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/* $Id$ */

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/** @file map_func.h Functions related to maps. */

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#ifndef MAP_FUNC_H

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#define MAP_FUNC_H

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#include "tile_type.h"

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#include "map_type.h"

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#include "direction_func.h"

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extern uint _map_tile_mask;

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/**

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 * 'Wraps' the given tile to it is within the map. It does

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 * this by masking the 'high' bits of.

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 * @param x the tile to 'wrap'

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 */

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#define TILE_MASK(x) ((x) & _map_tile_mask)

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/**

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 * Asserts when the tile is outside of the map.

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 * @param x the tile to check

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 */

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#define TILE_ASSERT(x) assert(TILE_MASK(x) == (x));

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/**

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 * Pointer to the tile-array.

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 *

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 * This variable points to the tile-array which contains the tiles of

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 * the map.

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 */

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extern Tile *_m;

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/**

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 * Pointer to the extended tile-array.

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 *

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 * This variable points to the extended tile-array which contains the tiles

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 * of the map.

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 */

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extern TileExtended *_me;

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/**

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 * Allocate a new map with the given size.

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 */

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void AllocateMap(uint size_x, uint size_y);

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/**

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 * Logarithm of the map size along the X side.

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 * @note try to avoid using this one

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 * @return 2^"return value" == MapSizeX()

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 */

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static inline uint MapLogX()

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{

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	extern uint _map_log_x;

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	return _map_log_x;

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}

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/**

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 * Logarithm of the map size along the y side.

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 * @note try to avoid using this one

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 * @return 2^"return value" == MapSizeY()

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 */

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static inline uint MapLogY()

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{

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	extern uint _map_log_y;

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	return _map_log_y;

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}

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/**

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 * Get the size of the map along the X

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 * @return the number of tiles along the X of the map

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 */

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static inline uint MapSizeX()

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{

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	extern uint _map_size_x;

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	return _map_size_x;

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}

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/**

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 * Get the size of the map along the Y

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 * @return the number of tiles along the Y of the map

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 */

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static inline uint MapSizeY()

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{

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	extern uint _map_size_y;

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	return _map_size_y;

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}

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/**

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 * Get the size of the map

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 * @return the number of tiles of the map

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 */

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static inline uint MapSize()

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{

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	extern uint _map_size;

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	return _map_size;

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}

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/**

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 * Gets the maximum X coordinate within the map, including MP_VOID

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 * @return the maximum X coordinate

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 */

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static inline uint MapMaxX()

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{

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	return MapSizeX() - 1;

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}

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/**

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 * Gets the maximum X coordinate within the map, including MP_VOID

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 * @return the maximum X coordinate

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 */

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static inline uint MapMaxY()

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{

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	return MapSizeY() - 1;

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}

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/**

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 * Scales relative to the number of tiles.

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 */

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uint ScaleByMapSize(uint);

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/**

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 * Scale relative to the circumference of the map.

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 */

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uint ScaleByMapSize1D(uint);

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/**

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 * An offset value between to tiles.

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 *

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 * This value is used fro the difference between

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 * to tiles. It can be added to a tileindex to get

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 * the resulting tileindex of the start tile applied

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 * with this saved difference.

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 *

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 * @see TileDiffXY(int, int)

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 */

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typedef int32 TileIndexDiff;

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/**

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 * Returns the TileIndex of a coordinate.

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 *

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 * @param x The x coordinate of the tile

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 * @param y The y coordinate of the tile

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 * @return The TileIndex calculated by the coordinate

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 */

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static inline TileIndex TileXY(uint x, uint y)

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{

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	return (y * MapSizeX()) + x;

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}

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/**

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 * Calculates an offset for the given coordinate(-offset).

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 *

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 * This function calculate an offset value which can be added to an

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 * #TileIndex. The coordinates can be negative.

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 *

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 * @param x The offset in x direction

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 * @param y The offset in y direction

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 * @return The resulting offset value of the given coordinate

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 * @see ToTileIndexDiff(TileIndexDiffC)

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 */

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static inline TileIndexDiff TileDiffXY(int x, int y)

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{

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	/* Multiplication gives much better optimization on MSVC than shifting.

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	 * 0 << shift isn't optimized to 0 properly.

