Regal Chess

Regal Chess is a full-featured chess game with a polished browser UI, built-in computer opponent, and online multiplayer rooms over WebSockets.

Features

• Complete chess rules and legality:
  • All standard pieces and legal move generation
  • Check, checkmate, stalemate
  • Castling, en passant, and promotion
  • Draw detection (threefold repetition, 50-move rule, insufficient material)
• Premium board interface:
  • Responsive animated board
  • Legal move and capture highlights
  • Last move and in-check indicators
  • Move history and captured pieces with material edge
  • Board flip and undo controls
• Play modes:
  • Local two-player (same device)
  • Vs Computer (minimax AI, Easy/Medium/Hard)
  • Online multiplayer rooms (player or spectator)
• Time controls:
  • Untimed, 3|2, 5|0, 10|5, 15|10
  • Clock mode is disabled in online multiplayer (server-authoritative state)

Project Structure

• index.html - app layout and controls
• styles.css - visual design and responsive styling
• engine-core.js - shared chess engine (used by browser + server)
• app.js - frontend game controller (UI, AI, online client)
• server.js - static + WebSocket server for online multiplayer
• package.json - Node scripts and dependencies

Quick Start

1. Install dependencies:

   npm install

2. Start the server:

   npm start

3. Open: http://localhost:3000

Using AI Mode

1. Set Game Mode to Vs Computer.
2. Pick AI Difficulty and Play As color.
3. Press New Game.

Using Online Multiplayer

1. Set Game Mode to Online Multiplayer.
2. Enter a Room Code (or leave empty to auto-generate one).
3. Choose Preferred Color (or auto assign).
4. Press Connect.
5. Share the same room code with another player connected to the same server.

Notes:

• First two clients become White and Black players.
• Additional clients join as spectators.
• Request New Game resets board state for everyone in the room.

Development Notes

• The server validates online moves using the same engine as the frontend.
• Undo is intentionally disabled in online mode to keep room state consistent.