(svn r19345) -Feature: Realistic acceleration for road vehicles.

9 files changed, 77 insertions, 11 deletions

diff --git a/src/lang/english.txt b/src/lang/english.txt
index 214af8f9e..cc54f7bef 100644
--- a/src/lang/english.txt
+++ b/src/lang/english.txt
@@ -1083,6 +1083,9 @@ STR_CONFIG_SETTING_MAMMOTHTRAINS                                :{LTBLUE}Enable
 STR_CONFIG_SETTING_TRAIN_ACCELERATION_MODEL                     :{LTBLUE}Train acceleration model: {ORANGE}{STRING1}
 STR_CONFIG_SETTING_TRAIN_ACCELERATION_MODEL_ORIGINAL            :Original
 STR_CONFIG_SETTING_TRAIN_ACCELERATION_MODEL_REALISTIC           :Realistic
+STR_CONFIG_SETTING_ROAD_VEHICLE_ACCELERATION_MODEL              :{LTBLUE}Road vehicle acceleration model: {ORANGE}{STRING1}
+STR_CONFIG_SETTING_ROAD_VEHICLE_ACCELERATION_MODEL_ORIGINAL     :Original
+STR_CONFIG_SETTING_ROAD_VEHICLE_ACCELERATION_MODEL_REALISTIC    :Realistic
 STR_CONFIG_SETTING_TRAIN_SLOPE_STEEPNESS                        :{LTBLUE}Slope steepness for trains {ORANGE}{STRING1}%
 STR_CONFIG_SETTING_FORBID_90_DEG                                :{LTBLUE}Forbid trains and ships to make 90 deg turns: {ORANGE}{STRING1} {LTBLUE} (not with OPF)
 STR_CONFIG_SETTING_JOINSTATIONS                                 :{LTBLUE}Join train stations built next to each other: {ORANGE}{STRING1}
diff --git a/src/roadveh.h b/src/roadveh.h
index 97bdce49e..1355bcc54 100644
--- a/src/roadveh.h
+++ b/src/roadveh.h
@@ -133,6 +133,8 @@ struct RoadVehicle : public GroundVehicle<RoadVehicle, VEH_ROAD> {
 
 	bool IsBus() const;
 
+	int GetCurrentMaxSpeed() const;
+
 	/**
 	 * Check if vehicle is a front engine
 	 * @return Returns true if vehicle is a front engine
diff --git a/src/roadveh_cmd.cpp b/src/roadveh_cmd.cpp
index 4e2b2ea87..6f54f2ae9 100644
--- a/src/roadveh_cmd.cpp
+++ b/src/roadveh_cmd.cpp
@@ -287,6 +287,8 @@ CommandCost CmdBuildRoadVeh(TileIndex tile, DoCommandFlag flags, uint32 p1, uint
 			u->InvalidateNewGRFCache();
 		}
 		RoadVehUpdateCache(v);
+		/* Initialize cached values for realistic acceleration. */
+		if (_settings_game.vehicle.roadveh_acceleration_model != AM_ORIGINAL) v->CargoChanged();
 
 		VehicleMove(v, false);
 
@@ -431,6 +433,7 @@ void RoadVehicle::MarkDirty()
 	for (Vehicle *v = this; v != NULL; v = v->Next()) {
 		v->UpdateViewport(false, false);
 	}
+	this->CargoChanged();
 }
 
 void RoadVehicle::UpdateDeltaXY(Direction direction)
@@ -456,6 +459,29 @@ void RoadVehicle::UpdateDeltaXY(Direction direction)
 	this->z_extent      = 6;
 }
 
