# elrail.cpp

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    00001 /* $Id: elrail.cpp 17347 2009-09-01 13:28:15Z rubidium $ */
    00002
    00049 #include "stdafx.h"
    00050 #include "openttd.h"
    00051 #include "station_map.h"
    00052 #include "viewport_func.h"
    00053 #include "landscape.h"
    00054 #include "train.h"
    00055 #include "rail_gui.h"
    00056 #include "tunnelbridge_map.h"
    00057 #include "vehicle_func.h"
    00058 #include "tunnelbridge.h"
    00059 #include "elrail_func.h"
    00060 #include "engine_base.h"
    00061
    00062 #include "table/sprites.h"
    00063 #include "table/elrail_data.h"
    00064
    00065 static inline TLG GetTLG(TileIndex t)
    00066 {
    00067   return (TLG)((HasBit(TileX(t), 0) << 1) + HasBit(TileY(t), 0));
    00068 }
    00069
    00076 static TrackBits GetRailTrackBitsUniversal(TileIndex t, byte *override)
    00077 {
    00078   switch (GetTileType(t)) {
    00079     case MP_RAILWAY:
    00080       if (!HasCatenary(GetRailType(t))) return TRACK_BIT_NONE;
    00081       switch (GetRailTileType(t)) {
    00082         case RAIL_TILE_NORMAL: case RAIL_TILE_SIGNALS:
    00083           return GetTrackBits(t);
    00084         case RAIL_TILE_WAYPOINT:
    00085           return GetRailWaypointBits(t);
    00086         default:
    00087           return TRACK_BIT_NONE;
    00088       }
    00089       break;
    00090
    00091     case MP_TUNNELBRIDGE:
    00092       if (!HasCatenary(GetRailType(t))) return TRACK_BIT_NONE;
    00093       if (override != NULL && (IsTunnel(t) || GetTunnelBridgeLength(t, GetOtherBridgeEnd(t)) > 0)) {
    00094         *override = 1 << GetTunnelBridgeDirection(t);
    00095       }
    00096       return DiagDirToDiagTrackBits(GetTunnelBridgeDirection(t));
    00097
    00098     case MP_ROAD:
    00099       if (!IsLevelCrossing(t)) return TRACK_BIT_NONE;
    00100       if (!HasCatenary(GetRailType(t))) return TRACK_BIT_NONE;
    00101       return GetCrossingRailBits(t);
    00102
    00103     case MP_STATION:
    00104       if (!IsRailwayStation(t)) return TRACK_BIT_NONE;
    00105       if (!HasCatenary(GetRailType(t))) return TRACK_BIT_NONE;
    00106       if (!IsStationTileElectrifiable(t)) return TRACK_BIT_NONE;
    00107       return TrackToTrackBits(GetRailStationTrack(t));
    00108
    00109     default:
    00110       return TRACK_BIT_NONE;
    00111   }
    00112 }
    00113
    00117 static TrackBits MaskWireBits(TileIndex t, TrackBits tracks)
    00118 {
    00119   if (!IsPlainRailTile(t)) return tracks;
    00120
    00121   TrackdirBits neighbour_tdb = TRACKDIR_BIT_NONE;
    00122   for (DiagDirection d = DIAGDIR_BEGIN; d < DIAGDIR_END; d++) {
    00123     /* If the neighbor tile is either not electrified or has no tracks that can be reached
    00124      * from this tile, mark all trackdirs that can be reached from the neighbour tile
    00125      * as needing no catenary. */
    00126     RailType rt = GetTileRailType(TileAddByDiagDir(t, d));
    00127     if (rt == INVALID_RAILTYPE || !HasCatenary(rt) || (TrackStatusToTrackBits(GetTileTrackStatus(TileAddByDiagDir(t, d), TRANSPORT_RAIL, 0)) & DiagdirReachesTracks(d)) == TRACK_BIT_NONE) {
    00128       neighbour_tdb |= DiagdirReachesTrackdirs(ReverseDiagDir(d));
