direction.h
author peter1138
Wed, 07 Jun 2006 07:20:28 +0000
changeset 3973 9d3cd1ed6ac0
parent 3953 e64bbd8598e2
child 4158 91ff9bb84ced
permissions -rw-r--r--
(svn r5146) - NewGRF: Support selection of aircraft default cargo type by checking its refit mask. If aircraft can be refitted to passengers, no change happens, else the first refittable type is chosen. Also use refit capacity to determine the default capacity.
/* $Id$ */

#ifndef DIRECTION_H
#define DIRECTION_H

/* Direction as commonly used in v->direction, 8 way. */
typedef enum Direction {
	DIR_N   = 0,
	DIR_NE  = 1,      /* Northeast, upper right on your monitor */
	DIR_E   = 2,
	DIR_SE  = 3,
	DIR_S   = 4,
	DIR_SW  = 5,
	DIR_W   = 6,
	DIR_NW  = 7,
	DIR_END,
	INVALID_DIR = 0xFF,
} Direction;

static inline Direction ReverseDir(Direction d)
{
	return (Direction)(4 ^ d);
}


typedef enum DirDiff {
	DIRDIFF_SAME    = 0,
	DIRDIFF_45RIGHT = 1,
	DIRDIFF_90RIGHT = 2,
	DIRDIFF_REVERSE = 4,
	DIRDIFF_90LEFT  = 6,
	DIRDIFF_45LEFT  = 7
} DirDiff;

static inline DirDiff DirDifference(Direction d0, Direction d1)
{
	return (DirDiff)((d0 + 8 - d1) % 8);
}

static inline DirDiff ChangeDirDiff(DirDiff d, DirDiff delta)
{
	return (DirDiff)((d + delta) % 8);
}


static inline Direction ChangeDir(Direction d, DirDiff delta)
{
	return (Direction)((d + delta) % 8);
}


/* Direction commonly used as the direction of entering and leaving tiles, 4-way */
typedef enum DiagDirection {
	DIAGDIR_NE  = 0,      /* Northeast, upper right on your monitor */
	DIAGDIR_SE  = 1,
	DIAGDIR_SW  = 2,
	DIAGDIR_NW  = 3,
	DIAGDIR_END,
	INVALID_DIAGDIR = 0xFF,
} DiagDirection;

static inline DiagDirection ReverseDiagDir(DiagDirection d)
{
	return (DiagDirection)(2 ^ d);
}


typedef enum DiagDirDiff {
	DIAGDIRDIFF_SAME    = 0,
	DIAGDIRDIFF_90RIGHT = 1,
	DIAGDIRDIFF_REVERSE = 2,
	DIAGDIRDIFF_90LEFT  = 3
} DiagDirDiff;

static inline DiagDirection ChangeDiagDir(DiagDirection d, DiagDirDiff delta)
{
	return (DiagDirection)((d + delta) % 4);
}


static inline DiagDirection DirToDiagDir(Direction dir)
{
	return (DiagDirection)(dir >> 1);
}


static inline Direction DiagDirToDir(DiagDirection dir)
{
	return (Direction)(dir * 2 + 1);
}


/* the 2 axis */
typedef enum Axis {
	AXIS_X = 0,
	AXIS_Y = 1,
	AXIS_END
} Axis;


static inline Axis DiagDirToAxis(DiagDirection d)
{
	return (Axis)(d & 1);
}


/*
 * Converts an Axis to a DiagDirection
 * Points always in the positive direction, i.e. S[EW]
 */
static inline DiagDirection AxisToDiagDir(Axis a)
{
	return (DiagDirection)(2 - a);
}

/**
 * Convert an axis and a flag for north/south into a DiagDirection
 * @param ns north -> 0, south -> 1
 */
static inline DiagDirection XYNSToDiagDir(Axis xy, uint ns)
{
	return (DiagDirection)(xy * 3 ^ ns * 2);
}


static inline bool IsValidDiagDirection(DiagDirection d)
{
	return d < DIAGDIR_END;
}

static inline bool IsValidDirection(Direction d)
{
	return d < DIR_END;
}

static inline bool IsValidAxis(Axis d)
{
	return d < AXIS_END;
}

#endif