mirrors
/
OpenTTD
mirror of https://github.com/OpenTTD/OpenTTD.git
2
0
Fork 0
Code Issues Projects Releases Wiki Activity

(svn r21106) -Change: Tuned realistic acceleration to be a bit more realistic in order to make acceleration "slower", which highlights the differences between vehicle types more.

This commit is contained in:
michi_cc 2010-11-07 13:35:07 +00:00
parent 1ee62de0a3
commit 2d801c64a1
4 changed files with 40 additions and 33 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

30
src/ground_vehicle.cpp
View File

@ -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;

4
src/ground_vehicle.hpp
View File

@ -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. */

20
src/roadveh.h
View File

@ -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;
}
/**

19
src/train.h
View File

@ -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;
}
/**