src/ground_vehicle.hpp

   1 /*
   2  * This file is part of OpenTTD.
   3  * 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.
   4  * 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.
   5  * 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/>.
   6  */
   7
   8 /** @file ground_vehicle.hpp Base class and functions for all vehicles that move through ground. */
   9
  10 #ifndef GROUND_VEHICLE_HPP
  11 #define GROUND_VEHICLE_HPP
  12
  13 #include "vehicle_base.h"
  14 #include "vehicle_gui.h"
  15 #include "landscape.h"
  16 #include "window_func.h"
  17
  18 #include "widgets/vehicle_widget.h"
  19
  20 /** What is the status of our acceleration? */
  21 enum AccelStatus {
  22         AS_ACCEL, ///< We want to go faster, if possible of course.
  23         AS_BRAKE, ///< We want to stop.
  24 };
  25
  26 /**
  27  * Cached, frequently calculated values.
  28  * All of these values except cached_slope_resistance are set only for the first part of a vehicle.
  29  */
  30 struct GroundVehicleCache {
  31         /* Cached acceleration values, recalculated when the cargo on a vehicle changes (in addition to the conditions below) */
  32         uint32_t cached_weight;           ///< Total weight of the consist (valid only for the first engine).
  33         uint32_t cached_slope_resistance; ///< Resistance caused by weight when this vehicle part is at a slope.
  34         uint32_t cached_max_te;           ///< Maximum tractive effort of consist (valid only for the first engine).
  35         uint16_t cached_axle_resistance;  ///< Resistance caused by the axles of the vehicle (valid only for the first engine).
  36
  37         /* Cached acceleration values, recalculated on load and each time a vehicle is added to/removed from the consist. */
  38         uint16_t cached_max_track_speed;  ///< Maximum consist speed (in internal units) limited by track type (valid only for the first engine).
  39         uint32_t cached_power;            ///< Total power of the consist (valid only for the first engine).
  40         uint32_t cached_air_drag;         ///< Air drag coefficient of the vehicle (valid only for the first engine).
  41
  42         /* Cached NewGRF values, recalculated on load and each time a vehicle is added to/removed from the consist. */
  43         uint16_t cached_total_length;     ///< Length of the whole vehicle (valid only for the first engine).
  44         EngineID first_engine;          ///< Cached EngineID of the front vehicle. INVALID_ENGINE for the front vehicle itself.
  45         uint8_t cached_veh_length;        ///< Length of this vehicle in units of 1/VEHICLE_LENGTH of normal length. It is cached because this can be set by a callback.
  46
  47         /* Cached UI information. */
  48         uint16_t last_speed;              ///< The last speed we did display, so we only have to redraw when this changes.
  49
  50         auto operator<=>(const GroundVehicleCache &) const = default;
  51 };
  52
  53 /** Ground vehicle flags. */
  54 enum GroundVehicleFlags {
  55         GVF_GOINGUP_BIT              = 0,  ///< Vehicle is currently going uphill. (Cached track information for acceleration)
  56         GVF_GOINGDOWN_BIT            = 1,  ///< Vehicle is currently going downhill. (Cached track information for acceleration)
  57         GVF_SUPPRESS_IMPLICIT_ORDERS = 2,  ///< Disable insertion and removal of automatic orders until the vehicle completes the real order.
  58 };
  59
  60 /**
  61  * Base class for all vehicles that move through ground.
  62  *
  63  * Child classes must define all of the following functions.
  64  * These functions are not defined as pure virtual functions at this class to improve performance.
  65  *
  66  * virtual uint16_t      GetPower() const = 0;
  67  * virtual uint16_t      GetPoweredPartPower(const T *head) const = 0;
  68  * virtual uint16_t      GetWeight() const = 0;
  69  * virtual uint8_t        GetTractiveEffort() const = 0;
  70  * virtual uint8_t        GetAirDrag() const = 0;
  71  * virtual uint8_t        GetAirDragArea() const = 0;
  72  * virtual AccelStatus GetAccelerationStatus() const = 0;
  73  * virtual uint16_t      GetCurrentSpeed() const = 0;
  74  * virtual uint32_t      GetRollingFriction() const = 0;
  75  * virtual int         GetAccelerationType() const = 0;
  76  * virtual int32_t       GetSlopeSteepness() const = 0;
  77  * virtual int         GetDisplayMaxSpeed() const = 0;
  78  * virtual uint16_t      GetMaxTrackSpeed() const = 0;
  79  * virtual bool        TileMayHaveSlopedTrack() const = 0;
  80  */
  81 template <class T, VehicleType Type>
  82 struct GroundVehicle : public SpecializedVehicle<T, Type> {
  83         GroundVehicleCache gcache; ///< Cache of often calculated values.
  84         uint16_t gv_flags;           ///< @see GroundVehicleFlags.
