/* $Id$ */
/*
* 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 .
*/
/**
* @file slope_type.h Definitions of a slope.
* This file defines the enumeration and helper functions for handling
* the slope info of a tile.
*/
#ifndef SLOPE_TYPE_H
#define SLOPE_TYPE_H
#include "core/enum_type.hpp"
/**
* Enumeration of tile corners
*/
enum Corner {
CORNER_W = 0,
CORNER_S = 1,
CORNER_E = 2,
CORNER_N = 3,
CORNER_END,
CORNER_INVALID = 0xFF
};
/**
* Enumeration for the slope-type.
*
* This enumeration use the chars N,E,S,W corresponding the
* direction north, east, south and west. The top corner of a tile
* is the north-part of the tile. The whole slope is encoded with
* 5 bits, 4 bits for each corner and 1 bit for a steep-flag.
*
* For halftile slopes an extra 3 bits are used to represent this
* properly; 1 bit for a halftile-flag and 2 bits to encode which
* extra side (corner) is leveled when the slope of the first 5
* bits is applied. This means that there can only be one leveled
* slope for steep slopes, which is logical because two leveled
* slopes would mean that it is not a steep slope as halftile
* slopes only span one height level.
*/
enum Slope {
SLOPE_FLAT = 0x00, ///< a flat tile
SLOPE_W = 0x01, ///< the west corner of the tile is raised
SLOPE_S = 0x02, ///< the south corner of the tile is raised
SLOPE_E = 0x04, ///< the east corner of the tile is raised
SLOPE_N = 0x08, ///< the north corner of the tile is raised
SLOPE_STEEP = 0x10, ///< indicates the slope is steep
SLOPE_NW = SLOPE_N | SLOPE_W, ///< north and west corner are raised
SLOPE_SW = SLOPE_S | SLOPE_W, ///< south and west corner are raised
SLOPE_SE = SLOPE_S | SLOPE_E, ///< south and east corner are raised
SLOPE_NE = SLOPE_N | SLOPE_E, ///< north and east corner are raised
SLOPE_EW = SLOPE_E | SLOPE_W, ///< east and west corner are raised
SLOPE_NS = SLOPE_N | SLOPE_S, ///< north and south corner are raised
SLOPE_ELEVATED = SLOPE_N | SLOPE_E | SLOPE_S | SLOPE_W, ///< bit mask containing all 'simple' slopes
SLOPE_NWS = SLOPE_N | SLOPE_W | SLOPE_S, ///< north, west and south corner are raised
SLOPE_WSE = SLOPE_W | SLOPE_S | SLOPE_E, ///< west, south and east corner are raised
SLOPE_SEN = SLOPE_S | SLOPE_E | SLOPE_N, ///< south, east and north corner are raised
SLOPE_ENW = SLOPE_E | SLOPE_N | SLOPE_W, ///< east, north and west corner are raised
SLOPE_STEEP_W = SLOPE_STEEP | SLOPE_NWS, ///< a steep slope falling to east (from west)
SLOPE_STEEP_S = SLOPE_STEEP | SLOPE_WSE, ///< a steep slope falling to north (from south)
SLOPE_STEEP_E = SLOPE_STEEP | SLOPE_SEN, ///< a steep slope falling to west (from east)
SLOPE_STEEP_N = SLOPE_STEEP | SLOPE_ENW, ///< a steep slope falling to south (from north)
SLOPE_HALFTILE = 0x20, ///< one halftile is leveled (non continuous slope)
SLOPE_HALFTILE_MASK = 0xE0, ///< three bits used for halftile slopes
SLOPE_HALFTILE_W = SLOPE_HALFTILE | (CORNER_W << 6), ///< the west halftile is leveled (non continuous slope)
SLOPE_HALFTILE_S = SLOPE_HALFTILE | (CORNER_S << 6), ///< the south halftile is leveled (non continuous slope)
SLOPE_HALFTILE_E = SLOPE_HALFTILE | (CORNER_E << 6), ///< the east halftile is leveled (non continuous slope)
SLOPE_HALFTILE_N = SLOPE_HALFTILE | (CORNER_N << 6), ///< the north halftile is leveled (non continuous slope)
};
DECLARE_ENUM_AS_BIT_SET(Slope)
/**
* Helper for creating a bitset of slopes.
* @param x The slope to convert into a bitset.
*/
#define M(x) (1 << (x))
/** Constant bitset with safe slopes for building a level crossing. */
static const uint32 VALID_LEVEL_CROSSING_SLOPES = M(SLOPE_SEN) | M(SLOPE_ENW) | M(SLOPE_NWS) | M(SLOPE_NS) | M(SLOPE_WSE) | M(SLOPE_EW) | M(SLOPE_FLAT);
#undef M
/**
* Enumeration for Foundations.
*/
enum Foundation {
FOUNDATION_NONE, ///< The tile has no foundation, the slope remains unchanged.
FOUNDATION_LEVELED, ///< The tile is leveled up to a flat slope.
FOUNDATION_INCLINED_X, ///< The tile has an along X-axis inclined foundation.
FOUNDATION_INCLINED_Y, ///< The tile has an along Y-axis inclined foundation.
FOUNDATION_STEEP_LOWER, ///< The tile has a steep slope. The lowest corner is raised by a foundation to allow building railroad on the lower halftile.
/* Halftile foundations */
FOUNDATION_STEEP_BOTH, ///< The tile has a steep slope. The lowest corner is raised by a foundation and the upper halftile is leveled.
FOUNDATION_HALFTILE_W, ///< Level west halftile non-continuously.
FOUNDATION_HALFTILE_S, ///< Level south halftile non-continuously.
FOUNDATION_HALFTILE_E, ///< Level east halftile non-continuously.
FOUNDATION_HALFTILE_N, ///< Level north halftile non-continuously.
/* Special anti-zig-zag foundations for single horizontal/vertical track */
FOUNDATION_RAIL_W, ///< Foundation for TRACK_BIT_LEFT, but not a leveled foundation.
FOUNDATION_RAIL_S, ///< Foundation for TRACK_BIT_LOWER, but not a leveled foundation.
FOUNDATION_RAIL_E, ///< Foundation for TRACK_BIT_RIGHT, but not a leveled foundation.
FOUNDATION_RAIL_N, ///< Foundation for TRACK_BIT_UPPER, but not a leveled foundation.
FOUNDATION_INVALID = 0xFF, ///< Used inside "rail_cmd.cpp" to indicate invalid slope/track combination.
};
#endif /* SLOPE_TYPE_H */