Files @ r6722:b6eb38b08e9f
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Location: cpp/openttd-patchpack/source/src/tunnel_map.cpp

rubidium
(svn r9954) -Fix [FS#811]: trolley AI crashed when trying to determine what the roadbits are.
/* $Id$ */

/** @file tunnel_map.cpp */

#include "stdafx.h"
#include "openttd.h"
#include "tile.h"
#include "tunnel_map.h"

/**
 * Gets the other end of the tunnel. Where a vehicle would reappear when it
 * enters at the given tile.
 * @param tile the tile to search from.
 * @return the tile of the other end of the tunnel.
 */
TileIndex GetOtherTunnelEnd(TileIndex tile)
{
	DiagDirection dir = GetTunnelDirection(tile);
	TileIndexDiff delta = TileOffsByDiagDir(dir);
	uint z = GetTileZ(tile);

	dir = ReverseDiagDir(dir);
	do {
		tile += delta;
	} while (
		!IsTunnelTile(tile) ||
		GetTunnelDirection(tile) != dir ||
		GetTileZ(tile) != z
	);

	return tile;
}


/**
 * Is there a tunnel in the way in the given direction?
 * @param tile the tile to search from.
 * @param z    the 'z' to search on.
 * @param dir  the direction to start searching to.
 * @return true if and only if there is a tunnel.
 */
static bool IsTunnelInWayDir(TileIndex tile, uint z, DiagDirection dir)
{
	TileIndexDiff delta = TileOffsByDiagDir(dir);
	uint height;

	do {
		tile -= delta;
		height = GetTileZ(tile);
	} while (z < height);

	return
		z == height &&
		IsTunnelTile(tile) &&
		GetTunnelDirection(tile) == dir;
}

/**
 * Is there a tunnel in the way in any direction?
 * @param tile the tile to search from.
 * @param z the 'z' to search on.
 * @return true if and only if there is a tunnel.
 */
bool IsTunnelInWay(TileIndex tile, uint z)
{
	return
		IsTunnelInWayDir(tile, z, DIAGDIR_NE) ||
		IsTunnelInWayDir(tile, z, DIAGDIR_SE) ||
		IsTunnelInWayDir(tile, z, DIAGDIR_SW) ||
		IsTunnelInWayDir(tile, z, DIAGDIR_NW);
}