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 "widgets/vehicle_widget.h"
  20
  21 /** What is the status of our acceleration? */
  22 enum AccelStatus {
  23         AS_ACCEL, ///< We want to go faster, if possible of course.
  24         AS_BRAKE, ///< We want to stop.
  25 };
  26
  27 /**
  28  * Cached, frequently calculated values.
  29  * All of these values except cached_slope_resistance are set only for the first part of a vehicle.
  30  */
  31 struct GroundVehicleCache {
  32         /* Cached acceleration values, recalculated when the cargo on a vehicle changes (in addition to the conditions below) */
  33         uint32 cached_weight;           ///< Total weight of the consist (valid only for the first engine).
  34         uint32 cached_slope_resistance; ///< Resistance caused by weight when this vehicle part is at a slope.
  35         uint32 cached_max_te;           ///< Maximum tractive effort of consist (valid only for the first engine).
  36         uint16 cached_axle_resistance;  ///< Resistance caused by the axles of the vehicle (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 };
  58
  59 /**
  60  * Base class for all vehicles that move through ground.
  61  *
  62  * Child classes must define all of the following functions.
  63  * These functions are not defined as pure virtual functions at this class to improve performance.
  64  *
  65  * virtual uint16      GetPower() const = 0;
  66  * virtual uint16      GetPoweredPartPower(const T *head) const = 0;
  67  * virtual uint16      GetWeight() const = 0;
  68  * virtual byte        GetTractiveEffort() const = 0;
  69  * virtual byte        GetAirDrag() const = 0;
  70  * virtual byte        GetAirDragArea() const = 0;
  71  * virtual AccelStatus GetAccelerationStatus() const = 0;
  72  * virtual uint16      GetCurrentSpeed() const = 0;
  73  * virtual uint32      GetRollingFriction() const = 0;
  74  * virtual int         GetAccelerationType() const = 0;
  75  * virtual int32       GetSlopeSteepness() const = 0;
  76  * virtual int         GetDisplayMaxSpeed() const = 0;
  77  * virtual uint16      GetMaxTrackSpeed() const = 0;
  78  * virtual bool        TileMayHaveSlopedTrack() const = 0;
  79  */
  80 template <class T, VehicleType Type>
  81 struct GroundVehicle : public SpecializedVehicle<T, Type> {
  82         GroundVehicleCache gcache; ///< Cache of often calculated values.
  83         uint16 gv_flags;           ///< @see GroundVehicleFlags.
  84
  85         typedef GroundVehicle<T, Type> GroundVehicleBase; ///< Our type
  86
  87         /**
  88          * The constructor at SpecializedVehicle must be called.
  89          */
  90         GroundVehicle() : SpecializedVehicle<T, Type>() {}
  91
  92         void PowerChanged();
  93         void CargoChanged();
  94         int GetAcceleration() const;
  95         bool IsChainInDepot() const;
  96
  97         /**
  98          * Common code executed for crashed ground vehicles
  99          * @param flooded was this vehicle flooded?
 100          * @return number of victims
 101          */
 102         /* virtual */ uint Crash(bool flooded)
 103         {
 104                 /* Crashed vehicles aren't going up or down */
 105                 for (T *v = T::From(this); v != NULL; v = v->Next()) {
 106                         ClrBit(v->gv_flags, GVF_GOINGUP_BIT);
 107                         ClrBit(v->gv_flags, GVF_GOINGDOWN_BIT);
 108                 }
 109                 return this->Vehicle::Crash(flooded);
 110         }
 111
 112         /**
 113          * Calculates the total slope resistance for this vehicle.
 114          * @return Slope resistance.
 115          */
 116         inline int32 GetSlopeResistance() const
 117         {
 118                 int32 incl = 0;
 119
 120                 for (const T *u = T::From(this); u != NULL; u = u->Next()) {
 121                         if (HasBit(u->gv_flags, GVF_GOINGUP_BIT)) {
 122                                 incl += u->gcache.cached_slope_resistance;
 123                         } else if (HasBit(u->gv_flags, GVF_GOINGDOWN_BIT)) {
 124                                 incl -= u->gcache.cached_slope_resistance;
 125                         }
 126                 }
 127
 128                 return incl;
 129         }
 130
 131         /**
 132          * Updates vehicle's Z position and inclination.
 133          * Used when the vehicle entered given tile.
