src/tunnel_map.cpp

   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 tunnel_map.cpp Map accessors for tunnels. */
  11
  12 #include "stdafx.h"
  13 #include "tunnelbridge_map.h"
  14
  15 #include "safeguards.h"
  16
  17
  18 /**
  19  * Gets the other end of the tunnel. Where a vehicle would reappear when it
  20  * enters at the given tile.
  21  * @param tile the tile to search from.
  22  * @return the tile of the other end of the tunnel.
  23  */
  24 TileIndex GetOtherTunnelEnd(TileIndex tile)
  25 {
  26         DiagDirection dir = GetTunnelBridgeDirection(tile);
  27         TileIndexDiff delta = TileOffsByDiagDir(dir);
  28         int z = GetTileZ(tile);
  29
  30         dir = ReverseDiagDir(dir);
  31         do {
  32                 tile += delta;
  33         } while (
  34                 !IsTunnelTile(tile) ||
  35                 GetTunnelBridgeDirection(tile) != dir ||
  36                 GetTileZ(tile) != z
  37         );
  38
  39         return tile;
  40 }
  41
  42
  43 /**
  44  * Is there a tunnel in the way in the given direction?
  45  * @param tile the tile to search from.
  46  * @param z    the 'z' to search on.
  47  * @param dir  the direction to start searching to.
  48  * @return true if and only if there is a tunnel.
  49  */
  50 bool IsTunnelInWayDir(TileIndex tile, int z, DiagDirection dir)
  51 {
  52         TileIndexDiff delta = TileOffsByDiagDir(dir);
  53         int height;
  54
  55         do {
  56                 tile -= delta;
  57                 if (!IsValidTile(tile)) return false;
  58                 height = GetTileZ(tile);
  59         } while (z < height);
  60
  61         return z == height && IsTunnelTile(tile) && GetTunnelBridgeDirection(tile) == dir;
  62 }
  63
  64 /**
  65  * Is there a tunnel in the way in any direction?
  66  * @param tile the tile to search from.
  67  * @param z the 'z' to search on.
  68  * @return true if and only if there is a tunnel.
  69  */
  70 bool IsTunnelInWay(TileIndex tile, int z)
  71 {
  72         return IsTunnelInWayDir(tile, z, (TileX(tile) > (MapMaxX() / 2)) ? DIAGDIR_NE : DIAGDIR_SW) ||
  73                         IsTunnelInWayDir(tile, z, (TileY(tile) > (MapMaxY() / 2)) ? DIAGDIR_NW : DIAGDIR_SE);
  74 }