♞Java Medieval Chess Engine

A fully functional, object-oriented Chess Engine built from scratch using Java 17 and JavaFX. This project features a robust MVC architecture, a custom Minimax AI opponent, and a polished medieval pixel-art interface

🚀 Features

Core Engine

• Complete Chess Rules: Handles complex moves including Castling (King/Queen side), En Passant, and Pawn Promotion.
• Move Validation: Validates legal moves for all pieces, preventing illegal actions (e.g., moving a pinned piece, moving into check).
• Game States: Detects Check, Checkmate, and Stalemate conditions accurately.

Artificial Intelligence

• Minimax Algorithm: Implements a recursive tree-search algorithm to determine the best move.
• Heuristic Evaluation: Scores board states based on material weight, mobility, and positional safety.
• Concurrency: Runs AI calculations on a background thread (JavaFX Task) to prevent UI freezing during deep searches.

User Interface (GUI)

• JavaFX Implementation: Built with a clean, responsive UI using StackPane, BorderPane, and GridPane layouts.
• Asset Management: Features a "Medieval Pixel Art" theme with video backgrounds (.mp4) and custom sound effects.
• Quality of Life:
  • Visual Feedback: Highlights legal moves and selected pieces.
  • Game Timer: Functional countdown clock with "Flag Fall" logic.
  • Menus: Interactive Main Menu, Game Setup (Mode/Difficulty/Time), and Pause/Game Over screens.

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🛠 Technology Stack

• Language: Java 17
• Framework: JavaFX 22.0.2 (Controls, FXML, Media, Graphics)
• Build Tool: Maven
• Testing: JUnit 5, Mockito
• Design Patterns:
  • MVC: Separates Board (Model), BoardPanel (View), and GameEngine (Controller).
  • Strategy Pattern: Used for AI Move selection (MoveStrategy).
  • Factory Pattern: Used for creating Moves (MoveFactory).
  • Builder Pattern: Used for constructing immutable Board states.
  • Singleton/Static Utilities: Used for SoundManager and ImageCache.

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⚙️ Installation & Setup

Prerequisites

• Java JDK 17 or higher.
• Maven installed.

Steps

1. Clone the repository

   git clone [https://github.com/dat-nnguyen/java-chess-engine.git](https://github.com/dat-nnguyen/java-chess-engine.git)
   cd java-chess-engine

2. Build the project (Downloads dependencies)

   mvn clean install

3. Run the Application

   mvn javafx:run

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🕹 Controls

• Left Click: Select a piece / Move a piece.
• Esc / Menu Button: Pause the game and open the in-game menu.
• Drag Game Over Screen: You can click and drag the victory popup to view the final board state underneath.

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🏗 Architecture Overview

The project follows strict Object-Oriented Principles:

• entities Package: Contains the core logic.
  • Board: Immutable state container representing the 64 squares.
  • Piece: Abstract class with subclasses (Rook, Pawn, etc.) defining movement vectors.
  • Move: Represents a state transition. Subclasses handle special logic (CastleMove, PawnJump).
• gui Package: Handles the presentation layer.
  • GameEngine: The central controller managing game loop, input handling, and AI triggers.
  • BoardPanel & SquarePanel: Renders the grid and handles click events.
• core.ai Package:
  • MiniMax: The decision-making algorithm.
  • StandardBoardEvaluator: The scoring system for board states.

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🧪 Testing

The project includes a JUnit test suite covering critical game mechanics.

To run tests:

mvn test

Author: Nguyen Tuan Dat

License: MIT