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-rw-r--r--src/ground_vehicle.cpp30
-rw-r--r--src/ground_vehicle.hpp4
-rw-r--r--src/roadveh.h20
-rw-r--r--src/train.h19
4 files changed, 40 insertions, 33 deletions
diff --git a/src/ground_vehicle.cpp b/src/ground_vehicle.cpp
index f3ba7d775..66e5b9933 100644
--- a/src/ground_vehicle.cpp
+++ b/src/ground_vehicle.cpp
@@ -30,12 +30,11 @@ void GroundVehicle<T, Type>::PowerChanged()
uint16 max_track_speed = v->GetDisplayMaxSpeed();
for (const T *u = v; u != NULL; u = u->Next()) {
- uint32 current_power = u->GetPower();
+ uint32 current_power = u->GetPower() + u->GetPoweredPartPower(u);
total_power += current_power;
/* Only powered parts add tractive effort. */
if (current_power > 0) max_te += u->GetWeight() * u->GetTractiveEffort();
- total_power += u->GetPoweredPartPower(v);
number_of_parts++;
/* Get minimum max speed for this track. */
@@ -43,8 +42,6 @@ void GroundVehicle<T, Type>::PowerChanged()
if (track_speed > 0) max_track_speed = min(max_track_speed, track_speed);
}
- this->acc_cache.cached_axle_resistance = 60 * number_of_parts;
-
byte air_drag;
byte air_drag_value = v->GetAirDrag();
@@ -87,11 +84,14 @@ void GroundVehicle<T, Type>::CargoChanged()
for (T *u = T::From(this); u != NULL; u = u->Next()) {
uint32 current_weight = u->GetWeight();
weight += current_weight;
- u->acc_cache.cached_slope_resistance = current_weight * u->GetSlopeSteepness();
+ /* Slope steepness is in percent, result in N. */
+ u->acc_cache.cached_slope_resistance = current_weight * u->GetSlopeSteepness() * 100;
}
/* Store consist weight in cache. */
this->acc_cache.cached_weight = max<uint32>(1, weight);
+ /* Friction in bearings and other mechanical parts is 0.1% of the weight (result in N). */
+ this->acc_cache.cached_axle_resistance = 10 * weight;
/* Now update vehicle power (tractive effort is dependent on weight). */
this->PowerChanged();
@@ -106,7 +106,7 @@ int GroundVehicle<T, Type>::GetAcceleration() const
{
/* Templated class used for function calls for performance reasons. */
const T *v = T::From(this);
- int32 speed = v->GetCurrentSpeed();
+ int32 speed = v->GetCurrentSpeed(); // [km/h-ish]
/* Weight is stored in tonnes. */
int32 mass = this->acc_cache.cached_weight;
@@ -120,16 +120,15 @@ int GroundVehicle<T, Type>::GetAcceleration() const
const int area = v->GetAirDragArea();
if (!maglev) {
- resistance = (13 * mass) / 10;
- resistance += this->acc_cache.cached_axle_resistance;
- resistance += (v->GetRollingFriction() * mass * speed) / 1000;
- resistance += (area * this->acc_cache.cached_air_drag * speed * speed) / 10000;
- } else {
- resistance += (area * this->acc_cache.cached_air_drag * speed * speed) / 20000;
+ /* Static resistance plus rolling friction. */
+ resistance = this->acc_cache.cached_axle_resistance;
+ resistance += mass * v->GetRollingFriction();
}
+ /* Air drag; the air drag coefficient is in an arbitrary NewGRF-unit,
+ * so we need some magic conversion factor. */
+ resistance += (area * this->acc_cache.cached_air_drag * speed * speed) / 500;
resistance += this->GetSlopeResistance();
- resistance *= 4; //[N]
/* This value allows to know if the vehicle is accelerating or braking. */
AccelStatus mode = v->GetAccelerationStatus();
@@ -138,9 +137,8 @@ int GroundVehicle<T, Type>::GetAcceleration() const
int force;
if (speed > 0) {
if (!maglev) {
- force = power / speed; //[N]
- force *= 22;
- force /= 10;
+ /* Conversion factor from km/h to m/s is 5/18 to get [N] in the end. */
+ force = power * 18 / (speed * 5);
if (mode == AS_ACCEL && force > max_te) force = max_te;
} else {
force = power / 25;
diff --git a/src/ground_vehicle.hpp b/src/ground_vehicle.hpp
index 77822abc9..e518e183f 100644
--- a/src/ground_vehicle.hpp
+++ b/src/ground_vehicle.hpp
@@ -30,12 +30,12 @@ struct AccelerationCache {
uint32 cached_weight; ///< Total weight of the consist.
uint32 cached_slope_resistance; ///< Resistance caused by weight when this vehicle part is at a slope.
uint32 cached_max_te; ///< Maximum tractive effort of consist.
