/**
* Convert a DiagDirection to a TileIndexDiff
*
* @param dir The DiagDirection
* @return The resulting TileIndexDiff
* @see TileIndexDiffCByDiagDir
*/
//inline
public static TileIndexDiff TileOffsByDiagDir(DiagDirection dir)
{
if (dir.IsValidDiagDirection() == false)
{
throw new ArgumentOutOfRangeException(nameof(dir));
}
return(ToTileIndexDiff(_tileoffs_by_diagdir[(int)dir]));
}
/**
* 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
*/
//inline
public static Axis DiagDirToAxis(this DiagDirection d)
{
if (d.IsValidDiagDirection() == false)
{
throw new ArgumentOutOfRangeException(nameof(d));
}
return((Axis)((int)d & 1));
}
/**
* Returns the reverse direction of the given DiagDirection
*
* @param d The DiagDirection to get the reverse from
* @return The reverse direction
*/
//inline
public static DiagDirection ReverseDiagDir(this DiagDirection d)
{
if (d.IsValidDiagDirection() == false)
{
throw new ArgumentOutOfRangeException(nameof(d));
}
return((DiagDirection)(2 ^ (int)d));
}
/**
* 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
*/
//inline
public static Direction DiagDirToDir(this DiagDirection dir)
{
if (dir.IsValidDiagDirection() == false)
{
throw new ArgumentOutOfRangeException(nameof(dir));
}
return((Direction)((int)dir * 2 + 1));
;
}
/**
* 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 apply on
* @return The new direction which was calculated
*/
//inline
public static DiagDirection ChangeDiagDir(this DiagDirection d, DiagDirDiff delta)
{
if (d.IsValidDiagDirection() == false)
{
throw new ArgumentOutOfRangeException(nameof(d));
}
/* Cast to uint so compiler can use bitmask. Result can never be negative. */
return((DiagDirection)(((int)d + (int)delta) % 4));
}
/**
* Calculate the difference between two DiagDirection values
*
* @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 direction drifts of the first one.
*/
//inline
public static DiagDirDiff DiagDirDifference(this DiagDirection d0, DiagDirection d1)
{
if (d0.IsValidDiagDirection() == false)
{
throw new ArgumentOutOfRangeException(nameof(d0));
}
if (d1.IsValidDiagDirection() == false)
{
throw new ArgumentOutOfRangeException(nameof(d1));
}
/* Cast to uint so compiler can use bitmask. Result can never be negative. */
return((DiagDirDiff)(((int)d0 - (int)d1) % 4));
}
