yapf_costrail.hpp

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/*
 * This file is part of OpenTTD.
 * 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.
 * 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.
 * 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/>.
 */
 
#ifndef YAPF_COSTRAIL_HPP
#define YAPF_COSTRAIL_HPP
 
 
#include "../../pbs.h"
#include "../follow_track.hpp"
#include "../pathfinder_type.h"
#include "yapf_type.hpp"
#include "yapf_costbase.hpp"
 
template <class Types>
class CYapfCostRailT : public CYapfCostBase {
public:
  typedef typename Types::Tpf Tpf; 
  typedef typename Types::TrackFollower TrackFollower;
  typedef typename Types::NodeList::Item Node; 
  typedef typename Node::Key Key; 
  typedef typename Node::CachedData CachedData;
 
protected:
 
  /* Structure used inside PfCalcCost() to keep basic tile information. */
  struct TILE {
    TileIndex   tile;
    Trackdir    td;
    TileType    tile_type;
    RailType    rail_type;
 
    TILE() : tile(INVALID_TILE), td(INVALID_TRACKDIR), tile_type(MP_VOID), rail_type(INVALID_RAILTYPE) { }
 
    TILE(TileIndex tile, Trackdir td) : tile(tile), td(td), tile_type(GetTileType(tile)), rail_type(GetTileRailType(tile)) { }
  };
 
protected:
  int max_cost = 0;
  bool disable_cache = false;
  std::vector<int> sig_look_ahead_costs = {};
  bool treat_first_red_two_way_signal_as_eol = false;
 
public:
  bool stopped_on_first_two_way_signal = false;
 
protected:
  static constexpr int MAX_SEGMENT_COST = 10000;
 
  CYapfCostRailT()
  {
    /* pre-compute look-ahead penalties into array */
    int p0 = Yapf().PfGetSettings().rail_look_ahead_signal_p0;
    int p1 = Yapf().PfGetSettings().rail_look_ahead_signal_p1;
    int p2 = Yapf().PfGetSettings().rail_look_ahead_signal_p2;
    this->sig_look_ahead_costs.clear();
    this->sig_look_ahead_costs.reserve(Yapf().PfGetSettings().rail_look_ahead_max_signals);
    for (uint i = 0; i < Yapf().PfGetSettings().rail_look_ahead_max_signals; i++) {
      this->sig_look_ahead_costs.push_back(p0 + i * (p1 + i * p2));
    }
  }
 
  Tpf &Yapf()
  {
    return *static_cast<Tpf *>(this);
  }
 
public:
  void SetTreatFirstRedTwoWaySignalAsEOL(bool enabled)
  {
    this->treat_first_red_two_way_signal_as_eol = enabled;
  }
 
  inline bool TreatFirstRedTwoWaySignalAsEOL()
  {
    return Yapf().PfGetSettings().rail_firstred_twoway_eol && this->treat_first_red_two_way_signal_as_eol;
  }
 
  inline int SlopeCost(TileIndex tile, Trackdir td)
  {
    if (!stSlopeCost(tile, td)) return 0;
    return Yapf().PfGetSettings().rail_slope_penalty;
  }
 
  inline int CurveCost(Trackdir td1, Trackdir td2)
  {
    assert(IsValidTrackdir(td1));
    assert(IsValidTrackdir(td2));
    int cost = 0;
    if (TrackFollower::Allow90degTurns()
        && HasTrackdir(TrackdirCrossesTrackdirs(td1), td2)) {
      /* 90-deg curve penalty */
      cost += Yapf().PfGetSettings().rail_curve90_penalty;
    } else if (td2 != NextTrackdir(td1)) {
      /* 45-deg curve penalty */
      cost += Yapf().PfGetSettings().rail_curve45_penalty;
    }
    return cost;
  }
 
