src/ground_vehicle.hpp

   1 /* $Id$ */
   2
   3 /*
   4  * This file is part of OpenTTD.
   5  * 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.
   6  * 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.
   7  * 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/>.
   8  */
   9
  10 /** @file ground_vehicle.hpp Base class and functions for all vehicles that move through ground. */
  11
  12 #ifndef GROUND_VEHICLE_HPP
  13 #define GROUND_VEHICLE_HPP
  14
  15 #include "vehicle_base.h"
  16 #include "vehicle_gui.h"
  17 #include "landscape.h"
  18 #include "window_func.h"
  19 #include "tunnel_map.h"
  20 #include "widgets/vehicle_widget.h"
  21
  22 /** What is the status of our acceleration? */
  23 enum AccelStatus {
  24         AS_ACCEL, ///< We want to go faster, if possible of course.
  25         AS_BRAKE, ///< We want to stop.
  26 };
  27
  28 /**
  29  * Cached, frequently calculated values.
  30  * All of these values except cached_slope_resistance are set only for the first part of a vehicle.
  31  */
  32 struct GroundVehicleCache {
  33         /* Cached acceleration values, recalculated when the cargo on a vehicle changes (in addition to the conditions below) */
  34         uint32 cached_weight;           ///< Total weight of the consist (valid only for the first engine).
  35         uint32 cached_slope_resistance; ///< Resistance caused by weight when this vehicle part is at a slope.
  36         uint32 cached_max_te;           ///< Maximum tractive effort of consist (valid only for the first engine).
  37
  38         /* Cached acceleration values, recalculated on load and each time a vehicle is added to/removed from the consist. */
  39         uint16 cached_max_track_speed;  ///< Maximum consist speed limited by track type (valid only for the first engine).
  40         uint32 cached_power;            ///< Total power of the consist (valid only for the first engine).
  41         uint32 cached_air_drag;         ///< Air drag coefficient of the vehicle (valid only for the first engine).
  42
  43         /* Cached NewGRF values, recalculated on load and each time a vehicle is added to/removed from the consist. */
  44         uint16 cached_total_length;     ///< Length of the whole vehicle (valid only for the first engine).
  45         EngineID first_engine;          ///< Cached EngineID of the front vehicle. INVALID_ENGINE for the front vehicle itself.
  46         uint8 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.
  47
  48         /* Cached UI information. */
  49         uint16 last_speed;              ///< The last speed we did display, so we only have to redraw when this changes.
  50 };
  51
  52 /** Ground vehicle flags. */
  53 enum GroundVehicleFlags {
  54         GVF_GOINGUP_BIT              = 0,  ///< Vehicle is currently going uphill. (Cached track information for acceleration)
  55         GVF_GOINGDOWN_BIT            = 1,  ///< Vehicle is currently going downhill. (Cached track information for acceleration)
  56         GVF_SUPPRESS_IMPLICIT_ORDERS = 2,  ///< Disable insertion and removal of automatic orders until the vehicle completes the real order.
  57         GVF_CHUNNEL_BIT              = 3,  ///< Vehicle may currently be in a chunnel. (Cached track information for inclination changes)
  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      GetPower() const = 0;
  67  * virtual uint16      GetPoweredPartPower(const T *head) const = 0;
  68  * virtual uint16      GetWeight() const = 0;
  69  * virtual byte        GetTractiveEffort() const = 0;
  70  * virtual byte        GetAirDrag() const = 0;
  71  * virtual byte        GetAirDragArea() const = 0;
  72  * virtual AccelStatus GetAccelerationStatus() const = 0;
  73  * virtual uint16      GetCurrentSpeed() const = 0;
  74  * virtual uint32      GetRollingFriction() const = 0;
  75  * virtual int         GetAccelerationType() const = 0;
  76  * virtual int32       GetSlopeSteepness() const = 0;
  77  * virtual int         GetDisplayMaxSpeed() const = 0;
  78  * virtual uint16      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 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;
  97
  98         /**
  99          * Common code executed for crashed ground vehicles
 100          * @param flooded was this vehicle flooded?