    00129     }
    00130   }
    00131
    00132   /* If the tracks from either a diagonal crossing or don't overlap, both
    00133    * trackdirs have to be marked to mask the corresponding track bit. Else
    00134    * one marked trackdir is enough the mask the track bit. */
    00135   TrackBits mask;
    00136   if (tracks == TRACK_BIT_CROSS || !TracksOverlap(tracks)) {
    00137     /* If the tracks form either a diagonal crossing or don't overlap, both
    00138      * trackdirs have to be marked to mask the corresponding track bit. */
    00139     mask = ~(TrackBits)((neighbour_tdb & (neighbour_tdb >> 8)) & TRACK_BIT_MASK);
    00140     /* If that results in no masked tracks and it is not a diagonal crossing,
    00141      * require only one marked trackdir to mask. */
    00142     if (tracks != TRACK_BIT_CROSS && (mask & TRACK_BIT_MASK) == TRACK_BIT_MASK) mask = ~TrackdirBitsToTrackBits(neighbour_tdb);
    00143   } else {
    00144     /* Require only one marked trackdir to mask the track. */
    00145     mask = ~TrackdirBitsToTrackBits(neighbour_tdb);
    00146     /* If that results in an empty set, require both trackdirs for diagonal track. */
    00147     if ((tracks & mask) == TRACK_BIT_NONE) {
    00148       if ((neighbour_tdb & TRACKDIR_BIT_X_NE) == 0 || (neighbour_tdb & TRACKDIR_BIT_X_SW) == 0) mask |= TRACK_BIT_X;
    00149       if ((neighbour_tdb & TRACKDIR_BIT_Y_NW) == 0 || (neighbour_tdb & TRACKDIR_BIT_Y_SE) == 0) mask |= TRACK_BIT_Y;
    00150       /* If that still is not enough, require both trackdirs for any track. */
    00151       if ((tracks & mask) == TRACK_BIT_NONE) mask = ~(TrackBits)((neighbour_tdb & (neighbour_tdb >> 8)) & TRACK_BIT_MASK);
    00152     }
    00153   }
    00154
    00155   /* Mask the tracks only if at least one track bit would remain. */
    00156   return (tracks & mask) != TRACK_BIT_NONE ? tracks & mask : tracks;
    00157 }
    00158
    00162 static inline SpriteID GetWireBase(TileIndex tile)
    00163 {
    00164   return SPR_WIRE_BASE;
    00165 }
    00166
    00170 static inline SpriteID GetPylonBase(TileIndex tile)
    00171 {
    00172   return SPR_PYLON_BASE;
    00173 }
    00174
    00179 static void AdjustTileh(TileIndex tile, Slope *tileh)
    00180 {
    00181   if (IsTileType(tile, MP_TUNNELBRIDGE)) {
    00182     if (IsTunnel(tile)) {
    00183       *tileh = SLOPE_STEEP; // XXX - Hack to make tunnel entrances to always have a pylon
    00184     } else if (*tileh != SLOPE_FLAT) {
    00185       *tileh = SLOPE_FLAT;
    00186     } else {
    00187       *tileh = InclinedSlope(GetTunnelBridgeDirection(tile));
    00188     }
    00189   }
    00190 }
    00191
    00199 static byte GetPCPElevation(TileIndex tile, DiagDirection PCPpos)
    00200 {
    00201   /* The elevation of the "pylon"-sprite should be the elevation at the PCP.
    00202    * PCPs are always on a tile edge.
    00203    *
    00204    * This position can be outside of the tile, i.e. ?_pcp_offset == TILE_SIZE > TILE_SIZE - 1.
    00205    * So we have to move it inside the tile, because if the neighboured tile has a foundation,
    00206    * that does not smoothly connect to the current tile, we will get a wrong elevation from GetSlopeZ().