  inline int SwitchCost(TileIndex tile1, TileIndex tile2, DiagDirection exitdir)
  {
    if (IsPlainRailTile(tile1) && IsPlainRailTile(tile2)) {
      bool t1 = KillFirstBit(GetTrackBits(tile1) & DiagdirReachesTracks(ReverseDiagDir(exitdir))) != TRACK_BIT_NONE;
      bool t2 = KillFirstBit(GetTrackBits(tile2) & DiagdirReachesTracks(exitdir)) != TRACK_BIT_NONE;
      if (t1 && t2) return Yapf().PfGetSettings().rail_doubleslip_penalty;
    }
    return 0;
  }
 
  inline int OneTileCost(TileIndex &tile, Trackdir trackdir)
  {
    int cost = 0;
    /* set base cost */
    if (IsDiagonalTrackdir(trackdir)) {
      cost += YAPF_TILE_LENGTH;
      switch (GetTileType(tile)) {
        case MP_ROAD:
          /* Increase the cost for level crossings */
          if (IsLevelCrossing(tile)) {
            cost += Yapf().PfGetSettings().rail_crossing_penalty;
          }
          break;
 
        default:
          break;
      }
    } else {
      /* non-diagonal trackdir */
      cost = YAPF_TILE_CORNER_LENGTH;
    }
    return cost;
  }
 
  inline bool IsAnyStationTileReserved(TileIndex tile, Trackdir trackdir, int skipped)
  {
    TileIndexDiff diff = TileOffsByDiagDir(TrackdirToExitdir(ReverseTrackdir(trackdir)));
    for (; skipped >= 0; skipped--, tile += diff) {
      if (HasStationReservation(tile)) return true;
    }
    return false;
  }
 
  inline int ReservationCost(Node &n, TileIndex tile, Trackdir trackdir, int skipped)
  {
    if (n.num_signals_passed >= this->sig_look_ahead_costs.size() / 2) return 0;
    if (!IsPbsSignal(n.last_signal_type)) return 0;
 
    if (IsRailStationTile(tile) && IsAnyStationTileReserved(tile, trackdir, skipped)) {
      return Yapf().PfGetSettings().rail_pbs_station_penalty * (skipped + 1);
    } else if (TrackOverlapsTracks(GetReservedTrackbits(tile), TrackdirToTrack(trackdir))) {
      int cost = Yapf().PfGetSettings().rail_pbs_cross_penalty;
      if (!IsDiagonalTrackdir(trackdir)) cost = (cost * YAPF_TILE_CORNER_LENGTH) / YAPF_TILE_LENGTH;
      return cost * (skipped + 1);
    }
    return 0;
  }
 
  int SignalCost(Node &n, TileIndex tile, Trackdir trackdir)
  {
    int cost = 0;
    /* if there is one-way signal in the opposite direction, then it is not our way */
    if (IsTileType(tile, MP_RAILWAY)) {
      bool has_signal_against = HasSignalOnTrackdir(tile, ReverseTrackdir(trackdir));
      bool has_signal_along = HasSignalOnTrackdir(tile, trackdir);
      if (has_signal_against && !has_signal_along && IsOnewaySignal(tile, TrackdirToTrack(trackdir))) {
        /* one-way signal in opposite direction */
        n.segment->end_segment_reason |= ESRB_DEAD_END;
      } else {
        if (has_signal_along) {
          SignalState sig_state = GetSignalStateByTrackdir(tile, trackdir);
          SignalType sig_type = GetSignalType(tile, TrackdirToTrack(trackdir));
 
          n.last_signal_type = sig_type;
 
