return true;
}
- // Some variants don't have en-passant
+ // Or castle
+ static get HasCastle() {
+ return V.HasFlags;
+ }
+
+ // Pawns specifications
+ static get PawnSpecs() {
+ return {
+ directions: { 'w': -1, 'b': 1 },
+ twoSquares: true,
+ promotions: [V.ROOK, V.KNIGHT, V.BISHOP, V.QUEEN],
+ canCapture: true,
+ captureBackward: false,
+ bidirectional: false
+ };
+ }
+
+ // En-passant captures need a stack of squares:
static get HasEnpassant() {
return true;
}
static get CanAnalyze() {
return true;
}
+ // Patch: issues with javascript OOP, objects can't access static fields.
+ get canAnalyze() {
+ return V.CanAnalyze;
+ }
// Some variants show incomplete information,
// and thus show only a partial moves list or no list at all.
static get ShowMoves() {
return "all";
}
+ get showMoves() {
+ return V.ShowMoves;
+ }
+
+ // Some variants always show the same orientation
+ static get CanFlip() {
+ return true;
+ }
+ get canFlip() {
+ return V.CanFlip;
+ }
- // Path to pieces
- static getPpath(b) {
- return b; //usual pieces in pieces/ folder
+ // Some variants require turn indicator
+ // (generally when analysis or flip is diabled)
+ static get ShowTurn() {
+ return !V.CanAnalyze || V.ShowMoves != "all" || !V.CanFlip;
+ }
+ get showTurn() {
+ return V.ShowTurn;
+ }
+
+ static get IMAGE_EXTENSION() {
+ // All pieces should be in the SVG format
+ return ".svg";
}
// Turn "wb" into "B" (for FEN)
return f.charCodeAt() <= 90 ? "w" + f.toLowerCase() : "b" + f;
}
- // Check if FEN describe a board situation correctly
+ // Check if FEN describes a board situation correctly
static IsGoodFen(fen) {
const fenParsed = V.ParseFen(fen);
// 1) Check position
if (position.length == 0) return false;
const rows = position.split("/");
if (rows.length != V.size.x) return false;
- let kings = {};
+ let kings = { "k": 0, "K": 0 };
for (let row of rows) {
let sumElts = 0;
for (let i = 0; i < row.length; i++) {
- if (['K','k'].includes(row[i]))
- kings[row[i]] = true;
+ if (['K','k'].includes(row[i])) kings[row[i]]++;
if (V.PIECES.includes(row[i].toLowerCase())) sumElts++;
else {
const num = parseInt(row[i]);
}
if (sumElts != V.size.y) return false;
}
- // Both kings should be on board:
- if (Object.keys(kings).length != 2)
- return false;
+ // Both kings should be on board. Exactly one per color.
+ if (Object.values(kings).some(v => v != 1)) return false;
return true;
}
// For FEN checking
static IsGoodFlags(flags) {
- return !!flags.match(/^[01]{4,4}$/);
+ // NOTE: a little too permissive to work with more variants
+ return !!flags.match(/^[a-z]{4,4}$/);
}
static IsGoodEnpassant(enpassant) {
return V.CoordToColumn(coords.y) + (V.size.x - coords.x);
}
+ // Path to pieces (standard ones in pieces/ folder)
+ getPpath(b) {
+ return b;
+ }
+
+ // Path to promotion pieces (usually the same)
+ getPPpath(b) {
+ return this.getPpath(b);
+ }
+
// Aggregates flags into one object
aggregateFlags() {
return this.castleFlags;
}
// Argument is a move:
const move = moveOrSquare;
- const [sx, sy, ex] = [move.start.x, move.start.y, move.end.x];
- // NOTE: next conditions are first for Atomic, and last for Checkered
+ const s = move.start,
+ e = move.end;
if (
- move.appear.length > 0 &&
- Math.abs(sx - ex) == 2 &&
- move.appear[0].p == V.PAWN &&
- ["w", "b"].includes(move.appear[0].c)
+ Math.abs(s.x - e.x) == 2 &&
+ s.y == e.y &&
+ move.appear[0].p == V.PAWN
) {
return {
- x: (sx + ex) / 2,
- y: sy
+ x: (s.x + e.x) / 2,
+ y: s.y
};
}
return undefined; //default
// On which squares is color under check ? (for interface)
getCheckSquares(color) {
- return this.isAttacked(this.kingPos[color], [V.GetOppCol(color)])
- ? [JSON.parse(JSON.stringify(this.kingPos[color]))] //need to duplicate!
