+// (Orthodox) Chess rules are defined in ChessRules class.
+// Variants generally inherit from it, and modify some parts.
+
class PiPo //Piece+Position
{
// o: {piece[p], color[c], posX[x], posY[y]}
}
}
+// TODO: for animation, moves should contains "moving" and "fading" maybe...
class Move
{
// o: {appear, vanish, [start,] [end,]}
// NOTE: x coords = top to bottom; y = left to right (from white player perspective)
class ChessRules
{
+ //////////////
+ // MISC UTILS
+
+ static get HasFlags() { return true; } //some variants don't have flags
+
+ static get HasEnpassant() { return true; } //some variants don't have ep.
+
// Path to pieces
static getPpath(b)
{
return b; //usual pieces in pieces/ folder
}
+
// Turn "wb" into "B" (for FEN)
static board2fen(b)
{
return b[0]=='w' ? b[1].toUpperCase() : b[1];
}
+
// Turn "p" into "bp" (for board)
static fen2board(f)
{
return f.charCodeAt()<=90 ? "w"+f.toLowerCase() : "b"+f;
}
- /////////////////
+ // Check if FEN describe a position
+ static IsGoodFen(fen)
+ {
+ const fenParsed = V.ParseFen(fen);
+ // 1) Check position
+ if (!V.IsGoodPosition(fenParsed.position))
+ return false;
+ // 2) Check turn
+ if (!fenParsed.turn || !V.IsGoodTurn(fenParsed.turn))
+ return false;
+ // 3) Check moves count
+ if (!fenParsed.movesCount || !(parseInt(fenParsed.movesCount) >= 0))
+ return false;
+ // 4) Check flags
+ if (V.HasFlags && (!fenParsed.flags || !V.IsGoodFlags(fenParsed.flags)))
+ return false;
+ // 5) Check enpassant
+ if (V.HasEnpassant &&
+ (!fenParsed.enpassant || !V.IsGoodEnpassant(fenParsed.enpassant)))
+ {
+ return false;
+ }
+ return true;
+ }
+
+ // Is position part of the FEN a priori correct?
+ static IsGoodPosition(position)
+ {
+ if (position.length == 0)
+ return false;
+ const rows = position.split("/");
+ if (rows.length != V.size.x)
+ return false;
+ for (let row of rows)
+ {
+ let sumElts = 0;
+ for (let i=0; i<row.length; i++)
+ {
+ if (V.PIECES.includes(row[i].toLowerCase()))
+ sumElts++;
+ else
+ {
+ const num = parseInt(row[i]);
+ if (isNaN(num))
+ return false;
+ sumElts += num;
+ }
+ }
+ if (sumElts != V.size.y)
+ return false;
+ }
+ return true;
+ }
+
+ // For FEN checking
+ static IsGoodTurn(turn)
+ {
+ return ["w","b"].includes(turn);
+ }
+
+ // For FEN checking
+ static IsGoodFlags(flags)
+ {
+ return !!flags.match(/^[01]{4,4}$/);
+ }
+
+ static IsGoodEnpassant(enpassant)
+ {
+ if (enpassant != "-")
+ {
+ const ep = V.SquareToCoords(fenParsed.enpassant);
+ if (isNaN(ep.x) || !V.OnBoard(ep))
+ return false;
+ }
+ return true;
+ }
+
+ // 3 --> d (column number to letter)
+ static CoordToColumn(colnum)
+ {
+ return String.fromCharCode(97 + colnum);
+ }
+
+ // d --> 3 (column letter to number)
+ static ColumnToCoord(column)
+ {
+ return column.charCodeAt(0) - 97;
+ }
+
+ // a4 --> {x:3,y:0}
+ static SquareToCoords(sq)
+ {
+ return {
+ // NOTE: column is always one char => max 26 columns
+ // row is counted from black side => subtraction
+ x: V.size.x - parseInt(sq.substr(1)),
+ y: sq[0].charCodeAt() - 97
+ };
+ }
+
+ // {x:0,y:4} --> e8
+ static CoordsToSquare(coords)
+ {
+ return V.CoordToColumn(coords.y) + (V.size.x - coords.x);
+ }
+
+ // Aggregates flags into one object
+ aggregateFlags()
+ {
+ return this.castleFlags;
+ }
+
+ // Reverse operation
+ disaggregateFlags(flags)
+ {
+ this.castleFlags = flags;
+ }
+
+ // En-passant square, if any
+ getEpSquare(moveOrSquare)
+ {
+ if (!moveOrSquare)
+ return undefined;
+ if (typeof moveOrSquare === "string")
+ {
+ const square = moveOrSquare;
+ if (square == "-")
+ return undefined;
+ return V.SquareToCoords(square);
+ }
+ // Argument is a move:
+ const move = moveOrSquare;
+ const [sx,sy,ex] = [move.start.x,move.start.y,move.end.x];
+ // TODO: next conditions are first for Atomic, and third for Checkered
+ if (move.appear.length > 0 && move.appear[0].p == V.PAWN && ["w","b"].includes(move.appear[0].c) && Math.abs(sx - ex) == 2)
+ {
+ return {
+ x: (sx + ex)/2,
+ y: sy
+ };
+ }
+ return undefined; //default
+ }
+
+ // Can thing on square1 take thing on square2
+ canTake([x1,y1], [x2,y2])
+ {
+ return this.getColor(x1,y1) !== this.getColor(x2,y2);
+ }
+
+ // Is (x,y) on the chessboard?
+ static OnBoard(x,y)
+ {
+ return (x>=0 && x<V.size.x && y>=0 && y<V.size.y);
+ }
+
+ // Used in interface: 'side' arg == player color
+ canIplay(side, [x,y])
+ {
+ return (this.turn == side && this.getColor(x,y) == side);
+ }
+
+ // On which squares is color under check ? (for interface)
+ getCheckSquares(color)
+ {
+ return this.isAttacked(this.kingPos[color], [this.getOppCol(color)])
+ ? [JSON.parse(JSON.stringify(this.kingPos[color]))] //need to duplicate!