          /* cache the look-ahead polynomial constant only if we didn't pass more signals than the look-ahead limit is */
          int look_ahead_cost = (n.num_signals_passed < this->sig_look_ahead_costs.size()) ? this->sig_look_ahead_costs[n.num_signals_passed] : 0;
          if (sig_state != SIGNAL_STATE_RED) {
            /* green signal */
            n.flags_u.flags_s.last_signal_was_red = false;
            /* negative look-ahead red-signal penalties would cause problems later, so use them as positive penalties for green signal */
            if (look_ahead_cost < 0) {
              /* add its negation to the cost */
              cost -= look_ahead_cost;
            }
          } else {
            /* we have a red signal in our direction
             * was it first signal which is two-way? */
            if (!IsPbsSignal(sig_type) && Yapf().TreatFirstRedTwoWaySignalAsEOL() && n.flags_u.flags_s.choice_seen && has_signal_against && n.num_signals_passed == 0) {
              /* yes, the first signal is two-way red signal => DEAD END. Prune this branch... */
              Yapf().PruneIntermediateNodeBranch(&n);
              n.segment->end_segment_reason |= ESRB_DEAD_END;
              Yapf().stopped_on_first_two_way_signal = true;
              return -1;
            }
            n.last_red_signal_type = sig_type;
            n.flags_u.flags_s.last_signal_was_red = true;
 
            /* look-ahead signal penalty */
            if (!IsPbsSignal(sig_type) && look_ahead_cost > 0) {
              /* add the look ahead penalty only if it is positive */
              cost += look_ahead_cost;
            }
 
            /* special signal penalties */
            if (n.num_signals_passed == 0) {
              switch (sig_type) {
                case SIGTYPE_COMBO:
                case SIGTYPE_EXIT:   cost += Yapf().PfGetSettings().rail_firstred_exit_penalty; break; // first signal is red pre-signal-exit
                case SIGTYPE_BLOCK:
                case SIGTYPE_ENTRY:  cost += Yapf().PfGetSettings().rail_firstred_penalty; break;
                default: break;
              }
            }
          }
 
          n.num_signals_passed++;
          n.segment->last_signal_tile = tile;
          n.segment->last_signal_td = trackdir;
        }
 
        if (has_signal_against && IsPbsSignal(GetSignalType(tile, TrackdirToTrack(trackdir)))) {
          cost += n.num_signals_passed < Yapf().PfGetSettings().rail_look_ahead_max_signals ? Yapf().PfGetSettings().rail_pbs_signal_back_penalty : 0;
        }
      }
    }
    return cost;
  }
 
  inline int PlatformLengthPenalty(int platform_length)
  {
    int cost = 0;
    const Train *v = Yapf().GetVehicle();
    assert(v != nullptr);
    assert(v->type == VEH_TRAIN);
    assert(v->gcache.cached_total_length != 0);
    int missing_platform_length = CeilDiv(v->gcache.cached_total_length, TILE_SIZE) - platform_length;
    if (missing_platform_length < 0) {
      /* apply penalty for longer platform than needed */
      cost += Yapf().PfGetSettings().rail_longer_platform_penalty + Yapf().PfGetSettings().rail_longer_platform_per_tile_penalty * -missing_platform_length;
    } else if (missing_platform_length > 0) {
      /* apply penalty for shorter platform than needed */
      cost += Yapf().PfGetSettings().rail_shorter_platform_penalty + Yapf().PfGetSettings().rail_shorter_platform_per_tile_penalty * missing_platform_length;
    }
    return cost;
  }
 
public:
  inline void SetMaxCost(int max_cost)
  {
    this->max_cost = max_cost;
  }
 
  inline bool PfCalcCost(Node &n, const TrackFollower *tf)
  {
    assert(!n.flags_u.flags_s.target_seen);
    assert(tf->new_tile == n.key.tile);
    assert((HasTrackdir(tf->new_td_bits, n.key.td)));
 
    /* Does the node have some parent node? */
    bool has_parent = (n.parent != nullptr);
 
    /* Do we already have a cached segment? */
    CachedData &segment = *n.segment;
    bool is_cached_segment = (segment.cost >= 0);
 
    int parent_cost = has_parent ? n.parent->cost : 0;
 
