chess-legal-moves
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Analyses a given chess game position in Fen notation to return legal moves and provides the next game position after a given move
43 lines (42 loc) • 1.82 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
exports.generateSouthWestAttacks = void 0;
var moveHelpers_1 = require("../../moveHelpers");
var rays_1 = require("../rays");
/**
* Populates an array of 64 IRayAttacks objects with south-west attacks
* @param attacksList an IRayAttack array of directional attacks
* @returns attacksList populated with south-west attacks
*/
function generateSouthWestAttacks(attacksList) {
/**************
* 8 .......x *
* 7 ......1. *
* 6 .....1.. *
* 5 ....1... *
* 4 ...1.... *
* 3 ..1..... *
* 2 .1...... *
* 1 1....... * -- G7_A1
* ABCDEFGH
*************/
// G7_A1 south-west attack mask is used as a placeholder to be slid on each square
var southWestAttackMask = rays_1.RAYS.G7_A1;
// Loop through each file of the board: A, B, ... G, H
// at the end of each loop, slide the mask up and remove the highest bit for the next iteration
for (var file = 0; file < 8; file++) {
// Set temporary south-west mask to be used by the following for loop
var southWest = southWestAttackMask;
// Loop through each square (from top to bottom) on the current file
// at the end of each loop, slide down the mask for the next iteration
for (var square = 63; square >= 0; square -= 8) {
// populate each attacksList square south-west property
attacksList[square - file].soWe = southWest;
southWest = (0, moveHelpers_1.slideDown)(southWest);
}
southWestAttackMask = (0, moveHelpers_1.slideUp)(southWestAttackMask);
southWestAttackMask = (0, moveHelpers_1.removeHighestBit)(southWestAttackMask);
}
return attacksList;
}
exports.generateSouthWestAttacks = generateSouthWestAttacks;