+ : [];
+ }
+
+ /////////////
+ // FEN UTILS
+
+ // Setup the initial random (assymetric) position
+ static GenRandInitFen()
+ {
+ let pieces = { "w": new Array(8), "b": new Array(8) };
+ // Shuffle pieces on first and last rank
+ for (let c of ["w","b"])
+ {
+ let positions = _.range(8);
+
+ // Get random squares for bishops
+ let randIndex = 2 * _.random(3);
+ const bishop1Pos = positions[randIndex];
+ // The second bishop must be on a square of different color
+ let randIndex_tmp = 2 * _.random(3) + 1;
+ const bishop2Pos = positions[randIndex_tmp];
+ // Remove chosen squares
+ positions.splice(Math.max(randIndex,randIndex_tmp), 1);
+ positions.splice(Math.min(randIndex,randIndex_tmp), 1);
+
+ // Get random squares for knights
+ randIndex = _.random(5);
+ const knight1Pos = positions[randIndex];
+ positions.splice(randIndex, 1);
+ randIndex = _.random(4);
+ const knight2Pos = positions[randIndex];
+ positions.splice(randIndex, 1);
+
+ // Get random square for queen
+ randIndex = _.random(3);
+ const queenPos = positions[randIndex];
+ positions.splice(randIndex, 1);
+
+ // Rooks and king positions are now fixed,
+ // because of the ordering rook-king-rook
+ const rook1Pos = positions[0];
+ const kingPos = positions[1];
+ const rook2Pos = positions[2];
+
+ // Finally put the shuffled pieces in the board array
+ pieces[c][rook1Pos] = 'r';
+ pieces[c][knight1Pos] = 'n';
+ pieces[c][bishop1Pos] = 'b';
+ pieces[c][queenPos] = 'q';
+ pieces[c][kingPos] = 'k';
+ pieces[c][bishop2Pos] = 'b';
+ pieces[c][knight2Pos] = 'n';
+ pieces[c][rook2Pos] = 'r';
+ }
+ return pieces["b"].join("") +
+ "/pppppppp/8/8/8/8/PPPPPPPP/" +
+ pieces["w"].join("").toUpperCase() +
+ " w 1111 -"; //add turn + flags + enpassant
+ }
+
+ // "Parse" FEN: just return untransformed string data
+ static ParseFen(fen)
+ {
+ const fenParts = fen.split(" ");
+ let res =
+ {
+ position: fenParts[0],
+ turn: fenParts[1],
+ movesCount: fenParts[2],
+ };
+ let nextIdx = 3;
+ if (V.HasFlags)
+ Object.assign(res, {flags: fenParts[nextIdx++]});
+ if (V.HasEnpassant)
+ Object.assign(res, {enpassant: fenParts[nextIdx]});
+ return res;
+ }
+
+ // Return current fen (game state)
+ getFen()
+ {
+ return this.getBaseFen() + " " +
+ this.getTurnFen() + " " + this.movesCount +
+ (V.HasFlags ? (" " + this.getFlagsFen()) : "") +
+ (V.HasEnpassant ? (" " + this.getEnpassantFen()) : "");
+ }
+
+ // Position part of the FEN string
+ getBaseFen()
+ {
+ let position = "";
+ for (let i=0; i<V.size.x; i++)
+ {
+ let emptyCount = 0;
+ for (let j=0; j<V.size.y; j++)
+ {
+ if (this.board[i][j] == V.EMPTY)
+ emptyCount++;
+ else
+ {
+ if (emptyCount > 0)
+ {
+ // Add empty squares in-between
+ position += emptyCount;
+ emptyCount = 0;
+ }
+ position += V.board2fen(this.board[i][j]);
+ }
+ }
+ if (emptyCount > 0)
+ {
+ // "Flush remainder"
+ position += emptyCount;
+ }
+ if (i < V.size.x - 1)
+ position += "/"; //separate rows
+ }
+ return position;
+ }
+
+ getTurnFen()
+ {
+ return this.turn;
+ }
+
+ // Flags part of the FEN string
+ getFlagsFen()
+ {
+ let flags = "";
+ // Add castling flags
+ for (let i of ['w','b'])
+ {
+ for (let j=0; j<2; j++)
+ flags += (this.castleFlags[i][j] ? '1' : '0');
+ }
+ return flags;
+ }
+
+ // Enpassant part of the FEN string
+ getEnpassantFen()
+ {
+ const L = this.epSquares.length;
+ if (!this.epSquares[L-1])
+ return "-"; //no en-passant
+ return V.CoordsToSquare(this.epSquares[L-1]);
+ }
+
+ // Turn position fen into double array ["wb","wp","bk",...]
+ static GetBoard(position)
+ {
+ const rows = position.split("/");
+ let board = doubleArray(V.size.x, V.size.y, "");
+ for (let i=0; i<rows.length; i++)
+ {
+ let j = 0;
+ for (let indexInRow = 0; indexInRow < rows[i].length; indexInRow++)
+ {
+ const character = rows[i][indexInRow];
+ const num = parseInt(character);
+ if (!isNaN(num))
+ j += num; //just shift j
+ else //something at position i,j
+ board[i][j++] = V.fen2board(character);
+ }
+ }
+ return board;
+ }
+
+ // Extract (relevant) flags from fen
+ setFlags(fenflags)
+ {
+ // white a-castle, h-castle, black a-castle, h-castle
+ this.castleFlags = {'w': [true,true], 'b': [true,true]};
+ if (!fenflags)
+ return;
+ for (let i=0; i<4; i++)
+ this.castleFlags[i < 2 ? 'w' : 'b'][i%2] = (fenflags.charAt(i) == '1');
+ }
+
+ //////////////////
// INITIALIZATION
- // fen == "position flags"
- constructor(fen, moves)
+ // Fen string fully describes the game state
+ constructor(fen)
{
- this.moves = moves;
- // Use fen string to initialize variables, flags and board
- this.board = VariantRules.GetBoard(fen);
- this.setFlags(fen);
- this.initVariables(fen);
+ const fenParsed = V.ParseFen(fen);
+ this.board = V.GetBoard(fenParsed.position);
+ this.turn = fenParsed.turn[0]; //[0] to work with MarseilleRules
+ this.movesCount = parseInt(fenParsed.movesCount);
+ this.setOtherVariables(fen);
}
- initVariables(fen)
+ // Scan board for kings and rooks positions
+ scanKingsRooks(fen)
{
this.INIT_COL_KING = {'w':-1, 'b':-1};
this.INIT_COL_ROOK = {'w':[-1,-1], 'b':[-1,-1]};
- this.kingPos = {'w':[-1,-1], 'b':[-1,-1]}; //respective squares of white and black king
- const fenParts = fen.split(" ");
- const position = fenParts[0].split("/");
- for (let i=0; i<position.length; i++)
+ this.kingPos = {'w':[-1,-1], 'b':[-1,-1]}; //squares of white and black king
+ const fenRows = V.ParseFen(fen).position.split("/");
+ for (let i=0; i<fenRows.length; i++)
{
let k = 0; //column index on board
- for (let j=0; j<position[i].length; j++)
+ for (let j=0; j<fenRows[i].length; j++)
{
- switch (position[i].charAt(j))
+ switch (fenRows[i].charAt(j))
{
case 'k':
this.kingPos['b'] = [i,k];
this.INIT_COL_ROOK['w'][1] = k;
break;
default:
- let num = parseInt(position[i].charAt(j));
+ const num = parseInt(fenRows[i].charAt(j));
if (!isNaN(num))
k += (num-1);
}
k++;
}
}
- const epSq = this.moves.length > 0 ? this.getEpSquare(this.lastMove) : undefined;
- this.epSquares = [ epSq ];
}
- // Turn diagram fen into double array ["wb","wp","bk",...]
