X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=www%2Fjs%2Fchess.js;h=531a08fec291ee6f5fb430d7031ef7ff055c95f1;hb=9a650e4ec1cd349367ab7c59a9ec47a8cdbb79c9;hp=9a2d383047dc167bebb571e4e4b515601cbd6589;hpb=84758bbacfaaceb5e328ff01fe2c003bc58e939c;p=remoteglot diff --git a/www/js/chess.js b/www/js/chess.js index 9a2d383..531a08f 100644 --- a/www/js/chess.js +++ b/www/js/chess.js @@ -68,44 +68,6 @@ var Chess = function(fen) { k: [-17, -16, -15, 1, 17, 16, 15, -1] }; - var ATTACKS = [ - 20, 0, 0, 0, 0, 0, 0, 24, 0, 0, 0, 0, 0, 0,20, 0, - 0,20, 0, 0, 0, 0, 0, 24, 0, 0, 0, 0, 0,20, 0, 0, - 0, 0,20, 0, 0, 0, 0, 24, 0, 0, 0, 0,20, 0, 0, 0, - 0, 0, 0,20, 0, 0, 0, 24, 0, 0, 0,20, 0, 0, 0, 0, - 0, 0, 0, 0,20, 0, 0, 24, 0, 0,20, 0, 0, 0, 0, 0, - 0, 0, 0, 0, 0,20, 2, 24, 2,20, 0, 0, 0, 0, 0, 0, - 0, 0, 0, 0, 0, 2,53, 56, 53, 2, 0, 0, 0, 0, 0, 0, - 24,24,24,24,24,24,56, 0, 56,24,24,24,24,24,24, 0, - 0, 0, 0, 0, 0, 2,53, 56, 53, 2, 0, 0, 0, 0, 0, 0, - 0, 0, 0, 0, 0,20, 2, 24, 2,20, 0, 0, 0, 0, 0, 0, - 0, 0, 0, 0,20, 0, 0, 24, 0, 0,20, 0, 0, 0, 0, 0, - 0, 0, 0,20, 0, 0, 0, 24, 0, 0, 0,20, 0, 0, 0, 0, - 0, 0,20, 0, 0, 0, 0, 24, 0, 0, 0, 0,20, 0, 0, 0, - 0,20, 0, 0, 0, 0, 0, 24, 0, 0, 0, 0, 0,20, 0, 0, - 20, 0, 0, 0, 0, 0, 0, 24, 0, 0, 0, 0, 0, 0,20 - ]; - - var RAYS = [ - 17, 0, 0, 0, 0, 0, 0, 16, 0, 0, 0, 0, 0, 0, 15, 0, - 0, 17, 0, 0, 0, 0, 0, 16, 0, 0, 0, 0, 0, 15, 0, 0, - 0, 0, 17, 0, 0, 0, 0, 16, 0, 0, 0, 0, 15, 0, 0, 0, - 0, 0, 0, 17, 0, 0, 0, 16, 0, 0, 0, 15, 0, 0, 0, 0, - 0, 0, 0, 0, 17, 0, 0, 16, 0, 0, 15, 0, 0, 0, 0, 0, - 0, 0, 0, 0, 0, 17, 0, 16, 0, 15, 0, 0, 0, 0, 0, 0, - 0, 0, 0, 0, 0, 0, 17, 16, 15, 0, 0, 0, 0, 0, 0, 0, - 1, 1, 1, 1, 1, 1, 1, 0, -1, -1, -1,-1, -1, -1, -1, 0, - 0, 0, 0, 0, 0, 0,-15,-16,-17, 0, 0, 0, 0, 0, 0, 0, - 0, 0, 0, 0, 0,-15, 0,-16, 0,-17, 0, 0, 0, 0, 0, 0, - 0, 0, 0, 0,-15, 0, 0,-16, 0, 0,-17, 0, 0, 0, 0, 0, - 0, 0, 0,-15, 0, 0, 0,-16, 0, 0, 0,-17, 0, 0, 0, 0, - 0, 0,-15, 0, 0, 0, 0,-16, 0, 0, 0, 0,-17, 0, 0, 0, - 0,-15, 0, 0, 0, 0, 0,-16, 0, 0, 0, 0, 0,-17, 0, 0, - -15, 0, 0, 0, 0, 0, 0,-16, 0, 0, 0, 0, 0, 0,-17 - ]; - - var SHIFTS = { p: 0, n: 1, b: 2, r: 3, q: 4, k: 5 }; - var FLAGS = { NORMAL: 'n', CAPTURE: 'c', @@ -824,40 +786,71 @@ var Chess = function(fen) { } function attacked(color, square) { - for (var i = SQUARES.a8; i <= SQUARES.h1; i++) { - /* did we run off the end of the board */ - if (i & 0x88) { i += 7; continue; } + // Check for attacks by the king. + if (Math.abs(rank(kings[color]) - rank(square)) <= 1 && + Math.abs(file(kings[color]) - file(square)) <= 1) { + return true; + } - /* if empty square or wrong color */ - if (board[i] == null || board[i].color !== color) continue; + // Check for attacks by knights. + for (const offset of PIECE_OFFSETS[KNIGHT]) { + let knight_sq = square + offset; + if (knight_sq & 0x88) continue; - var piece = board[i]; - var difference = i - square; - var index = difference + 119; + if (board[knight_sq] != null && + board[knight_sq].type === KNIGHT && + board[knight_sq].color === color) { + return true; + } + } - if (ATTACKS[index] & (1 << SHIFTS[piece.type])) { - if (piece.type === PAWN) { - if (difference > 0) { - if (piece.color === WHITE) return true; - } else { - if (piece.color === BLACK) return true; + // Check for attacks by pawns. + const p1sq = square - PAWN_OFFSETS[color][2]; + const p2sq = square - PAWN_OFFSETS[color][3]; + if (!