    /* Each node cost contains 2 or 3 main components:
     *  1. Transition cost - cost of the move from previous node (tile):
     *    - curve cost (or zero for straight move)
     *  2. Tile cost:
     *    - base tile cost
     *      - YAPF_TILE_LENGTH for diagonal tiles
     *      - YAPF_TILE_CORNER_LENGTH for non-diagonal tiles
     *    - tile penalties
     *      - tile slope penalty (upward slopes)
     *      - red signal penalty
     *      - level crossing penalty
     *      - speed-limit penalty (bridges)
     *      - station platform penalty
     *      - penalty for reversing in the depot
     *      - etc.
     *  3. Extra cost (applies to the last node only)
     *    - last red signal penalty
     *    - penalty for too long or too short platform on the destination station
     */
    int transition_cost = 0;
    int extra_cost = 0;
 
    /* Segment: one or more tiles connected by contiguous tracks of the same type.
     * Each segment cost includes 'Tile cost' for all its tiles (including the first
     * and last), and the 'Transition cost' between its tiles. The first transition
     * cost of segment entry (move from the 'parent' node) is not included!
     */
    int segment_entry_cost = 0;
    int segment_cost = 0;
 
    const Train *v = Yapf().GetVehicle();
 
    /* start at n.key.tile / n.key.td and walk to the end of segment */
    TILE cur(n.key.tile, n.key.td);
 
    /* the previous tile will be needed for transition cost calculations */
    TILE prev = !has_parent ? TILE() : TILE(n.parent->GetLastTile(), n.parent->GetLastTrackdir());
 
    EndSegmentReasonBits end_segment_reason = ESRB_NONE;
 
    TrackFollower tf_local(v, Yapf().GetCompatibleRailTypes());
 
    if (!has_parent) {
      /* We will jump to the middle of the cost calculator assuming that segment cache is not used. */
      assert(!is_cached_segment);
      /* Skip the first transition cost calculation. */
      goto no_entry_cost;
    }
 
    for (;;) {
      /* Transition cost (cost of the move from previous tile) */
      transition_cost = Yapf().CurveCost(prev.td, cur.td);
      transition_cost += Yapf().SwitchCost(prev.tile, cur.tile, TrackdirToExitdir(prev.td));
 
      /* First transition cost counts against segment entry cost, other transitions
       * inside segment will come to segment cost (and will be cached) */
      if (segment_cost == 0) {
        /* We just entered the loop. First transition cost goes to segment entry cost)*/
        segment_entry_cost = transition_cost;
        transition_cost = 0;
 
        /* It is the right time now to look if we can reuse the cached segment cost. */
        if (is_cached_segment) {
          /* Yes, we already know the segment cost. */
          segment_cost = segment.cost;
          /* We know also the reason why the segment ends. */
          end_segment_reason = segment.end_segment_reason;
          /* We will need also some information about the last signal (if it was red). */
          if (segment.last_signal_tile != INVALID_TILE) {
            assert(HasSignalOnTrackdir(segment.last_signal_tile, segment.last_signal_td));
            SignalState sig_state = GetSignalStateByTrackdir(segment.last_signal_tile, segment.last_signal_td);
            bool is_red = (sig_state == SIGNAL_STATE_RED);
            n.flags_u.flags_s.last_signal_was_red = is_red;
            if (is_red) {
              n.last_red_signal_type = GetSignalType(segment.last_signal_tile, TrackdirToTrack(segment.last_signal_td));
            }
          }
          /* No further calculation needed. */
          cur = TILE(n.GetLastTile(), n.GetLastTrackdir());
          break;
        }
      } else {
        /* Other than first transition cost count as the regular segment cost. */
        segment_cost += transition_cost;
      }
 
no_entry_cost: // jump here at the beginning if the node has no parent (it is the first node)
 
      /* All other tile costs will be calculated here. */
      segment_cost += Yapf().OneTileCost(cur.tile, cur.td);
 