- static GetBoard(fen)
+ // Some additional variables from FEN (variant dependant)
+ setOtherVariables(fen)
{
- let rows = fen.split(" ")[0].split("/");
- const [sizeX,sizeY] = VariantRules.size;
- let board = doubleArray(sizeX, sizeY, "");
- for (let i=0; i<rows.length; i++)
+ // Set flags and enpassant:
+ const parsedFen = V.ParseFen(fen);
+ if (V.HasFlags)
+ this.setFlags(parsedFen.flags);
+ if (V.HasEnpassant)
{
- let j = 0;
- for (let indexInRow = 0; indexInRow < rows[i].length; indexInRow++)
- {
- let character = rows[i][indexInRow];
- let num = parseInt(character);
- if (!isNaN(num))
- j += num; //just shift j
- else //something at position i,j
- board[i][j++] = VariantRules.fen2board(character);
- }
+ const epSq = parsedFen.enpassant != "-"
+ ? V.SquareToCoords(parsedFen.enpassant)
+ : undefined;
+ this.epSquares = [ epSq ];
}
- return board;
+ // Search for king and rooks positions:
+ this.scanKingsRooks(fen);
}
- // Overridable: flags can change a lot
- setFlags(fen)
+ /////////////////////
+ // GETTERS & SETTERS
+
+ static get size()
{
- // white a-castle, h-castle, black a-castle, h-castle
- this.castleFlags = {'w': new Array(2), 'b': new Array(2)};
- let flags = fen.split(" ")[1]; //flags right after position
- for (let i=0; i<4; i++)
- this.castleFlags[i < 2 ? 'w' : 'b'][i%2] = (flags.charAt(i) == '1');
+ return {x:8, y:8};
}
- ///////////////////
- // GETTERS, SETTERS
-
- // Simple useful getters
- static get size() { return [8,8]; }
- // Two next functions return 'undefined' if called on empty square
- getColor(i,j) { return this.board[i][j].charAt(0); }
- getPiece(i,j) { return this.board[i][j].charAt(1); }
-
- // Color
- getOppCol(color) { return color=="w" ? "b" : "w"; }
+ // Color of thing on suqare (i,j). 'undefined' if square is empty
+ getColor(i,j)
+ {
+ return this.board[i][j].charAt(0);
+ }
- get lastMove() {
- const L = this.moves.length;
- return L>0 ? this.moves[L-1] : null;
+ // Piece type on square (i,j). 'undefined' if square is empty
+ getPiece(i,j)
+ {
+ return this.board[i][j].charAt(1);
}
- get turn() {
- return this.moves.length%2==0 ? 'w' : 'b';
+
+ // Get opponent color
+ getOppCol(color)
+ {
+ return (color=="w" ? "b" : "w");
}
- // Pieces codes
+ // Pieces codes (for a clearer code)
static get PAWN() { return 'p'; }
static get ROOK() { return 'r'; }
static get KNIGHT() { return 'n'; }
static get QUEEN() { return 'q'; }
static get KING() { return 'k'; }
+ // For FEN checking:
+ static get PIECES()
+ {
+ return [V.PAWN,V.ROOK,V.KNIGHT,V.BISHOP,V.QUEEN,V.KING];
+ }
+
// Empty square
- static get EMPTY() { return ''; }
+ static get EMPTY() { return ""; }
// Some pieces movements
- static get steps() {
+ static get steps()
+ {
return {
'r': [ [-1,0],[1,0],[0,-1],[0,1] ],
'n': [ [-1,-2],[-1,2],[1,-2],[1,2],[-2,-1],[-2,1],[2,-1],[2,1] ],
'b': [ [-1,-1],[-1,1],[1,-1],[1,1] ],
- 'q': [ [-1,0],[1,0],[0,-1],[0,1],[-1,-1],[-1,1],[1,-1],[1,1] ]
};
}
- // Aggregates flags into one object
- get flags() {
- return this.castleFlags;
- }
-
- // Reverse operation
- parseFlags(flags)
- {
- this.castleFlags = flags;
- }
-
- // En-passant square, if any
- getEpSquare(move)
- {
- const [sx,sy,ex] = [move.start.x,move.start.y,move.end.x];
- if (this.getPiece(sx,sy) == VariantRules.PAWN && Math.abs(sx - ex) == 2)
- {
- return {
- x: (sx + ex)/2,
- y: sy
- };
- }
- return undefined; //default
- }
-
- // can thing on square1 take thing on square2
- canTake([x1,y1], [x2,y2])
- {
- return this.getColor(x1,y1) != this.getColor(x2,y2);
- }
-
- ///////////////////
+ ////////////////////
// MOVES GENERATION
// All possible moves from selected square (assumption: color is OK)
{
switch (this.getPiece(x,y))
{
- case VariantRules.PAWN:
+ case V.PAWN:
return this.getPotentialPawnMoves([x,y]);
- case VariantRules.ROOK:
+ case V.ROOK:
return this.getPotentialRookMoves([x,y]);
- case VariantRules.KNIGHT:
+ case V.KNIGHT:
return this.getPotentialKnightMoves([x,y]);
- case VariantRules.BISHOP:
+ case V.BISHOP:
return this.getPotentialBishopMoves([x,y]);
- case VariantRules.QUEEN:
+ case V.QUEEN:
return this.getPotentialQueenMoves([x,y]);
- case VariantRules.KING:
+ case V.KING:
return this.getPotentialKingMoves([x,y]);
}
}
- // Build a regular move from its initial and destination squares; tr: transformation
+ // Build a regular move from its initial and destination squares.
+ // tr: transformation
getBasicMove([sx,sy], [ex,ey], tr)
{
let mv = new Move({
});
// The opponent piece disappears if we take it
- if (this.board[ex][ey] != VariantRules.EMPTY)
+ if (this.board[ex][ey] != V.EMPTY)
{
mv.vanish.push(
new PiPo({
return mv;
}
- // Generic method to find possible moves of non-pawn pieces ("sliding or jumping")
+ // Generic method to find possible moves of non-pawn pieces:
+ // "sliding or jumping"
getSlideNJumpMoves([x,y], steps, oneStep)
{
const color = this.getColor(x,y);
let moves = [];
- const [sizeX,sizeY] = VariantRules.size;
outerLoop:
for (let step of steps)
{
let i = x + step[0];
let j = y + step[1];
- while (i>=0 && i<sizeX && j>=0 && j<sizeY && this.board[i][j] == VariantRules.EMPTY)
+ while (V.OnBoard(i,j) && this.board[i][j] == V.EMPTY)
{
moves.push(this.getBasicMove([x,y], [i,j]));
if (oneStep !== undefined)
i += step[0];
j += step[1];
}
- if (i>=0 && i<8 && j>=0 && j<8 && this.canTake([x,y], [i,j]))
+ if (V.OnBoard(i,j) && this.canTake([x,y], [i,j]))
moves.push(this.getBasicMove([x,y], [i,j]));
}
return moves;
}
- // What are the pawn moves from square x,y considering color "color" ?
+ // What are the pawn moves from square x,y ?
