Files @ r10911:571c959dc9ed
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Location: cpp/openttd-patchpack/source/src/pbs.cpp

rubidium
(svn r15246) -Fix [FS#2577]: close all windows *before* starting a new game/loading a game instead of doing that as one of the latest steps of loading the game. This caused, in some cases, the NewGRF settings to be reset when the game was already loaded resulting in instant desyncs when joining a network game
/* $Id$ */

/** @file pbs.cpp */
#include "stdafx.h"
#include "openttd.h"
#include "pbs.h"
#include "rail_map.h"
#include "road_map.h"
#include "station_map.h"
#include "tunnelbridge_map.h"
#include "functions.h"
#include "debug.h"
#include "direction_func.h"
#include "settings_type.h"
#include "road_func.h"
#include "vehicle_base.h"
#include "vehicle_func.h"
#include "yapf/follow_track.hpp"

/**
 * Get the reserved trackbits for any tile, regardless of type.
 * @param t the tile
 * @return the reserved trackbits. TRACK_BIT_NONE on nothing reserved or
 *     a tile without rail.
 */
TrackBits GetReservedTrackbits(TileIndex t)
{
	switch (GetTileType(t)) {
		case MP_RAILWAY:
			if (IsRailWaypoint(t) || IsRailDepot(t)) return GetRailWaypointReservation(t);
			if (IsPlainRailTile(t)) return GetTrackReservation(t);
			break;

		case MP_ROAD:
			if (IsLevelCrossing(t)) return GetRailCrossingReservation(t);
			break;

		case MP_STATION:
			if (IsRailwayStation(t)) return GetRailStationReservation(t);
			break;

		case MP_TUNNELBRIDGE:
			if (GetTunnelBridgeTransportType(t) == TRANSPORT_RAIL) return GetRailTunnelBridgeReservation(t);
			break;

		default:
			break;
	}
	return TRACK_BIT_NONE;
}

/**
 * Set the reservation for a complete station platform.
 * @pre IsRailwayStationTile(start)
 * @param start starting tile of the platform
 * @param dir the direction in which to follow the platform
 * @param b the state the reservation should be set to
 */
void SetRailwayStationPlatformReservation(TileIndex start, DiagDirection dir, bool b)
{
	TileIndex     tile = start;
	TileIndexDiff diff = TileOffsByDiagDir(dir);

	assert(IsRailwayStationTile(start));
	assert(GetRailStationAxis(start) == DiagDirToAxis(dir));

	do {
		SetRailwayStationReservation(tile, b);
		MarkTileDirtyByTile(tile);
		tile = TILE_ADD(tile, diff);
	} while (IsCompatibleTrainStationTile(tile, start));
}

/**
 * Try to reserve a specific track on a tile
 * @param tile the tile
 * @param t the track
 * @return true if reservation was successfull, i.e. the track was
 *     free and didn't cross any other reserved tracks.
 */
bool TryReserveRailTrack(TileIndex tile, Track t)
{
	assert((GetTileTrackStatus(tile, TRANSPORT_RAIL, 0) & TrackToTrackBits(t)) != 0);

	if (_settings_client.gui.show_track_reservation) {
		/* show the reserved rail if needed */
		MarkTileDirtyByTile(tile);
	}

	switch (GetTileType(tile)) {
		case MP_RAILWAY:
			if (IsPlainRailTile(tile)) return TryReserveTrack(tile, t);
			if (IsRailWaypoint(tile) || IsRailDepot(tile)) {
				if (!GetDepotWaypointReservation(tile)) {
					SetDepotWaypointReservation(tile, true);
					MarkTileDirtyByTile(tile); // some GRFs change their appearance when tile is reserved
					return true;
				}
			}
			break;

		case MP_ROAD:
			if (IsLevelCrossing(tile) && !GetCrossingReservation(tile)) {
				SetCrossingReservation(tile, true);
				BarCrossing(tile);
				MarkTileDirtyByTile(tile); // crossing barred, make tile dirty
				return true;
			}
			break;