    00207    *
    00208    * When we move the position inside the tile, we will get a wrong elevation if we have a slope.
    00209    * To catch all cases we round the Z position to the next (TILE_HEIGHT / 2).
    00210    * This will return the correct elevation for slopes and will also detect non-continuous elevation on edges.
    00211    *
    00212    * Also note that the result of GetSlopeZ() is very special on bridge-ramps.
    00213    */
    00214
    00215   byte z = GetSlopeZ(TileX(tile) * TILE_SIZE + min(x_pcp_offsets[PCPpos], TILE_SIZE - 1), TileY(tile) * TILE_SIZE + min(y_pcp_offsets[PCPpos], TILE_SIZE - 1));
    00216   return (z + 2) & ~3; // this means z = (z + TILE_HEIGHT / 4) / (TILE_HEIGHT / 2) * (TILE_HEIGHT / 2);
    00217 }
    00218
    00226 void DrawCatenaryOnTunnel(const TileInfo *ti)
    00227 {
    00228   /* xmin, ymin, xmax + 1, ymax + 1 of BB */
    00229   static const int _tunnel_wire_BB[4][4] = {
    00230     { 0, 1, 16, 15 }, // NE
    00231     { 1, 0, 15, 16 }, // SE
    00232     { 0, 1, 16, 15 }, // SW
    00233     { 1, 0, 15, 16 }, // NW
    00234   };
    00235
    00236   DiagDirection dir = GetTunnelBridgeDirection(ti->tile);
    00237
    00238   SpriteID wire_base = GetWireBase(ti->tile);
    00239
    00240   const SortableSpriteStruct *sss = &CatenarySpriteData_Tunnel[dir];
    00241   const int *BB_data = _tunnel_wire_BB[dir];
    00242   AddSortableSpriteToDraw(
    00243     wire_base + sss->image_offset, PAL_NONE, ti->x + sss->x_offset, ti->y + sss->y_offset,
    00244     BB_data[2] - sss->x_offset, BB_data[3] - sss->y_offset, BB_Z_SEPARATOR - sss->z_offset + 1,
    00245     GetTileZ(ti->tile) + sss->z_offset,
    00246     IsTransparencySet(TO_CATENARY),
    00247     BB_data[0] - sss->x_offset, BB_data[1] - sss->y_offset, BB_Z_SEPARATOR - sss->z_offset
    00248   );
    00249 }
    00250
    00254 static void DrawCatenaryRailway(const TileInfo *ti)
    00255 {
    00256   /* Pylons are placed on a tile edge, so we need to take into account
    00257    * the track configuration of 2 adjacent tiles. trackconfig[0] stores the
    00258    * current tile (home tile) while [1] holds the neighbour */
    00259   TrackBits trackconfig[TS_END];
    00260   TrackBits wireconfig[TS_END];
    00261   bool isflat[TS_END];
    00262   /* Note that ti->tileh has already been adjusted for Foundations */
    00263   Slope tileh[TS_END] = { ti->tileh, SLOPE_FLAT };
    00264
    00265   /* Half tile slopes coincide only with horizontal/vertical track.
    00266    * Faking a flat slope results in the correct sprites on positions. */
    00267   if (IsHalftileSlope(tileh[TS_HOME])) tileh[TS_HOME] = SLOPE_FLAT;
    00268
    00269   TLG tlg = GetTLG(ti->tile);
    00270   byte PCPstatus = 0;
    00271   byte OverridePCP = 0;
    00272   byte PPPpreferred[DIAGDIR_END];
    00273   byte PPPallowed[DIAGDIR_END];
    00274
    00275   /* Find which rail bits are present, and select the override points.