- : [];
+ return (
+ this.underCheck(color)
+ ? [JSON.parse(JSON.stringify(this.kingPos[color]))] //need to duplicate!
+ : []
+ );
}
/////////////
// FEN UTILS
- // Setup the initial random (assymetric) position
- static GenRandInitFen() {
+ // Setup the initial random (asymmetric) position
+ static GenRandInitFen(randomness) {
+ if (randomness == 0)
+ // Deterministic:
+ return "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w 0 ahah -";
+
let pieces = { w: new Array(8), b: new Array(8) };
- // Shuffle pieces on first and last rank
+ let flags = "";
+ // Shuffle pieces on first (and last rank if randomness == 2)
for (let c of ["w", "b"]) {
+ if (c == 'b' && randomness == 1) {
+ pieces['b'] = pieces['w'];
+ flags += flags;
+ break;
+ }
+
let positions = ArrayFun.range(8);
// Get random squares for bishops
pieces[c][bishop2Pos] = "b";
pieces[c][knight2Pos] = "n";
pieces[c][rook2Pos] = "r";
+ flags += V.CoordToColumn(rook1Pos) + V.CoordToColumn(rook2Pos);
}
+ // Add turn + flags + enpassant
return (
pieces["b"].join("") +
"/pppppppp/8/8/8/8/PPPPPPPP/" +
pieces["w"].join("").toUpperCase() +
- " w 0 1111 -"
- ); //add turn + flags + enpassant
+ " w 0 " + flags + " -"
+ );
}
// "Parse" FEN: just return untransformed string data
// Return current fen (game state)
getFen() {
return (
- this.getBaseFen() +
- " " +
- this.getTurnFen() +
- " " +
+ this.getBaseFen() + " " +
+ this.getTurnFen() + " " +
this.movesCount +
(V.HasFlags ? " " + this.getFlagsFen() : "") +
(V.HasEnpassant ? " " + this.getEnpassantFen() : "")
);
}
+ getFenForRepeat() {
+ // Omit movesCount, only variable allowed to differ
+ return (
+ this.getBaseFen() + "_" +
+ this.getTurnFen() +
+ (V.HasFlags ? "_" + this.getFlagsFen() : "") +
+ (V.HasEnpassant ? "_" + this.getEnpassantFen() : "")
+ );
+ }
+
// Position part of the FEN string
getBaseFen() {
+ const format = (count) => {
+ // if more than 9 consecutive free spaces, break the integer,
+ // otherwise FEN parsing will fail.
+ if (count <= 9) return count;
+ // Currently only boards of size up to 11 or 12:
+ return "9" + (count - 9);
+ };
let position = "";
for (let i = 0; i < V.size.x; i++) {
let emptyCount = 0;
else {
if (emptyCount > 0) {
// Add empty squares in-between
- position += emptyCount;
+ position += format(emptyCount);
emptyCount = 0;
}
position += V.board2fen(this.board[i][j]);
}
if (emptyCount > 0) {
// "Flush remainder"
- position += emptyCount;
+ position += format(emptyCount);
}
if (i < V.size.x - 1) position += "/"; //separate rows
}
// 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";
- }
+ // Castling flags
+ for (let c of ["w", "b"])
+ flags += this.castleFlags[c].map(V.CoordToColumn).join("");
return flags;
}
for (let indexInRow = 0; indexInRow < rows[i].length; indexInRow++) {
const character = rows[i][indexInRow];
const num = parseInt(character);
+ // If num is a number, just shift j:
if (!isNaN(num)) j += num;
- //just shift j
- //something at position i,j
+ // Else: something at position i,j
else board[i][j++] = V.fen2board(character);
}
}
// 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";
+ this.castleFlags = { w: [-1, -1], b: [-1, -1] };
+ for (let i = 0; i < 4; i++) {
+ this.castleFlags[i < 2 ? "w" : "b"][i % 2] =
+ V.ColumnToCoord(fenflags.charAt(i));
+ }
}
//////////////////
// INITIALIZATION
- constructor(fen) {
- this.re_init(fen);
- }
-
// Fen string fully describes the game state
- re_init(fen) {
+ constructor(fen) {
+ if (!fen)
+ // In printDiagram() fen isn't supply because only getPpath() is used
+ // TODO: find a better solution!