		case MP_STATION:
			if (IsRailwayStation(tile) && !GetRailwayStationReservation(tile)) {
				SetRailwayStationReservation(tile, true);
				MarkTileDirtyByTile(tile); // some GRFs need redraw after reserving track
				return true;
			}
			break;

		case MP_TUNNELBRIDGE:
			if (GetTunnelBridgeTransportType(tile) == TRANSPORT_RAIL && !GetRailTunnelBridgeReservation(tile)) {
				SetTunnelBridgeReservation(tile, true);
				return true;
			}
			break;

		default:
			break;
	}
	return false;
}

/**
 * Lift the reservation of a specific track on a tile
 * @param tile the tile
 * @param t the track
 */
 void UnreserveRailTrack(TileIndex tile, Track t)
{
	assert((GetTileTrackStatus(tile, TRANSPORT_RAIL, 0) & TrackToTrackBits(t)) != 0);

	if (_settings_client.gui.show_track_reservation) {
		MarkTileDirtyByTile(tile);
	}

	switch (GetTileType(tile)) {
		case MP_RAILWAY:
			if (IsRailWaypoint(tile) || IsRailDepot(tile)) {
				SetDepotWaypointReservation(tile, false);
				MarkTileDirtyByTile(tile);
				break;
			}
			if (IsPlainRailTile(tile)) UnreserveTrack(tile, t);
			break;

		case MP_ROAD:
			if (IsLevelCrossing(tile)) {
				SetCrossingReservation(tile, false);
				UpdateLevelCrossing(tile);
			}
			break;

		case MP_STATION:
			if (IsRailwayStation(tile)) {
				SetRailwayStationReservation(tile, false);
				MarkTileDirtyByTile(tile);
			}
			break;

		case MP_TUNNELBRIDGE:
			if (GetTunnelBridgeTransportType(tile) == TRANSPORT_RAIL) SetTunnelBridgeReservation(tile, false);
			break;

		default:
			break;
	}
}


/** Follow a reservation starting from a specific tile to the end. */
static PBSTileInfo FollowReservation(Owner o, RailTypes rts, TileIndex tile, Trackdir trackdir, bool ignore_oneway = false)
{
	TileIndex start_tile = tile;
	Trackdir  start_trackdir = trackdir;
	bool      first_loop = true;

	/* Start track not reserved? This can happen if two trains
	 * are on the same tile. The reservation on the next tile
	 * is not ours in this case, so exit. */
	if (!HasReservedTracks(tile, TrackToTrackBits(TrackdirToTrack(trackdir)))) return PBSTileInfo(tile, trackdir, false);

	/* Do not disallow 90 deg turns as the setting might have changed between reserving and now. */
	CFollowTrackRail ft(o, rts);
	while (ft.Follow(tile, trackdir)) {
		TrackdirBits reserved = ft.m_new_td_bits & TrackBitsToTrackdirBits(GetReservedTrackbits(ft.m_new_tile));

		/* No reservation --> path end found */
		if (reserved == TRACKDIR_BIT_NONE) break;

		/* Can't have more than one reserved trackdir */
		Trackdir new_trackdir = FindFirstTrackdir(reserved);

		/* One-way signal against us. The reservation can't be ours as it is not
		 * a safe position from our direction and we can never pass the signal. */
		if (!ignore_oneway && HasOnewaySignalBlockingTrackdir(ft.m_new_tile, new_trackdir)) break;

		tile = ft.m_new_tile;
		trackdir = new_trackdir;

		if (first_loop) {
			/* Update the start tile after we followed the track the first
			 * time. This is neccessary because the track follower can skip
			 * tiles (in stations for example) which means that we might
			 * never visit our original starting tile again. */
			start_tile = tile;
			start_trackdir = trackdir;
			first_loop = false;
		} else {
			/* Loop encountered? */
			if (tile == start_tile && trackdir == start_trackdir) break;
		}
		/* Depot tile? Can't continue. */
		if (IsRailDepotTile(tile)) break;
		/* Non-pbs signal? Reservation can't continue. */
		if (IsTileType(tile, MP_RAILWAY) && HasSignalOnTrackdir(tile, trackdir) && !IsPbsSignal(GetSignalType(tile, TrackdirToTrack(trackdir)))) break;
	}

	return PBSTileInfo(tile, trackdir, false);
}

/**
 * Helper struct for finding the best matching vehicle on a specific track.
 */
struct FindTrainOnTrackInfo {
	PBSTileInfo res; ///< Information about the track.
	Vehicle *best;   ///< The currently "best" vehicle we have found.