    00276    * We don't draw a pylon:
    00277    * 1) INSIDE a tunnel (we wouldn't see it anyway)
    00278    * 2) on the "far" end of a bridge head (the one that connects to bridge middle),
    00279    *    because that one is drawn on the bridge. Exception is for length 0 bridges
    00280    *    which have no middle tiles */
    00281   trackconfig[TS_HOME] = GetRailTrackBitsUniversal(ti->tile, &OverridePCP);
    00282   wireconfig[TS_HOME] = MaskWireBits(ti->tile, trackconfig[TS_HOME]);
    00283   /* If a track bit is present that is not in the main direction, the track is level */
    00284   isflat[TS_HOME] = ((trackconfig[TS_HOME] & (TRACK_BIT_HORZ | TRACK_BIT_VERT)) != 0);
    00285
    00286   AdjustTileh(ti->tile, &tileh[TS_HOME]);
    00287
    00288   SpriteID pylon_base = GetPylonBase(ti->tile);
    00289
    00290   for (DiagDirection i = DIAGDIR_BEGIN; i < DIAGDIR_END; i++) {
    00291     TileIndex neighbour = ti->tile + TileOffsByDiagDir(i);
    00292     Foundation foundation = FOUNDATION_NONE;
    00293     byte elevation = GetPCPElevation(ti->tile, i);
    00294
    00295     /* Here's one of the main headaches. GetTileSlope does not correct for possibly
    00296      * existing foundataions, so we do have to do that manually later on.*/
    00297     tileh[TS_NEIGHBOUR] = GetTileSlope(neighbour, NULL);
    00298     trackconfig[TS_NEIGHBOUR] = GetRailTrackBitsUniversal(neighbour, NULL);
    00299     wireconfig[TS_NEIGHBOUR] = MaskWireBits(neighbour, trackconfig[TS_NEIGHBOUR]);
    00300     if (IsTunnelTile(neighbour) && i != GetTunnelBridgeDirection(neighbour)) wireconfig[TS_NEIGHBOUR] = trackconfig[TS_NEIGHBOUR] = TRACK_BIT_NONE;
    00301
    00302     /* If the neighboured tile does not smoothly connect to the current tile (because of a foundation),
    00303      * we have to draw all pillars on the current tile. */
    00304     if (elevation != GetPCPElevation(neighbour, ReverseDiagDir(i))) wireconfig[TS_NEIGHBOUR] = trackconfig[TS_NEIGHBOUR] = TRACK_BIT_NONE;
    00305
    00306     isflat[TS_NEIGHBOUR] = ((trackconfig[TS_NEIGHBOUR] & (TRACK_BIT_HORZ | TRACK_BIT_VERT)) != 0);
    00307
    00308     PPPpreferred[i] = 0xFF; // We start with preferring everything (end-of-line in any direction)
    00309     PPPallowed[i] = AllowedPPPonPCP[i];
    00310
    00311     /* We cycle through all the existing tracks at a PCP and see what
    00312      * PPPs we want to have, or may not have at all */
    00313     for (uint k = 0; k < NUM_TRACKS_AT_PCP; k++) {
    00314       /* Next to us, we have a bridge head, don't worry about that one, if it shows away from us */
    00315       if (TrackSourceTile[i][k] == TS_NEIGHBOUR &&
    00316           IsBridgeTile(neighbour) &&
    00317           GetTunnelBridgeDirection(neighbour) == ReverseDiagDir(i)) {
    00318         continue;
    00319       }
    00320
    00321       /* We check whether the track in question (k) is present in the tile