getPotentialPawnMoves([x,y])
{
const color = this.turn;
let moves = [];
- const V = VariantRules;
- const [sizeX,sizeY] = VariantRules.size;
- const shift = (color == "w" ? -1 : 1);
- const firstRank = (color == 'w' ? sizeY-1 : 0);
- const startRank = (color == "w" ? sizeY-2 : 1);
- const lastRank = (color == "w" ? 0 : sizeY-1);
-
- if (x+shift >= 0 && x+shift < sizeX && x+shift != lastRank)
+ const [sizeX,sizeY] = [V.size.x,V.size.y];
+ const shiftX = (color == "w" ? -1 : 1);
+ const firstRank = (color == 'w' ? sizeX-1 : 0);
+ const startRank = (color == "w" ? sizeX-2 : 1);
+ const lastRank = (color == "w" ? 0 : sizeX-1);
+ const pawnColor = this.getColor(x,y); //can be different for checkered
+
+ // NOTE: next condition is generally true (no pawn on last rank)
+ if (x+shiftX >= 0 && x+shiftX < sizeX)
{
- // Normal moves
- if (this.board[x+shift][y] == V.EMPTY)
+ const finalPieces = x + shiftX == lastRank
+ ? [V.ROOK,V.KNIGHT,V.BISHOP,V.QUEEN]
+ : [V.PAWN]
+ // One square forward
+ if (this.board[x+shiftX][y] == V.EMPTY)
{
- moves.push(this.getBasicMove([x,y], [x+shift,y]));
- // Next condition because variants with pawns on 1st rank generally allow them to jump
- if ([startRank,firstRank].includes(x) && this.board[x+2*shift][y] == V.EMPTY)
+ for (let piece of finalPieces)
+ {
+ moves.push(this.getBasicMove([x,y], [x+shiftX,y],
+ {c:pawnColor,p:piece}));
+ }
+ // Next condition because pawns on 1st rank can generally jump
+ if ([startRank,firstRank].includes(x)
+ && this.board[x+2*shiftX][y] == V.EMPTY)
{
// Two squares jump
- moves.push(this.getBasicMove([x,y], [x+2*shift,y]));
+ moves.push(this.getBasicMove([x,y], [x+2*shiftX,y]));
}
}
// Captures
- if (y>0 && this.canTake([x,y], [x+shift,y-1]) && this.board[x+shift][y-1] != V.EMPTY)
- moves.push(this.getBasicMove([x,y], [x+shift,y-1]));
- if (y<sizeY-1 && this.canTake([x,y], [x+shift,y+1]) && this.board[x+shift][y+1] != V.EMPTY)
- moves.push(this.getBasicMove([x,y], [x+shift,y+1]));
- }
-
- if (x+shift == lastRank)
- {
- // Promotion
- let promotionPieces = [V.ROOK,V.KNIGHT,V.BISHOP,V.QUEEN];
- promotionPieces.forEach(p => {
- // Normal move
- if (this.board[x+shift][y] == V.EMPTY)
- moves.push(this.getBasicMove([x,y], [x+shift,y], {c:color,p:p}));
- // Captures
- if (y>0 && this.canTake([x,y], [x+shift,y-1]) && this.board[x+shift][y-1] != V.EMPTY)
- moves.push(this.getBasicMove([x,y], [x+shift,y-1], {c:color,p:p}));
- if (y<sizeY-1 && this.canTake([x,y], [x+shift,y+1]) && this.board[x+shift][y+1] != V.EMPTY)
- moves.push(this.getBasicMove([x,y], [x+shift,y+1], {c:color,p:p}));
- });
+ for (let shiftY of [-1,1])
+ {
+ if (y + shiftY >= 0 && y + shiftY < sizeY
+ && this.board[x+shiftX][y+shiftY] != V.EMPTY
+ && this.canTake([x,y], [x+shiftX,y+shiftY]))
+ {
+ for (let piece of finalPieces)
+ {
+ moves.push(this.getBasicMove([x,y], [x+shiftX,y+shiftY],
+ {c:pawnColor,p:piece}));
+ }
+ }
+ }
}
- // En passant
- const Lep = this.epSquares.length;
- const epSquare = Lep>0 ? this.epSquares[Lep-1] : undefined;
- if (!!epSquare && epSquare.x == x+shift && Math.abs(epSquare.y - y) == 1)
+ if (V.HasEnpassant)
{
- let epStep = epSquare.y - y;
- var enpassantMove = this.getBasicMove([x,y], [x+shift,y+epStep]);
- enpassantMove.vanish.push({
- x: x,
- y: y+epStep,
- p: 'p',
- c: this.getColor(x,y+epStep)
- });
- moves.push(enpassantMove);
+ // En passant
+ const Lep = this.epSquares.length;
+ const epSquare = this.epSquares[Lep-1]; //always at least one element
+ if (!!epSquare && epSquare.x == x+shiftX && Math.abs(epSquare.y - y) == 1)
+ {
+ let enpassantMove = this.getBasicMove([x,y], [epSquare.x,epSquare.y]);
+ enpassantMove.vanish.push({
+ x: x,
+ y: epSquare.y,
+ p: 'p',
+ c: this.getColor(x,epSquare.y)
+ });
+ moves.push(enpassantMove);
+ }
}
return moves;
// What are the rook moves from square x,y ?
getPotentialRookMoves(sq)
{
- return this.getSlideNJumpMoves(sq, VariantRules.steps[VariantRules.ROOK]);
+ return this.getSlideNJumpMoves(sq, V.steps[V.ROOK]);
}
// What are the knight moves from square x,y ?
getPotentialKnightMoves(sq)
{
- return this.getSlideNJumpMoves(sq, VariantRules.steps[VariantRules.KNIGHT], "oneStep");
+ return this.getSlideNJumpMoves(sq, V.steps[V.KNIGHT], "oneStep");
}
// What are the bishop moves from square x,y ?
getPotentialBishopMoves(sq)
{
- return this.getSlideNJumpMoves(sq, VariantRules.steps[VariantRules.BISHOP]);
+ return this.getSlideNJumpMoves(sq, V.steps[V.BISHOP]);
}
// What are the queen moves from square x,y ?
getPotentialQueenMoves(sq)
{
- return this.getSlideNJumpMoves(sq, VariantRules.steps[VariantRules.QUEEN]);
+ return this.getSlideNJumpMoves(sq,
+ V.steps[V.ROOK].concat(V.steps[V.BISHOP]));
}
// What are the king moves from square x,y ?
getPotentialKingMoves(sq)
{
// Initialize with normal moves
- let moves = this.getSlideNJumpMoves(sq, VariantRules.steps[VariantRules.QUEEN], "oneStep");
+ let moves = this.getSlideNJumpMoves(sq,
+ V.steps[V.ROOK].concat(V.steps[V.BISHOP]), "oneStep");
return moves.concat(this.getCastleMoves(sq));
}
getCastleMoves([x,y])
{
const c = this.getColor(x,y);
- if (x != (c=="w" ? 7 : 0) || y != this.INIT_COL_KING[c])
+ if (x != (c=="w" ? V.size.x-1 : 0) || y != this.INIT_COL_KING[c])
return []; //x isn't first rank, or king has moved (shortcut)
- const V = VariantRules;
-
// Castling ?
const oppCol = this.getOppCol(c);
let moves = [];
let i = 0;
- const finalSquares = [ [2,3], [6,5] ]; //king, then rook
+ const finalSquares = [ [2,3], [V.size.y-2,V.size.y-3] ]; //king, then rook
castlingCheck:
for (let castleSide=0; castleSide < 2; castleSide++) //large, then small
{
continue;
// If this code is reached, rooks and king are on initial position
- // Nothing on the path of the king (and no checks; OK also if y==finalSquare)?
+ // Nothing on the path of the king ?