  85
  86         typedef GroundVehicle<T, Type> GroundVehicleBase; ///< Our type
  87
  88         /**
  89          * The constructor at SpecializedVehicle must be called.
  90          */
  91         GroundVehicle() : SpecializedVehicle<T, Type>() {}
  92
  93         void PowerChanged();
  94         void CargoChanged();
  95         int GetAcceleration() const;
  96         bool IsChainInDepot() const override;
  97
  98         /**
  99          * Common code executed for crashed ground vehicles
 100          * @param flooded was this vehicle flooded?
 101          * @return number of victims
 102          */
 103         uint Crash(bool flooded) override
 104         {
 105                 /* Crashed vehicles aren't going up or down */
 106                 for (T *v = T::From(this); v != nullptr; v = v->Next()) {
 107                         ClrBit(v->gv_flags, GVF_GOINGUP_BIT);
 108                         ClrBit(v->gv_flags, GVF_GOINGDOWN_BIT);
 109                 }
 110                 return this->Vehicle::Crash(flooded);
 111         }
 112
 113         /**
 114          * Calculates the total slope resistance for this vehicle.
 115          * @return Slope resistance.
 116          */
 117         inline int64_t GetSlopeResistance() const
 118         {
 119                 int64_t incl = 0;
 120
 121                 for (const T *u = T::From(this); u != nullptr; u = u->Next()) {
 122                         if (HasBit(u->gv_flags, GVF_GOINGUP_BIT)) {
 123                                 incl += u->gcache.cached_slope_resistance;
 124                         } else if (HasBit(u->gv_flags, GVF_GOINGDOWN_BIT)) {
 125                                 incl -= u->gcache.cached_slope_resistance;
 126                         }
 127                 }
 128
 129                 return incl;
 130         }
 131
 132         /**
 133          * Updates vehicle's Z position and inclination.
 134          * Used when the vehicle entered given tile.
 135          * @pre The vehicle has to be at (or near to) a border of the tile,
 136          *      directed towards tile centre
 137          */
 138         inline void UpdateZPositionAndInclination()
 139         {
 140                 this->z_pos = GetSlopePixelZ(this->x_pos, this->y_pos, true);
 141                 ClrBit(this->gv_flags, GVF_GOINGUP_BIT);
 142                 ClrBit(this->gv_flags, GVF_GOINGDOWN_BIT);
 143
 144                 if (T::From(this)->TileMayHaveSlopedTrack()) {
 145                         /* To check whether the current tile is sloped, and in which
 146                          * direction it is sloped, we get the 'z' at the center of
 147                          * the tile (middle_z) and the edge of the tile (old_z),
 148                          * which we then can compare. */
 149                         int middle_z = GetSlopePixelZ((this->x_pos & ~TILE_UNIT_MASK) | (TILE_SIZE / 2), (this->y_pos & ~TILE_UNIT_MASK) | (TILE_SIZE / 2), true);
 150
 151                         if (middle_z != this->z_pos) {
 152                                 SetBit(this->gv_flags, (middle_z > this->z_pos) ? GVF_GOINGUP_BIT : GVF_GOINGDOWN_BIT);
 153                         }
 154                 }
 155         }
 156
 157         /**
 158          * Updates vehicle's Z position.
 159          * Inclination can't change in the middle of a tile.
 160          * The faster code is used for trains and road vehicles unless they are
 161          * reversing on a sloped tile.
 162          */
 163         inline void UpdateZPosition()
 164         {
 165 #if 0
 166                 /* The following code does this: */
 167
 168                 if (HasBit(this->gv_flags, GVF_GOINGUP_BIT)) {
 169                         switch (this->direction) {
 170                                 case DIR_NE:
 171                                         this->z_pos += (this->x_pos & 1) ^ 1; break;
 172                                 case DIR_SW:
 173                                         this->z_pos += (this->x_pos & 1); break;
 174                                 case DIR_NW:
 175                                         this->z_pos += (this->y_pos & 1) ^ 1; break;
 176                                 case DIR_SE:
 177                                         this->z_pos += (this->y_pos & 1); break;
 178                                 default: break;
 179                         }
 180                 } else if (HasBit(this->gv_flags, GVF_GOINGDOWN_BIT)) {
 181                         switch (this->direction) {
 182                                 case DIR_NE:
 183                                         this->z_pos -= (this->x_pos & 1) ^ 1; break;
 184                                 case DIR_SW:
 185                                         this->z_pos -= (this->x_pos & 1); break;
 186                                 case DIR_NW:
 187                                         this->z_pos -= (this->y_pos & 1) ^ 1; break;
 188                                 case DIR_SE:
 189                                         this->z_pos -= (this->y_pos & 1); break;
 190                                 default: break;
 191                         }
 192                 }
 193
 194                 /* But gcc 4.4.5 isn't able to nicely optimise it, and the resulting
 195                  * code is full of conditional jumps. */
 196 #endif
 197
 198                 /* Vehicle's Z position can change only if it has GVF_GOINGUP_BIT or GVF_GOINGDOWN_BIT set.