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	 * Typically x and y are constants, and then this doesn't result

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	 * in any actual multiplication in the assembly code.. */

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	return (y * MapSizeX()) + x;

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}

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static inline TileIndex TileVirtXY(uint x, uint y)

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{

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	return (y >> 4 << MapLogX()) + (x >> 4);

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}

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/**

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 * Get the X component of a tile

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 * @param tile the tile to get the X component of

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 * @return the X component

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 */

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static inline uint TileX(TileIndex tile)

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{

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	return tile & MapMaxX();

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}

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/**

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 * Get the Y component of a tile

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 * @param tile the tile to get the Y component of

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 * @return the Y component

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 */

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static inline uint TileY(TileIndex tile)

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{

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	return tile >> MapLogX();

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}

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/**

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 * Return the offset between to tiles from a TileIndexDiffC struct.

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 *

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 * This function works like #TileDiffXY(int, int) and returns the

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 * difference between two tiles.

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 *

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 * @param tidc The coordinate of the offset as TileIndexDiffC

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 * @return The difference between two tiles.

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 * @see TileDiffXY(int, int)

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 */

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static inline TileIndexDiff ToTileIndexDiff(TileIndexDiffC tidc)

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{

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	return (tidc.y << MapLogX()) + tidc.x;

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}

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#ifndef _DEBUG

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	/**

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	 * Adds to tiles together.

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	 *

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	 * @param x One tile

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	 * @param y An other tile to add

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	 * @return The resulting tile(index)

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	 */

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	#define TILE_ADD(x,y) ((x) + (y))

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#else

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	extern TileIndex TileAdd(TileIndex tile, TileIndexDiff add,

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		const char *exp, const char *file, int line);

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	#define TILE_ADD(x, y) (TileAdd((x), (y), #x " + " #y, __FILE__, __LINE__))

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#endif

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/**

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 * Adds a given offset to a tile.

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 *

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 * @param tile The tile to add an offset on it

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 * @param x The x offset to add to the tile

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 * @param y The y offset to add to the tile

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 */

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#define TILE_ADDXY(tile, x, y) TILE_ADD(tile, TileDiffXY(x, y))

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/**

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 * Adds an offset to a tile and check if we are still on the map.

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 */

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TileIndex TileAddWrap(TileIndex tile, int addx, int addy);

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/**

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 * Returns the TileIndexDiffC offset from a DiagDirection.

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 *

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 * @param dir The given direction

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 * @return The offset as TileIndexDiffC value

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 */

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static inline TileIndexDiffC TileIndexDiffCByDiagDir(DiagDirection dir)

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{

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	extern const TileIndexDiffC _tileoffs_by_diagdir[DIAGDIR_END];

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	assert(IsValidDiagDirection(dir));

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	return _tileoffs_by_diagdir[dir];

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}

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/**

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 * Returns the TileIndexDiffC offset from a Direction.

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 *

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 * @param dir The given direction

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 * @return The offset as TileIndexDiffC value

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 */

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static inline TileIndexDiffC TileIndexDiffCByDir(Direction dir)

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{

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	extern const TileIndexDiffC _tileoffs_by_dir[DIR_END];

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	assert(IsValidDirection(dir));

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	return _tileoffs_by_dir[dir];

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}

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/**

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 * Add a TileIndexDiffC to a TileIndex and returns the new one.

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 *

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 * Returns tile + the diff given in diff. If the result tile would end up

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 * outside of the map, INVALID_TILE is returned instead.

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 *

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 * @param tile The base tile to add the offset on

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 * @param diff The offset to add on the tile

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 * @return The resulting TileIndex

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 */

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static inline TileIndex AddTileIndexDiffCWrap(TileIndex tile, TileIndexDiffC diff)

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{

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	int x = TileX(tile) + diff.x;

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	int y = TileY(tile) + diff.y;

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	if (x < 0 || y < 0 || x > (int)MapMaxX() || y > (int)MapMaxY())

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		return INVALID_TILE;

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	else

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		return TileXY(x, y);

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}

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/**

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 * Returns the diff between two tiles

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 *

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 * @param tile_a from tile

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 * @param tile_b to tile

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 * @return the difference between tila_a and tile_b