+ // (And no checks; OK also if y==finalSquare)
let step = finalSquares[castleSide][0] < y ? -1 : 1;
for (i=y; i!=finalSquares[castleSide][0]; i+=step)
{
- if (this.isAttacked([x,i], oppCol) || (this.board[x][i] != V.EMPTY &&
+ if (this.isAttacked([x,i], [oppCol]) || (this.board[x][i] != V.EMPTY &&
// NOTE: next check is enough, because of chessboard constraints
- (this.getColor(x,i) != c || ![V.KING,V.ROOK].includes(this.getPiece(x,i)))))
+ (this.getColor(x,i) != c
+ || ![V.KING,V.ROOK].includes(this.getPiece(x,i)))))
{
continue castlingCheck;
}
return moves;
}
- ///////////////////
+ ////////////////////
// MOVES VALIDATION
- canIplay(side, [x,y])
- {
- return ((side=='w' && this.moves.length%2==0) || (side=='b' && this.moves.length%2==1))
- && this.getColor(x,y) == side;
- }
-
+ // For the interface: possible moves for the current turn from square sq
getPossibleMovesFrom(sq)
{
- // Assuming color is right (already checked)
return this.filterValid( this.getPotentialMovesFrom(sq) );
}
- // TODO: once a promotion is filtered, the others results are same: useless computations
+ // TODO: promotions (into R,B,N,Q) should be filtered only once
filterValid(moves)
{
if (moves.length == 0)
return [];
- let color = this.turn;
- return moves.filter(m => { return !this.underCheck(m, color); });
+ const color = this.turn;
+ return moves.filter(m => {
+ this.play(m);
+ const res = !this.underCheck(color);
+ this.undo(m);
+ return res;
+ });
}
- // Search for all valid moves considering current turn (for engine and game end)
+ // Search for all valid moves considering current turn
+ // (for engine and game end)
getAllValidMoves()
{
const color = this.turn;
const oppCol = this.getOppCol(color);
- var potentialMoves = [];
- let [sizeX,sizeY] = VariantRules.size;
- for (var i=0; i<sizeX; i++)
+ let potentialMoves = [];
+ for (let i=0; i<V.size.x; i++)
{
- for (var j=0; j<sizeY; j++)
+ for (let j=0; j<V.size.y; j++)
{
- // Next condition ... != oppCol is a little HACK to work with checkered variant
- if (this.board[i][j] != VariantRules.EMPTY && this.getColor(i,j) != oppCol)
- Array.prototype.push.apply(potentialMoves, this.getPotentialMovesFrom([i,j]));
+ // Next condition "!= oppCol" to work with checkered variant
+ if (this.board[i][j] != V.EMPTY && this.getColor(i,j) != oppCol)
+ {
+ Array.prototype.push.apply(potentialMoves,
+ this.getPotentialMovesFrom([i,j]));
+ }
}
}
- // NOTE: prefer lazy undercheck tests, letting the king being taken?
- // No: if happen on last 1/2 move, could lead to forbidden moves, wrong evals
return this.filterValid(potentialMoves);
}
-
+
// Stop at the first move found
atLeastOneMove()
{
const color = this.turn;
const oppCol = this.getOppCol(color);
- let [sizeX,sizeY] = VariantRules.size;
- for (var i=0; i<sizeX; i++)
+ for (let i=0; i<V.size.x; i++)
{
- for (var j=0; j<sizeY; j++)
+ for (let j=0; j<V.size.y; j++)
{
- if (this.board[i][j] != VariantRules.EMPTY && this.getColor(i,j) != oppCol)
+ if (this.board[i][j] != V.EMPTY && this.getColor(i,j) != oppCol)
{
const moves = this.getPotentialMovesFrom([i,j]);
if (moves.length > 0)
{
- for (let i=0; i<moves.length; i++)
+ for (let k=0; k<moves.length; k++)
{
- if (this.filterValid([moves[i]]).length > 0)
+ if (this.filterValid([moves[k]]).length > 0)
return true;
}
}
return false;
}
- // Check if pieces of color 'colors' are attacking square x,y
+ // Check if pieces of color in 'colors' are attacking (king) on square x,y
isAttacked(sq, colors)
{
return (this.isAttackedByPawn(sq, colors)
|| this.isAttackedByKing(sq, colors));
}
- // Is square x,y attacked by pawns of color c ?
+ // Is square x,y attacked by 'colors' pawns ?
isAttackedByPawn([x,y], colors)
{
for (let c of colors)
{
let pawnShift = (c=="w" ? 1 : -1);
- if (x+pawnShift>=0 && x+pawnShift<8)
+ if (x+pawnShift>=0 && x+pawnShift<V.size.x)
{
for (let i of [-1,1])
{
- if (y+i>=0 && y+i<8 && this.getPiece(x+pawnShift,y+i)==VariantRules.PAWN
+ if (y+i>=0 && y+i<V.size.y && this.getPiece(x+pawnShift,y+i)==V.PAWN
&& this.getColor(x+pawnShift,y+i)==c)
{
return true;
return false;
}
- // Is square x,y attacked by rooks of color c ?
+ // Is square x,y attacked by 'colors' rooks ?
isAttackedByRook(sq, colors)
{
- return this.isAttackedBySlideNJump(sq, colors,
- VariantRules.ROOK, VariantRules.steps[VariantRules.ROOK]);
+ return this.isAttackedBySlideNJump(sq, colors, V.ROOK, V.steps[V.ROOK]);
}
- // Is square x,y attacked by knights of color c ?
+ // Is square x,y attacked by 'colors' knights ?
isAttackedByKnight(sq, colors)
{
return this.isAttackedBySlideNJump(sq, colors,
- VariantRules.KNIGHT, VariantRules.steps[VariantRules.KNIGHT], "oneStep");
+ V.KNIGHT, V.steps[V.KNIGHT], "oneStep");
}
- // Is square x,y attacked by bishops of color c ?
+ // Is square x,y attacked by 'colors' bishops ?
isAttackedByBishop(sq, colors)
{
- return this.isAttackedBySlideNJump(sq, colors,
- VariantRules.BISHOP, VariantRules.steps[VariantRules.BISHOP]);
+ return this.isAttackedBySlideNJump(sq, colors, V.BISHOP, V.steps[V.BISHOP]);
}
- // Is square x,y attacked by queens of color c ?
+ // Is square x,y attacked by 'colors' queens ?
isAttackedByQueen(sq, colors)
{
- return this.isAttackedBySlideNJump(sq, colors,
- VariantRules.QUEEN, VariantRules.steps[VariantRules.QUEEN]);
+ return this.isAttackedBySlideNJump(sq, colors, V.QUEEN,
+ V.steps[V.ROOK].concat(V.steps[V.BISHOP]));
}
- // Is square x,y attacked by king of color c ?
+ // Is square x,y attacked by 'colors' king(s) ?
isAttackedByKing(sq, colors)
{
- return this.isAttackedBySlideNJump(sq, colors,
- VariantRules.KING, VariantRules.steps[VariantRules.QUEEN], "oneStep");
+ return this.isAttackedBySlideNJump(sq, colors, V.KING,
+ V.steps[V.ROOK].concat(V.steps[V.BISHOP]), "oneStep");
}
- // Generic method for non-pawn pieces ("sliding or jumping"): is x,y attacked by piece != color ?
+ // Generic method for non-pawn pieces ("sliding or jumping"):
+ // is x,y attacked by a piece of color in array 'colors' ?
isAttackedBySlideNJump([x,y], colors, piece, steps, oneStep)
{
for (let step of steps)
{
let rx = x+step[0], ry = y+step[1];
- while (rx>=0 && rx<8 && ry>=0 && ry<8 && this.board[rx][ry] == VariantRules.EMPTY
- && !oneStep)
+ while (V.OnBoard(rx,ry) && this.board[rx][ry] == V.EMPTY && !oneStep)
{
rx += step[0];
ry += step[1];
}
- if (rx>=0 && rx<8 && ry>=0 && ry<8 && this.board[rx][ry] != VariantRules.EMPTY
- && this.getPiece(rx,ry) == piece && colors.includes(this.getColor(rx,ry)))
+ if (V.OnBoard(rx,ry) && this.getPiece(rx,ry) === piece
+ && colors.includes(this.getColor(rx,ry)))
{
return true;
}
return false;
}
- // Is color c under check after move ?
- underCheck(move)
+ // Is color under check after his move ?
+ underCheck(color)
{
- const color = this.turn;
- this.play(move);
- let res = this.isAttacked(this.kingPos[color], this.getOppCol(color));
- this.undo(move);
- return res;
+ return this.isAttacked(this.kingPos[color], [this.getOppCol(color)]);
}
- // On which squares is color c under check (after move) ?