+ uint16 cached_axle_resistance; ///< Resistance caused by the axles of the vehicle.
/* Cached values, recalculated on load and each time a vehicle is added to/removed from the consist. */
+ uint16 cached_max_track_speed; ///< Maximum consist speed limited by track type.
uint32 cached_power; ///< Total power of the consist.
uint32 cached_air_drag; ///< Air drag coefficient of the vehicle.
- uint16 cached_axle_resistance; ///< Resistance caused by the axles of the vehicle.
- uint16 cached_max_track_speed; ///< Maximum consist speed limited by track type.
};
/** Ground vehicle flags. */
diff --git a/src/roadveh.h b/src/roadveh.h
index 96a86bafa..faaadab35 100644
--- a/src/roadveh.h
+++ b/src/roadveh.h
@@ -217,11 +217,11 @@ protected: // These functions should not be called outside acceleration code.
/**
* Gets the area used for calculating air drag.
- * @return Area of the engine.
+ * @return Area of the engine in m^2.
*/
FORCEINLINE byte GetAirDragArea() const
{
- return 60;
+ return 6;
}
/**
@@ -244,21 +244,25 @@ protected: // These functions should not be called outside acceleration code.
/**
* Calculates the current speed of this vehicle.
- * @return Current speed in mph.
+ * @return Current speed in km/h-ish.
*/
FORCEINLINE uint16 GetCurrentSpeed() const
{
- return this->cur_speed * 10 / 32;
+ return this->cur_speed / 2;
}
/**
* Returns the rolling friction coefficient of this vehicle.
- * @return Rolling friction coefficient in [1e-3].
+ * @return Rolling friction coefficient in [1e-4].
*/
FORCEINLINE uint32 GetRollingFriction() const
{
- /* Trams have a slightly greater friction coefficient than trains. The rest of road vehicles have bigger values. */
- return (this->roadtype == ROADTYPE_TRAM) ? 50 : 75;
+ /* Trams have a slightly greater friction coefficient than trains.
+ * The rest of road vehicles have bigger values. */
+ uint32 coeff = (this->roadtype == ROADTYPE_TRAM) ? 40 : 75;
+ /* The friction coefficient increases with speed in a way that
+ * it doubles at 128 km/h, triples at 256 km/h and so on. */
+ return coeff * (128 + this->GetCurrentSpeed()) / 128;
}
/**
@@ -276,7 +280,7 @@ protected: // These functions should not be called outside acceleration code.
*/
FORCEINLINE uint32 GetSlopeSteepness() const
{
- return 20 * _settings_game.vehicle.roadveh_slope_steepness; // 1% slope * slope steepness
+ return _settings_game.vehicle.roadveh_slope_steepness;
}
/**
diff --git a/src/train.h b/src/train.h
index b334c0b92..d407c48ee 100644
--- a/src/train.h
+++ b/src/train.h
@@ -438,11 +438,12 @@ protected: // These functions should not be called outside acceleration code.
/**
* Gets the area used for calculating air drag.
- * @return Area of the engine.
+ * @return Area of the engine in m^2.
*/
FORCEINLINE byte GetAirDragArea() const
{
- return 120;
+ /* Air drag is higher in tunnels due to the limited cross-section. */
+ return (this->track == TRACK_BIT_WORMHOLE && this->vehstatus & VS_HIDDEN) ? 28 : 14;
}
/**
@@ -465,20 +466,24 @@ protected: // These functions should not be called outside acceleration code.
/**
* Calculates the current speed of this vehicle.
- * @return Current speed in mph.
+ * @return Current speed in km/h-ish.
*/
FORCEINLINE uint16 GetCurrentSpeed() const
{
- return this->cur_speed * 10 / 16;
+ return this->cur_speed;
}
/**
* Returns the rolling friction coefficient of this vehicle.
- * @return Rolling friction coefficient in [1e-3].
+ * @return Rolling friction coefficient in [1e-4].
*/
FORCEINLINE uint32 GetRollingFriction() const
{
- return 35;
+ /* Rolling friction for steel on steel is between 0.1% and 0.2%,
+ * but we use a higher value here to get better game-play results.
+ * The friction coefficient increases with speed in a way that
+ * it doubles at 512 km/h, triples at 1024 km/h and so on. */
+ return 30 * (512 + this->GetCurrentSpeed()) / 512;
}
/**
@@ -496,7 +501,7 @@ protected: // These functions should not be called outside acceleration code.
*/
FORCEINLINE uint32 GetSlopeSteepness() const
{
- return 20 * _settings_game.vehicle.train_slope_steepness; // 1% slope * slope steepness
+ return _settings_game.vehicle.train_slope_steepness;
}
/**
generated by cgit v1.2.3-54-g00ecf (git 2.44.0) at 2024-06-30 02:19:37 +0000