+ return;
const fenParsed = V.ParseFen(fen);
this.board = V.GetBoard(fenParsed.position);
this.turn = fenParsed.turn[0]; //[0] to work with MarseilleRules
this.setOtherVariables(fen);
}
- // Scan board for kings and rooks positions
- scanKingsRooks(fen) {
+ // Scan board for kings positions
+ scanKings(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] }; //squares of white and black king
const fenRows = V.ParseFen(fen).position.split("/");
+ const startRow = { 'w': V.size.x - 1, 'b': 0 };
for (let i = 0; i < fenRows.length; i++) {
let k = 0; //column index on board
for (let j = 0; j < fenRows[i].length; j++) {
this.kingPos["w"] = [i, k];
this.INIT_COL_KING["w"] = k;
break;
- case "r":
- if (this.INIT_COL_ROOK["b"][0] < 0) this.INIT_COL_ROOK["b"][0] = k;
- else this.INIT_COL_ROOK["b"][1] = k;
- break;
- case "R":
- if (this.INIT_COL_ROOK["w"][0] < 0) this.INIT_COL_ROOK["w"][0] = k;
- else this.INIT_COL_ROOK["w"][1] = k;
- break;
default: {
const num = parseInt(fenRows[i].charAt(j));
if (!isNaN(num)) k += num - 1;
: undefined;
this.epSquares = [epSq];
}
- // Search for king and rooks positions:
- this.scanKingsRooks(fen);
+ // Search for kings positions:
+ this.scanKings(fen);
}
/////////////////////
return { x: 8, y: 8 };
}
- // Color of thing on suqare (i,j). 'undefined' if square is empty
+ // Color of thing on square (i,j). 'undefined' if square is empty
getColor(i, j) {
return this.board[i][j].charAt(0);
}
////////////////////
// MOVES GENERATION
- // All possible moves from selected square (assumption: color is OK)
+ // All possible moves from selected square
getPotentialMovesFrom([x, y]) {
switch (this.getPiece(x, y)) {
case V.PAWN:
// Build a regular move from its initial and destination squares.
// tr: transformation
getBasicMove([sx, sy], [ex, ey], tr) {
+ const initColor = this.getColor(sx, sy);
+ const initPiece = this.getPiece(sx, sy);
let mv = new Move({
appear: [
new PiPo({
x: ex,
y: ey,
- c: tr ? tr.c : this.getColor(sx, sy),
- p: tr ? tr.p : this.getPiece(sx, sy)
+ c: tr ? tr.c : initColor,
+ p: tr ? tr.p : initPiece
})
],
vanish: [
new PiPo({
x: sx,
y: sy,
- c: this.getColor(sx, sy),
- p: this.getPiece(sx, sy)
+ c: initColor,
+ p: initPiece
})
]
});
})
);
}
+
return mv;
}
let j = y + step[1];
while (V.OnBoard(i, j) && this.board[i][j] == V.EMPTY) {
moves.push(this.getBasicMove([x, y], [i, j]));
- if (oneStep !== undefined) continue outerLoop;
+ if (oneStep) continue outerLoop;
i += step[0];
j += step[1];
}
return moves;
}
+ // Special case of en-passant captures: treated separately
+ getEnpassantCaptures([x, y], shiftX) {
+ const Lep = this.epSquares.length;
+ const epSquare = this.epSquares[Lep - 1]; //always at least one element
+ let enpassantMove = null;
+ if (
+ !!epSquare &&
+ epSquare.x == x + shiftX &&
+ Math.abs(epSquare.y - y) == 1
+ ) {
+ enpassantMove = this.getBasicMove([x, y], [epSquare.x, epSquare.y]);
+ enpassantMove.vanish.push({
+ x: x,
+ y: epSquare.y,
+ // Captured piece is usually a pawn, but next line seems harmless
+ p: this.getPiece(x, epSquare.y),
+ c: this.getColor(x, epSquare.y)
+ });
+ }
+ return !!enpassantMove ? [enpassantMove] : [];
+ }
+
+ // Consider all potential promotions:
+ addPawnMoves([x1, y1], [x2, y2], moves, promotions) {
+ let finalPieces = [V.PAWN];
+ const color = this.turn;
+ const lastRank = (color == "w" ? 0 : V.size.x - 1);
+ if (x2 == lastRank) {
+ // promotions arg: special override for Hiddenqueen variant
+ if (!!promotions) finalPieces = promotions;
+ else if (!!V.PawnSpecs.promotions)
+ finalPieces = V.PawnSpecs.promotions;
+ }
+ let tr = null;
+ for (let piece of finalPieces) {
+ tr = (piece != V.PAWN ? { c: color, p: piece } : null);
+ moves.push(this.getBasicMove([x1, y1], [x2, y2], tr));
+ }
+ }
+
// What are the pawn moves from square x,y ?
