-ish/h)
+				svi->max_speed = buf->ReadWord();
+				break;
+
+			case 0x24: // Acceleration (1 unit is 0.5 km-ish/h per tick)
+				svi->acceleration = std::max<uint8_t>(1, buf->ReadByte());
+				break;
+
 			default:
 				ret = CommonVehicleChangeInfo(ei, prop, buf);
 				break;

src/saveload/afterload.cpp

@@ -3273,6 +3273,13 @@ bool AfterLoadGame()
 		}
 	}
 
+	if (IsSavegameVersionBefore(SLV_SHIP_ACCELERATION)) {
+		/* NewGRF acceleration information was added to ships. */
+		for (Ship *s : Ship::Iterate()) {
+			if (s->acceleration == 0) s->acceleration = ShipVehInfo(s->engine_type)->acceleration;
+		}
+	}
+
 	for (Company *c : Company::Iterate()) {
 		UpdateCompanyLiveries(c);
 	}

src/saveload/saveload.h

@@ -371,6 +371,7 @@ enum SaveLoadVersion : uint16_t {
 	SLV_ECONOMY_DATE,                       ///< 326  PR#10700 Split calendar and economy timers and dates.
 	SLV_ECONOMY_MODE_TIMEKEEPING_UNITS,     ///< 327  PR#11341 Mode to display economy measurements in wallclock units.
 	SLV_CALENDAR_SUB_DATE_FRACT,            ///< 328  PR#11428 Add sub_date_fract to measure calendar days.
+	SLV_SHIP_ACCELERATION,                  ///< 329  PR#10734 Start using Vehicle's acceleration field for ships too.
 
 	SL_MAX_VERSION,                         ///< Highest possible saveload version
 };

src/ship_cmd.cpp

@@ -449,8 +449,7 @@ static bool CheckShipLeaveDepot(Ship *v)
 static uint ShipAccelerate(Vehicle *v)
 {
 	uint speed;
-
-	speed = std::min<uint>(v->cur_speed + 1, v->vcache.cached_max_speed);
+	speed = std::min<uint>(v->cur_speed + v->acceleration, v->vcache.cached_max_speed);
 	speed = std::min<uint>(speed, v->current_order.GetMaxSpeed() * 2);
 
 	/* updates statusbar only if speed have changed to save CPU time */
@@ -745,6 +744,8 @@ static void ShipController(Ship *v)
 
 	const uint number_of_steps = ShipAccelerate(v);
 	for (uint i = 0; i < number_of_steps; ++i) {
+		if (ShipMoveUpDownOnLock(v)) return;
+
 		GetNewVehiclePosResult gp = GetNewVehiclePos(v);
 		if (v->state != TRACK_BIT_WORMHOLE) {
 			/* Not on a bridge */
@@ -949,6 +950,7 @@ CommandCost CmdBuildShip(DoCommandFlag flags, TileIndex tile, const Engine *e, V
 		v->sprite_cache.sprite_seq.Set(SPR_IMG_QUERY);
 		v->random_bits = Random();
 
+		v->acceleration = svi->acceleration;
 		v->UpdateCache();
 
 		if (e->flags & ENGINE_EXCLUSIVE_PREVIEW) SetBit(v->vehicle_flags, VF_BUILT_AS_PROTOTYPE);