+/**
+ * Calculates the maximum speed of the vehicle under its current conditions.
+ * @return Maximum speed of the vehicle.
+ */
+FORCEINLINE int RoadVehicle::GetCurrentMaxSpeed() const
+{
+	if (_settings_game.vehicle.roadveh_acceleration_model == AM_ORIGINAL) return this->max_speed;
+
+	int max_speed = this->max_speed;
+
+	/* Limit speed to 50% while reversing, 75% in curves. */
+	for (const RoadVehicle *u = this; u != NULL; u = u->Next()) {
+		if (this->state <= RVSB_TRACKDIR_MASK && IsReversingRoadTrackdir((Trackdir)this->state)) {
+			max_speed = this->max_speed / 2;
+			break;
+		} else if ((u->direction & 1) == 0) {
+			max_speed = this->max_speed * 3 / 4;
+		}
+	}
+
+	return max_speed;
+}
+
 static void DeleteLastRoadVeh(RoadVehicle *v)
 {
 	Vehicle *u = v;
@@ -725,17 +751,20 @@ static void RoadVehArrivesAt(const RoadVehicle *v, Station *st)
 static int RoadVehAccelerate(RoadVehicle *v)
 {
 	uint oldspeed = v->cur_speed;
-	uint accel = 256 + (v->overtaking != 0 ? 256 : 0);
+	uint accel = v->overtaking != 0 ? 256 : 0;
+	accel += (_settings_game.vehicle.roadveh_acceleration_model == AM_ORIGINAL) ? 256 : v->GetAcceleration();
 	uint spd = v->subspeed + accel;
 
 	v->subspeed = (uint8)spd;
 
-	int tempmax = v->max_speed;
-	if (v->cur_speed > v->max_speed) {
+	int tempmax = v->GetCurrentMaxSpeed();
+	if (v->cur_speed > tempmax) {
 		tempmax = v->cur_speed - (v->cur_speed / 10) - 1;
 	}
 
-	v->cur_speed = spd = Clamp(v->cur_speed + ((int)spd >> 8), 0, tempmax);
+	/* Force a minimum speed of 1 km/h when realistic acceleration is on. */
+	int min_speed = (_settings_game.vehicle.roadveh_acceleration_model == AM_ORIGINAL) ? 0 : 4;
+	v->cur_speed = spd = Clamp(v->cur_speed + ((int)spd >> 8), min_speed, tempmax);
 
 	/* Apply bridge speed limit */
 	if (v->state == RVSB_WORMHOLE && !(v->vehstatus & VS_HIDDEN)) {
@@ -873,7 +902,7 @@ static void RoadVehCheckOvertake(RoadVehicle *v, RoadVehicle *u)
 
 static void RoadZPosAffectSpeed(RoadVehicle *v, byte old_z)
 {
-	if (old_z == v->z_pos) return;
+	if (old_z == v->z_pos || _settings_game.vehicle.roadveh_acceleration_model != AM_ORIGINAL) return;
 
 	if (old_z < v->z_pos) {
 		v->cur_speed = v->cur_speed * 232 / 256; // slow down by ~10%
@@ -1317,7 +1346,7 @@ again:
 		}
 		if (new_dir != v->direction) {
 			v->direction = new_dir;
-			v->cur_speed -= v->cur_speed >> 2;
+			if (_settings_game.vehicle.roadveh_acceleration_model == AM_ORIGINAL) v->cur_speed -= v->cur_speed >> 2;
 		}
 		v->x_pos = x;
 		v->y_pos = y;
@@ -1382,7 +1411,7 @@ again:
 
 		if (new_dir != v->direction) {
 			v->direction = new_dir;
-			v->cur_speed -= v->cur_speed >> 2;
+			if (_settings_game.vehicle.roadveh_acceleration_model == AM_ORIGINAL) v->cur_speed -= v->cur_speed >> 2;
 		}
 
