README.md

Chess

A Chess Engine with a GUI.

Features

• Bitboard Board Representation
• Magic Bitboard Sliding Move Generation
• Opening Book based on ~8000 games
• Move Searching using Minimax with Alpha-Beta pruning, MTDF, Null Move Pruning, Move Ordering, Quiescence Search, Memoization, and Iterative Deepening

Usage

Below is an example showing usage of the chess engine without a GUI.

#include "Chess/bitboard.h"
#include "Chess/board.h"
#include "Chess/move.h"
#include "Chess/search.h"
#include "Chess/hashmap.h"

int main() {
    init_magic_tables();
    Board board;
    board_from_fen(&board, "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1");

    HashMap* hashmap = hashmap_alloc(20);

    Move selected;
    Move moves[MAX_MOVES];

    while (1) {
        int n_moves = gen_moves(&board, moves); // Generate all possible moves.
        Move move = moves[...]; // Select a move.
        make_move(&board, &move); // Make the move on the board.

        // Then the AI selects a move. If it could not, then you've either won or the game is
        // in stalemate.
        if (!select_move(&board, hashmap, &selected)) {
            if (is_in_check(&board)) {
                // Checkmate.
            } else {
                // Stalemate.
            }
            break;
        }
        make_move(&board, &selected);
    }

    hashmap_free(hashmap);
    
    return 0;
}

Compilation

Currently only configured for Windows. Compilation commands available in Makefile.

# Chess GUI
make chess

# Perft Tests
make perft
perft <depth>

Resources

The following resources/projects were very helpful in the creation of this Chess Engine.

• Blog Post by Josh Ervin on Move Generation
• Blog Post by Rhys Rustad-Elliott on Magic Bitboards
• Blog Post by Markus Boeck about Chess Engines
• Michael Fogleman's MisterQueen Chess Engine