    00322        * (TrackSourceTile) */
    00323       DiagDirection PCPpos = i;
    00324       if (HasBit(wireconfig[TrackSourceTile[i][k]], TracksAtPCP[i][k])) {
    00325         /* track found, if track is in the neighbour tile, adjust the number
    00326          * of the PCP for preferred/allowed determination*/
    00327         PCPpos = (TrackSourceTile[i][k] == TS_HOME) ? i : ReverseDiagDir(i);
    00328         SetBit(PCPstatus, i); // This PCP is in use
    00329         PPPpreferred[i] &= PreferredPPPofTrackAtPCP[TracksAtPCP[i][k]][PCPpos];
    00330       }
    00331
    00332       if (HasBit(trackconfig[TrackSourceTile[i][k]], TracksAtPCP[i][k])) {
    00333         PPPallowed[i] &= ~DisallowedPPPofTrackAtPCP[TracksAtPCP[i][k]][PCPpos];
    00334       }
    00335     }
    00336
    00337     /* Deactivate all PPPs if PCP is not used */
    00338     if (!HasBit(PCPstatus, i)) {
    00339       PPPpreferred[i] = 0;
    00340       PPPallowed[i] = 0;
    00341     }
    00342
    00343     /* A station is always "flat", so adjust the tileh accordingly */
    00344     if (IsTileType(neighbour, MP_STATION)) tileh[TS_NEIGHBOUR] = SLOPE_FLAT;
    00345
    00346     /* Read the foundataions if they are present, and adjust the tileh */
    00347     if (trackconfig[TS_NEIGHBOUR] != TRACK_BIT_NONE && IsTileType(neighbour, MP_RAILWAY) && HasCatenary(GetRailType(neighbour))) foundation = GetRailFoundation(tileh[TS_NEIGHBOUR], trackconfig[TS_NEIGHBOUR]);
    00348     if (IsBridgeTile(neighbour)) {
    00349       foundation = GetBridgeFoundation(tileh[TS_NEIGHBOUR], DiagDirToAxis(GetTunnelBridgeDirection(neighbour)));
    00350     }
    00351
    00352     ApplyFoundationToSlope(foundation, &tileh[TS_NEIGHBOUR]);
    00353
    00354     /* Half tile slopes coincide only with horizontal/vertical track.
    00355      * Faking a flat slope results in the correct sprites on positions. */
    00356     if (IsHalftileSlope(tileh[TS_NEIGHBOUR])) tileh[TS_NEIGHBOUR] = SLOPE_FLAT;
    00357
    00358     AdjustTileh(neighbour, &tileh[TS_NEIGHBOUR]);
    00359
    00360     /* If we have a straight (and level) track, we want a pylon only every 2 tiles
    00361      * Delete the PCP if this is the case.
    00362      * Level means that the slope is the same, or the track is flat */
    00363     if (tileh[TS_HOME] == tileh[TS_NEIGHBOUR] || (isflat[TS_HOME] && isflat[TS_NEIGHBOUR])) {
    00364       for (uint k = 0; k < NUM_IGNORE_GROUPS; k++) {
    00365         if (PPPpreferred[i] == IgnoredPCP[k][tlg][i]) ClrBit(PCPstatus, i);
    00366       }
    00367     }
    00368
    00369     /* Now decide where we draw our pylons. First try the preferred PPPs, but they may not exist.
    00370      * In that case, we try the any of the allowed ones. if they don't exist either, don't draw
    00371      * anything. Note that the preferred PPPs still contain the end-of-line markers.