      /* If we skipped some tunnel/bridge/station tiles, add their base cost */
      segment_cost += YAPF_TILE_LENGTH * tf->tiles_skipped;
 
      /* Slope cost. */
      segment_cost += Yapf().SlopeCost(cur.tile, cur.td);
 
      /* Signal cost (routine can modify segment data). */
      segment_cost += Yapf().SignalCost(n, cur.tile, cur.td);
 
      /* Reserved tiles. */
      segment_cost += Yapf().ReservationCost(n, cur.tile, cur.td, tf->tiles_skipped);
 
      end_segment_reason = segment.end_segment_reason;
 
      /* Tests for 'potential target' reasons to close the segment. */
      if (cur.tile == prev.tile) {
        /* Penalty for reversing in a depot. */
        assert(IsRailDepot(cur.tile));
        segment_cost += Yapf().PfGetSettings().rail_depot_reverse_penalty;
 
      } else if (IsRailDepotTile(cur.tile)) {
        /* We will end in this pass (depot is possible target) */
        end_segment_reason |= ESRB_DEPOT;
 
      } else if (cur.tile_type == MP_STATION && IsRailWaypoint(cur.tile)) {
        if (v->current_order.IsType(OT_GOTO_WAYPOINT) &&
            GetStationIndex(cur.tile) == v->current_order.GetDestination() &&
            !Waypoint::Get(v->current_order.GetDestination())->IsSingleTile()) {
          /* This waypoint is our destination; maybe this isn't an unreserved
           * one, so check that and if so see that as the last signal being
           * red. This way waypoints near stations should work better. */
          CFollowTrackRail ft(v);
          TileIndex t = cur.tile;
          Trackdir td = cur.td;
          /* Arbitrary maximum tiles to follow to avoid infinite loops. */
          uint max_tiles = 20;
          while (ft.Follow(t, td)) {
            assert(t != ft.new_tile);
            t = ft.new_tile;
            if (t == cur.tile || --max_tiles == 0) {
              /* We looped back on ourself or found another loop, bail out. */
              td = INVALID_TRACKDIR;
              break;
            }
            if (KillFirstBit(ft.new_td_bits) != TRACKDIR_BIT_NONE) {
              /* We encountered a junction; it's going to be too complex to
               * handle this perfectly, so just bail out. There is no simple
               * free path, so try the other possibilities. */
              td = INVALID_TRACKDIR;
              break;
            }
            td = RemoveFirstTrackdir(&ft.new_td_bits);
            /* If this is a safe waiting position we're done searching for it */
            if (IsSafeWaitingPosition(v, t, td, true, _settings_game.pf.forbid_90_deg)) break;
          }
 
          /* In the case this platform is (possibly) occupied we add penalty so the
           * other platforms of this waypoint are evaluated as well, i.e. we assume
           * that there is a red signal in the waypoint when it's occupied. */
          if (td == INVALID_TRACKDIR ||
              !IsSafeWaitingPosition(v, t, td, true, _settings_game.pf.forbid_90_deg) ||
              !IsWaitingPositionFree(v, t, td, _settings_game.pf.forbid_90_deg)) {
            extra_cost += Yapf().PfGetSettings().rail_lastred_penalty;
          }
        }
        /* Waypoint is also a good reason to finish. */
        end_segment_reason |= ESRB_WAYPOINT;
 
      } else if (tf->is_station) {
        /* Station penalties. */
        uint platform_length = tf->tiles_skipped + 1;
        /* We don't know yet if the station is our target or not. Act like
         * if it is pass-through station (not our destination). */
        segment_cost += Yapf().PfGetSettings().rail_station_penalty * platform_length;
        /* We will end in this pass (station is possible target) */
        end_segment_reason |= ESRB_STATION;
 
