148 lines
2.6 KiB
C
148 lines
2.6 KiB
C
/* $Id$ */
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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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static inline Direction ReverseDir(Direction d)
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{
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return (Direction)(4 ^ d);
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}
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typedef enum DirDiff {
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DIRDIFF_SAME = 0,
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DIRDIFF_45RIGHT = 1,
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DIRDIFF_90RIGHT = 2,
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DIRDIFF_REVERSE = 4,
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DIRDIFF_90LEFT = 6,
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DIRDIFF_45LEFT = 7
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} DirDiff;
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static inline DirDiff DirDifference(Direction d0, Direction d1)
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{
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return (DirDiff)((d0 + 8 - d1) % 8);
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}
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static inline DirDiff ChangeDirDiff(DirDiff d, DirDiff delta)
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{
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return (DirDiff)((d + delta) % 8);
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}
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static inline Direction ChangeDir(Direction d, DirDiff delta)
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{
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return (Direction)((d + delta) % 8);
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}
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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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typedef enum DiagDirDiff {
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DIAGDIRDIFF_SAME = 0,
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DIAGDIRDIFF_90RIGHT = 1,
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DIAGDIRDIFF_REVERSE = 2,
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DIAGDIRDIFF_90LEFT = 3
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} DiagDirDiff;
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static inline DiagDirection ChangeDiagDir(DiagDirection d, DiagDirDiff delta)
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{
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return (DiagDirection)((d + delta) % 4);
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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_END
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} Axis;
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static inline Axis OtherAxis(Axis a)
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{
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return (Axis)(a ^ 1);
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}
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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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/*
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* Converts an Axis to a DiagDirection
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* Points always in the positive direction, i.e. S[EW]
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*/
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static inline DiagDirection AxisToDiagDir(Axis a)
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{
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return (DiagDirection)(2 - a);
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}
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/**
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* Convert an axis and a flag for north/south into a DiagDirection
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* @param ns north -> 0, south -> 1
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*/
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static inline DiagDirection XYNSToDiagDir(Axis xy, uint ns)
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{
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return (DiagDirection)(xy * 3 ^ ns * 2);
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}
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static inline bool IsValidDiagDirection(DiagDirection d)
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{
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return d < DIAGDIR_END;
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}
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static inline bool IsValidDirection(Direction d)
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{
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return d < DIR_END;
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}
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static inline bool IsValidAxis(Axis d)
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{
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return d < AXIS_END;
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}
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#endif
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