Go

An implementation of the Go board game using Java Swing. The rules of Go are implemented fully except for the ko rule, which has partial support.

Implementation Details

1. Representation: A 2d array is used to represent the gameboard. The 2d array is contained inside a StoneArray object. The elements of the 2d array are objects of the Stone class which is an extension of the GameObj class. The Stone objects maintain information about their positions on the board and their state (EMPTY, BLACK, WHITE). By default, the StoneArray object is initialized with EMPTY states for all Stone objects.

2. Save and Load: The game state can be saved or restored from a previously saved file. The complete state of the saved game is contained in the savedGame.txt file whose first line is the number of points black had, second line is the number of points white had, 3-15 lines are a string representation of the saved StoneArray (0 for empty, 1 for white, 2 for black), and the line 16 is the player whose turn it is (1 for white, 2 for black).

3. Recursive capture: In Go, a group of stones of one player is captured (removed from the board) if each of them is surrounded on all four side by other stones. This is implemented through a recursive method. The recursive method, for the position it is applied on, checks whether the stone has any empty sides and returns true if it does. Otherwise it recurses onto stones surrounding it of the same type that have not been previously checked and performs an OR operation on the results and returns this. Ultimately, the method checks whether any of the stones of a group have an empty intersection.

A Set structure is used for the recursive method. The recursive method must not call on the same stones continuously to prevent an infinite loop. So, the method is called with a Set object that keeps track of all of the stones that the method has been applied to.

Classes

The enum Player represents the possible Players (Black or White). The enum Stone represents the possible state of a Stone (Black, White, or Empty). The enum InvalidMove represents the possible moves that are not allowed as well as errors or warnings that can be displayed. The Game object is the same as the original with a few added buttons and an additional instructions frame. The GameBoard is the background of the Go Board. The GameCourt is contains most of the logic operations outside of StoneArray as well as I/O and Clicking functionality The GameObj class is the same as original with the unnecessary velocity values removed. The Stone class represents each of the stone objects which are gameObjects that know their state. The StoneArray class contains all of the Stone objects in a 2D array and acts as an intermediary between GameCourt and the Stones. Its methods can alter the state of the 2D array and contains most of the logic operations (especially the more complex ones like checking for the validity of a placement).

Challenges

The game logic, specifically the recursive algorithm and the associated removal feature
are the most challenging aspect to implement. This requiras the methods to create additional StoneArray
objects to simulate possible changes to the game and whether a move would be legal.