/* $Id$ */

/** @file map_type.h Types related to maps. */

#ifndef MAP_TYPE_H
#define MAP_TYPE_H

/**
 * Data that is stored per tile. Also used TileExtended for this.
 * Look at docs/landscape.html for the exact meaning of the members.
 */
struct Tile {
	byte   type_height; ///< The type (bits 4..7) and height of the northern corner
	byte   m1;          ///< Primarily used for ownership information
	uint16 m2;          ///< Primarily used for indices to towns, industries and stations
	byte   m3;          ///< General purpose
	byte   m4;          ///< General purpose
	byte   m5;          ///< General purpose
	byte   m6;          ///< Primarily used for bridges and rainforest/desert
};

/**
 * Data that is stored per tile. Also used Tile for this.
 * Look at docs/landscape.html for the exact meaning of the members.
 */
struct TileExtended {
	byte m7; ///< Primarily used for newgrf support
};

/**
 * An offset value between to tiles.
 *
 * This value is used fro the difference between
 * to tiles. It can be added to a tileindex to get
 * the resulting tileindex of the start tile applied
 * with this saved difference.
 *
 * @see TileDiffXY(int, int)
 */
typedef int32 TileIndexDiff;

/**
 * A pair-construct of a TileIndexDiff.
 *
 * This can be used to save the difference between to
 * tiles as a pair of x and y value.
 */
struct TileIndexDiffC {
	int16 x;        ///< The x value of the coordinate
	int16 y;        ///< The y value of the coordinate
};

/** Minimal and maximal map width and height */
enum {
	MIN_MAP_SIZE_BITS = 6,                      ///< Minimal size of map is equal to 2 ^ MIN_MAP_SIZE_BITS
	MAX_MAP_SIZE_BITS = 11,                     ///< Maximal size of map is equal to 2 ^ MAX_MAP_SIZE_BITS
	MIN_MAP_SIZE      = 1 << MIN_MAP_SIZE_BITS, ///< Minimal map size = 64
	MAX_MAP_SIZE      = 1 << MAX_MAP_SIZE_BITS, ///< Maximal map size = 2048
};

/**
 * Approximation of the length of a straight track, relative to a diagonal
 * track (ie the size of a tile side).
 *
 * #defined instead of const so it can
 * stay integer. (no runtime float operations) Is this needed?
 * Watch out! There are _no_ brackets around here, to prevent intermediate
 * rounding! Be careful when using this!
 * This value should be sqrt(2)/2 ~ 0.7071
 */
#define STRAIGHT_TRACK_LENGTH 7071/10000

#endif /* MAP_TYPE_H */