 101          * @return number of victims
 102          */
 103         /* virtual */ uint Crash(bool flooded)
 104         {
 105                 /* Crashed vehicles aren't going up or down */
 106                 for (T *v = T::From(this); v != NULL; 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 GetSlopeResistance() const
 118         {
 119                 int64 incl = 0;
 120
 121                 for (const T *u = T::From(this); u != NULL; 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);
 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));
 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); break;
 172                                 case DIR_SW:
 173                                         this->z_pos += (this->x_pos & 1) ^ 1; break;
 174                                 case DIR_NW:
 175                                         this->z_pos += (this->y_pos & 1); break;
 176                                 case DIR_SE:
 177                                         this->z_pos += (this->y_pos & 1) ^ 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); break;
 184                                 case DIR_SW:
 185                                         this->z_pos -= (this->x_pos & 1) ^ 1; break;
 186                                 case DIR_NW:
 187                                         this->z_pos -= (this->y_pos & 1); break;
 188                                 case DIR_SE:
 189                                         this->z_pos -= (this->y_pos & 1) ^ 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);
 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 x_pos = this->x_pos;
 213                         int8 y_pos = this->y_pos;
 214                         /* DiagDirToAxis() is a simple mask */
 215                         int8 d = DiagDirToAxis(dir) == AXIS_X ? x_pos : y_pos;
 216                         /* We need only the least significant bit */
 217                         d &= 1;
 218                         /* Conditional "^ 1". Optimised to "(dir - 1) <= 1". */
 219                         d ^= (int8)(dir == DIAGDIR_SW || dir == DIAGDIR_SE);
 220                         /* Subtraction instead of addition because we are testing for GVF_GOINGUP_BIT.
 221                          * GVF_GOINGUP_BIT is used because it's bit 0, so simple AND can be used,
 222                          * without any shift */
 223                         this->z_pos += HasBit(this->gv_flags, GVF_GOINGUP_BIT) ? d : -d;
 224                 }
 225
 226                 if (HasBit(this->gv_flags, GVF_CHUNNEL_BIT) && !IsTunnelTile(this->tile)) {
 227                         ClrBit(this->gv_flags, GVF_CHUNNEL_BIT);
 228                 }
 229
 230 #ifdef _DEBUG
 231                 assert(this->z_pos == GetSlopePixelZ(this->x_pos, this->y_pos));
 232 #endif
 233         }
 234
 235         void UpdateZPositionInWormhole();
 236
 237         /**
 238          * Checks if the vehicle is in a slope and sets the required flags in that case.
 239          * @param new_tile True if the vehicle reached a new tile.
 240          * @param update_delta Indicates to also update the delta.
 241          * @return Old height of the vehicle.
 242          */
 243         inline int UpdateInclination(bool new_tile, bool update_delta, bool in_wormhole = false)
 244         {
 245                 int old_z = this->z_pos;
 246
 247                 if (in_wormhole) {
 248                         if (HasBit(this->gv_flags, GVF_CHUNNEL_BIT)) this->UpdateZPositionInWormhole();
 249                 } else if (new_tile) {
 250                         this->UpdateZPositionAndInclination();
 251                 } else {
 252                         this->UpdateZPosition();
 253                 }
 254
 255                 this->UpdateViewport(true, update_delta);
 256                 return old_z;
 257         }
 258
 259         /**
 260          * Set front engine state.
 261          */
 262         inline void SetFrontEngine() { SetBit(this->subtype, GVSF_FRONT); }
 263
 264         /**
 265          * Remove the front engine state.
 266          */
 267         inline void ClearFrontEngine() { ClrBit(this->subtype, GVSF_FRONT); }
 268
 269         /**
 270          * Set a vehicle to be an articulated part.
 271          */
 272         inline void SetArticulatedPart() { SetBit(this->subtype, GVSF_ARTICULATED_PART); }
 273
 274         /**
 275          * Clear a vehicle from being an articulated part.
 276          */
 277         inline void ClearArticulatedPart() { ClrBit(this->subtype, GVSF_ARTICULATED_PART); }
 278
 279         /**
 280          * Set a vehicle to be a wagon.
 281          */
 282         inline void SetWagon() { SetBit(this->subtype, GVSF_WAGON); }
 283
 284         /**
 285          * Clear wagon property.
 286          */
 287         inline void ClearWagon() { ClrBit(this->subtype, GVSF_WAGON); }
 288
 289         /**
 290          * Set engine status.
 291          */
 292         inline void SetEngine() { SetBit(this->subtype, GVSF_ENGINE); }
 293
 294         /**
 295          * Clear engine status.
 296          */
 297         inline void ClearEngine() { ClrBit(this->subtype, GVSF_ENGINE); }
 298
 299         /**
 300          * Set a vehicle as a free wagon.
 301          */
 302         inline void SetFreeWagon() { SetBit(this->subtype, GVSF_FREE_WAGON); }
 303
 304         /**
 305          * Clear a vehicle from being a free wagon.
 306          */
 307         inline void ClearFreeWagon() { ClrBit(this->subtype, GVSF_FREE_WAGON); }
 308
 309         /**
 310          * Set a vehicle as a virtual vehicle.
 311          */
 312         inline void SetVirtual() { SetBit(this->subtype, GVSF_VIRTUAL); }
 313
 314         /**
 315          * Clear a vehicle from being a virtual vehicle.