    00372      * Remove those (simply by ANDing with allowed, since these markers are never allowed) */
    00373     if ((PPPallowed[i] & PPPpreferred[i]) != 0) PPPallowed[i] &= PPPpreferred[i];
    00374
    00375     if (MayHaveBridgeAbove(ti->tile) && IsBridgeAbove(ti->tile)) {
    00376       Track bridgetrack = GetBridgeAxis(ti->tile) == AXIS_X ? TRACK_X : TRACK_Y;
    00377       uint height = GetBridgeHeight(GetNorthernBridgeEnd(ti->tile));
    00378
    00379       if ((height <= GetTileMaxZ(ti->tile) + TILE_HEIGHT) &&
    00380           (i == PCPpositions[bridgetrack][0] || i == PCPpositions[bridgetrack][1])) {
    00381         SetBit(OverridePCP, i);
    00382       }
    00383     }
    00384
    00385     if (PPPallowed[i] != 0 && HasBit(PCPstatus, i) && !HasBit(OverridePCP, i)) {
    00386       for (Direction k = DIR_BEGIN; k < DIR_END; k++) {
    00387         byte temp = PPPorder[i][GetTLG(ti->tile)][k];
    00388
    00389         if (HasBit(PPPallowed[i], temp)) {
    00390           uint x  = ti->x + x_pcp_offsets[i] + x_ppp_offsets[temp];
    00391           uint y  = ti->y + y_pcp_offsets[i] + y_ppp_offsets[temp];
    00392
    00393           /* Don't build the pylon if it would be outside the tile */
    00394           if (!HasBit(OwnedPPPonPCP[i], temp)) {
    00395             /* We have a neighour that will draw it, bail out */
    00396             if (trackconfig[TS_NEIGHBOUR] != TRACK_BIT_NONE) break;
    00397             continue; // No neighbour, go looking for a better position
    00398           }
    00399
    00400           AddSortableSpriteToDraw(pylon_base + pylon_sprites[temp], PAL_NONE, x, y, 1, 1, BB_HEIGHT_UNDER_BRIDGE,
    00401             elevation, IsTransparencySet(TO_CATENARY), -1, -1);
    00402
    00403           break; // We already have drawn a pylon, bail out
    00404         }
    00405       }
    00406     }
    00407   }
    00408
    00409   /* The wire above the tunnel is drawn together with the tunnel-roof (see DrawCatenaryOnTunnel()) */
    00410   if (IsTunnelTile(ti->tile)) return;
    00411
    00412   /* Don't draw a wire under a low bridge */
    00413   if (MayHaveBridgeAbove(ti->tile) && IsBridgeAbove(ti->tile) && !IsTransparencySet(TO_CATENARY)) {
    00414     uint height = GetBridgeHeight(GetNorthernBridgeEnd(ti->tile));
    00415
    00416     if (height <= GetTileMaxZ(ti->tile) + TILE_HEIGHT) return;
    00417   }
    00418
    00419   SpriteID wire_base = GetWireBase(ti->tile);
    00420
    00421   /* Drawing of pylons is finished, now draw the wires */
    00422   for (Track t = TRACK_BEGIN; t < TRACK_END; t++) {
    00423     if (HasBit(wireconfig[TS_HOME], t)) {
    00424       byte PCPconfig = HasBit(PCPstatus, PCPpositions[t][0]) +
    00425         (HasBit(PCPstatus, PCPpositions[t][1]) << 1);
    00426
    00427       const SortableSpriteStruct *sss;
    00428       int tileh_selector = !(tileh[TS_HOME] % 3) * tileh[TS_HOME] / 3; // tileh for the slopes, 0 otherwise
    00429
    00430       assert(PCPconfig != 0); // We have a pylon on neither end of the wire, that doesn't work (since we have no sprites for that)
    00431       assert(!IsSteepSlope(tileh[TS_HOME]));
    00432       sss = &CatenarySpriteData[Wires[tileh_selector][t][PCPconfig]];
    00433
    00434       /*
    00435        * The "wire"-sprite position is inside the tile, i.e. 0 <= sss->?_offset < TILE_SIZE.
    00436        * Therefore it is safe to use GetSlopeZ() for the elevation.
    00437        * Also note, that the result of GetSlopeZ() is very special for bridge-ramps.