	/** Init the best location to NULL always! */
	FindTrainOnTrackInfo() : best(NULL) {}
};

/** Callback for Has/FindVehicleOnPos to find a train on a specific track. */
static Vehicle *FindTrainOnTrackEnum(Vehicle *v, void *data)
{
	FindTrainOnTrackInfo *info = (FindTrainOnTrackInfo *)data;

	if (v->type == VEH_TRAIN && !(v->vehstatus & VS_CRASHED) && HasBit((TrackBits)v->u.rail.track, TrackdirToTrack(info->res.trackdir))) {
		v = v->First();

		/* ALWAYS return the lowest ID (anti-desync!) */
		if (info->best == NULL || v->index < info->best->index) info->best = v;
		return v;
	}

	return NULL;
}

/**
 * Follow a train reservation to the last tile.
 *
 * @param v the vehicle
 * @param train_on_res Is set to a train we might encounter
 * @returns The last tile of the reservation or the current train tile if no reservation present.
 */
PBSTileInfo FollowTrainReservation(const Vehicle *v, bool *train_on_res)
{
	assert(v->type == VEH_TRAIN);

	TileIndex tile = v->tile;
	Trackdir  trackdir = GetVehicleTrackdir(v);

	if (IsRailDepotTile(tile) && !GetRailDepotReservation(tile)) return PBSTileInfo(tile, trackdir, false);

	FindTrainOnTrackInfo ftoti;
	ftoti.res = FollowReservation(v->owner, GetRailTypeInfo(v->u.rail.railtype)->compatible_railtypes, tile, trackdir);
	ftoti.res.okay = IsSafeWaitingPosition(v, ftoti.res.tile, ftoti.res.trackdir, true, _settings_game.pf.forbid_90_deg);
	if (train_on_res != NULL) *train_on_res = HasVehicleOnPos(ftoti.res.tile, &ftoti, FindTrainOnTrackEnum);
	return ftoti.res;
}

/**
 * Find the train which has reserved a specific path.
 *
 * @param tile A tile on the path.
 * @param track A reserved track on the tile.
 * @return The vehicle holding the reservation or NULL if the path is stray.
 */
Vehicle *GetTrainForReservation(TileIndex tile, Track track)
{
	assert(HasReservedTracks(tile, TrackToTrackBits(track)));
	Trackdir  trackdir = TrackToTrackdir(track);

	RailTypes rts = GetRailTypeInfo(GetTileRailType(tile))->compatible_railtypes;

	/* Follow the path from tile to both ends, one of the end tiles should
	 * have a train on it. We need FollowReservation to ignore one-way signals
	 * here, as one of the two search directions will be the "wrong" way. */
	for (int i = 0; i < 2; ++i, trackdir = ReverseTrackdir(trackdir)) {
		FindTrainOnTrackInfo ftoti;
		ftoti.res = FollowReservation(GetTileOwner(tile), rts, tile, trackdir, true);

		FindVehicleOnPos(ftoti.res.tile, &ftoti, FindTrainOnTrackEnum);
		if (ftoti.best != NULL) return ftoti.best;

		/* Special case for stations: check the whole platform for a vehicle. */
		if (IsRailwayStationTile(ftoti.res.tile)) {
			TileIndexDiff diff = TileOffsByDiagDir(TrackdirToExitdir(ReverseTrackdir(ftoti.res.trackdir)));
			for (TileIndex st_tile = ftoti.res.tile + diff; IsCompatibleTrainStationTile(st_tile, ftoti.res.tile); st_tile += diff) {
				FindVehicleOnPos(st_tile, &ftoti, FindTrainOnTrackEnum);
				if (ftoti.best != NULL) return ftoti.best;
			}
		}