 199                  * Furthermore, if this function is called once every time the vehicle's position changes,
 200                  * we know the Z position changes by +/-1 at certain moments - when x_pos, y_pos is odd/even,
 201                  * depending on orientation of the slope and vehicle's direction */
 202
 203                 if (HasBit(this->gv_flags, GVF_GOINGUP_BIT) || HasBit(this->gv_flags, GVF_GOINGDOWN_BIT)) {
 204                         if (T::From(this)->HasToUseGetSlopePixelZ()) {
 205                                 /* In some cases, we have to use GetSlopePixelZ() */
 206                                 this->z_pos = GetSlopePixelZ(this->x_pos, this->y_pos, true);
 207                                 return;
 208                         }
 209                         /* DirToDiagDir() is a simple right shift */
 210                         DiagDirection dir = DirToDiagDir(this->direction);
 211                         /* Read variables, so the compiler knows the access doesn't trap */
 212                         int8_t x_pos = this->x_pos;
 213                         int8_t y_pos = this->y_pos;
 214                         /* DiagDirToAxis() is a simple mask */
 215                         int8_t d = DiagDirToAxis(dir) == AXIS_X ? x_pos : y_pos;
 216                         /* We need only the least significant bit */
 217                         d &= 1;
 218                         d ^= (int8_t)(dir == DIAGDIR_NW || dir == DIAGDIR_NE);
 219                         /* Subtraction instead of addition because we are testing for GVF_GOINGUP_BIT.
 220                          * GVF_GOINGUP_BIT is used because it's bit 0, so simple AND can be used,
 221                          * without any shift */
 222                         this->z_pos += HasBit(this->gv_flags, GVF_GOINGUP_BIT) ? d : -d;
 223                 }
 224
 225                 assert(this->z_pos == GetSlopePixelZ(this->x_pos, this->y_pos, true));
 226         }
 227
 228         /**
 229          * Checks if the vehicle is in a slope and sets the required flags in that case.
 230          * @param new_tile True if the vehicle reached a new tile.
 231          * @param update_delta Indicates to also update the delta.
 232          * @return Old height of the vehicle.
 233          */
 234         inline int UpdateInclination(bool new_tile, bool update_delta)
 235         {
 236                 int old_z = this->z_pos;
 237
 238                 if (new_tile) {
 239                         this->UpdateZPositionAndInclination();
 240                 } else {
 241                         this->UpdateZPosition();
 242                 }
 243
 244                 this->UpdateViewport(true, update_delta);
 245                 return old_z;
 246         }
 247
 248         /**
 249          * Set front engine state.
 250          */
 251         inline void SetFrontEngine() { SetBit(this->subtype, GVSF_FRONT); }
 252
 253         /**
 254          * Remove the front engine state.
 255          */
 256         inline void ClearFrontEngine() { ClrBit(this->subtype, GVSF_FRONT); }
 257
 258         /**
 259          * Set a vehicle to be an articulated part.
 260          */
 261         inline void SetArticulatedPart() { SetBit(this->subtype, GVSF_ARTICULATED_PART); }
 262
 263         /**
 264          * Clear a vehicle from being an articulated part.
 265          */
 266         inline void ClearArticulatedPart() { ClrBit(this->subtype, GVSF_ARTICULATED_PART); }
 267
 268         /**
 269          * Set a vehicle to be a wagon.
 270          */
 271         inline void SetWagon() { SetBit(this->subtype, GVSF_WAGON); }
 272
 273         /**
 274          * Clear wagon property.
 275          */
 276         inline void ClearWagon() { ClrBit(this->subtype, GVSF_WAGON); }
 277
 278         /**
 279          * Set engine status.
 280          */
 281         inline void SetEngine() { SetBit(this->subtype, GVSF_ENGINE); }
 282
 283         /**
 284          * Clear engine status.
 285          */
 286         inline void ClearEngine() { ClrBit(this->subtype, GVSF_ENGINE); }
 287
 288         /**
 289          * Set a vehicle as a free wagon.