      } else if (TrackFollower::DoTrackMasking() && cur.tile_type == MP_RAILWAY) {
        /* Searching for a safe tile? */
        if (HasSignalOnTrackdir(cur.tile, cur.td) && !IsPbsSignal(GetSignalType(cur.tile, TrackdirToTrack(cur.td)))) {
          end_segment_reason |= ESRB_SAFE_TILE;
        }
      }
 
      /* Apply min/max speed penalties only when inside the look-ahead radius. Otherwise
       * it would cause desync in MP. */
      if (n.num_signals_passed < this->sig_look_ahead_costs.size())
      {
        int min_speed = 0;
        int max_speed = tf->GetSpeedLimit(&min_speed);
        int max_veh_speed = std::min<int>(v->GetDisplayMaxSpeed(), v->current_order.GetMaxSpeed());
        if (max_speed < max_veh_speed) {
          extra_cost += YAPF_TILE_LENGTH * (max_veh_speed - max_speed) * (4 + tf->tiles_skipped) / max_veh_speed;
        }
        if (min_speed > max_veh_speed) {
          extra_cost += YAPF_TILE_LENGTH * (min_speed - max_veh_speed);
        }
      }
 
      /* Finish if we already exceeded the maximum path cost (i.e. when
       * searching for the nearest depot). */
      if (this->max_cost > 0 && (parent_cost + segment_entry_cost + segment_cost) > this->max_cost) {
        end_segment_reason |= ESRB_PATH_TOO_LONG;
      }
 
      /* Move to the next tile/trackdir. */
      tf = &tf_local;
      tf_local.Init(v, Yapf().GetCompatibleRailTypes());
 
      if (!tf_local.Follow(cur.tile, cur.td)) {
        assert(tf_local.err != TrackFollower::EC_NONE);
        /* Can't move to the next tile (EOL?). */
        if (tf_local.err == TrackFollower::EC_RAIL_ROAD_TYPE) {
          end_segment_reason |= ESRB_RAIL_TYPE;
        } else {
          end_segment_reason |= ESRB_DEAD_END;
        }
 
        if (TrackFollower::DoTrackMasking() && !HasOnewaySignalBlockingTrackdir(cur.tile, cur.td)) {
          end_segment_reason |= ESRB_SAFE_TILE;
        }
        break;
      }
 
      /* Check if the next tile is not a choice. */
      if (KillFirstBit(tf_local.new_td_bits) != TRACKDIR_BIT_NONE) {
        /* More than one segment will follow. Close this one. */
        end_segment_reason |= ESRB_CHOICE_FOLLOWS;
        break;
      }
 
      /* Gather the next tile/trackdir/tile_type/rail_type. */
      TILE next(tf_local.new_tile, (Trackdir)FindFirstBit(tf_local.new_td_bits));
 
      if (TrackFollower::DoTrackMasking() && IsTileType(next.tile, MP_RAILWAY)) {
        if (HasSignalOnTrackdir(next.tile, next.td) && IsPbsSignal(GetSignalType(next.tile, TrackdirToTrack(next.td)))) {
          /* Possible safe tile. */
          end_segment_reason |= ESRB_SAFE_TILE;
        } else if (HasSignalOnTrackdir(next.tile, ReverseTrackdir(next.td)) && GetSignalType(next.tile, TrackdirToTrack(next.td)) == SIGTYPE_PBS_ONEWAY) {
          /* Possible safe tile, but not so good as it's the back of a signal... */
          end_segment_reason |= ESRB_SAFE_TILE | ESRB_DEAD_END;
          extra_cost += Yapf().PfGetSettings().rail_lastred_exit_penalty;
        }
      }
 
      /* Check the next tile for the rail type. */
      if (next.rail_type != cur.rail_type) {
        /* Segment must consist from the same rail_type tiles. */
        end_segment_reason |= ESRB_RAIL_TYPE;
        break;
      }
 