- getPotentialPawnMoves([x, y]) {
+ getPotentialPawnMoves([x, y], promotions) {
const color = this.turn;
- let moves = [];
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) {
- 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) {
- 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 * shiftX, y]));
+ const pawnShiftX = V.PawnSpecs.directions[color];
+ const firstRank = (color == "w" ? sizeX - 1 : 0);
+ const startRank = (color == "w" ? sizeX - 2 : 1);
+
+ // Pawn movements in shiftX direction:
+ const getPawnMoves = (shiftX) => {
+ let moves = [];
+ // NOTE: next condition is generally true (no pawn on last rank)
+ if (x + shiftX >= 0 && x + shiftX < sizeX) {
+ if (this.board[x + shiftX][y] == V.EMPTY) {
+ // One square forward
+ this.addPawnMoves([x, y], [x + shiftX, y], moves, promotions);
+ // Next condition because pawns on 1st rank can generally jump
+ if (
+ V.PawnSpecs.twoSquares &&
+ [startRank, firstRank].includes(x) &&
+ this.board[x + 2 * shiftX][y] == V.EMPTY
+ ) {
+ // Two squares jump
+ moves.push(this.getBasicMove([x, y], [x + 2 * shiftX, y]));
+ }
}
- }
- // Captures
- 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
- })
- );
+ // Captures
+ if (V.PawnSpecs.canCapture) {
+ for (let shiftY of [-1, 1]) {
+ if (
+ y + shiftY >= 0 &&
+ y + shiftY < sizeY
+ ) {
+ if (
+ this.board[x + shiftX][y + shiftY] != V.EMPTY &&
+ this.canTake([x, y], [x + shiftX, y + shiftY])
+ ) {
+ this.addPawnMoves(
+ [x, y], [x + shiftX, y + shiftY],
+ moves, promotions
+ );
+ }
+ if (
+ V.PawnSpecs.captureBackward &&
+ x - shiftX >= 0 && x - shiftX < V.size.x &&
+ this.board[x - shiftX][y + shiftY] != V.EMPTY &&
+ this.canTake([x, y], [x - shiftX, y + shiftY])
+ ) {
+ this.addPawnMoves(
+ [x, y], [x + shiftX, y + shiftY],
+ moves, promotions
+ );
+ }
+ }
}
}
}
+ return moves;
}
+ let pMoves = getPawnMoves(pawnShiftX);
+ if (V.PawnSpecs.bidirectional)
+ pMoves = pMoves.concat(getPawnMoves(-pawnShiftX));
+
if (V.HasEnpassant) {
- // 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);
- }
+ // NOTE: backward en-passant captures are not considered
+ // because no rules define them (for now).
+ Array.prototype.push.apply(
+ pMoves,
+ this.getEnpassantCaptures([x, y], pawnShiftX)
+ );
}
- return moves;
+ return pMoves;
}
// What are the rook moves from square x,y ?
V.steps[V.ROOK].concat(V.steps[V.BISHOP]),
"oneStep"
);
- return moves.concat(this.getCastleMoves(sq));
+ if (V.HasCastle) moves = moves.concat(this.getCastleMoves(sq));
+ return moves;
}
- getCastleMoves([x, y]) {
+ // "castleInCheck" arg to let some variants castle under check
+ getCastleMoves([x, y], castleInCheck) {
const c = this.getColor(x, y);
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)
castleSide < 2;
castleSide++ //large, then small
) {
- if (!this.castleFlags[c][castleSide]) continue;
- // If this code is reached, rooks and king are on initial position
+ if (this.castleFlags[c][castleSide] >= V.size.y) continue;
+ // If this code is reached, rook and king are on initial position
+
+ // NOTE: in some variants this is not a rook, but let's keep variable name
+ const rookPos = this.castleFlags[c][castleSide];
+ const castlingPiece = this.getPiece(x, rookPos);
+ if (this.getColor(x, rookPos) != c)
+ // Rook is here but changed color (see Benedict)
+ continue;
// Nothing on the path of the king ? (and no checks)
const finDist = finalSquares[castleSide][0] - y;
i = y;
do {
if (
- this.isAttacked([x, i], [oppCol]) ||
+ (!castleInCheck && 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))))
+ ![V.KING, castlingPiece].includes(this.getPiece(x, i))))
) {
continue castlingCheck;
}
// Nothing on the path to the rook?