src/table/engines.h

@@ -557,29 +557,30 @@ static const RailVehicleInfo _orig_rail_vehicle_info[] = {
  * @see ShipVehicleInfo
  * @param a image_index
  * @param b cost_factor
- * @param c max_speed (1 unit = 1/3.2 mph = 0.5 km-ish/h)
- * @param d capacity (persons, bags, tons, pieces, items, cubic metres, ...)
- * @param e running_cost
- * @param f sound effect
- * @param g refittable
+ * @param c acceleration (1 unit = 1/3.2 mph per tick = 0.5 km-ish/h per tick)
+ * @param d max_speed (1 unit = 1/3.2 mph = 0.5 km-ish/h)
+ * @param e capacity (persons, bags, tons, pieces, items, cubic metres, ...)
+ * @param f running_cost
+ * @param g sound effect
+ * @param h refittable
  */
-#define SVI(a, b, c, d, e, f, g) { a, b, c, d, e, f, g, VE_DEFAULT, 0, 0 }
+#define SVI(a, b, c, d, e, f, g, h) { a, b, c, d, e, f, g, h, VE_DEFAULT, 0, 0 }
 static const ShipVehicleInfo _orig_ship_vehicle_info[] = {
-	/*   image_index    capacity                              refittable
-	 *   |    cost_factor    running_cost                     |
-	 *   |    |    max_speed |  sfx                           |
-	 *   |    |    |    |    |  |                             | */
-	SVI( 1, 160,  48, 220, 140, SND_06_DEPARTURE_CARGO_SHIP,  0 ), //  0 MPS Oil Tanker
-	SVI( 1, 176,  80, 350, 125, SND_06_DEPARTURE_CARGO_SHIP,  0 ), //  1 CS-Inc. Oil Tanker
-	SVI( 2,  96,  64, 100,  90, SND_07_DEPARTURE_FERRY,       0 ), //  2 MPS Passenger Ferry
-	SVI( 2, 112, 128, 130,  80, SND_07_DEPARTURE_FERRY,       0 ), //  3 FFP Passenger Ferry
-	SVI( 3, 148, 224, 100, 190, SND_07_DEPARTURE_FERRY,       0 ), //  4 Bakewell 300 Hovercraft
-	SVI( 2,  96,  64, 100,  90, SND_07_DEPARTURE_FERRY,       0 ), //  5 Chugger-Chug Passenger Ferry
-	SVI( 2, 112, 128, 130,  80, SND_07_DEPARTURE_FERRY,       0 ), //  6 Shivershake Passenger Ferry
-	SVI( 0, 128,  48, 160, 150, SND_06_DEPARTURE_CARGO_SHIP,  1 ), //  7 Yate Cargo ship
-	SVI( 0, 144,  80, 190, 113, SND_06_DEPARTURE_CARGO_SHIP,  1 ), //  8 Bakewell Cargo ship
-	SVI( 0, 128,  48, 160, 150, SND_06_DEPARTURE_CARGO_SHIP,  1 ), //  9 Mightymover Cargo ship
-	SVI( 0, 144,  80, 190, 113, SND_06_DEPARTURE_CARGO_SHIP,  1 ), // 10 Powernaut Cargo ship
+	/*   image_index  max_speed         sfx                      refittable
+	 *   |    cost_factor  capacity     |                        |
+	 *   |    |  acceleration   running_cost                     |
+	 *   |    |  |    |    |    |       |                        | */
+	SVI( 1, 160, 1,  48, 220, 140, SND_06_DEPARTURE_CARGO_SHIP,  0 ), //  0 MPS Oil Tanker
+	SVI( 1, 176, 1,  80, 350, 125, SND_06_DEPARTURE_CARGO_SHIP,  0 ), //  1 CS-Inc. Oil Tanker
+	SVI( 2,  96, 1,  64, 100,  90, SND_07_DEPARTURE_FERRY,       0 ), //  2 MPS Passenger Ferry
+	SVI( 2, 112, 1, 128, 130,  80, SND_07_DEPARTURE_FERRY,       0 ), //  3 FFP Passenger Ferry
+	SVI( 3, 148, 1, 224, 100, 190, SND_07_DEPARTURE_FERRY,       0 ), //  4 Bakewell 300 Hovercraft
+	SVI( 2,  96, 1,  64, 100,  90, SND_07_DEPARTURE_FERRY,       0 ), //  5 Chugger-Chug Passenger Ferry
+	SVI( 2, 112, 1, 128, 130,  80, SND_07_DEPARTURE_FERRY,       0 ), //  6 Shivershake Passenger Ferry
+	SVI( 0, 128, 1,  48, 160, 150, SND_06_DEPARTURE_CARGO_SHIP,  1 ), //  7 Yate Cargo ship
+	SVI( 0, 144, 1,  80, 190, 113, SND_06_DEPARTURE_CARGO_SHIP,  1 ), //  8 Bakewell Cargo ship
+	SVI( 0, 128, 1,  48, 160, 150, SND_06_DEPARTURE_CARGO_SHIP,  1 ), //  9 Mightymover Cargo ship
+	SVI( 0, 144, 1,  80, 190, 113, SND_06_DEPARTURE_CARGO_SHIP,  1 ), // 10 Powernaut Cargo ship
 };
 #undef SVI