    00438        */
    00439       AddSortableSpriteToDraw(wire_base + sss->image_offset, PAL_NONE, ti->x + sss->x_offset, ti->y + sss->y_offset,
    00440         sss->x_size, sss->y_size, sss->z_size, GetSlopeZ(ti->x + sss->x_offset, ti->y + sss->y_offset) + sss->z_offset,
    00441         IsTransparencySet(TO_CATENARY));
    00442     }
    00443   }
    00444 }
    00445
    00446 void DrawCatenaryOnBridge(const TileInfo *ti)
    00447 {
    00448   TileIndex end = GetSouthernBridgeEnd(ti->tile);
    00449   TileIndex start = GetOtherBridgeEnd(end);
    00450
    00451   uint length = GetTunnelBridgeLength(start, end);
    00452   uint num = GetTunnelBridgeLength(ti->tile, start) + 1;
    00453   uint height;
    00454
    00455   const SortableSpriteStruct *sss;
    00456   Axis axis = GetBridgeAxis(ti->tile);
    00457   TLG tlg = GetTLG(ti->tile);
    00458
    00459   CatenarySprite offset = (CatenarySprite)(axis == AXIS_X ? 0 : WIRE_Y_FLAT_BOTH - WIRE_X_FLAT_BOTH);
    00460
    00461   if ((length % 2) && num == length) {
    00462     /* Draw the "short" wire on the southern end of the bridge
    00463      * only needed if the length of the bridge is odd */
    00464     sss = &CatenarySpriteData[WIRE_X_FLAT_BOTH + offset];
    00465   } else {
    00466     /* Draw "long" wires on all other tiles of the bridge (one pylon every two tiles) */
    00467     sss = &CatenarySpriteData[WIRE_X_FLAT_SW + (num % 2) + offset];
    00468   }
    00469
    00470   height = GetBridgeHeight(end);
    00471
    00472   SpriteID wire_base = GetWireBase(start);
    00473
    00474   AddSortableSpriteToDraw(wire_base + sss->image_offset, PAL_NONE, ti->x + sss->x_offset, ti->y + sss->y_offset,
    00475     sss->x_size, sss->y_size, sss->z_size, height + sss->z_offset,
    00476     IsTransparencySet(TO_CATENARY)
    00477   );
    00478
    00479   SpriteID pylon_base = GetPylonBase(start);
    00480
    00481   /* Finished with wires, draw pylons
    00482    * every other tile needs a pylon on the northern end */
    00483   if (num % 2) {
    00484     DiagDirection PCPpos = (axis == AXIS_X ? DIAGDIR_NE : DIAGDIR_NW);
    00485     Direction PPPpos = (axis == AXIS_X ? DIR_NW : DIR_NE);
    00486     if (HasBit(tlg, (axis == AXIS_X ? 0 : 1))) PPPpos = ReverseDir(PPPpos);
    00487     uint x = ti->x + x_pcp_offsets[PCPpos] + x_ppp_offsets[PPPpos];
    00488     uint y = ti->y + y_pcp_offsets[PCPpos] + y_ppp_offsets[PPPpos];
    00489     AddSortableSpriteToDraw(pylon_base + pylon_sprites[PPPpos], PAL_NONE, x, y, 1, 1, BB_HEIGHT_UNDER_BRIDGE, height, IsTransparencySet(TO_CATENARY), -1, -1);
    00490   }
    00491
    00492   /* need a pylon on the southern end of the bridge */
    00493   if (GetTunnelBridgeLength(ti->tile, start) + 1 == length) {
    00494     DiagDirection PCPpos = (axis == AXIS_X ? DIAGDIR_SW : DIAGDIR_SE);
    00495     Direction PPPpos = (axis == AXIS_X ? DIR_NW : DIR_NE);
    00496     if (HasBit(tlg, (axis == AXIS_X ? 0 : 1))) PPPpos = ReverseDir(PPPpos);
    00497     uint x = ti->x + x_pcp_offsets[PCPpos] + x_ppp_offsets[PPPpos];
    00498     uint y = ti->y + y_pcp_offsets[PCPpos] + y_ppp_offsets[PPPpos];
    00499     AddSortableSpriteToDraw(pylon_base + pylon_sprites[PPPpos], PAL_NONE, x, y, 1, 1, BB_HEIGHT_UNDER_BRIDGE, height, IsTransparencySet(TO_CATENARY), -1, -1);
    00500   }
    00501 }
    00502
    00503 void DrawCatenary(const TileInfo *ti)