step = castleSide == 0 ? -1 : 1;
- for (i = y + step; i != this.INIT_COL_ROOK[c][castleSide]; i += step) {
+ for (i = y + step; i != rookPos; i += step) {
if (this.board[x][i] != V.EMPTY) continue castlingCheck;
}
- const rookPos = this.INIT_COL_ROOK[c][castleSide];
// Nothing on final squares, except maybe king and castling rook?
for (i = 0; i < 2; i++) {
new Move({
appear: [
new PiPo({ x: x, y: finalSquares[castleSide][0], p: V.KING, c: c }),
- new PiPo({ x: x, y: finalSquares[castleSide][1], p: V.ROOK, c: c })
+ new PiPo({ x: x, y: finalSquares[castleSide][1], p: castlingPiece, c: c })
],
vanish: [
new PiPo({ x: x, y: y, p: V.KING, c: c }),
- new PiPo({ x: x, y: rookPos, p: V.ROOK, c: c })
+ new PiPo({ x: x, y: rookPos, p: castlingPiece, c: c })
],
end:
Math.abs(y - rookPos) <= 2
// (for engine and game end)
getAllValidMoves() {
const color = this.turn;
- const oppCol = V.GetOppCol(color);
let potentialMoves = [];
for (let i = 0; i < V.size.x; i++) {
for (let j = 0; j < V.size.y; j++) {
- // Next condition "!= oppCol" to work with checkered variant
- if (this.board[i][j] != V.EMPTY && this.getColor(i, j) != oppCol) {
+ if (this.getColor(i, j) == color) {
Array.prototype.push.apply(
potentialMoves,
this.getPotentialMovesFrom([i, j])
// Stop at the first move found
atLeastOneMove() {
const color = this.turn;
- const oppCol = V.GetOppCol(color);
for (let i = 0; i < V.size.x; i++) {
for (let j = 0; j < V.size.y; j++) {
- if (this.board[i][j] != V.EMPTY && this.getColor(i, j) != oppCol) {
+ if (this.getColor(i, j) == color) {
const moves = this.getPotentialMovesFrom([i, j]);
if (moves.length > 0) {
for (let k = 0; k < moves.length; k++) {
return false;
}
- // Check if pieces of color in 'colors' are attacking (king) on square x,y
- isAttacked(sq, colors) {
+ // Check if pieces of given color are attacking (king) on square x,y
+ isAttacked(sq, color) {
return (
- this.isAttackedByPawn(sq, colors) ||
- this.isAttackedByRook(sq, colors) ||
- this.isAttackedByKnight(sq, colors) ||
- this.isAttackedByBishop(sq, colors) ||
- this.isAttackedByQueen(sq, colors) ||
- this.isAttackedByKing(sq, colors)
+ this.isAttackedByPawn(sq, color) ||
+ this.isAttackedByRook(sq, color) ||
+ this.isAttackedByKnight(sq, color) ||
+ this.isAttackedByBishop(sq, color) ||
+ this.isAttackedByQueen(sq, color) ||
+ this.isAttackedByKing(sq, color)
);
}
- // 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 < V.size.x) {
- for (let i of [-1, 1]) {
- 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;
- }
+ // Generic method for non-pawn pieces ("sliding or jumping"):
+ // is x,y attacked by a piece of given color ?
+ isAttackedBySlideNJump([x, y], color, piece, steps, oneStep) {
+ for (let step of steps) {
+ let rx = x + step[0],
+ ry = y + step[1];
+ while (V.OnBoard(rx, ry) && this.board[rx][ry] == V.EMPTY && !oneStep) {
+ rx += step[0];
+ ry += step[1];
+ }
+ if (
+ V.OnBoard(rx, ry) &&
+ this.getPiece(rx, ry) == piece &&
+ this.getColor(rx, ry) == color
+ ) {
+ return true;
+ }
+ }
+ return false;
+ }
+
+ // Is square x,y attacked by 'color' pawns ?
