Chess

A C++20 chess game with text-based display and modern graphical mode using SDL2.
Supports human vs human, human vs AI, and AI vs AI with four difficulty levels.

Note: This project has been migrated from X11 to SDL2 for better cross-platform support and modern graphics capabilities.

Project Structure

chess-engine/
├── src/
│   ├── core/       # Game logic, board, and main entry point
│   ├── pieces/     # Chess piece implementations
│   ├── players/    # Human and computer player classes
│   ├── ai/         # AI difficulty levels (1-4)
│   ├── display/    # Text, graphics, and log displays
│   ├── patterns/   # Observer/Subject design patterns
│   └── utils/      # Utility classes (PRNG, window)
├── Makefile
└── README.md

Requirements

• C++20 compiler (tested with g++)
• Make
• SDL2 and SDL2_ttf libraries (for graphics)

Installing SDL2

Ubuntu/Debian:

sudo apt-get install libsdl2-dev libsdl2-ttf-dev

Fedora/RHEL:

sudo dnf install SDL2-devel SDL2_ttf-devel

macOS (Homebrew):

brew install sdl2 sdl2_ttf

Windows (MSYS2):

pacman -S mingw-w64-x86_64-SDL2 mingw-w64-x86_64-SDL2_ttf

Building

Important: Make sure SDL2 libraries are installed first (see Installing SDL2 above).

Build the game:

make

This produces: ./chess

Clean build artifacts:

make clean

Running

Text-only mode:

./chess

With graphics:

./chess -g

With logging:

./chess -l

With both:

./chess -g -l

Commands

• Start a game

  game white-player black-player
  

  Example:

  game human computer1
  

  where computer1–computer5 are AI difficulty levels.

• Make a move

  move e2 e4
  

  or just move for AI moves.

• Resign

  resign
  

• Setup mode

  setup
  

  Then use + K e1, - e1, etc.

• Quit
  Press Ctrl+D or type quit.

Displays

• TextDisplay: ASCII chessboard
• GraphicsDisplay: Modern SDL2-based GUI with hardware acceleration
• LogDisplay: optional file-based move log

Multiple displays can be attached simultaneously. The graphics display features:

• Cross-platform support (Windows, Linux, macOS)
• Smooth rendering with hardware acceleration
• Modern, clean interface

AI Levels

• computer1: random moves
• computer2: simple heuristics
• computer3: improved heuristics
• computer4: 2-ply lookahead
• computer5: strongest AI (4-ply alpha-beta, static eval, piece-square tables, quiescence)

Web Build (WASM)

The engine can be compiled to WebAssembly for the browser. See web/README.md for build instructions. A minimal web UI is included; deploy the web folder to GitHub Pages or any static host.

Example

$ ./chess
Welcome to Chess!
Commands:
  game white-player black-player
  move e2 e4
  autoplay
  resign
  setup
  Ctrl+D to quit.

> game human computer1
> move e2 e4