- getCheckSquares(move)
- {
- this.play(move);
- const color = this.turn; //opponent
- let res = this.isAttacked(this.kingPos[color], this.getOppCol(color))
- ? [ JSON.parse(JSON.stringify(this.kingPos[color])) ] //need to duplicate!
- : [ ];
- this.undo(move);
- return res;
- }
+ /////////////////
+ // MOVES PLAYING
// Apply a move on board
static PlayOnBoard(board, move)
{
for (let psq of move.vanish)
- board[psq.x][psq.y] = VariantRules.EMPTY;
+ board[psq.x][psq.y] = V.EMPTY;
for (let psq of move.appear)
board[psq.x][psq.y] = psq.c + psq.p;
}
static UndoOnBoard(board, move)
{
for (let psq of move.appear)
- board[psq.x][psq.y] = VariantRules.EMPTY;
+ board[psq.x][psq.y] = V.EMPTY;
for (let psq of move.vanish)
board[psq.x][psq.y] = psq.c + psq.p;
}
- // Before move is played, update variables + flags
+ // After move is played, update variables + flags
updateVariables(move)
{
- const piece = this.getPiece(move.start.x,move.start.y);
- const c = this.getColor(move.start.x,move.start.y);
- const firstRank = (c == "w" ? 7 : 0);
+ let piece = undefined;
+ let c = undefined;
+ if (move.vanish.length >= 1)
+ {
+ // Usual case, something is moved
+ piece = move.vanish[0].p;
+ c = move.vanish[0].c;
+ }
+ else
+ {
+ // Crazyhouse-like variants
+ piece = move.appear[0].p;
+ c = move.appear[0].c;
+ }
+ if (c == "c") //if (!["w","b"].includes(c))
+ {
+ // 'c = move.vanish[0].c' doesn't work for Checkered
+ c = this.getOppCol(this.turn);
+ }
+ const firstRank = (c == "w" ? V.size.x-1 : 0);
// Update king position + flags
- if (piece == VariantRules.KING && move.appear.length > 0)
+ if (piece == V.KING && move.appear.length > 0)
{
this.kingPos[c][0] = move.appear[0].x;
this.kingPos[c][1] = move.appear[0].y;
- this.castleFlags[c] = [false,false];
+ if (V.HasFlags)
+ this.castleFlags[c] = [false,false];
return;
}
- const oppCol = this.getOppCol(c);
- const oppFirstRank = 7 - firstRank;
- if (move.start.x == firstRank //our rook moves?
- && this.INIT_COL_ROOK[c].includes(move.start.y))
+ if (V.HasFlags)
{
- const flagIdx = (move.start.y == this.INIT_COL_ROOK[c][0] ? 0 : 1);
- this.castleFlags[c][flagIdx] = false;
- }
- else if (move.end.x == oppFirstRank //we took opponent rook?
- && this.INIT_COL_ROOK[c].includes(move.end.y))
- {
- const flagIdx = (move.end.y == this.INIT_COL_ROOK[oppCol][0] ? 0 : 1);
- this.castleFlags[oppCol][flagIdx] = false;
+ // Update castling flags if rooks are moved
+ const oppCol = this.getOppCol(c);
+ const oppFirstRank = (V.size.x-1) - firstRank;
+ if (move.start.x == firstRank //our rook moves?
+ && this.INIT_COL_ROOK[c].includes(move.start.y))
+ {
+ const flagIdx = (move.start.y == this.INIT_COL_ROOK[c][0] ? 0 : 1);
+ this.castleFlags[c][flagIdx] = false;
+ }
+ else if (move.end.x == oppFirstRank //we took opponent rook?
+ && this.INIT_COL_ROOK[oppCol].includes(move.end.y))
+ {
+ const flagIdx = (move.end.y == this.INIT_COL_ROOK[oppCol][0] ? 0 : 1);
+ this.castleFlags[oppCol][flagIdx] = false;
+ }
}
}
+ // After move is undo-ed *and flags resetted*, un-update other variables
+ // TODO: more symmetry, by storing flags increment in move (?!)
unupdateVariables(move)
{
// (Potentially) Reset king position
const c = this.getColor(move.start.x,move.start.y);
- if (this.getPiece(move.start.x,move.start.y) == VariantRules.KING)
+ if (this.getPiece(move.start.x,move.start.y) == V.KING)
this.kingPos[c] = [move.start.x, move.start.y];
}
play(move, ingame)
{
- console.log("AVANT " + this.getNotation(move) + " " + this.board[1][5]);
+ // DEBUG:
+// if (!this.states) this.states = [];
+// if (!ingame) this.states.push(this.getFen());
+
if (!!ingame)
move.notation = this.getNotation(move);
- move.flags = JSON.stringify(this.flags); //save flags (for undo)
+ if (V.HasFlags)
+ move.flags = JSON.stringify(this.aggregateFlags()); //save flags (for undo)
+ if (V.HasEnpassant)
+ this.epSquares.push( this.getEpSquare(move) );
+ V.PlayOnBoard(this.board, move);
+ this.turn = this.getOppCol(this.turn);
+ this.movesCount++;
this.updateVariables(move);
- this.moves.push(move);
- this.epSquares.push( this.getEpSquare(move) );
- VariantRules.PlayOnBoard(this.board, move);
+
+ if (!!ingame)
+ {
+ // Hash of current game state *after move*, to detect repetitions
+ move.hash = hex_md5(this.getFen());
+ }
}
undo(move)
{
- VariantRules.UndoOnBoard(this.board, move);
- this.epSquares.pop();
- this.moves.pop();
+ if (V.HasEnpassant)
+ this.epSquares.pop();
+ if (V.HasFlags)
+ this.disaggregateFlags(JSON.parse(move.flags));
+ V.UndoOnBoard(this.board, move);
+ this.turn = this.getOppCol(this.turn);
+ this.movesCount--;
this.unupdateVariables(move);
- this.parseFlags(JSON.parse(move.flags));
- console.log("APRES " + this.getNotation(move) + " " + this.board[1][5]);
+
+ // DEBUG:
+// if (this.getFen() != this.states[this.states.length-1])
+// debugger;
+// this.states.pop();
}
- //////////////
+ ///////////////
// END OF GAME
- checkRepetition()
- {
- // Check for 3 repetitions
- if (this.moves.length >= 8)
- {
- // NOTE: crude detection, only moves repetition
- const L = this.moves.length;
- if (_.isEqual(this.moves[L-1], this.moves[L-5]) &&
- _.isEqual(this.moves[L-2], this.moves[L-6]) &&
- _.isEqual(this.moves[L-3], this.moves[L-7]) &&
- _.isEqual(this.moves[L-4], this.moves[L-8]))
- {
- return true;
- }
- }
- return false;
- }
-
+ // Is game over ? And if yes, what is the score ?
checkGameOver()
{
- if (this.checkRepetition())
- return "1/2";
-
if (this.atLeastOneMove()) // game not over
return "*";
{
const color = this.turn;
// No valid move: stalemate or checkmate?
- if (!this.isAttacked(this.kingPos[color], this.getOppCol(color)))
+ if (!this.isAttacked(this.kingPos[color], [this.getOppCol(color)]))
return "1/2";
// OK, checkmate
- return color == "w" ? "0-1" : "1-0";
+ return (color == "w" ? "0-1" : "1-0");
}
- ////////
- //ENGINE
+ ///////////////
+ // ENGINE PLAY
// Pieces values
- static get VALUES() {
+ static get VALUES()
+ {
return {
'p': 1,
'r': 5,
};
}
+ // "Checkmate" (unreachable eval)
+ static get INFINITY() { return 9999; }
+
+ // At this value or above, the game is over
+ static get THRESHOLD_MATE() { return V.INFINITY; }
+
+ // Search depth: 2 for high branching factor, 4 for small (Loser chess, eg.)