 134          * @pre The vehicle has to be at (or near to) a border of the tile,
 135          *      directed towards tile centre
 136          */
 137         inline void UpdateZPositionAndInclination()
 138         {
 139                 this->z_pos = GetSlopePixelZ(this->x_pos, this->y_pos);
 140                 ClrBit(this->gv_flags, GVF_GOINGUP_BIT);
 141                 ClrBit(this->gv_flags, GVF_GOINGDOWN_BIT);
 142
 143                 if (T::From(this)->TileMayHaveSlopedTrack()) {
 144                         /* To check whether the current tile is sloped, and in which
 145                          * direction it is sloped, we get the 'z' at the center of
 146                          * the tile (middle_z) and the edge of the tile (old_z),
 147                          * which we then can compare. */
 148                         int middle_z = GetSlopePixelZ((this->x_pos & ~TILE_UNIT_MASK) | (TILE_SIZE / 2), (this->y_pos & ~TILE_UNIT_MASK) | (TILE_SIZE / 2));
 149
 150                         if (middle_z != this->z_pos) {
 151                                 SetBit(this->gv_flags, (middle_z > this->z_pos) ? GVF_GOINGUP_BIT : GVF_GOINGDOWN_BIT);
 152                         }
 153                 }
 154         }
 155
 156         /**
 157          * Updates vehicle's Z position.
 158          * Inclination can't change in the middle of a tile.
 159          * The faster code is used for trains and road vehicles unless they are
 160          * reversing on a sloped tile.
 161          */
 162         inline void UpdateZPosition()
 163         {
 164 #if 0
 165                 /* The following code does this: */
 166
 167                 if (HasBit(this->gv_flags, GVF_GOINGUP_BIT)) {
 168                         switch (this->direction) {
 169                                 case DIR_NE:
 170                                         this->z_pos += (this->x_pos & 1); break;
 171                                 case DIR_SW:
 172                                         this->z_pos += (this->x_pos & 1) ^ 1; break;
 173                                 case DIR_NW:
 174                                         this->z_pos += (this->y_pos & 1); break;
 175                                 case DIR_SE:
 176                                         this->z_pos += (this->y_pos & 1) ^ 1; break;
 177                                 default: break;
 178                         }
 179                 } else if (HasBit(this->gv_flags, GVF_GOINGDOWN_BIT)) {
 180                         switch (this->direction) {
 181                                 case DIR_NE:
 182                                         this->z_pos -= (this->x_pos & 1); break;
 183                                 case DIR_SW:
 184                                         this->z_pos -= (this->x_pos & 1) ^ 1; break;
 185                                 case DIR_NW:
 186                                         this->z_pos -= (this->y_pos & 1); break;
 187                                 case DIR_SE:
 188                                         this->z_pos -= (this->y_pos & 1) ^ 1; break;
 189                                 default: break;
 190                         }
 191                 }
 192
 193                 /* But gcc 4.4.5 isn't able to nicely optimise it, and the resulting
 194                  * code is full of conditional jumps. */
 195 #endif
 196
 197                 /* Vehicle's Z position can change only if it has GVF_GOINGUP_BIT or GVF_GOINGDOWN_BIT set.
 198                  * Furthermore, if this function is called once every time the vehicle's position changes,
 199                  * we know the Z position changes by +/-1 at certain moments - when x_pos, y_pos is odd/even,
 200                  * depending on orientation of the slope and vehicle's direction */
 201
 202                 if (HasBit(this->gv_flags, GVF_GOINGUP_BIT) || HasBit(this->gv_flags, GVF_GOINGDOWN_BIT)) {
 203                         if (T::From(this)->HasToUseGetSlopePixelZ()) {
 204                                 /* In some cases, we have to use GetSlopePixelZ() */
 205                                 this->z_pos = GetSlopePixelZ(this->x_pos, this->y_pos);
 206                                 return;
 207                         }
 208                         /* DirToDiagDir() is a simple right shift */
 209                         DiagDirection dir = DirToDiagDir(this->direction);
 210                         /* Read variables, so the compiler knows the access doesn't trap */
 211                         int8 x_pos = this->x_pos;
 212                         int8 y_pos = this->y_pos;
 213                         /* DiagDirToAxis() is a simple mask */
 214                         int8 d = DiagDirToAxis(dir) == AXIS_X ? x_pos : y_pos;
 215                         /* We need only the least significant bit */
 216                         d &= 1;
 217                         /* Conditional "^ 1". Optimised to "(dir - 1) <= 1". */
 218                         d ^= (int8)(dir == DIAGDIR_SW || dir == DIAGDIR_SE);
 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));
 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 byte UpdateInclination(bool new_tile, bool update_delta)
 235         {
 236                 byte 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 = (byte)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 = 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 = max(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 */