/* $Id$ */ /* * This file is part of OpenTTD. * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2. * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>. */ /** @file ground_vehicle.cpp Implementation of GroundVehicle. */ #include "stdafx.h" #include "train.h" #include "roadveh.h" #include "vehicle_gui.h" #include "window_func.h" /** * Recalculates the cached total power of a vehicle. Should be called when the consist is changed. */ template <class T, VehicleType Type> void GroundVehicle<T, Type>::PowerChanged() { assert(this->First() == this); const T *v = T::From(this); uint32 total_power = 0; uint32 max_te = 0; uint32 number_of_parts = 0; uint16 max_track_speed = v->GetInitialMaxSpeed(); for (const T *u = v; u != NULL; u = u->Next()) { uint32 current_power = u->GetPower(); 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. */ uint16 track_speed = u->GetMaxTrackSpeed(); 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(); /* If air drag is set to zero (default), the resulting air drag coefficient is dependent on max speed. */ if (air_drag_value == 0) { /* Simplification of the method used in TTDPatch. It uses <= 10 to change more steadily from 128 to 196. */ air_drag = (max_track_speed <= 10) ? 192 : max(2048 / max_track_speed, 1); } else { /* According to the specs, a value of 0x01 in the air drag property means "no air drag". */ air_drag = (air_drag_value == 1) ? 0 : air_drag_value; } this->acc_cache.cached_air_drag = air_drag + 3 * air_drag * number_of_parts / 20; max_te *= 10000; // Tractive effort in (tonnes * 1000 * 10 =) N. max_te /= 256; // Tractive effort is a [0-255] coefficient. if (this->acc_cache.cached_power != total_power || this->acc_cache.cached_max_te != max_te) { /* Stop the vehicle if it has no power. */ if (total_power == 0) this->vehstatus |= VS_STOPPED; this->acc_cache.cached_power = total_power; this->acc_cache.cached_max_te = max_te; SetWindowDirty(WC_VEHICLE_DETAILS, this->index); SetWindowWidgetDirty(WC_VEHICLE_VIEW, this->index, VVW_WIDGET_START_STOP_VEH); } this->acc_cache.cached_max_track_speed = max_track_speed; } /** * Recalculates the cached weight of a vehicle and its parts. Should be called each time the cargo on * the consist changes. */ template <class T, VehicleType Type> void GroundVehicle<T, Type>::CargoChanged() { assert(this->First() == this); uint32 weight = 0; 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(); } /* Store consist weight in cache. */ this->acc_cache.cached_weight = max<uint32>(1, weight); /* Now update vehicle power (tractive effort is dependent on weight). */ this->PowerChanged(); } /** * Calculates the acceleration of the vehicle under its current conditions. * @return Current acceleration of the vehicle. */ template <class T, VehicleType Type> 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(); /* Weight is stored in tonnes. */ int32 mass = this->acc_cache.cached_weight; /* Power is stored in HP, we need it in watts. */ int32 power = this->acc_cache.cached_power * 746; int32 resistance = 0; bool maglev = v->GetAccelerationType() == 2; 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; } resistance += this->GetSlopeResistance(); resistance *= 4; //[N] /* This value allows to know if the vehicle is accelerating or braking. */ AccelStatus mode = v->GetAccelerationStatus(); const int max_te = this->acc_cache.cached_max_te; // [N] int force; if (speed > 0) { if (!maglev) { force = power / speed; //[N] force *= 22; force /= 10; if (mode == AS_ACCEL && force > max_te) force = max_te; } else { force = power / 25; } } else { /* "Kickoff" acceleration. */ force = (mode == AS_ACCEL && !maglev) ? min(max_te, power) : power; force = max(force, (mass * 8) + resistance); } if (mode == AS_ACCEL) { return (force - resistance) / (mass * 2); } else { return min(-force - resistance, -10000) / mass; } } /* Instantiation for Train */ template struct GroundVehicle<Train, VEH_TRAIN>; /* Instantiation for RoadVehicle */ template struct GroundVehicle<RoadVehicle, VEH_ROAD>;