+ static get SEARCH_DEPTH() { return 3; }
+
// Assumption: at least one legal move
+ // NOTE: works also for extinction chess because depth is 3...
getComputerMove()
{
+ const maxeval = V.INFINITY;
const color = this.turn;
+ // Some variants may show a bigger moves list to the human (Switching),
+ // thus the argument "computer" below (which is generally ignored)
+ let moves1 = this.getAllValidMoves("computer");
- // Rank moves using a min-max at depth 2
- let moves1 = this.getAllValidMoves();
-
- for (let i=0; i<moves1.length; i++)
+ // Can I mate in 1 ? (for Magnetic & Extinction)
+ for (let i of _.shuffle(_.range(moves1.length)))
{
- moves1[i].eval = (color=="w" ? -1 : 1) * 1000; //very low, I'm checkmated
- let eval2 = (color=="w" ? 1 : -1) * 1000; //initialized with very high (checkmate) value
this.play(moves1[i]);
- // Second half-move:
- let moves2 = this.getAllValidMoves();
- // If no possible moves AND underCheck, eval2 is correct.
- // If !underCheck, eval2 is 0 (stalemate).
- if (moves2.length == 0 && this.checkGameEnd() == "1/2")
- eval2 = 0;
- for (let j=0; j<moves2.length; j++)
+ let finish = (Math.abs(this.evalPosition()) >= V.THRESHOLD_MATE);
+ if (!finish && !this.atLeastOneMove())
{
- this.play(moves2[j]);
- let evalPos = this.evalPosition();
- if ((color == "w" && evalPos < eval2) || (color=="b" && evalPos > eval2))
- eval2 = evalPos;
- this.undo(moves2[j]);
+ // Test mate (for other variants)
+ const score = this.checkGameEnd();
+ if (score != "1/2")
+ finish = true;
}
- if ((color=="w" && eval2 > moves1[i].eval) || (color=="b" && eval2 < moves1[i].eval))
- moves1[i].eval = eval2;
this.undo(moves1[i]);
+ if (finish)
+ return moves1[i];
}
- moves1.sort( (a,b) => { return (color=="w" ? 1 : -1) * (b.eval - a.eval); });
- // TODO: show current analyzed move for depth 3, allow stopping eval (return moves1[0])
+ // Rank moves using a min-max at depth 2
for (let i=0; i<moves1.length; i++)
{
+ // Initial self evaluation is very low: "I'm checkmated"
+ moves1[i].eval = (color=="w" ? -1 : 1) * maxeval;
this.play(moves1[i]);
- // 0.1 * oldEval : heuristic to avoid some bad moves (not all...)
- moves1[i].eval = 0.1*moves1[i].eval + this.alphabeta(2, -1000, 1000);
+ let eval2 = undefined;
+ if (this.atLeastOneMove())
+ {
+ // Initial enemy evaluation is very low too, for him
+ eval2 = (color=="w" ? 1 : -1) * maxeval;
+ // Second half-move:
+ let moves2 = this.getAllValidMoves("computer");
+ for (let j=0; j<moves2.length; j++)
+ {
+ this.play(moves2[j]);
+ let evalPos = undefined;
+ if (this.atLeastOneMove())
+ evalPos = this.evalPosition()
+ else
+ {
+ // Working with scores is more accurate (necessary for Loser variant)
+ const score = this.checkGameEnd();
+ evalPos = (score=="1/2" ? 0 : (score=="1-0" ? 1 : -1) * maxeval);
+ }
+ if ((color == "w" && evalPos < eval2)
+ || (color=="b" && evalPos > eval2))
+ {
+ eval2 = evalPos;
+ }
+ this.undo(moves2[j]);
+ }
+ }
+ else
+ {
+ const score = this.checkGameEnd();
+ eval2 = (score=="1/2" ? 0 : (score=="1-0" ? 1 : -1) * maxeval);
+ }
+ if ((color=="w" && eval2 > moves1[i].eval)
+ || (color=="b" && eval2 < moves1[i].eval))
+ {
+ moves1[i].eval = eval2;
+ }
this.undo(moves1[i]);
}
moves1.sort( (a,b) => { return (color=="w" ? 1 : -1) * (b.eval - a.eval); });
let candidates = [0]; //indices of candidates moves
for (let j=1; j<moves1.length && moves1[j].eval == moves1[0].eval; j++)
candidates.push(j);
+ let currentBest = moves1[_.sample(candidates, 1)];
- //console.log(moves1.map(m => { return [this.getNotation(m), m.eval]; }));
+ // From here, depth >= 3: may take a while, so we control time
+ const timeStart = Date.now();
+
+ // Skip depth 3+ if we found a checkmate (or if we are checkmated in 1...)
+ if (V.SEARCH_DEPTH >= 3 && Math.abs(moves1[0].eval) < V.THRESHOLD_MATE)
+ {
+ for (let i=0; i<moves1.length; i++)
+ {
+ if (Date.now()-timeStart >= 5000) //more than 5 seconds
+ return currentBest; //depth 2 at least
+ this.play(moves1[i]);
+ // 0.1 * oldEval : heuristic to avoid some bad moves (not all...)
+ moves1[i].eval = 0.1*moves1[i].eval +
+ this.alphabeta(V.SEARCH_DEPTH-1, -maxeval, maxeval);
+ this.undo(moves1[i]);
+ }
+ moves1.sort( (a,b) => {
+ return (color=="w" ? 1 : -1) * (b.eval - a.eval); });
+ }
+ else
+ return currentBest;
+// console.log(moves1.map(m => { return [this.getNotation(m), m.eval]; }));
+
+ candidates = [0];
+ for (let j=1; j<moves1.length && moves1[j].eval == moves1[0].eval; j++)
+ candidates.push(j);
return moves1[_.sample(candidates, 1)];
}
alphabeta(depth, alpha, beta)
{
+ const maxeval = V.INFINITY;
const color = this.turn;
if (!this.atLeastOneMove())
{
switch (this.checkGameEnd())
{
- case "1/2": return 0;
- default: return color=="w" ? -1000 : 1000;
+ case "1/2":
+ return 0;
+ default:
+ const score = this.checkGameEnd();
+ return (score=="1/2" ? 0 : (score=="1-0" ? 1 : -1) * maxeval);
}
}
if (depth == 0)
return this.evalPosition();
- const moves = this.getAllValidMoves();
- let v = color=="w" ? -1000 : 1000;
+ const moves = this.getAllValidMoves("computer");
+ let v = color=="w" ? -maxeval : maxeval;
if (color == "w")
{
for (let i=0; i<moves.length; i++)
evalPosition()
{
- const [sizeX,sizeY] = VariantRules.size;
let evaluation = 0;
- //Just count material for now
- for (let i=0; i<sizeX; i++)
+ // Just count material for now
+ for (let i=0; i<V.size.x; i++)
{
- for (let j=0; j<sizeY; j++)
+ for (let j=0; j<V.size.y; j++)
{
- if (this.board[i][j] != VariantRules.EMPTY)
+ if (this.board[i][j] != V.EMPTY)
{
const sign = this.getColor(i,j) == "w" ? 1 : -1;
- evaluation += sign * VariantRules.VALUES[this.getPiece(i,j)];
+ evaluation += sign * V.VALUES[this.getPiece(i,j)];
}
}
}
return evaluation;
}
- ////////////
- // FEN utils
-
- // Overridable..