+ isAttackedByPawn([x, y], color) {
+ const pawnShift = (color == "w" ? 1 : -1);
+ if (x + pawnShift >= 0 && x + pawnShift < V.size.x) {
+ for (let i of [-1, 1]) {
+ if (
+ y + i >= 0 &&
+ y + i < V.size.y &&
+ this.getPiece(x + pawnShift, y + i) == V.PAWN &&
+ this.getColor(x + pawnShift, y + i) == color
+ ) {
+ return true;
}
}
}
return false;
}
- // Is square x,y attacked by 'colors' rooks ?
- isAttackedByRook(sq, colors) {
- return this.isAttackedBySlideNJump(sq, colors, V.ROOK, V.steps[V.ROOK]);
+ // Is square x,y attacked by 'color' rooks ?
+ isAttackedByRook(sq, color) {
+ return this.isAttackedBySlideNJump(sq, color, V.ROOK, V.steps[V.ROOK]);
}
- // Is square x,y attacked by 'colors' knights ?
- isAttackedByKnight(sq, colors) {
+ // Is square x,y attacked by 'color' knights ?
+ isAttackedByKnight(sq, color) {
return this.isAttackedBySlideNJump(
sq,
- colors,
+ color,
V.KNIGHT,
V.steps[V.KNIGHT],
"oneStep"
);
}
- // Is square x,y attacked by 'colors' bishops ?
- isAttackedByBishop(sq, colors) {
- return this.isAttackedBySlideNJump(sq, colors, V.BISHOP, V.steps[V.BISHOP]);
+ // Is square x,y attacked by 'color' bishops ?
+ isAttackedByBishop(sq, color) {
+ return this.isAttackedBySlideNJump(sq, color, V.BISHOP, V.steps[V.BISHOP]);
}
- // Is square x,y attacked by 'colors' queens ?
- isAttackedByQueen(sq, colors) {
+ // Is square x,y attacked by 'color' queens ?
+ isAttackedByQueen(sq, color) {
return this.isAttackedBySlideNJump(
sq,
- colors,
+ color,
V.QUEEN,
V.steps[V.ROOK].concat(V.steps[V.BISHOP])
);
}
- // Is square x,y attacked by 'colors' king(s) ?
- isAttackedByKing(sq, colors) {
+ // Is square x,y attacked by 'color' king(s) ?
+ isAttackedByKing(sq, color) {
return this.isAttackedBySlideNJump(
sq,
- colors,
+ color,
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 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 (V.OnBoard(rx, ry) && this.board[rx][ry] == V.EMPTY && !oneStep) {
- rx += step[0];
- ry += step[1];
- }
- if (
- V.OnBoard(rx, ry) &&
- this.getPiece(rx, ry) === piece &&
- colors.includes(this.getColor(rx, ry))
- ) {
- return true;
- }
- }
- return false;
- }
-
// Is color under check after his move ?
underCheck(color) {
- return this.isAttacked(this.kingPos[color], [V.GetOppCol(color)]);
+ return this.isAttacked(this.kingPos[color], V.GetOppCol(color));
}
/////////////////
for (let psq of move.vanish) board[psq.x][psq.y] = psq.c + psq.p;
}
+ prePlay() {}
+
+ play(move) {
+ // DEBUG:
+// if (!this.states) this.states = [];
+// const stateFen = this.getFen() + JSON.stringify(this.kingPos);
+// this.states.push(stateFen);
+
+ this.prePlay(move);
+ 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 = V.GetOppCol(this.turn);
+ this.movesCount++;
+ this.postPlay(move);
+ }
+
+ updateCastleFlags(move, piece) {
+ const c = V.GetOppCol(this.turn);
+ const firstRank = (c == "w" ? V.size.x - 1 : 0);
+ // Update castling flags if rooks are moved
+ const oppCol = V.GetOppCol(c);
+ const oppFirstRank = V.size.x - 1 - firstRank;
+ if (piece == V.KING && move.appear.length > 0)
+ this.castleFlags[c] = [V.size.y, V.size.y];
+ else if (
+ move.start.x == firstRank && //our rook moves?