 316          */
 317         inline void ClearVirtual() { ClrBit(this->subtype, GVSF_VIRTUAL); }
 318
 319         /**
 320          * Set a vehicle as a multiheaded engine.
 321          */
 322         inline void SetMultiheaded() { SetBit(this->subtype, GVSF_MULTIHEADED); }
 323
 324         /**
 325          * Clear multiheaded engine property.
 326          */
 327         inline void ClearMultiheaded() { ClrBit(this->subtype, GVSF_MULTIHEADED); }
 328
 329         /**
 330          * Check if the vehicle is a free wagon (got no engine in front of it).
 331          * @return Returns true if the vehicle is a free wagon.
 332          */
 333         inline bool IsFreeWagon() const { return HasBit(this->subtype, GVSF_FREE_WAGON); }
 334
 335         /**
 336          * Check if a vehicle is an engine (can be first in a consist).
 337          * @return Returns true if vehicle is an engine.
 338          */
 339         inline bool IsEngine() const { return HasBit(this->subtype, GVSF_ENGINE); }
 340
 341         /**
 342          * Check if a vehicle is a wagon.
 343          * @return Returns true if vehicle is a wagon.
 344          */
 345         inline bool IsWagon() const { return HasBit(this->subtype, GVSF_WAGON); }
 346
 347         /**
 348          * Check if the vehicle is a multiheaded engine.
 349          * @return Returns true if the vehicle is a multiheaded engine.
 350          */
 351         inline bool IsMultiheaded() const { return HasBit(this->subtype, GVSF_MULTIHEADED); }
 352
 353         /**
 354         * Tell if we are dealing with a virtual vehicle (used for templates).
 355         * @return True if the vehicle is a virtual vehicle.
 356         */
 357         inline bool IsVirtual() const { return HasBit(this->subtype, GVSF_VIRTUAL); }
 358
 359         /**
 360          * Tell if we are dealing with the rear end of a multiheaded engine.
 361          * @return True if the engine is the rear part of a dualheaded engine.
 362          */
 363         inline bool IsRearDualheaded() const { return this->IsMultiheaded() && !this->IsEngine(); }
 364
 365         /**
 366          * Update the GUI variant of the current speed of the vehicle.
 367          * Also mark the widget dirty when that is needed, i.e. when
 368          * the speed of this vehicle has changed.
 369          */
 370         inline void SetLastSpeed()
 371         {
 372                 if (this->cur_speed != this->gcache.last_speed) {
 373                         SetWindowWidgetDirty(WC_VEHICLE_VIEW, this->index, WID_VV_START_STOP);
 374                         this->gcache.last_speed = this->cur_speed;
 375                 }
 376         }
 377
 378 protected:
 379         /**
 380          * Update the speed of the vehicle.
 381          *
 382          * It updates the cur_speed and subspeed variables depending on the state
 383          * of the vehicle; in this case the current acceleration, minimum and
 384          * maximum speeds of the vehicle. It returns the distance that that the
 385          * vehicle can drive this tick. #Vehicle::GetAdvanceDistance() determines
 386          * the distance to drive before moving a step on the map.
 387          * @param accel     The acceleration we would like to give this vehicle.
 388          * @param min_speed The minimum speed here, in vehicle specific units.
 389          * @param max_speed The maximum speed here, in vehicle specific units.
 390          * @return Distance to drive.
 391          */
 392         inline uint DoUpdateSpeed(uint accel, int min_speed, int max_speed)
 393         {
 394                 uint spd = this->subspeed + accel;
 395                 this->subspeed = (byte)spd;
 396
 397                 /* When we are going faster than the maximum speed, reduce the speed
 398                  * somewhat gradually. But never lower than the maximum speed. */
 399                 int tempmax = max_speed;
 400                 if (this->cur_speed > max_speed) {
 401                         tempmax = max(this->cur_speed - (this->cur_speed / 10) - 1, max_speed);
 402                 }
 403
 404                 /* Enforce a maximum and minimum speed. Normally we would use something like
 405                  * Clamp for this, but in this case min_speed might be below the maximum speed
 406                  * threshold for some reason. That makes acceleration fail and assertions
 407                  * happen in Clamp. So make it explicit that min_speed overrules the maximum
 408                  * speed by explicit ordering of min and max. */
 409                 this->cur_speed = spd = max(min(this->cur_speed + ((int)spd >> 8), tempmax), min_speed);
 410
 411                 int scaled_spd = this->GetAdvanceSpeed(spd);
 412
 413                 scaled_spd += this->progress;
 414                 this->progress = 0; // set later in *Handler or *Controller
 415                 return scaled_spd;
 416         }
 417 };
 418
 419 #endif /* GROUND_VEHICLE_HPP */