ground_vehicle.hpp

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00001 /* $Id$ */
00002 
00003 /*
00004  * This file is part of OpenTTD.
00005  * 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.
00006  * 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.
00007  * 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/>.
00008  */
00009 
00012 #ifndef GROUND_VEHICLE_HPP
00013 #define GROUND_VEHICLE_HPP
00014 
00015 #include "vehicle_base.h"
00016 #include "vehicle_gui.h"
00017 #include "landscape.h"
00018 #include "window_func.h"
00019 #include "widgets/vehicle_widget.h"
00020 
00022 enum AccelStatus {
00023   AS_ACCEL, 
00024   AS_BRAKE, 
00025 };
00026 
00031 struct GroundVehicleCache {
00032   /* Cached acceleration values, recalculated when the cargo on a vehicle changes (in addition to the conditions below) */
00033   uint32 cached_weight;           
00034   uint32 cached_slope_resistance; 
00035   uint32 cached_max_te;           
00036   uint16 cached_axle_resistance;  
00037 
00038   /* Cached acceleration values, recalculated on load and each time a vehicle is added to/removed from the consist. */
00039   uint16 cached_max_track_speed;  
00040   uint32 cached_power;            
00041   uint32 cached_air_drag;         
00042 
00043   /* Cached NewGRF values, recalculated on load and each time a vehicle is added to/removed from the consist. */
00044   uint16 cached_total_length;     
00045   EngineID first_engine;          
00046   uint8 cached_veh_length;        
00047 
00048   /* Cached UI information. */
00049   uint16 last_speed;              
00050 };
00051 
00053 enum GroundVehicleFlags {
00054   GVF_GOINGUP_BIT              = 0,  
00055   GVF_GOINGDOWN_BIT            = 1,  
00056   GVF_SUPPRESS_IMPLICIT_ORDERS = 2,  
00057 };
00058 
00080 template <class T, VehicleType Type>
00081 struct GroundVehicle : public SpecializedVehicle<T, Type> {
00082   GroundVehicleCache gcache; 
00083   uint16 gv_flags;           
00084 
00085   typedef GroundVehicle<T, Type> GroundVehicleBase; 
00086 
00090   GroundVehicle() : SpecializedVehicle<T, Type>() {}
00091 
00092   void PowerChanged();
00093   void CargoChanged();
00094   int GetAcceleration() const;
00095   bool IsChainInDepot() const;
00096 
00102   /* virtual */ uint Crash(bool flooded)
00103   {
00104     /* Crashed vehicles aren't going up or down */
00105     for (T *v = T::From(this); v != NULL; v = v->Next()) {
00106       ClrBit(v->gv_flags, GVF_GOINGUP_BIT);
00107       ClrBit(v->gv_flags, GVF_GOINGDOWN_BIT);
00108     }
00109     return this->Vehicle::Crash(flooded);
00110   }
00111 
00116   inline int32 GetSlopeResistance() const
00117   {
00118     int32 incl = 0;
00119 
00120     for (const T *u = T::From(this); u != NULL; u = u->Next()) {
00121       if (HasBit(u->gv_flags, GVF_GOINGUP_BIT)) {
00122         incl += u->gcache.cached_slope_resistance;
00123       } else if (HasBit(u->gv_flags, GVF_GOINGDOWN_BIT)) {
00124         incl -= u->gcache.cached_slope_resistance;
00125       }
00126     }
00127 
00128     return incl;
00129   }
00130 
00137   inline void UpdateZPositionAndInclination()
00138   {
00139     this->z_pos = GetSlopePixelZ(this->x_pos, this->y_pos);
00140     ClrBit(this->gv_flags, GVF_GOINGUP_BIT);
00141     ClrBit(this->gv_flags, GVF_GOINGDOWN_BIT);
00142 
