// Holds the move for negamax
public CalculatedMove(float value, Position moveFrom, MoveSet moveset)
{
// Automatically does the negating
Value = -value;
MoveFrom = moveFrom;
Moveset = moveset;
}
public MoveSet(MoveSet moveset)
{
_moves = new List <Position>();
if (moveset.NumberOfStages() > 0)
{
foreach (Position p in moveset.Moves)
{
_moves.Add(p);
}
}
}
// Non recursive checking the 4 moves around the piece
public override List <MoveSet> GetNonTakeMoves(Board board)
{
List <MoveSet> Moves = new List <MoveSet>();
// Adds backwards non take moves
Position LB = this.CurrentPosition.GetLeftBack(IsWhite);
Position RB = this.CurrentPosition.GetRightBack(IsWhite);
Position LF = this.CurrentPosition.GetLeftForward(IsWhite);
Position RF = this.CurrentPosition.GetRightForward(IsWhite);
if (LF.InBoard())
{
if (board.GetPiece(LF) == null)
{
MoveSet moveset = new MoveSet(LF);
Moves.Add(moveset);
}
}
if (RF.InBoard())
{
if (board.GetPiece(RF) == null)
{
MoveSet moveset = new MoveSet(RF);
Moves.Add(moveset);
}
}
if (LB.InBoard())
{
if (board.GetPiece(LB) == null)
{
MoveSet moveset = new MoveSet(LB);
Moves.Add(moveset);
}
}
if (RB.InBoard())
{
if (board.GetPiece(RB) == null)
{
MoveSet moveset = new MoveSet(RB);
Moves.Add(moveset);
}
}
return(Moves);
}
// Searches Depth moves ahead in the game and finds the best move
private CalculatedMove NegaMax(int Depth, int PlayerColour, float alpha, float beta, Board board, BackgroundWorker worker)
{
// Setup
float BestValue = float.MinValue;
bool FoundTakeMove = false;
bool AppliedTakeMove = false;
List <MoveSet> possibleMovesets;
List <Position> usablepieces = new List <Position>();
if (PlayerColour == 1)
{
usablepieces = board.GetWhitePositions();
}
else
{
usablepieces = board.GetBlackPositions();
}
//Show the tree (to the console)
if (Debug && Depth > 0)
{
Console.WriteLine();
for (int p = 0; p < (DepthOfSearch - Depth); p++)
{
Console.Write("\t");
}
if ((DepthOfSearch % 2 == Depth % 2 && IsWhite) || (DepthOfSearch % 2 != Depth % 2 && !IsWhite))
{
Console.Write("> MAX | ");
}
else
{
Console.Write("> MIN | ");
}
Console.Write("Depth: " + Depth.ToString());
Console.WriteLine();
}
if (Debug)
{
ShowBoard(board, Depth + 1);
}
// detect if we should stop
if (Depth == 0 || usablepieces.Count == 0 || board.WhiteHasWon() || board.BlackHasWon())
{
return(new CalculatedMove(PlayerColour * board.EvaluateBoard(), new Position(-1, -1), new MoveSet()));
}
// If we can carry on searching, setup BestPiece and BestMoveset with first valid move we come accross
Position BestPiecePosition = new Position(-1, -1);
MoveSet BestMoveset = new MoveSet();
foreach (Position p in usablepieces)
{
BestPiecePosition = p;
if (board.GetPiece(p).GetMoves(board).Count > 0)
{
BestMoveset = board.GetPiece(p).GetMoves(board).First();
break;
}
}
// Counts the number of pieces we have searched
int piececount = 0;
foreach (Position pieceposition in usablepieces)
{
if (Debug)
{
Console.WriteLine();
for (int p = -1; p < (DepthOfSearch - Depth); p++)
{
Console.Write("\t");
}
Console.WriteLine("NEW PIECE at " + pieceposition.ToString());
}
// generate all possible take movesets
possibleMovesets = board.GetPiece(pieceposition).GetTakeMovesOnly(board);
if (possibleMovesets.Count > 0)
{
if (!FoundTakeMove && !AppliedTakeMove)
{
// if this is the first piece that has take movesets, mark it so that every move is better than what we had.