 		v->x_pos = x;
@@ -1434,7 +1463,7 @@ again:
 	Direction old_dir = v->direction;
 	if (new_dir != old_dir) {
 		v->direction = new_dir;
-		v->cur_speed -= (v->cur_speed >> 2);
+		if (_settings_game.vehicle.roadveh_acceleration_model == AM_ORIGINAL) v->cur_speed -= v->cur_speed >> 2;
 		if (old_dir != v->state) {
 			/* The vehicle is in a road stop */
 			v->UpdateInclination(false, true);
@@ -1731,6 +1760,7 @@ CommandCost CmdRefitRoadVeh(TileIndex tile, DoCommandFlag flags, uint32 p1, uint
 	if (flags & DC_EXEC) {
 		RoadVehicle *front = v->First();
 		RoadVehUpdateCache(front);
+		if (_settings_game.vehicle.roadveh_acceleration_model != AM_ORIGINAL) front->CargoChanged();
 		SetWindowDirty(WC_VEHICLE_DETAILS, front->index);
 		SetWindowDirty(WC_VEHICLE_DEPOT, front->tile);
 		InvalidateWindowClassesData(WC_ROADVEH_LIST, 0);
diff --git a/src/saveload/vehicle_sl.cpp b/src/saveload/vehicle_sl.cpp
index 5c02573c1..d3f3e44d7 100644
--- a/src/saveload/vehicle_sl.cpp
+++ b/src/saveload/vehicle_sl.cpp
@@ -324,6 +324,9 @@ void AfterLoadVehicles(bool part_of_load)
 			RoadVehicle *rv = RoadVehicle::From(v);
 			if (rv->IsRoadVehFront()) {
 				RoadVehUpdateCache(rv);
+				if (_settings_game.vehicle.roadveh_acceleration_model != AM_ORIGINAL) {
+					rv->CargoChanged();
+				}
 			}
 		}
 	}
diff --git a/src/settings.cpp b/src/settings.cpp
index 051a11e11..b190292e4 100644
--- a/src/settings.cpp
+++ b/src/settings.cpp
@@ -64,6 +64,7 @@
 #include "company_base.h"
 #include "engine_base.h"
 #include "smallmap_gui.h"
+#include "roadveh.h"
 
 #include "void_map.h"
 #include "station_base.h"
@@ -774,6 +775,25 @@ static bool TrainSlopeSteepnessChanged(int32 p1)
 	return true;
 }
 
+/**
+ * This function updates realistic acceleration caches when the setting "Road vehicle acceleration model" is set.
+ * @param p1 Callback parameter
+ * @return Always true
+ */
+static bool RoadVehAccelerationModelChanged(int32 p1)
+{
+	if (_settings_game.vehicle.roadveh_acceleration_model != AM_ORIGINAL) {
+		RoadVehicle *rv;
+		FOR_ALL_ROADVEHICLES(rv) {
+			if (rv->IsRoadVehFront()) {
+				rv->CargoChanged();
+			}
+		}
+	}
+
+	return true;
+}
+
 static bool DragSignalsDensityChanged(int32)
 {
 	InvalidateWindowData(WC_BUILD_SIGNAL, 0);
diff --git a/src/settings_gui.cpp b/src/settings_gui.cpp
index 70dc8a47c..7ce4753e2 100644
--- a/src/settings_gui.cpp
+++ b/src/settings_gui.cpp
@@ -1465,6 +1465,7 @@ static SettingEntry _settings_vehicles[] = {
 	SettingEntry("vehicle.plane_crashes"),
 	SettingEntry("order.timetabling"),
 	SettingEntry("vehicle.dynamic_engines"),
+	SettingEntry("vehicle.roadveh_acceleration_model"),
 };
 /** Vehicles sub-page */
 static SettingsPage _settings_vehicles_page = {_settings_vehicles, lengthof(_settings_vehicles)};
diff --git a/src/settings_type.h b/src/settings_type.h
index 8a7c15ed4..83bce21ad 100644
--- a/src/settings_type.h
+++ b/src/settings_type.h
@@ -310,6 +310,7 @@ struct OrderSettings {
 struct VehicleSettings {
 	bool   mammoth_trains;                   ///< allow very long trains
 	uint8  train_acceleration_model;         ///< realistic acceleration for trains
+	uint8  roadveh_acceleration_model;       ///< realistic acceleration for road vehicles
 	uint8  train_slope_steepness;            ///< Steepness of hills for trains when using realistic acceleration
 	bool   wagon_speed_limits;               ///< enable wagon speed limits
 	bool   disable_elrails;                  ///< when true, the elrails are disabled
diff --git a/src/table/settings.h b/src/table/settings.h
index 81b7a7a9d..e96a1cf35 100644
--- a/src/table/settings.h
+++ b/src/table/settings.h
@@ -23,6 +23,7 @@ static bool DeleteSelectStationWindow(int32 p1);
 static bool UpdateConsists(int32 p1);
 static bool CheckInterval(int32 p1);
 static bool TrainAccelerationModelChanged(int32 p1);
+static bool RoadVehAccelerationModelChanged(int32 p1);
 static bool TrainSlopeSteepnessChanged(int32 p1);
 static bool DragSignalsDensityChanged(int32);
 static bool TownFoundingChanged(int32 p1);
@@ -371,6 +372,7 @@ const SettingDesc _settings[] = {
 	 SDT_CONDVAR(GameSettings, economy.found_town,                   SLE_UINT8,128, SL_MAX_VERSION, 0,MS,TF_FORBIDDEN,TF_BEGIN,TF_END - 1, 1, STR_CONFIG_SETTING_TOWN_FOUNDING, TownFoundingChanged),
 
