dave/openttd
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Add feature: realistic train braking

Browse Source 
Add setting to select train braking model.
This commit is contained in:
Jonathan G Rennison
2021-01-25 02:33:14 +00:00
parent 2b02318c7e
commit ed0ffb6220
37 changed files with 2556 additions and 291 deletions
Download Patch File Download Diff File Expand all files Collapse all files

40
src/ground_vehicle.cpp
View File

@@ -105,6 +105,7 @@ void GroundVehicle<T, Type>::CargoChanged()
for (T *u = T::From(this); u != nullptr; u = u->Next()) {
uint32 current_weight = u->GetWeight();
if (Type == VEH_TRAIN) Train::From(u)->tcache.cached_veh_weight = current_weight;
weight += current_weight;
/* Slope steepness is in percent, result in N. */
u->gcache.cached_slope_resistance = current_weight * u->GetSlopeSteepness() * 100;
@@ -123,10 +124,10 @@ void GroundVehicle<T, Type>::CargoChanged()
/**
* Calculates the acceleration of the vehicle under its current conditions.
* @return Current acceleration of the vehicle.
* @return Current upper and lower bounds of acceleration of the vehicle.
*/
template <class T, VehicleType Type>
int GroundVehicle<T, Type>::GetAcceleration()
GroundVehicleAcceleration GroundVehicle<T, Type>::GetAcceleration()
{
/* Templated class used for function calls for performance reasons. */
const T *v = T::From(this);
@@ -172,6 +173,8 @@ int GroundVehicle<T, Type>::GetAcceleration()
/* This value allows to know if the vehicle is accelerating or braking. */
AccelStatus mode = v->GetAccelerationStatus();
const int braking_power = power;
/* handle breakdown power reduction */
uint32 max_te = this->gcache.cached_max_te; // [N]
if (Type == VEH_TRAIN && mode == AS_ACCEL && HasBit(Train::From(this)->flags, VRF_BREAKDOWN_POWER)) {
@@ -185,18 +188,22 @@ int GroundVehicle<T, Type>::GetAcceleration()
/* Constructued from power, with need to multiply by 18 and assuming
* low speed, it needs to be a 64 bit integer too. */
int64 force;
int64 braking_force;
if (speed > 0) {
if (!maglev) {
/* Conversion factor from km/h to m/s is 5/18 to get [N] in the end. */
force = power * 18 / (speed * 5);
braking_force = force;
if (mode == AS_ACCEL && force > (int)max_te) force = max_te;
} else {
force = power / 25;
braking_force = force;
}
} else {
/* "Kickoff" acceleration. */
force = (mode == AS_ACCEL && !maglev) ? min(max_te, power) : power;
force = max(force, (mass * 8) + resistance);
braking_force = force;
}
/* If power is 0 because of a breakdown, we make the force 0 if accelerating */
@@ -204,6 +211,15 @@ int GroundVehicle<T, Type>::GetAcceleration()
force = 0;
}
if (power != braking_power) {
if (!maglev && speed > 0) {
/* Conversion factor from km/h to m/s is 5/18 to get [N] in the end. */
braking_force = braking_power * 18 / (speed * 5);
} else {
braking_force = braking_power / 25;
}
}
/* Calculate the breakdown chance */
if (_settings_game.vehicle.improved_breakdowns) {
assert(this->gcache.cached_max_track_speed > 0);
@@ -225,9 +241,23 @@ int GroundVehicle<T, Type>::GetAcceleration()
this->breakdown_chance_factor = max(breakdown_factor >> 16, (uint64)5);
}
int braking_accel;
if (Type == VEH_TRAIN && _settings_game.vehicle.train_braking_model == TBM_REALISTIC) {
/* Assume that every part of a train is braked, not just the engine.
* Exceptionally heavy freight trains should still have a sensible braking distance.
* The total braking force is generally larger than the total tractive force. */
braking_accel = ClampToI32((-braking_force - resistance - (this->gcache.cached_total_length * 300)) / mass);
/* Defensive driving: prevent ridiculously fast deceleration.
* -130 corresponds to a braking distance of about 6.2 tiles from 160 km/h. */
braking_accel = max(braking_accel, -130);
} else {
braking_accel = ClampToI32(min(-braking_force - resistance, -10000) / mass);
}
if (mode == AS_ACCEL) {
/* Easy way out when there is no acceleration. */
if (force == resistance) return 0;
if (force == resistance) return { 0, braking_accel };
/* When we accelerate, make sure we always keep doing that, even when
* the excess force is more than the mass. Otherwise a vehicle going
@@ -256,9 +286,9 @@ int GroundVehicle<T, Type>::GetAcceleration()
}
}
return accel;
return { accel, braking_accel };
} else {
return ClampToI32(min(-force - resistance, -10000) / mass);
return { braking_accel, braking_accel };
}
}