		/* Special case for bridges/tunnels: check the other end as well. */
		if (IsTileType(ftoti.res.tile, MP_TUNNELBRIDGE)) {
			FindVehicleOnPos(GetOtherTunnelBridgeEnd(ftoti.res.tile), &ftoti, FindTrainOnTrackEnum);
			if (ftoti.best != NULL) return ftoti.best;
		}
	}

	return NULL;
}

/**
 * Determine whether a certain track on a tile is a safe position to end a path.
 *
 * @param v the vehicle to test for
 * @param tile The tile
 * @param trackdir The trackdir to test
 * @param include_line_end Should end-of-line tiles be considered safe?
 * @param forbid_90def Don't allow trains to make 90 degree turns
 * @return True if it is a safe position
 */
bool IsSafeWaitingPosition(const Vehicle *v, TileIndex tile, Trackdir trackdir, bool include_line_end, bool forbid_90deg)
{
	if (IsRailDepotTile(tile)) return true;

	if (IsTileType(tile, MP_RAILWAY)) {
		/* For non-pbs signals, stop on the signal tile. */
		if (HasSignalOnTrackdir(tile, trackdir) && !IsPbsSignal(GetSignalType(tile, TrackdirToTrack(trackdir)))) return true;
	}

	/* Check next tile. For perfomance reasons, we check for 90 degree turns ourself. */
	CFollowTrackRail ft(v, GetRailTypeInfo(v->u.rail.railtype)->compatible_railtypes);

	/* End of track? */
	if (!ft.Follow(tile, trackdir)) {
		/* Last tile of a terminus station is a safe position. */
		if (include_line_end) return true;
	}

	/* Check for reachable tracks. */
	ft.m_new_td_bits &= DiagdirReachesTrackdirs(ft.m_exitdir);
	if (forbid_90deg) ft.m_new_td_bits &= ~TrackdirCrossesTrackdirs(trackdir);
	if (ft.m_new_td_bits == TRACKDIR_BIT_NONE) return include_line_end;

	if (ft.m_new_td_bits != TRACKDIR_BIT_NONE && KillFirstBit(ft.m_new_td_bits) == TRACKDIR_BIT_NONE) {
		/* PBS signal on next trackdir? Safe position. */
		if (HasPbsSignalOnTrackdir(ft.m_new_tile, FindFirstTrackdir(ft.m_new_td_bits))) return true;
	}

	return false;
}

/**
 * Check if a safe position is free.
 *
 * @param v the vehicle to test for
 * @param tile The tile
 * @param trackdir The trackdir to test
 * @param forbid_90def Don't allow trains to make 90 degree turns
 * @return True if the position is free
 */
bool IsWaitingPositionFree(const Vehicle *v, TileIndex tile, Trackdir trackdir, bool forbid_90deg)
{
	Track     track = TrackdirToTrack(trackdir);
	TrackBits reserved = GetReservedTrackbits(tile);

	/* Tile reserved? Can never be a free waiting position. */
	if (TrackOverlapsTracks(reserved, track)) return false;

	/* Not reserved and depot or not a pbs signal -> free. */
	if (IsRailDepotTile(tile)) return true;
	if (IsTileType(tile, MP_RAILWAY) && HasSignalOnTrackdir(tile, trackdir) && !IsPbsSignal(GetSignalType(tile, track))) return true;

	/* Check the next tile, if it's a PBS signal, it has to be free as well. */
	CFollowTrackRail ft(v, GetRailTypeInfo(v->u.rail.railtype)->compatible_railtypes);

	if (!ft.Follow(tile, trackdir)) return true;

	/* Check for reachable tracks. */
	ft.m_new_td_bits &= DiagdirReachesTrackdirs(ft.m_exitdir);
	if (forbid_90deg) ft.m_new_td_bits &= ~TrackdirCrossesTrackdirs(trackdir);

	return !HasReservedTracks(ft.m_new_tile, TrackdirBitsToTrackBits(ft.m_new_td_bits));
}