+ this.castleFlags[c].includes(move.start.y)
+ ) {
+ const flagIdx = (move.start.y == this.castleFlags[c][0] ? 0 : 1);
+ this.castleFlags[c][flagIdx] = V.size.y;
+ }
+ // NOTE: not "else if" because a rook could take an opposing rook
+ if (
+ move.end.x == oppFirstRank && //we took opponent rook?
+ this.castleFlags[oppCol].includes(move.end.y)
+ ) {
+ const flagIdx = (move.end.y == this.castleFlags[oppCol][0] ? 0 : 1);
+ this.castleFlags[oppCol][flagIdx] = V.size.y;
+ }
+ }
+
// After move is played, update variables + flags
- updateVariables(move) {
+ postPlay(move) {
+ const c = V.GetOppCol(this.turn);
let piece = undefined;
- // TODO: update variables before move is played, and just use this.turn ?
- // (doesn't work in general, think MarseilleChess)
- let c = undefined;
- if (move.vanish.length >= 1) {
+ if (move.vanish.length >= 1)
// Usual case, something is moved
piece = move.vanish[0].p;
- c = move.vanish[0].c;
- } else {
+ else
// Crazyhouse-like variants
piece = move.appear[0].p;
- c = move.appear[0].c;
- }
- if (!['w','b'].includes(c)) {
- // Checkered, for example
- c = V.GetOppCol(this.turn);
- }
- const firstRank = c == "w" ? V.size.x - 1 : 0;
// Update king position + flags
if (piece == V.KING && move.appear.length > 0) {
this.kingPos[c][0] = move.appear[0].x;
this.kingPos[c][1] = move.appear[0].y;
- if (V.HasFlags) this.castleFlags[c] = [false, false];
return;
}
- if (V.HasFlags) {
- // Update castling flags if rooks are moved
- const oppCol = V.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) == V.KING)
- this.kingPos[c] = [move.start.x, move.start.y];
+ if (V.HasCastle) this.updateCastleFlags(move, piece);
}
- play(move) {
- // DEBUG:
-// if (!this.states) this.states = [];
-// const stateFen = this.getBaseFen() + this.getTurnFen() + this.getFlagsFen();
-// this.states.push(stateFen);
-
- 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 = V.GetOppCol(this.turn);
- this.movesCount++;
- this.updateVariables(move);
- }
+ preUndo() {}
undo(move) {
+ this.preUndo(move);
if (V.HasEnpassant) this.epSquares.pop();
if (V.HasFlags) this.disaggregateFlags(JSON.parse(move.flags));
V.UndoOnBoard(this.board, move);
this.turn = V.GetOppCol(this.turn);
this.movesCount--;
- this.unupdateVariables(move);
+ this.postUndo(move);
// DEBUG:
-// const stateFen = this.getBaseFen() + this.getTurnFen() + this.getFlagsFen();
+// const stateFen = this.getFen() + JSON.stringify(this.kingPos);
// if (stateFen != this.states[this.states.length-1]) debugger;
// this.states.pop();
}
+ // After move is undo-ed *and flags resetted*, un-update other variables
+ // TODO: more symmetry, by storing flags increment in move (?!)
+ postUndo(move) {
+ // (Potentially) Reset king position
+ const c = this.getColor(move.start.x, move.start.y);
+ if (this.getPiece(move.start.x, move.start.y) == V.KING)
+ this.kingPos[c] = [move.start.x, move.start.y];
+ }
+
///////////////
// END OF GAME
// What is the score ? (Interesting if game is over)
getCurrentScore() {
- if (this.atLeastOneMove())
- return "*";
-
+ if (this.atLeastOneMove()) return "*";
// Game over
const color = this.turn;
// No valid move: stalemate or checkmate?
- if (!this.isAttacked(this.kingPos[color], [V.GetOppCol(color)]))
- return "1/2";
+ if (!this.underCheck(color)) return "1/2";
// OK, checkmate
- return color == "w" ? "0-1" : "1-0";
+ return (color == "w" ? "0-1" : "1-0");
}
///////////////
return V.INFINITY;
}
- // Search depth: 2 for high branching factor, 4 for small (Loser chess, eg.)
