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) • 1.83 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
exports.generateNorthEastAttacks = void 0;
var moveHelpers_1 = require("../../moveHelpers");
var rays_1 = require("../rays");
/**
* Populates an array of 64 IRayAttacks objects with north-east attacks
* @param attacksList an IRayAttack array of directional attacks
* @returns attacksList populated with north-east attacks
*/
function generateNorthEastAttacks(attacksList) {
/**************
* 8 .......1 *
* 7 ......1. *
* 6 .....1.. *
* 5 ....1... *
* 4 ...1.... *
* 3 ..1..... *
* 2 .1...... *
* 1 x....... * -- B2_H8
* ABCDEFGH
*************/
// B2_H8 north-east attack mask is used as a placeholder to be slid on each square
var northEastAttackMask = rays_1.RAYS.B2_H8;
// Loop through each file of the board: A, B, ... G, H
// at the end of each loop, slide the mask down and remove the smallest bit for the next iteration
for (var file = 0; file < 8; file++) {
// Set temporary north-east mask to be used by the following for loop
var northEast = northEastAttackMask;
// Loop through each square (from bottom to top) on the current file
// at the end of each loop, slide the mask to the top for the next iteration
for (var square = 0; square < 8 * 8; square += 8) {
// populate each attacksList square north-east property
attacksList[square + file].noEa = northEast;
northEast = (0, moveHelpers_1.slideUp)(northEast);
}
northEastAttackMask = (0, moveHelpers_1.slideDown)(northEastAttackMask);
northEastAttackMask = (0, moveHelpers_1.removeLowestBit)(northEastAttackMask);
}
return attacksList;
}
exports.generateNorthEastAttacks = generateNorthEastAttacks;