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 */

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static inline TileIndexDiffC TileIndexToTileIndexDiffC(TileIndex tile_a, TileIndex tile_b)

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{

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	TileIndexDiffC difference;

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	difference.x = TileX(tile_a) - TileX(tile_b);

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	difference.y = TileY(tile_a) - TileY(tile_b);

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	return difference;

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}

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/* Functions to calculate distances */

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uint DistanceManhattan(TileIndex, TileIndex); ///< also known as L1-Norm. Is the shortest distance one could go over diagonal tracks (or roads)

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uint DistanceSquare(TileIndex, TileIndex); ///< euclidian- or L2-Norm squared

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uint DistanceMax(TileIndex, TileIndex); ///< also known as L-Infinity-Norm

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uint DistanceMaxPlusManhattan(TileIndex, TileIndex); ///< Max + Manhattan

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uint DistanceFromEdge(TileIndex); ///< shortest distance from any edge of the map

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/**

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 * Starts a loop which iterates to a square of tiles

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 *

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 * This macro starts 2 nested loops which iterates over a square of tiles.

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 *

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 * @param var The name of the variable which contains the current tile

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 * @param w The width (x-width) of the square

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 * @param h The heigth (y-width) of the square

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 * @param tile The start tile of the square

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 */

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#define BEGIN_TILE_LOOP(var, w, h, tile)                      \

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	{                                                        \

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		int h_cur = h;                                         \

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		uint var = tile;                                       \

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		do {                                                   \

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			int w_cur = w;                                       \

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			do {

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/**

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 * Ends the square-loop used before

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 *

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 * @see BEGIN_TILE_LOOP

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 */

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#define END_TILE_LOOP(var, w, h, tile)                        \

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			} while (++var, --w_cur != 0);                       \

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		} while (var += TileDiffXY(0, 1) - (w), --h_cur != 0); \

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	}

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/**

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 * Convert a DiagDirection to a TileIndexDiff

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 *

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 * @param dir The DiagDirection

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 * @return The resulting TileIndexDiff

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 * @see TileIndexDiffCByDiagDir

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 */

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static inline TileIndexDiff TileOffsByDiagDir(DiagDirection dir)

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{

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	extern const TileIndexDiffC _tileoffs_by_diagdir[DIAGDIR_END];

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	assert(IsValidDiagDirection(dir));

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	return ToTileIndexDiff(_tileoffs_by_diagdir[dir]);

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}

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/**

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 * Convert a Direction to a TileIndexDiff.

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 *

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 * @param dir The direction to convert from

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 * @return The resulting TileIndexDiff

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 */

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static inline TileIndexDiff TileOffsByDir(Direction dir)

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{

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	extern const TileIndexDiffC _tileoffs_by_dir[DIR_END];

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	assert(IsValidDirection(dir));

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	return ToTileIndexDiff(_tileoffs_by_dir[dir]);

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}

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/**

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 * Adds a DiagDir to a tile.

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 *

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 * @param tile The current tile

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 * @param dir The direction in which we want to step

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 * @return the moved tile

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 */

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static inline TileIndex TileAddByDiagDir(TileIndex tile, DiagDirection dir)

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{

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	return TILE_ADD(tile, TileOffsByDiagDir(dir));

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}

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/**

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 * A callback function type for searching tiles.

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 *

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 * @param tile The tile to test

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 * @param user_data additional data for the callback function to use

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 * @return A boolean value, depend on the definition of the function.

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 */

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typedef bool TestTileOnSearchProc(TileIndex tile, void *user_data);

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/**

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 * Searches for some cirumstances of a tile around a given tile with a helper function.

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 */

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bool CircularTileSearch(TileIndex *tile, uint size, TestTileOnSearchProc proc, void *user_data);

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/**

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 * Get a random tile out of a given seed.

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 * @param r the random 'seed'

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 * @return a valid tile

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 */

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static inline TileIndex RandomTileSeed(uint32 r)

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{

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	return TILE_MASK(r);

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}

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/**

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 * Get a valid random tile.

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 * @note a define so 'random' gets inserted in the place where it is actually

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 *       called, thus making the random traces more explicit.

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 * @return a valid tile

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 */

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#define RandomTile() RandomTileSeed(Random())

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#endif /* MAP_FUNC_H */