public/javascripts/variants/Half.js

   1 class HalfRules extends ChessRules
   2 {
   3     // Standard rules on a 4x8 board with no pawns
   4
   5     initVariables(fen) { } //nothing to do
   6
   7     setFlags(fen)
   8     {
   9         // No castling, hence no flags; but flags defined for compatibility
  10         this.castleFlags = { "w":[false,false], "b":[false,false] };
  11     }
  12
  13     static get size() { return [8,4]; }
  14
  15     getPotentialKingMoves(sq)
  16     {
  17         const V = VariantRules;
  18         // No castling
  19         return this.getSlideNJumpMoves(sq,
  20             V.steps[V.ROOK].concat(V.steps[V.BISHOP]), "oneStep");
  21     }
  22
  23     isAttacked(sq, colors)
  24     {
  25         return (this.isAttackedByRook(sq, colors)
  26             || this.isAttackedByKnight(sq, colors)
  27             || this.isAttackedByBishop(sq, colors)
  28             || this.isAttackedByQueen(sq, colors)
  29             || this.isAttackedByKing(sq, colors));
  30     }
  31
  32     // Unused:
  33     updateVariables(move) { }
  34     unupdateVariables(move) { }
  35
  36     static get SEARCH_DEPTH() { return 4; }
  37
  38     static GenRandInitFen()
  39     {
  40         let minorPieces = { "w": new Array(4), "b": new Array(4) };
  41         let majorPieces = { "w": new Array(4), "b": new Array(4) };
  42         for (let c of ["w","b"])
  43         {
  44             // Minor pieces first (on 2nd rank)
  45             let positions = _.range(4);
  46
  47             // Get random squares for bishops
  48             let randIndex = 2 * _.random(1);
  49             let bishop1Pos = positions[randIndex];
  50             let randIndex_tmp = 2 * _.random(1) + 1;
  51             let bishop2Pos = positions[randIndex_tmp];
  52             positions.splice(Math.max(randIndex,randIndex_tmp), 1);
  53             positions.splice(Math.min(randIndex,randIndex_tmp), 1);
  54
  55             // Get random squares for knights
  56             randIndex = _.random(1);
  57             let knight1Pos = positions[randIndex];
  58             positions.splice(randIndex, 1);
  59             let knight2Pos = positions[0];
  60
  61             minorPieces[c][bishop1Pos] = 'b';
  62             minorPieces[c][bishop2Pos] = 'b';
  63             minorPieces[c][knight1Pos] = 'n';
  64             minorPieces[c][knight2Pos] = 'n';
  65
  66             // Major pieces then (on 1st rank)
  67             positions = _.range(4);
  68
  69             // Get random square for queen
  70             randIndex = _.random(3);
  71             let queenPos = positions[randIndex];
  72             positions.splice(randIndex, 1);
  73
  74             // Rooks and king positions:
  75             let rook1Pos = positions[0];
  76             let kingPos = positions[1];
  77             let rook2Pos = positions[2];
  78
  79             majorPieces[c][rook1Pos] = 'r';
  80             majorPieces[c][rook2Pos] = 'r';
  81             majorPieces[c][kingPos] = 'k';
  82             majorPieces[c][queenPos] = 'q';
  83         }
  84         return majorPieces["b"].join("") + "/" + minorPieces["b"].join("") + "/4/4/4/4/" +
  85             minorPieces["w"].join("").toUpperCase() + "/" +
  86             majorPieces["w"].join("").toUpperCase() + " 0000"; //TODO: flags?!
  87     }
  88 }