00143     if (T::From(this)->TileMayHaveSlopedTrack()) {
00144       /* To check whether the current tile is sloped, and in which
00145        * direction it is sloped, we get the 'z' at the center of
00146        * the tile (middle_z) and the edge of the tile (old_z),
00147        * which we then can compare. */
00148       int middle_z = GetSlopePixelZ((this->x_pos & ~TILE_UNIT_MASK) | HALF_TILE_SIZE, (this->y_pos & ~TILE_UNIT_MASK) | HALF_TILE_SIZE);
00149 
00150       if (middle_z != this->z_pos) {
00151         SetBit(this->gv_flags, (middle_z > this->z_pos) ? GVF_GOINGUP_BIT : GVF_GOINGDOWN_BIT);
00152       }
00153     }
00154   }
00155 
00162   inline void UpdateZPosition()
00163   {
00164 #if 0
00165     /* The following code does this: */
00166 
00167     if (HasBit(this->gv_flags, GVF_GOINGUP_BIT)) {
00168       switch (this->direction) {
00169         case DIR_NE:
00170           this->z_pos += (this->x_pos & 1); break;
00171         case DIR_SW:
00172           this->z_pos += (this->x_pos & 1) ^ 1; break;
00173         case DIR_NW:
00174           this->z_pos += (this->y_pos & 1); break;
00175         case DIR_SE:
00176           this->z_pos += (this->y_pos & 1) ^ 1; break;
00177         default: break;
00178       }
00179     } else if (HasBit(this->gv_flags, GVF_GOINGDOWN_BIT)) {
00180       switch (this->direction) {
00181         case DIR_NE:
00182           this->z_pos -= (this->x_pos & 1); break;
00183         case DIR_SW:
00184           this->z_pos -= (this->x_pos & 1) ^ 1; break;
00185         case DIR_NW:
00186           this->z_pos -= (this->y_pos & 1); break;
00187         case DIR_SE:
00188           this->z_pos -= (this->y_pos & 1) ^ 1; break;
00189         default: break;
00190       }
00191     }
00192 
00193     /* But gcc 4.4.5 isn't able to nicely optimise it, and the resulting
00194      * code is full of conditional jumps. */
00195 #endif
00196 
00197     /* Vehicle's Z position can change only if it has GVF_GOINGUP_BIT or GVF_GOINGDOWN_BIT set.
00198      * Furthermore, if this function is called once every time the vehicle's position changes,
00199      * we know the Z position changes by +/-1 at certain moments - when x_pos, y_pos is odd/even,
00200      * depending on orientation of the slope and vehicle's direction */
00201 
00202     if (HasBit(this->gv_flags, GVF_GOINGUP_BIT) || HasBit(this->gv_flags, GVF_GOINGDOWN_BIT)) {
00203       if (T::From(this)->HasToUseGetSlopePixelZ()) {
00204         /* In some cases, we have to use GetSlopePixelZ() */
00205         this->z_pos = GetSlopePixelZ(this->x_pos, this->y_pos);
00206         return;
00207       }
00208       /* DirToDiagDir() is a simple right shift */
00209       DiagDirection dir = DirToDiagDir(this->direction);
00210       /* Read variables, so the compiler knows the access doesn't trap */
00211       int8 x_pos = this->x_pos;
00212       int8 y_pos = this->y_pos;
00213       /* DiagDirToAxis() is a simple mask */
00214       int8 d = DiagDirToAxis(dir) == AXIS_X ? x_pos : y_pos;
00215       /* We need only the least significant bit */
00216       d &= 1;
00217       /* Conditional "^ 1". Optimised to "(dir - 1) <= 1". */
00218       d ^= (int8)(dir == DIAGDIR_SW || dir == DIAGDIR_SE);
00219       /* Subtraction instead of addition because we are testing for GVF_GOINGUP_BIT.