    00504 {
    00505   switch (GetTileType(ti->tile)) {
    00506     case MP_RAILWAY:
    00507       if (IsRailDepot(ti->tile)) {
    00508         const SortableSpriteStruct *sss = &CatenarySpriteData_Depot[GetRailDepotDirection(ti->tile)];
    00509
    00510         SpriteID wire_base = GetWireBase(ti->tile);
    00511
    00512         /* This wire is not visible with the default depot sprites */
    00513         AddSortableSpriteToDraw(
    00514           wire_base + sss->image_offset, PAL_NONE, ti->x + sss->x_offset, ti->y + sss->y_offset,
    00515           sss->x_size, sss->y_size, sss->z_size,
    00516           GetTileMaxZ(ti->tile) + sss->z_offset,
    00517           IsTransparencySet(TO_CATENARY)
    00518         );
    00519         return;
    00520       }
    00521       break;
    00522
    00523     case MP_TUNNELBRIDGE:
    00524     case MP_ROAD:
    00525     case MP_STATION:
    00526       break;
    00527
    00528     default: return;
    00529   }
    00530   DrawCatenaryRailway(ti);
    00531 }
    00532
    00533 bool SettingsDisableElrail(int32 p1)
    00534 {
    00535   Vehicle *v;
    00536   Company *c;
    00537   bool disable = (p1 != 0);
    00538
    00539   /* we will now walk through all electric train engines and change their railtypes if it is the wrong one*/
    00540   const RailType old_railtype = disable ? RAILTYPE_ELECTRIC : RAILTYPE_RAIL;
    00541   const RailType new_railtype = disable ? RAILTYPE_RAIL : RAILTYPE_ELECTRIC;
    00542
    00543   /* walk through all train engines */
    00544   Engine *e;
    00545   FOR_ALL_ENGINES_OF_TYPE(e, VEH_TRAIN) {
    00546     RailVehicleInfo *rv_info = &e->u.rail;
    00547     /* if it is an electric rail engine and its railtype is the wrong one */
    00548     if (rv_info->engclass == 2 && rv_info->railtype == old_railtype) {
    00549       /* change it to the proper one */
    00550       rv_info->railtype = new_railtype;
    00551     }
    00552   }
    00553
    00554   /* when disabling elrails, make sure that all existing trains can run on
    00555    *  normal rail too */
    00556   if (disable) {
    00557     FOR_ALL_VEHICLES(v) {
    00558       if (v->type == VEH_TRAIN && v->u.rail.railtype == RAILTYPE_ELECTRIC) {
    00559         /* this railroad vehicle is now compatible only with elrail,
    00560          *  so add there also normal rail compatibility */
    00561         v->u.rail.compatible_railtypes |= RAILTYPES_RAIL;
    00562         v->u.rail.railtype = RAILTYPE_RAIL;
    00563         SetBit(v->u.rail.flags, VRF_EL_ENGINE_ALLOWED_NORMAL_RAIL);
    00564       }
    00565     }
    00566   }
    00567
    00568   /* Fix the total power and acceleration for trains */
    00569   FOR_ALL_VEHICLES(v) {
    00570     /* power and acceleration is cached only for front engines */
    00571     if (v->type == VEH_TRAIN && IsFrontEngine(v)) {
    00572       TrainPowerChanged(v);
    00573       UpdateTrainAcceleration(v);
    00574     }
    00575   }
    00576
    00577   FOR_ALL_COMPANIES(c) c->avail_railtypes = GetCompanyRailtypes(c->index);
    00578
    00579   /* This resets the _last_built_railtype, which will be invalid for electric
    00580    * rails. It may have unintended consequences if that function is ever
    00581    * extended, though. */
    00582   ReinitGuiAfterToggleElrail(disable);
    00583   return true;
    00584 }