 290          */
 291         inline void SetFreeWagon() { SetBit(this->subtype, GVSF_FREE_WAGON); }
 292
 293         /**
 294          * Clear a vehicle from being a free wagon.
 295          */
 296         inline void ClearFreeWagon() { ClrBit(this->subtype, GVSF_FREE_WAGON); }
 297
 298         /**
 299          * Set a vehicle as a multiheaded engine.
 300          */
 301         inline void SetMultiheaded() { SetBit(this->subtype, GVSF_MULTIHEADED); }
 302
 303         /**
 304          * Clear multiheaded engine property.
 305          */
 306         inline void ClearMultiheaded() { ClrBit(this->subtype, GVSF_MULTIHEADED); }
 307
 308         /**
 309          * Check if the vehicle is a free wagon (got no engine in front of it).
 310          * @return Returns true if the vehicle is a free wagon.
 311          */
 312         inline bool IsFreeWagon() const { return HasBit(this->subtype, GVSF_FREE_WAGON); }
 313
 314         /**
 315          * Check if a vehicle is an engine (can be first in a consist).
 316          * @return Returns true if vehicle is an engine.
 317          */
 318         inline bool IsEngine() const { return HasBit(this->subtype, GVSF_ENGINE); }
 319
 320         /**
 321          * Check if a vehicle is a wagon.
 322          * @return Returns true if vehicle is a wagon.
 323          */
 324         inline bool IsWagon() const { return HasBit(this->subtype, GVSF_WAGON); }
 325
 326         /**
 327          * Check if the vehicle is a multiheaded engine.
 328          * @return Returns true if the vehicle is a multiheaded engine.
 329          */
 330         inline bool IsMultiheaded() const { return HasBit(this->subtype, GVSF_MULTIHEADED); }
 331
 332         /**
 333          * Tell if we are dealing with the rear end of a multiheaded engine.
 334          * @return True if the engine is the rear part of a dualheaded engine.
 335          */
 336         inline bool IsRearDualheaded() const { return this->IsMultiheaded() && !this->IsEngine(); }
 337
 338         /**
 339          * Update the GUI variant of the current speed of the vehicle.
 340          * Also mark the widget dirty when that is needed, i.e. when
 341          * the speed of this vehicle has changed.
 342          */
 343         inline void SetLastSpeed()
 344         {
 345                 if (this->cur_speed != this->gcache.last_speed) {
 346                         SetWindowWidgetDirty(WC_VEHICLE_VIEW, this->index, WID_VV_START_STOP);
 347                         this->gcache.last_speed = this->cur_speed;
 348                 }
 349         }
 350
 351 protected:
 352         /**
 353          * Update the speed of the vehicle.
 354          *
 355          * It updates the cur_speed and subspeed variables depending on the state
 356          * of the vehicle; in this case the current acceleration, minimum and
 357          * maximum speeds of the vehicle. It returns the distance that that the
 358          * vehicle can drive this tick. #Vehicle::GetAdvanceDistance() determines
 359          * the distance to drive before moving a step on the map.
 360          * @param accel     The acceleration we would like to give this vehicle.
 361          * @param min_speed The minimum speed here, in vehicle specific units.
 362          * @param max_speed The maximum speed here, in vehicle specific units.
 363          * @return Distance to drive.
 364          */
 365         inline uint DoUpdateSpeed(uint accel, int min_speed, int max_speed)
 366         {
 367                 uint spd = this->subspeed + accel;
 368                 this->subspeed = (uint8_t)spd;
 369
 370                 /* When we are going faster than the maximum speed, reduce the speed
 371                  * somewhat gradually. But never lower than the maximum speed. */
 372                 int tempmax = max_speed;
 373                 if (this->cur_speed > max_speed) {
 374                         tempmax = std::max(this->cur_speed - (this->cur_speed / 10) - 1, max_speed);
 375                 }
 376
 377                 /* Enforce a maximum and minimum speed. Normally we would use something like
 378                  * Clamp for this, but in this case min_speed might be below the maximum speed
 379                  * threshold for some reason. That makes acceleration fail and assertions
 380                  * happen in Clamp. So make it explicit that min_speed overrules the maximum
 381                  * speed by explicit ordering of min and max. */
 382                 this->cur_speed = spd = std::max(std::min(this->cur_speed + ((int)spd >> 8), tempmax), min_speed);
 383
 384                 int scaled_spd = this->GetAdvanceSpeed(spd);
 385
 386                 scaled_spd += this->progress;
 387                 this->progress = 0; // set later in *Handler or *Controller
 388                 return scaled_spd;
 389         }
 390 };
 391
 392 #endif /* GROUND_VEHICLE_HPP */