/// <summary>
/// Gets the first side reached rotating clockwise.
/// If All, North is returned.
/// If None, None is returned.
/// </summary>
/// <param name="side"></param>
/// <returns></returns>
public static GridNeighbour FirstSide(this GridNeighbour side)
{
if (side == GridNeighbour.All)
{
return(GridNeighbour.North);
}
if (side == GridNeighbour.None)
{
return(GridNeighbour.None);
}
GridNeighbour start = GridNeighbour.North;
if (side.HasFlag(start))
{
if (!side.HasFlag(GridNeighbour.North.Rotate(-1)))
{
return(GridNeighbour.North);
}
for (int i = 1; i < 8; i++)
{
if (!side.HasFlag(1 << i))
{
start = (GridNeighbour)(1 << (i + 1));
}
}
}
while (!side.HasFlag(start))
{
start = (GridNeighbour)((int)start << 1);
}
return(start);
}
public T GetNeighbour(int x, int y, GridNeighbour side)
{
switch (side)
{
case GridNeighbour.North:
return(this[x, y + 1]);
case GridNeighbour.NE:
return(this[x + 1, y + 1]);
case GridNeighbour.East:
return(this[x + 1, y]);
case GridNeighbour.SE:
return(this[x + 1, y - 1]);
case GridNeighbour.South:
return(this[x, y - 1]);
case GridNeighbour.SW:
return(this[x - 1, y - 1]);
case GridNeighbour.West:
return(this[x - 1, y]);
case GridNeighbour.NW:
return(this[x - 1, y + 1]);
default:
return(default(T));
}
}
public GridNeighbour GetSide(T from, T to)
{
int index = this.IndexOf(from);
if (index < 0)
{
return(GridNeighbour.None);
}
if (!this.Contains(to))
{
return(GridNeighbour.None);
}
int x = index % _colCount;
int y = index / _colCount;
for (int i = 0; i < 8; i++)
{
GridNeighbour f = (GridNeighbour)(1 << i);
if (_comparer.Equals(this.GetNeighbour(x, y, f), to))
{
return(f);
}
}
return(GridNeighbour.None);
}
public IEnumerable <T> GetNeighbours(int x, int y, GridNeighbour sides)
{
int e = (int)sides;
for (int i = 0; i < 8; i++)
{
int f = 1 << i;
if ((e & (1 << i)) != 0)
{
yield return(this.GetNeighbour(x, y, (GridNeighbour)f));
}
}
}
/// <summary>
/// Returns the side opposite of input.
/// </summary>
/// <param name="side"></param>
/// <returns></returns>
public static GridNeighbour Opposite(this GridNeighbour side)
{
int e = (int)side;
int result = 0;
for (int i = 0; i < 8; i++)
{
int f = 1 << i;
if ((e & (1 << i)) != 0)
{
result |= (i < 4) ? f << 4 : f >> 4;
}
}
return((GridNeighbour)result);
}
public int GetNeighbours(T node, GridNeighbour sides, ICollection <T> buffer)
{
if (node == null)
{
return(0);
}
int index = this.IndexOf(node);
if (index < 0)
{
return(0);
}
return(GetNeighbours(index % _colCount, index / _colCount, sides, buffer));
}
public IEnumerable <T> GetNeighbours(T node, GridNeighbour sides)
{
if (node == null)
{
return(Enumerable.Empty <T>());
}
int index = this.IndexOf(node);
if (index < 0)
{
return(Enumerable.Empty <T>());
}
return(GetNeighbours(index % _colCount, index / _colCount, sides));
}
public T GetNeighbour(T node, GridNeighbour side)
{
if (node == null)
{
throw new ArgumentNullException("node");
}
int index = this.IndexOf(node);
if (index < 0)
{
return(default(T));
}
return(GetNeighbour(index % _colCount, index / _colCount, side));
}
/// <summary>
/// Rotates side x number of 45 degree turns around the cardinal directions clockwise.
/// North turned twice is East, South turned -1 is SouthEast.
/// </summary>
/// <param name="side"></param>
/// <param name="turns"></param>
/// <returns></returns>
public static GridNeighbour Rotate(this GridNeighbour side, int turns)
{
turns = turns % 8;
if (turns == 0)
{
return(side);
}
if (turns < 0)
{
turns = System.Math.Abs(turns);
int i = (int)side << (8 - turns);
i = (i & 255) | (i >> 8);
return((GridNeighbour)i);
}
else
{
return((GridNeighbour)(((int)side << turns) % 255));
}
}
public int GetNeighbours(int x, int y, GridNeighbour sides, ICollection <T> buffer)
{
if (buffer == null)
{
throw new ArgumentNullException("buffer");
}
int cnt = 0;
int e = (int)sides;
for (int i = 0; i < 8; i++)
{
int f = 1 << i;
if ((e & (1 << i)) != 0)
{
buffer.Add(this.GetNeighbour(x, y, (GridNeighbour)f));
cnt++;
}
}
return(cnt);
}
/// <summary>
/// Gets the first side reached rotating clockwise.
/// If All, North is returned.
/// If None, None is returned.
/// </summary>
/// <param name="side"></param>
/// <returns></returns>
public static GridNeighbour FirstSide(this GridNeighbour side)
{
if (side == GridNeighbour.All)
{
return(GridNeighbour.North);
}
if (side == GridNeighbour.None)
{
return(GridNeighbour.None);
}
GridNeighbour start = GridNeighbour.North;
if ((side & start) != 0) //if start
{
//if (!side.HasFlag(GridNeighbour.North.Rotate(-1))) return GridNeighbour.North;
if ((side & GridNeighbour.North.Rotate(-1)) == 0)
{
return(GridNeighbour.North);
}
for (int i = 1; i < 8; i++)
{
//if(!side.HasFlag(1 << i))
if (((int)side & (1 << i)) == 0)
{
start = (GridNeighbour)(1 << (i + 1));
}
}
}
while ((side & start) == 0) //while not start
{
start = (GridNeighbour)((int)start << 1);
}
return(start);
}
public int GetNeighboursOfIndex(int index, GridNeighbour sides, ICollection <T> buffer)
{
return(GetNeighbours(index % _colCount, index / _colCount, sides, buffer));
}
public IEnumerable <T> GetNeighboursOfIndex(int index, GridNeighbour sides)
{
return(GetNeighbours(index % _colCount, index / _colCount, sides));
}
public T GetNeighbourOfIndex(int index, GridNeighbour side)
{
return(GetNeighbour(index % _colCount, index / _colCount, side));
}