- static GenRandInitFen()
- {
- let pieces = [new Array(8), new Array(8)];
- // Shuffle pieces on first and last rank
- for (let c = 0; c <= 1; c++)
- {
- let positions = _.range(8);
-
- // Get random squares for bishops
- let randIndex = 2 * _.random(3);
- let bishop1Pos = positions[randIndex];
- // The second bishop must be on a square of different color
- let randIndex_tmp = 2 * _.random(3) + 1;
- let bishop2Pos = positions[randIndex_tmp];
- // Remove chosen squares
- positions.splice(Math.max(randIndex,randIndex_tmp), 1);
- positions.splice(Math.min(randIndex,randIndex_tmp), 1);
-
- // Get random squares for knights
- randIndex = _.random(5);
- let knight1Pos = positions[randIndex];
- positions.splice(randIndex, 1);
- randIndex = _.random(4);
- let knight2Pos = positions[randIndex];
- positions.splice(randIndex, 1);
-
- // Get random square for queen
- randIndex = _.random(3);
- let queenPos = positions[randIndex];
- positions.splice(randIndex, 1);
-
- // Rooks and king positions are now fixed, because of the ordering rook-king-rook
- let rook1Pos = positions[0];
- let kingPos = positions[1];
- let rook2Pos = positions[2];
-
- // Finally put the shuffled pieces in the board array
- pieces[c][rook1Pos] = 'r';
- pieces[c][knight1Pos] = 'n';
- pieces[c][bishop1Pos] = 'b';
- pieces[c][queenPos] = 'q';
- pieces[c][kingPos] = 'k';
- pieces[c][bishop2Pos] = 'b';
- pieces[c][knight2Pos] = 'n';
- pieces[c][rook2Pos] = 'r';
- }
- let fen = pieces[0].join("") +
- "/pppppppp/8/8/8/8/PPPPPPPP/" +
- pieces[1].join("").toUpperCase() +
- " 1111"; //add flags
- return fen;
- }
-
- // Return current fen according to pieces+colors state
- getFen()
- {
- return this.getBaseFen() + " " + this.getFlagsFen();
- }
-
- getBaseFen()
- {
- let fen = "";
- let [sizeX,sizeY] = VariantRules.size;
- for (let i=0; i<sizeX; i++)
- {
- let emptyCount = 0;
- for (let j=0; j<sizeY; j++)
- {
- if (this.board[i][j] == VariantRules.EMPTY)
- emptyCount++;
- else
- {
- if (emptyCount > 0)
- {
- // Add empty squares in-between
- fen += emptyCount;
- emptyCount = 0;
- }
- fen += VariantRules.board2fen(this.board[i][j]);
- }
- }
- if (emptyCount > 0)
- {
- // "Flush remainder"
- fen += emptyCount;
- }
- if (i < sizeX - 1)
- fen += "/"; //separate rows
- }
- return fen;
- }
-
- // Overridable..
- getFlagsFen()
- {
- let fen = "";
- // Add castling flags
- for (let i of ['w','b'])
- {
- for (let j=0; j<2; j++)
- fen += this.castleFlags[i][j] ? '1' : '0';
- }
- return fen;
- }
+ /////////////////////////
+ // MOVES + GAME NOTATION
+ /////////////////////////
// Context: just before move is played, turn hasn't changed
+ // TODO: un-ambiguous notation (switch on piece type, check directions...)
getNotation(move)
{
- if (move.appear.length == 2)
- {
- // Castle
- if (move.end.y < move.start.y)
- return "0-0-0";
- else
- return "0-0";
- }
+ if (move.appear.length == 2 && move.appear[0].p == V.KING) //castle
+ return (move.end.y < move.start.y ? "0-0-0" : "0-0");
// Translate final square
- let finalSquare =
- String.fromCharCode(97 + move.end.y) + (VariantRules.size[0]-move.end.x);
+ const finalSquare = V.CoordsToSquare(move.end);
- let piece = this.getPiece(move.start.x, move.start.y);
- if (piece == VariantRules.PAWN)
+ const piece = this.getPiece(move.start.x, move.start.y);
+ if (piece == V.PAWN)
{
// Pawn move
let notation = "";
- if (move.vanish.length > 1)
+ if (move.vanish.length > move.appear.length)
{
// Capture
- let startColumn = String.fromCharCode(97 + move.start.y);
+ const startColumn = V.CoordToColumn(move.start.y);
notation = startColumn + "x" + finalSquare;
}
else //no capture
notation = finalSquare;
- if (move.appear.length > 0 && piece != move.appear[0].p) //promotion
+ if (move.appear.length > 0 && move.appear[0].p != V.PAWN) //promotion
notation += "=" + move.appear[0].p.toUpperCase();
return notation;
}
else
{
// Piece movement
- return piece.toUpperCase() + (move.vanish.length > 1 ? "x" : "") + finalSquare;
+ return piece.toUpperCase() +
+ (move.vanish.length > move.appear.length ? "x" : "") + finalSquare;
}
}
+ // Complete the usual notation, may be required for de-ambiguification
+ getLongNotation(move)
+ {
+ // Not encoding move. But short+long is enough
+ return V.CoordsToSquare(move.start) + V.CoordsToSquare(move.end);
+ }
+
// The score is already computed when calling this function
- getPGN(mycolor, score, fenStart, mode)
+ getPGN(moves, mycolor, score, fenStart, mode)
{
let pgn = "";
- pgn += '[Site "vchess.club"]<br>';
- const d = new Date();
+ pgn += '[Site "vchess.club"]\n';
const opponent = mode=="human" ? "Anonymous" : "Computer";
- pgn += '[Date "' + d.getFullYear() + '-' + (d.getMonth()+1) + '-' + d.getDate() + '"]<br>';
- pgn += '[White "' + (mycolor=='w'?'Myself':opponent) + '"]<br>';
- pgn += '[Black "' + (mycolor=='b'?'Myself':opponent) + '"]<br>';
- pgn += '[Fen "' + fenStart + '"]<br>';
- pgn += '[Result "' + score + '"]<br><br>';
-
- for (let i=0; i<this.moves.length; i++)
+ pgn += '[Variant "' + variant + '"]\n';
+ pgn += '[Date "' + getDate(new Date()) + '"]\n';
+ // TODO: later when users are a bit less anonymous, use better names
+ const whiteName = ["human","computer"].includes(mode)
+ ? (mycolor=='w'?'Myself':opponent)
+ : "analyze";
+ const blackName = ["human","computer"].includes(mode)
+ ? (mycolor=='b'?'Myself':opponent)
+ : "analyze";
+ pgn += '[White "' + whiteName + '"]\n';
+ pgn += '[Black "' + blackName + '"]\n';
+ pgn += '[Fen "' + fenStart + '"]\n';
+ pgn += '[Result "' + score + '"]\n\n';
+
+ // Print moves
+ for (let i=0; i<moves.length; i++)
{
if (i % 2 == 0)
pgn += ((i/2)+1) + ".";
- pgn += this.moves[i].notation + " ";
+ pgn += moves[i].notation + " ";
}
- pgn += score;
- return pgn;
+ return pgn + "\n";
}
}
projects / vchess.git / blobdiff