(svn r10763) -Documentation [FS#1098]: document direction.h. Patch by Progman.

1 files changed, 195 insertions, 41 deletions

diff --git a/src/direction.h b/src/direction.h
index 837fa149f..84d6b952e 100644
--- a/src/direction.h
+++ b/src/direction.h
@@ -7,66 +7,128 @@
 
 #include "helpers.hpp"
 
-/* Direction as commonly used in v->direction, 8 way. */
+/**
+ * Defines the 8 directions on the map.
+ *
+ * This enum defines 8 possible directions which are used for
+ * the vehicles in the game. The directions are aligned straight
+ * to the viewport, not to the map. So north points to the top of
+ * your viewport and not rotated by 45 degrees left or right to get
+ * a "north" used in you games.
+ */
 enum Direction {
-	DIR_BEGIN = 0,
-	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,
+	DIR_BEGIN = 0,          ///< Used to iterate
+	DIR_N   = 0,            ///< North
+	DIR_NE  = 1,            ///< Northeast
+	DIR_E   = 2,            ///< East
+	DIR_SE  = 3,            ///< Southeast
+	DIR_S   = 4,            ///< South
+	DIR_SW  = 5,            ///< Southwest
+	DIR_W   = 6,            ///< West
+	DIR_NW  = 7,            ///< Northwest
+	DIR_END,                ///< Used to iterate
+	INVALID_DIR = 0xFF,     ///< Flag for an invalid direction
 };
 
 /** Define basic enum properties */
 template <> struct EnumPropsT<Direction> : MakeEnumPropsT<Direction, byte, DIR_BEGIN, DIR_END, INVALID_DIR> {};
 typedef TinyEnumT<Direction> DirectionByte; //typedefing-enumification of Direction
 
+/**
+ * Return the reverse of a direction
+ *
+ * @param d The direction to get the reverse from
+ * @return The reverse Direction
+ */
 static inline Direction ReverseDir(Direction d)
 {
 	return (Direction)(4 ^ d);
 }
 
 
+/**
+ * Enumeration for the difference between two directions.
+ *
+ * This enumeration is used to mark differences between
+ * two directions. If you get one direction you can align
+ * a second direction in 8 different ways. This enumeration
+ * only contains 6 of these 8 differences, but the remaining
+ * two can be calculated by adding to differences together.
+ * This also means you can add two differences together and
+ * get the difference you really want to get. The difference
+ * of 45 degrees left + the difference of 45 degrees right results in the
+ * difference of 0 degrees.
+ *
+ * @note To get this mentioned addition of direction you must use
+ *       modulo DIR_END or use the #ChangeDirDiff(DirDiff, DirDiff) function.
+ * @see ChangeDirDiff(DirDiff, DirDiff)
+ */
 enum DirDiff {
-	DIRDIFF_SAME    = 0,
-	DIRDIFF_45RIGHT = 1,
-	DIRDIFF_90RIGHT = 2,
-	DIRDIFF_REVERSE = 4,
-	DIRDIFF_90LEFT  = 6,
-	DIRDIFF_45LEFT  = 7
+	DIRDIFF_SAME    = 0,    ///< Both directions faces to the same direction
+	DIRDIFF_45RIGHT = 1,    ///< Angle of 45 degrees right
+	DIRDIFF_90RIGHT = 2,    ///< Angle of 90 degrees right
+	DIRDIFF_REVERSE = 4,    ///< One direction is the opposit of the other one
+	DIRDIFF_90LEFT  = 6,    ///< Angle of 90 degrees left
+	DIRDIFF_45LEFT  = 7     ///< Angle of 45 degrees left
 };
 
+/**
+ * Calculate the difference between to directions
+ *
+ * @param d0 The first direction as the base
+ * @param d1 The second direction as the offset from the base
+ * @return The difference how the second directions drifts of the first one.
+ */
 static inline DirDiff DirDifference(Direction d0, Direction d1)
 {
 	return (DirDiff)((d0 + 8 - d1) % 8);
 }
 
