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/* $Id$ */

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#ifndef DIRECTION_H

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#define DIRECTION_H

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/* Direction as commonly used in v->direction, 8 way. */

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typedef enum Direction {

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	DIR_N   = 0,

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	DIR_NE  = 1,      /* Northeast, upper right on your monitor */

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	DIR_E   = 2,

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	DIR_SE  = 3,

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	DIR_S   = 4,

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	DIR_SW  = 5,

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	DIR_W   = 6,

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	DIR_NW  = 7,

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	DIR_END,

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	INVALID_DIR = 0xFF,

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} Direction;

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/* Direction commonly used as the direction of entering and leaving tiles, 4-way */

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typedef enum DiagDirection {

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	DIAGDIR_NE  = 0,      /* Northeast, upper right on your monitor */

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	DIAGDIR_SE  = 1,

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	DIAGDIR_SW  = 2,

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	DIAGDIR_NW  = 3,

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	DIAGDIR_END,

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	INVALID_DIAGDIR = 0xFF,

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} DiagDirection;

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static inline DiagDirection ReverseDiagDir(DiagDirection d)

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{

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	return (DiagDirection)(2 ^ d);

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}

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static inline DiagDirection DirToDiagDir(Direction dir)

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{

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	return (DiagDirection)(dir >> 1);

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}

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static inline Direction DiagDirToDir(DiagDirection dir)

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{

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	return (Direction)(dir * 2 + 1);

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}

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/* the 2 axis */

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typedef enum Axis {

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	AXIS_X = 0,

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	AXIS_Y = 1

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} Axis;

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static inline Axis DiagDirToAxis(DiagDirection d)

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{

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	return (Axis)(d & 1);

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}

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#endif