 	     SDT_VAR(GameSettings, vehicle.train_acceleration_model,     SLE_UINT8,                     0,MS,     0,     0,       1, 1, STR_CONFIG_SETTING_TRAIN_ACCELERATION_MODEL, TrainAccelerationModelChanged),
+	 SDT_CONDVAR(GameSettings, vehicle.roadveh_acceleration_model,   SLE_UINT8,139, SL_MAX_VERSION, 0,MS,     0,     0,       1, 1, STR_CONFIG_SETTING_ROAD_VEHICLE_ACCELERATION_MODEL, RoadVehAccelerationModelChanged),
 	 SDT_CONDVAR(GameSettings, vehicle.train_slope_steepness,        SLE_UINT8,133, SL_MAX_VERSION, 0, 0,     3,     0,      10, 1, STR_CONFIG_SETTING_TRAIN_SLOPE_STEEPNESS,  TrainSlopeSteepnessChanged),
 	    SDT_BOOL(GameSettings, pf.forbid_90_deg,                                                    0, 0, false,                    STR_CONFIG_SETTING_FORBID_90_DEG,          NULL),
 	    SDT_BOOL(GameSettings, vehicle.mammoth_trains,                                              0,NN,  true,                    STR_CONFIG_SETTING_MAMMOTHTRAINS,          NULL),
diff --git a/src/tunnelbridge_cmd.cpp b/src/tunnelbridge_cmd.cpp
index 0956c7002..612c49041 100644
--- a/src/tunnelbridge_cmd.cpp
+++ b/src/tunnelbridge_cmd.cpp
@@ -1477,9 +1477,13 @@ static VehicleEnterTileStatus VehicleEnter_TunnelBridge(Vehicle *v, TileIndex ti
 					ClrBit(t->gv_flags, GVF_GOINGDOWN_BIT);
 				} break;
 
-				case VEH_ROAD:
-					RoadVehicle::From(v)->state = RVSB_WORMHOLE;
-					break;
+				case VEH_ROAD: {
+					RoadVehicle *rv = RoadVehicle::From(v);
+					rv->state = RVSB_WORMHOLE;
+					/* There are no slopes inside bridges / tunnels. */
+					ClrBit(rv->gv_flags, GVF_GOINGUP_BIT);
+					ClrBit(rv->gv_flags, GVF_GOINGDOWN_BIT);
+				} break;
 
 				case VEH_SHIP:
 					Ship::From(v)->state = TRACK_BIT_WORMHOLE;