public SetIterator(GridSet<T> _set)
{
set = _set;
posIterator = new Vector2i.Iterator(set.grid.SizeXY());
cellIterator = new CellIterator();
reset = true;
}
/// <summary>
/// If the given piece placement/movement creates a block of identical pieces,
/// returns the min corner of that block.
/// Otherwise, returns null.
/// </summary>
/// <param name="movedPiecePos">The position of the piece after its movement.</param>
/// <param name="previousPiecePos">
/// The position of the piece before its movement,
/// or "null" if the piece is being placed onto the board.
/// </param>
public static Vector2i?GetHostBlock(Board board, Vector2i movedPiecePos,
Vector2i?previousPiecePos, Teams team)
{
//Assume the movement is made, and create a getter for the new board.
//First, figure out what happens at the piece's previous position (if it exists).
Teams?pieceAtPreviousPos = null;
if (previousPiecePos.HasValue)
{
//If a piece moves off of a host, the host creates a new piece in its place.
var host = board.Hosts.Get(previousPiecePos.Value);
if (host != null)
{
pieceAtPreviousPos = host.Team;
}
}
Func <Vector2i, Teams?> getPieceAt = (boardPos) =>
{
//Special cases:
//Previous position of the moving piece.
if (previousPiecePos.HasValue && boardPos == previousPiecePos.Value)
{
return(pieceAtPreviousPos);
}
//New position of the moving piece.
else if (boardPos == movedPiecePos)
{
return(team);
}
//Outside the board.
else if (!board.IsInRange(boardPos))
{
return(null);
}
var piece = board.Pieces.Get(boardPos);
return(piece == null ?
new Teams?() :
piece.Team);
};
//Try to find a square of identical pieces around the moved piece.
var minCornerRegion = new Vector2i.Iterator(movedPiecePos - GameConsts.HostBlockSize + 1,
movedPiecePos + 1);
foreach (Vector2i minCorner in minCornerRegion)
{
bool failed = false;
var blockRegion = new Vector2i.Iterator(minCorner,
minCorner + GameConsts.HostBlockSize);
foreach (Vector2i blockPos in blockRegion)
{
Teams?blockTeam = getPieceAt(blockPos);
if (!blockTeam.HasValue || blockTeam.Value != team)
{
failed = true;
break;
}
}
if (!failed)
{
return(minCorner);
}
}
//Nothing was found.
return(null);
}