(p1sq & 0x88) && + board[p1sq] != null && + board[p1sq].type === PAWN && + board[p1sq].color === color) { + return true; + } + if (!(p2sq & 0x88) && + board[p2sq] != null && + board[p2sq].type === PAWN && + board[p2sq].color === color) { + return true; + } + + // Check for attacks by rooks (where queens count as rooks). + for (const offset of PIECE_OFFSETS[ROOK]) { + let rook_sq = square; + while (true) { + rook_sq += offset; + if (rook_sq & 0x88) break; + + if (board[rook_sq] != null) { + if ((board[rook_sq].type === ROOK || board[rook_sq].type === QUEEN) && + board[rook_sq].color === color) { + return true; } - continue; + break; } + } + } - /* if the piece is a knight or a king */ - if (piece.type === 'n' || piece.type === 'k') return true; - - var offset = RAYS[index]; - var j = i + offset; + // And similarly for attacks by bishops (where queens count as bishops). + for (const offset of PIECE_OFFSETS[BISHOP]) { + let bishop_sq = square; + while (true) { + bishop_sq += offset; + if (bishop_sq & 0x88) break; - var blocked = false; - while (j !== square) { - if (board[j] != null) { blocked = true; break; } - j += offset; + if (board[bishop_sq] != null) { + if ((board[bishop_sq].type === BISHOP || board[bishop_sq].type === QUEEN) && + board[bishop_sq].color === color) { + return true; + } + break; } - - if (!blocked) return true; } } @@ -1127,7 +1120,14 @@ var Chess = function(fen) { return ''; } - let moves = find_attacking_moves(move.to, piece, move.color, sloppy); + let moves = find_attacking_moves(move.to, piece, move.color); + if (moves.length <= 1) { + // There can be no ambiguity, so don't bother checking legality + // (we assume the move has already been found legal). + return ''; + } + + moves = possibly_filter_moves(moves, move.color, !sloppy); var ambiguities = 0; var same_rank = 0; @@ -1176,11 +1176,12 @@ var Chess = function(fen) { return ''; } - // Find all moves featuring the given piece attacking the given square - // (using symmetry of all non-pawn-or-castle moves, we simply generate - // moves backwards). Does not support kings or pawns. Assumes there's - // not already a piece of our own color on the destination square. - function find_attacking_moves(to, piece, us, sloppy) { + // Find all pseudolegal moves featuring the given piece attacking + // the given square (using symmetry of all non-pawn-or-castle moves, + // we simply generate moves backwards). Does not support kings + // or pawns. Assumes there's not already a piece of our own color + // on the destination square. + function find_attacking_moves(to, piece, us) { let moves = []; function add_move(board, moves, from, to, flags, rook_sq) { @@ -1194,7 +1195,7 @@ var Chess = function(fen) { if (square & 0x88) break; if (board[square] != null) { - if (board[square].color !== us) break; + if (board[square].color !== us || board[square].type !== piece) break; if (board[to] == null) { add_move(board, moves, square, to, BITS.NORMAL); } else { @@ -1208,7 +1209,7 @@ var Chess = function(fen) { } } - return possibly_filter_moves(moves, us, !sloppy); + return moves; } function ascii() {