      /* Avoid infinite looping. */
      if (next.tile == n.key.tile && next.td == n.key.td) {
        end_segment_reason |= ESRB_INFINITE_LOOP;
        break;
      }
 
      if (segment_cost > MAX_SEGMENT_COST) {
        /* Potentially in the infinite loop (or only very long segment?). We should
         * not force it to finish prematurely unless we are on a regular tile. */
        if (IsTileType(tf->new_tile, MP_RAILWAY)) {
          end_segment_reason |= ESRB_SEGMENT_TOO_LONG;
          break;
        }
      }
 
      /* Any other reason bit set? */
      if (end_segment_reason != ESRB_NONE) {
        break;
      }
 
      /* For the next loop set new prev and cur tile info. */
      prev = cur;
      cur = next;
 
    } // for (;;)
 
    /* Don't consider path any further it if exceeded max_cost. */
    if (end_segment_reason & ESRB_PATH_TOO_LONG) return false;
 
    bool target_seen = false;
    if ((end_segment_reason & ESRB_POSSIBLE_TARGET) != ESRB_NONE) {
      /* Depot, station or waypoint. */
      if (Yapf().PfDetectDestination(cur.tile, cur.td)) {
        /* Destination found. */
        target_seen = true;
      }
    }
 
    /* Update the segment if needed. */
    if (!is_cached_segment) {
      /* Write back the segment information so it can be reused the next time. */
      segment.cost = segment_cost;
      segment.end_segment_reason = end_segment_reason & ESRB_CACHED_MASK;
      /* Save end of segment back to the node. */
      n.SetLastTileTrackdir(cur.tile, cur.td);
    }
 
    /* Do we have an excuse why not to continue pathfinding in this direction? */
    if (!target_seen && (end_segment_reason & ESRB_ABORT_PF_MASK) != ESRB_NONE) {
      /* Reason to not continue. Stop this PF branch. */
      return false;
    }
 
    /* Special costs for the case we have reached our target. */
    if (target_seen) {
      n.flags_u.flags_s.target_seen = true;
      /* Last-red and last-red-exit penalties. */
      if (n.flags_u.flags_s.last_signal_was_red) {
        if (n.last_red_signal_type == SIGTYPE_EXIT) {
          /* last signal was red pre-signal-exit */
          extra_cost += Yapf().PfGetSettings().rail_lastred_exit_penalty;
        } else if (!IsPbsSignal(n.last_red_signal_type)) {
          /* Last signal was red, but not exit or path signal. */
          extra_cost += Yapf().PfGetSettings().rail_lastred_penalty;
        }
      }
 
      /* Station platform-length penalty. */
      if ((end_segment_reason & ESRB_STATION) != ESRB_NONE) {
        const BaseStation *st = BaseStation::GetByTile(n.GetLastTile());
        assert(st != nullptr);
        uint platform_length = st->GetPlatformLength(n.GetLastTile(), ReverseDiagDir(TrackdirToExitdir(n.GetLastTrackdir())));
        /* Reduce the extra cost caused by passing-station penalty (each station receives it in the segment cost). */
        extra_cost -= Yapf().PfGetSettings().rail_station_penalty * platform_length;
        /* Add penalty for the inappropriate platform length. */
        extra_cost += PlatformLengthPenalty(platform_length);
      }
    }
 
    /* total node cost */
    n.cost = parent_cost + segment_entry_cost + segment_cost + extra_cost;
 
    return true;
  }
 
  inline bool CanUseGlobalCache(Node &n) const
  {
    return !this->disable_cache
      && (n.parent != nullptr)
      && (n.parent->num_signals_passed >= this->sig_look_ahead_costs.size());
  }
 
  inline void ConnectNodeToCachedData(Node &n, CachedData &ci)
  {
    n.segment = &ci;
    if (n.segment->cost < 0) {
      n.segment->last_tile = n.key.tile;
      n.segment->last_td = n.key.td;
    }
  }
 
  void DisableCache(bool disable)
  {
    this->disable_cache = disable;
  }
};
 
#endif /* YAPF_COSTRAIL_HPP */