00220        * GVF_GOINGUP_BIT is used because it's bit 0, so simple AND can be used,
00221        * without any shift */
00222       this->z_pos += HasBit(this->gv_flags, GVF_GOINGUP_BIT) ? d : -d;
00223     }
00224 
00225     assert(this->z_pos == GetSlopePixelZ(this->x_pos, this->y_pos));
00226   }
00227 
00234   inline byte UpdateInclination(bool new_tile, bool update_delta)
00235   {
00236     byte old_z = this->z_pos;
00237 
00238     if (new_tile) {
00239       this->UpdateZPositionAndInclination();
00240     } else {
00241       this->UpdateZPosition();
00242     }
00243 
00244     this->UpdateViewport(true, update_delta);
00245     return old_z;
00246   }
00247 
00251   inline void SetFrontEngine() { SetBit(this->subtype, GVSF_FRONT); }
00252 
00256   inline void ClearFrontEngine() { ClrBit(this->subtype, GVSF_FRONT); }
00257 
00261   inline void SetArticulatedPart() { SetBit(this->subtype, GVSF_ARTICULATED_PART); }
00262 
00266   inline void ClearArticulatedPart() { ClrBit(this->subtype, GVSF_ARTICULATED_PART); }
00267 
00271   inline void SetWagon() { SetBit(this->subtype, GVSF_WAGON); }
00272 
00276   inline void ClearWagon() { ClrBit(this->subtype, GVSF_WAGON); }
00277 
00281   inline void SetEngine() { SetBit(this->subtype, GVSF_ENGINE); }
00282 
00286   inline void ClearEngine() { ClrBit(this->subtype, GVSF_ENGINE); }
00287 
00291   inline void SetFreeWagon() { SetBit(this->subtype, GVSF_FREE_WAGON); }
00292 
00296   inline void ClearFreeWagon() { ClrBit(this->subtype, GVSF_FREE_WAGON); }
00297 
00301   inline void SetMultiheaded() { SetBit(this->subtype, GVSF_MULTIHEADED); }
00302 
00306   inline void ClearMultiheaded() { ClrBit(this->subtype, GVSF_MULTIHEADED); }
00307 
00312   inline bool IsFreeWagon() const { return HasBit(this->subtype, GVSF_FREE_WAGON); }
00313 
00318   inline bool IsEngine() const { return HasBit(this->subtype, GVSF_ENGINE); }
00319 
00324   inline bool IsWagon() const { return HasBit(this->subtype, GVSF_WAGON); }
00325 
00330   inline bool IsMultiheaded() const { return HasBit(this->subtype, GVSF_MULTIHEADED); }
00331 
00336   inline bool IsRearDualheaded() const { return this->IsMultiheaded() && !this->IsEngine(); }
00337 
00343   inline void SetLastSpeed()
00344   {
00345     if (this->cur_speed != this->gcache.last_speed) {
00346       SetWindowWidgetDirty(WC_VEHICLE_VIEW, this->index, WID_VV_START_STOP);
00347       this->gcache.last_speed = this->cur_speed;
00348     }
00349   }
00350 
00351 protected:
00365   inline uint DoUpdateSpeed(uint accel, int min_speed, int max_speed)
00366   {
00367     uint spd = this->subspeed + accel;
00368     this->subspeed = (byte)spd;
00369 
00370     /* When we are going faster than the maximum speed, reduce the speed
00371      * somewhat gradually. But never lower than the maximum speed. */
00372     int tempmax = max_speed;
00373     if (this->cur_speed > max_speed) {
00374       tempmax = max(this->cur_speed - (this->cur_speed / 10) - 1, max_speed);
00375     }
00376 
00377     /* Enforce a maximum and minimum speed. Normally we would use something like
00378      * Clamp for this, but in this case min_speed might be below the maximum speed
00379      * threshold for some reason. That makes acceleration fail and assertions
00380      * happen in Clamp. So make it explicit that min_speed overrules the maximum
00381      * speed by explicit ordering of min and max. */
00382     this->cur_speed = spd = max(min(this->cur_speed + ((int)spd >> 8), tempmax), min_speed);
00383 
00384     int scaled_spd = this->GetAdvanceSpeed(spd);
00385 
00386     scaled_spd += this->progress;
00387     this->progress = 0; // set later in *Handler or *Controller
00388     return scaled_spd;
00389   }
00390 };
00391 
00392 #endif /* GROUND_VEHICLE_HPP */