+ // Search depth: 1,2 for high branching factor, 4 for small (Loser chess, eg.)
static get SEARCH_DEPTH() {
return 3;
}
- // 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");
+ let moves1 = this.getAllValidMoves();
+
if (moves1.length == 0)
- //TODO: this situation should not happen
+ // TODO: this situation should not happen
return null;
- // Can I mate in 1 ? (for Magnetic & Extinction)
- for (let i of shuffle(ArrayFun.range(moves1.length))) {
+ // Rank moves using a min-max at depth 2 (if search_depth >= 2!)
+ for (let i = 0; i < moves1.length; i++) {
this.play(moves1[i]);
- let finish = Math.abs(this.evalPosition()) >= V.THRESHOLD_MATE;
- if (!finish) {
- const score = this.getCurrentScore();
- if (["1-0", "0-1"].includes(score)) finish = true;
+ const score1 = this.getCurrentScore();
+ if (score1 != "*") {
+ moves1[i].eval =
+ score1 == "1/2"
+ ? 0
+ : (score1 == "1-0" ? 1 : -1) * maxeval;
+ }
+ if (V.SEARCH_DEPTH == 1 || score1 != "*") {
+ if (!moves1[i].eval) moves1[i].eval = this.evalPosition();
+ this.undo(moves1[i]);
+ continue;
}
- this.undo(moves1[i]);
- if (finish) return moves1[i];
- }
-
- // 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]);
- const score1 = this.getCurrentScore();
- let eval2 = undefined;
- if (score1 == "*") {
- // 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]);
- const score2 = this.getCurrentScore();
- let evalPos = 0; //1/2 value
- switch (score2) {
- case "*":
- evalPos = this.evalPosition();
- break;
- case "1-0":
- evalPos = maxeval;
- break;
- case "0-1":
- evalPos = -maxeval;
- break;
- }
- if (
- (color == "w" && evalPos < eval2) ||
- (color == "b" && evalPos > eval2)
- ) {
- eval2 = evalPos;
- }
- this.undo(moves2[j]);
+ // Initial enemy evaluation is very low too, for him
+ let eval2 = (color == "w" ? 1 : -1) * maxeval;
+ // Second half-move:
+ let moves2 = this.getAllValidMoves();
+ for (let j = 0; j < moves2.length; j++) {
+ this.play(moves2[j]);
+ const score2 = this.getCurrentScore();
+ let evalPos = 0; //1/2 value
+ switch (score2) {
+ case "*":
+ evalPos = this.evalPosition();
+ break;
+ case "1-0":
+ evalPos = maxeval;
+ break;
+ case "0-1":
+ evalPos = -maxeval;
+ break;
+ }
+ if (
+ (color == "w" && evalPos < eval2) ||
+ (color == "b" && evalPos > eval2)
+ ) {
+ eval2 = evalPos;
}
- } else eval2 = score1 == "1/2" ? 0 : (score1 == "1-0" ? 1 : -1) * maxeval;
+ this.undo(moves2[j]);
+ }
if (
(color == "w" && eval2 > moves1[i].eval) ||
(color == "b" && eval2 < moves1[i].eval)
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[candidates[randInt(candidates.length)]];
+// console.log(moves1.map(m => { return [this.getNotation(m), m.eval]; }));
// 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) {
- // From here, depth >= 3: may take a while, so we control time
- const timeStart = Date.now();
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 =
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);
+ let candidates = [0];
+ for (let i = 1; i < moves1.length && moves1[i].eval == moves1[0].eval; i++)
+ candidates.push(i);
return moves1[candidates[randInt(candidates.length)]];
}
if (score != "*")
return score == "1/2" ? 0 : (score == "1-0" ? 1 : -1) * maxeval;
if (depth == 0) return this.evalPosition();
- const moves = this.getAllValidMoves("computer");
+ const moves = this.getAllValidMoves();
let v = color == "w" ? -maxeval : maxeval;
if (color == "w") {
for (let i = 0; i < moves.length; i++) {
alpha = Math.max(alpha, v);
if (alpha >= beta) break; //beta cutoff
}
- } //color=="b"
+ }
else {
+ // color=="b"
for (let i = 0; i < moves.length; i++) {
this.play(moves[i]);
v = Math.min(v, this.alphabeta(depth - 1, alpha, beta));
// TODO: un-ambiguous notation (switch on piece type, check directions...)
getNotation(move) {
if (move.appear.length == 2 && move.appear[0].p == V.KING)
- //castle
+ // Castle
return move.end.y < move.start.y ? "0-0-0" : "0-0";
// Translate final square
projects / vchess.git / blobdiff