+/**
+ * Applies two differences together
+ *
+ * This function adds two differences together and return the resulting
+ * difference. So adding two DIRDIFF_REVERSE together results in the
+ * DIRDIFF_SAME difference.
+ *
+ * @param d The first difference
+ * @param delta The second difference to add on
+ * @return The resulting difference
+ */
 static inline DirDiff ChangeDirDiff(DirDiff d, DirDiff delta)
 {
 	return (DirDiff)((d + delta) % 8);
 }
 
-
+/**
+ * Change a direction by a given difference
+ *
+ * This functions returns a new direction of the given direction
+ * which is rotated by the given difference.
+ *
+ * @param d The direction to get a new direction from
+ * @param delta The offset/drift applied to the direction
+ * @return The new direction
+ */
 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 */
+/**
+ * Enumeration for diagonal directions.
+ *
+ * This enumeration is used for the 4 direction of the tile-edges.
+ */
 enum DiagDirection {
-	DIAGDIR_BEGIN = 0,
-	DIAGDIR_NE  = 0,      ///< Northeast, upper right on your monitor
-	DIAGDIR_SE  = 1,
-	DIAGDIR_SW  = 2,
-	DIAGDIR_NW  = 3,
-	DIAGDIR_END,
-	INVALID_DIAGDIR = 0xFF,
+	DIAGDIR_BEGIN = 0,      ///< Used for iterations
+	DIAGDIR_NE  = 0,        ///< Northeast, upper right on your monitor
+	DIAGDIR_SE  = 1,        ///< Southeast
+	DIAGDIR_SW  = 2,        ///< Southwest
+	DIAGDIR_NW  = 3,        ///< Northwest
+	DIAGDIR_END,            ///< Used for iterations
+	INVALID_DIAGDIR = 0xFF, ///< Flag for an invalid DiagDirection
 };
 
 DECLARE_POSTFIX_INCREMENT(DiagDirection);
@@ -75,60 +137,135 @@ DECLARE_POSTFIX_INCREMENT(DiagDirection);
 template <> struct EnumPropsT<DiagDirection> : MakeEnumPropsT<DiagDirection, byte, DIAGDIR_BEGIN, DIAGDIR_END, INVALID_DIAGDIR> {};
 typedef TinyEnumT<DiagDirection> DiagDirectionByte; //typedefing-enumification of DiagDirection
 
+/**
+ * Returns the reverse direction of the given DiagDirection
+ *
+ * @param d The DiagDirection to get the reverse from
+ * @return The reverse direction
+ */
 static inline DiagDirection ReverseDiagDir(DiagDirection d)
 {
 	return (DiagDirection)(2 ^ d);
 }
 
-
+/**
+ * Enumeration for the difference between to DiagDirection.
+ *
+ * As the DiagDirection only contains 4 possible directions the
+ * difference between two of these directions can only be in 4 ways.
+ * As the DirDiff enumeration the values can be added together and
+ * you will get the resulting difference (use modulo DIAGDIR_END).
+ *
+ * @see DirDiff
+ */
 enum DiagDirDiff {
-	DIAGDIRDIFF_SAME    = 0,
-	DIAGDIRDIFF_90RIGHT = 1,
-	DIAGDIRDIFF_REVERSE = 2,
-	DIAGDIRDIFF_90LEFT  = 3
+	DIAGDIRDIFF_SAME    = 0,        ///< Same directions
+	DIAGDIRDIFF_90RIGHT = 1,        ///< 90 degrees right
+	DIAGDIRDIFF_REVERSE = 2,        ///< Reverse directions
+	DIAGDIRDIFF_90LEFT  = 3         ///< 90 degrees left
 };
 