FoundTakeMove = true;
}
}
else if (!FoundTakeMove)
{
possibleMovesets = board.GetPiece(pieceposition).GetMoves(board);
}
if (Debug)
{
for (int p = 0; p < (DepthOfSearch - Depth); p++)
{
Console.Write("\t");
}
Console.WriteLine("Take Moves found: " + FoundTakeMove);
}
bool BreakOuterLoop = false;
foreach (MoveSet moveset in possibleMovesets)
{
// Make test board
Board testboard = board.MakeNewCopyOf();
// Make move
Position oldpos = pieceposition;
foreach (Position move in moveset.Moves)
{
testboard.MovePeice(oldpos, move);
oldpos = move;
}
// Run the search
CalculatedMove Move = NegaMax(Depth - 1, -PlayerColour, -beta, -alpha, testboard, worker);
// Change the best result if we need to
if (BestValue < Move.Value || (FoundTakeMove && !AppliedTakeMove))
{
if (FoundTakeMove && !AppliedTakeMove)
{
AppliedTakeMove = true;
}
BestMoveset = moveset;
BestPiecePosition = pieceposition;
if (Debug && Move.Moveset.NumberOfStages() > 0)
{
for (int p = 0; p < (DepthOfSearch - Depth); p++)
{
Console.Write("\t");
}
Console.WriteLine("New best move from " + Move.MoveFrom.ToString() + " to " + Move.Moveset.Last().ToString() + " with score of: " + Move.Value.ToString() + " breating previous of: " + BestValue.ToString());
}
BestValue = Move.Value;
}
alpha = Math.Max(alpha, BestValue);
if (Debug)
{
for (int p = -1; p < (DepthOfSearch - Depth); p++)
{
Console.Write("\t");
}
Console.WriteLine(" | Current Board Score: " + (PlayerColour * testboard.EvaluateBoard()).ToString() + " | Best Value: " + BestValue.ToString());
}
if (alpha >= beta && UsePruning)
{
if (Debug)
{
for (int p = 0; p < (DepthOfSearch - Depth); p++)
{
Console.Write("\t");
}
Console.WriteLine(alpha.ToString() + " " + beta.ToString() + "Broke");
}
BreakOuterLoop = true;
break;
}
}
// If its the first call (highest depth) and we have finished a piece, report back to the worker our progress
if (Depth == DepthOfSearch)
{
worker.ReportProgress((int)(100f * piececount) / usablepieces.Count);
}
piececount++;
if (BreakOuterLoop)
{
break;
}
}
return(new CalculatedMove(BestValue, BestPiecePosition, BestMoveset));
}
// recursive structure to find multi-step moves around the piece
private List <MoveSet> GetTakeMoves(Board board, Position position, bool iswhite, MoveSet moveset)
{
List <MoveSet> Moves = new List <MoveSet>();
Position LB = position.GetLeftBack(iswhite);
Position LBT = position.GetLeftBackTake(IsWhite);
Position RB = position.GetRightBack(IsWhite);
Position RBT = position.GetRightBackTake(IsWhite);
Position LF = position.GetLeftForward(iswhite);
Position LFT = position.GetLeftForwardTake(IsWhite);
Position RF = position.GetRightForward(IsWhite);
Position RFT = position.GetRightForwardTake(IsWhite);
MoveSet CurrentMove = new MoveSet(moveset);
if (LB.InBoard() && LBT.InBoard())
{
if (board.GetPiece(LB) != null && board.GetPiece(LBT) == null)
{
if (board.GetPiece(LB).IsWhite != this.IsWhite)
{
Board testboard = board.MakeNewCopyOf();
testboard.RemovePeice(testboard.GetPiece(LB));
CurrentMove.Add(LBT);
Moves.Add(CurrentMove);
moveset.Add(LBT);
Moves.AddRange(GetTakeMoves(testboard, LBT, IsWhite, moveset));
moveset.Remove(LBT);
}
}
}
CurrentMove = new MoveSet(moveset);
if (RB.InBoard() && RBT.InBoard())
{
if (board.GetPiece(RB) != null && board.GetPiece(RBT) == null)
{
if (board.GetPiece(RB).IsWhite != this.IsWhite)
{
Board testboard = board.MakeNewCopyOf();
testboard.RemovePeice(testboard.GetPiece(RB));
CurrentMove.Add(RBT);
Moves.Add(CurrentMove);
moveset.Add(RBT);
Moves.AddRange(GetTakeMoves(testboard, RBT, IsWhite, moveset));
moveset.Remove(RBT);
}
}
}
CurrentMove = new MoveSet(moveset);
if (LF.InBoard() && LFT.InBoard())
{
if (board.GetPiece(LF) != null && board.GetPiece(LFT) == null)
{
if (board.GetPiece(LF).IsWhite != this.IsWhite)
{
Board testboard = board.MakeNewCopyOf();
testboard.RemovePeice(testboard.GetPiece(LF));
CurrentMove.Add(LFT);
Moves.Add(CurrentMove);
moveset.Add(LFT);
Moves.AddRange(GetTakeMoves(testboard, LFT, IsWhite, moveset));
moveset.Remove(LFT);
}
}
}
CurrentMove = new MoveSet(moveset);
if (RF.InBoard() && RFT.InBoard())
{
if (board.GetPiece(RF) != null && board.GetPiece(RFT) == null)
{
if (board.GetPiece(RF).IsWhite != this.IsWhite)
{
Board testboard = board.MakeNewCopyOf();
testboard.RemovePeice(testboard.GetPiece(RF));
CurrentMove.Add(RFT);
Moves.Add(CurrentMove);
moveset.Add(RFT);
Moves.AddRange(GetTakeMoves(testboard, RFT, IsWhite, moveset));
moveset.Remove(RFT);
}
}
}
return(Moves);
}
