TicTacToe-CX

A Tic Tac Toe game written in C with CLI, Nano AI opponents, LAN multiplayer, and cloudflared-based Internet multiplayer.

Features

• Single Player vs AI

  • Easy: Random moves (great for beginners)
  • Medium: Blocks wins and tries to win
  • Hard: Minimax algorithm

• Two Player (Local)

  • Play on the same machine
  • Choose your symbol (X or O)

• LAN Multiplayer

  • Host or join games via TCP sockets
  • Encrypted session with passphrase-based handshake
  • Real-time board synchronization

• Internet Multiplayer (CLI)

  • Host a game over the internet using cloudflared tunnel service
  • Join with a shared cloudflared link/hostname
  • Uses the same encrypted game handshake as LAN mode
  • If cloudflared is missing, the game can prompt to install it

Encryption Session (LAN)

LAN security is session-based and negotiated when a client connects:

1. The client attempts a secure session using OpenSSL.
2. If OpenSSL negotiation fails, it falls back to legacy compatibility mode.
3. A connection is considered secure only when: connected && security_ready && mode != NONE.

⚠ Legacy mode is provided for compatibility and does not provide encryption. It should only be used on trusted local networks.

OpenSSL Mode (Primary)

• Passphrase key material is derived using PBKDF2-HMAC-SHA256 (200,000 iterations).
• The handshake exchanges a salt and client/server nonces, then derives directional keys (client → server and server → client).
• Game packets are protected using AES-256-GCM authenticated encryption.
• Each frame includes a sequence number; replayed or stale sequence values are rejected.

Legacy Mode (Compatibility Fallback)

• Uses the older custom key/nonce stream + frame MAC path for compatibility.

• Still enforces monotonic nonce checks to reject replayed frames.

• OpenSSL mode is stronger and preferred for production LAN play.

• CLI

  • ANSI color themes (Default, Dark, Light, Retro)
  • Enhanced bright color palette
  • AI thinking indicators
  • Unicode board rendering with ASCII fallback
  • Live full-screen board redraw (video-like terminal flow)
  • About page in main menu (author/contact/version)
  • Code-driven sound effects (toggle in settings)

• GUI (SDL2)

  • Main menu flow aligned with CLI (AI, Local, LAN, Scores, Settings, About)
  • Keyboard + mouse navigation
  • In-window LAN host/join setup with encrypted handshake
  • Live board rendering with game-over overlays and rematch flow

• Customizable Settings

  • Board sizes: 3x3, 4x4, 5x5
  • Optional timer per move
  • Configurable color themes
  • Toggle sound effects

Building

Prerequisites

• C compiler (gcc, clang, or MSVC)
• CMake 3.10 or higher

Build Instructions

# Linux/macOS
cmake -S . -B build-linux
cmake --build build-linux -j

# Windows (Visual Studio or Ninja)
cmake -S . -B build-windows
cmake --build build-windows --config Release

Executable output is generated under build-<os>/bin/.

Platform Install Scripts

Use the scripts in building-scripts/:

• Linux: bash building-scripts/install-linux.sh
• macOS: bash building-scripts/install-macos.sh
• Windows: powershell -ExecutionPolicy Bypass -File .\building-scripts\install-windows.ps1
• Termux: bash building-scripts/install-termux.sh
• Linux -> Windows cross-build: bash building-scripts/build-windows-from-linux.sh

Each installer asks for:

1. Install mode (copy into a bin directory for regular use) or
2. Test mode (build only in build-<os>/bin/ inside the repo)

In Install mode, scripts detect existing installs:

1. If not installed yet, they do a normal install flow.
2. If already installed, they ask whether to:
   • Update existing install
   • Uninstall/remove it
   • Install to another path

Termux users should launch with bash building-scripts/run-termux.sh. --gui is intentionally blocked on Termux.

Running

# Run (Linux/macOS)
./build-linux/bin/tictactoe-cx

# Launch GUI mode (when SDL2 is available)
./build-linux/bin/tictactoe-cx --gui

# Print version and exit
./build-linux/bin/tictactoe-cx --version

If your terminal shows visual artifacts, you can force compatibility mode:

TICTACTOE_NO_LIVE=1 TICTACTOE_ASCII=1 ./build-linux/bin/tictactoe-cx

How to Play

1. Use Up/Down arrows and Enter to navigate menus
2. Enter moves as 23 or 2 3 (row, column)
3. In game, press Q to return to menu
4. Open About from main menu for game/author/version details

Internet Mode (CLI)

1. Open Internet Multiplayer.
2. Host:
   • choose Host Internet Game
   • share the generated cloudflared link with your opponent.
3. Join:
   • choose Join Internet Game
   • paste the host link (or hostname) and connect.

Notes:

• Both players should have cloudflared installed.
• The game can attempt automatic install when cloudflared is missing.

GUI Controls

1. Launch with --gui
2. Use Arrow Keys + Enter or Mouse Click
3. In game, click cells to move
4. Press Esc to return to main menu

Configuration

On first run, the game asks where to create its data directory. Default location:

• Linux/macOS/Termux: ~/.tictactoe-cx-config/
• Windows: %USERPROFILE%\.tictactoe-cx-config\

Inside that directory:

• config.ini
• saves/highscores.txt

Settings in config.ini include:

• Board size (3-5)
• AI difficulty
• Timer settings
• Color theme
• Sound enabled/disabled

The directory and files are auto-created and can be edited manually.

Project Structure

TicTacToe-CX/
├── src/
│   ├── main.c      # Main game loop and menus
│   ├── game.c/h    # Core game logic
│   ├── cli.c/h     # CLI rendering with ANSI colors
│   ├── ai.c/h      # AI opponents
│   ├── network.c/h # LAN multiplayer
│   ├── internet.c/h # Cloudflared tunnel integration
│   └── utils.c/h   # Data/config/score storage helpers
├── building-scripts/      # Install/test build scripts
├── CMakeLists.txt
└── README.md

License

See LICENSE file.

Author

• voltsparx - voltsparx@gmail.com