+/**
+ * Applies a difference on a DiagDirection
+ *
+ * This function applies a difference on a DiagDirection and returns
+ * the new DiagDirection.
+ *
+ * @param d The DiagDirection
+ * @param delta The difference to applie on
+ * @return The new direction which was calculated
+ */
 static inline DiagDirection ChangeDiagDir(DiagDirection d, DiagDirDiff delta)
 {
 	return (DiagDirection)((d + delta) % 4);
 }
 
-
+/**
+ * Convert a Direction to a DiagDirection.
+ *
+ * This function can be used to convert the 8-way Direction to
+ * the 4-way DiagDirection. If the direction cannot be mapped its
+ * "rounded clockwise". So DIR_N becomes DIAGDIR_NE.
+ *
+ * @param dir The direction to convert
+ * @return The resulting DiagDirection, maybe "rounded clockwise".
+ */
 static inline DiagDirection DirToDiagDir(Direction dir)
 {
 	return (DiagDirection)(dir >> 1);
 }
 
-
+/**
+ * Convert a DiagDirection to a Direction.
+ *
+ * This function can be used to convert the 4-way DiagDirection
+ * to the 8-way Direction. As 4-way are less than 8-way not all
+ * possible directions can be calculated.
+ *
+ * @param dir The direction to convert
+ * @return The resulting Direction
+ */
 static inline Direction DiagDirToDir(DiagDirection dir)
 {
 	return (Direction)(dir * 2 + 1);
 }
 
 
-/* the 2 axis */
+/**
+ * Enumeration for the two axis X and Y
+ *
+ * This enumeration represente the two axis X and Y in the game.
+ * The X axis is the one which goes align the north-west edge
+ * (and south-east edge). The Y axis must be so the one which goes
+ * align the north-east edge (and south-west) edge.
+ */
 enum Axis {
-	AXIS_X = 0,
-	AXIS_Y = 1,
-	AXIS_END
+	AXIS_X = 0,     ///< The X axis
+	AXIS_Y = 1,     ///< The y axis
+	AXIS_END        ///< Used for iterations
 };
 
 
+/**
+ * Select the other axis as provided.
+ *
+ * This is basically the not-operator for the axis.
+ *
+ * @param a The given axis
+ * @return The other axis
+ */
 static inline Axis OtherAxis(Axis a)
 {
 	return (Axis)(a ^ 1);
 }
 
 
+/**
+ * Convert a DiagDirection to the axis.
+ *
+ * This function returns the axis which belongs to the given
+ * DiagDirection. The axis X belongs to the DiagDirection
+ * north-east and south-west.
+ *
+ * @param d The DiagDirection
+ * @return The axis which belongs to the direction
+ */
 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]
+ *
+ * This function returns the DiagDirection which
+ * belongs to the axis. As 2 directions are mapped to an axis
+ * this function returns the one which points to south,
+ * either south-west (on X axis) or south-east (on Y axis)
+ *
+ * @param a The axis
+ * @return The direction pointed to south
  */
 static inline DiagDirection AxisToDiagDir(Axis a)
 {
@@ -146,17 +283,34 @@ static inline DiagDirection XYNSToDiagDir(Axis xy, uint ns)
 	return (DiagDirection)(xy * 3 ^ ns * 2);
 }
 
-
+/**
+ * Checks if an interger value is a valid DiagDirection
+ *
+ * @param d The value to check
+ * @return True if the value belongs to a DiagDirection, else false
+ */
 static inline bool IsValidDiagDirection(DiagDirection d)
 {
 	return d < DIAGDIR_END;
 }
 
+/**
+ * Checks if an integer value is a valid Direction
+ *
+ * @param d The value to check
+ * @return True if the value belongs to a Direction, else false
+ */
 static inline bool IsValidDirection(Direction d)
 {
 	return d < DIR_END;
 }
 
+/**
+ * Checks if an integer value is a valid Axis
+ *
+ * @param d The value to check
+ * @return True if the value belongs to an Axis, else false
+ */
 static inline bool IsValidAxis(Axis d)
 {
 	return d < AXIS_END;