Chess Game - Python & Pygame

This is a simple chess game implemented using Python and Pygame. It features drag-and-drop piece movement, check/checkmate detection, en passant, castling, and an undo/redo functionality. Play against a friend (PvP) or challenge the computer (PvC), which uses a Minimax algorithm with Alpha-Beta pruning for its moves.

Features:

• PvP Mode: Play against a friend on the same computer.
• PvC Mode: Play against an AI that uses the Minimax algorithm with Alpha-Beta pruning and transposition table caching.
• Drag-and-Drop Movement: Select and move pieces by dragging them.
• Undo/Redo: Undo your moves with the B key and redo undone moves with the Y key.
• En Passant: Special pawn capture is supported.
• Castling: Both kingside and queenside castling are implemented (with proper conditions).
• Valid Move Highlighting: When enabled (by pressing the S key), possible moves for a selected piece are highlighted.
• Check/Checkmate/Stalemate Detection: The game automatically detects check, checkmate, and stalemate.
• Pawn Promotion: When a pawn reaches the opposite end, a prompt allows promotion to a Queen, Rook, Bishop, or Knight (with auto-promotion for AI moves).

Requirements:

• Python 3.x
  Recommended: Python 3.10.11

I recommend you to use a virtual environment.

python -m venv .
source venv/bin/activate # On Linux/Mac
venv\Scripts\activate # On Windows

pip install --upgrade pip
pip install -r requirements.txt

Folder Structure:

📦 Chess-Game
├── 📂 background/               # Contains background-related assets
│
├── 📂 pieces/                   # Contains individual chess piece assets or logic
│
├── 📂 src/                      # Main source code directory
│   ├── board.py                 # Handles board representation and game logic
│   ├── computer_player.py       # AI logic using Minimax and Alpha-Beta pruning
│   ├── game.py                  # Game management (turns, win conditions, etc.)
│   ├── pieces.py                # Defines chess piece behaviors and movements
│   └── settings.py              # Configuration settings for the game
│
├── main.py                      # Entry point to start the game
├── .gitignore                   # Specifies files to ignore in version control
├── README.md                    # Project documentation
└── requirements.txt             # Lists dependencies for installation

How to Play:

1. Start the Game: Execute main.py to start playing.

   python main.py

   • First, You'll have to choose the opponent. You can choose between a friend or the computer.
   • If you choose a friend, you can play against each other on the same computer.
   • If you choose the computer, you'll play against the computer. You will be able to choose before the color you'll play as. The computer is using a minimax algorithm to search for the best move.
   • When you run the game, the chessboard will appear on the screen with all the pieces in their initial positions.

2. Move Pieces:

   • To move a piece, click on it, and drag it to a valid square on the board.
   • The possible moves for each piece will be highlighted in green, red for capture moves.

3. Undo a Move:

   • Press the B key to undo your last move. It's a simple way to try different moves without losing your progress but be careful when using it vs computer cause it might cause bugs. My advice i can give to you is to wait for your turn and then to click 2 times on "B".
   • This will revert the board to the previous state, allowing you to correct mistakes or reconsider your strategy.

4. Redo a Move:

   • Press the Y key to redo the last move you undid.
   • This allows you to restore a move that was previously undone.

5. Castling:

   • Castling is supported for both players, but only if the king and rook have not moved before.
   • Castling is a special move that lets the king move two squares towards a rook, and the rook then moves to the other side of the king.

6. En Passant:

   • En passant is a special pawn capture that can occur when a pawn moves two squares forward from its starting position, and lands beside an opponent's pawn.
   • In this case, the opponent's pawn may capture the first pawn as if it had moved only one square forward.
   • To perform en passant, click the opponent's pawn and drag your pawn diagonally over the space where the opponent’s pawn just moved, capturing it.

7. Promote a Pawn:

   • When a pawn reaches the opposite end of the board, it can be promoted to a Queen, Rook, Bishop, or Knight.
   • A prompt will appear, and you can choose which piece to promote to.

8. Endgame:

   • Checkmate: The game ends if a player's king is in check and cannot escape capture.
   • Stalemate: If the current player has no legal move and their king is not in check, it’s a stalemate, and the game ends in a draw.
   • Resignation: If you want to give up during the game, press Z to surrender. The opponent will win, and a message will be displayed announcing the victory.

9. Game Restart:

   • If you want to restart the game, press the Enter key.
   • The board will reset to its initial state, and the game will continue from the beginning.

Controls:

• Mouse:

  • Left-click: Select a piece to move.
  • Drag: Move the selected piece to a valid destination.

• Keyboard:

  • B Key: Undo the last move.
  • Y Key: Redo the last undone move.
  • Z Key: Surrender the game. The opponent wins.
  • Enter Key: Restart the game.
  • Escape Key: Quit the game.

Example of Playing a Game:

1. Start the game by running python main.py. Choose the game mode and your piece color.
2. White always goes first. Select a white piece by clicking on it, then drag it to a valid square. For example, move the white pawn from e2 to e4.
3. Black's turn – select a black piece and move it. If you accidentally make a bad move, press B to undo it. If you change your mind again, press Y to redo the move.
4. Continue playing until one player wins by checkmate, the game ends in a stalemate, or one player resigns.

Example of Moves:

• Pawn: Move one square forward, two squares on the first move, or diagonally to capture an enemy piece.
• Rook: Move vertically or horizontally any number of squares.
• Knight: Move in an "L" shape: two squares in one direction and then one square perpendicular, or vice versa.
• Bishop: Move diagonally any number of squares.
• Queen: Combine the movements of the rook and bishop (vertically, horizontally, or diagonally).
• King: Move one square in any direction. Castling is a special move to protect the king.

Example of Castling:

• White's king is on e1, and the white rook is on h1 (or a1).
• White can castle by moving the king two squares towards the rook (e.g., from e1 to g1), and the rook will jump to the square the king skipped (e.g., from h1 to f1).
• Conditions: The king and the rook must not have moved previously, and there should be no pieces between them.

Troubleshooting:

• Game not starting? Make sure you have installed the pygame library.
• Piece movement issue? Ensure you are dragging the pieces to valid squares. If you misplaced a piece, press B to undo the move.

Have fun playing chess!