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Preface

This question is a re-implementation of my other question here.

The Game

Go or weiqi is an amazingly simple yet complex board game. This game is typically played on a 19x19 grid, and pieces are played on the intersections of lines. Pieces are removed when they are surrounded by opposing stones on all orthogonally adjacent points, in which case the stone or group is captured and removed from the board.

The game ends when both players pass a turn, such as beliving that nothing can be accomplished from further play.

Score is calculated by adding the amount of your pieces on the board and the amount of empty spaces on the board completely encircled and surrounded by your pieces ONLY.

An complete description of the game can be found here: https://en.wikipedia.org/wiki/Go_(game)

My attempt

My code is an attempt to clone this game, trying to keep things accurate, playable, and enjoyable.

An algorithm for detecting pieces that should be removed has been inspired by FirefoxMetzger.

Further notes

Komi, which can be found at the bottom of my code, is well described here: https://en.wikipedia.org/wiki/Go_(game)#Komi. To summarize it, komi is added to white (black goes first) to compensate for the disadvantage of going second. Also, komi is sometimes also a decimal number (such as 4.5) to prevent any ties.

Main questions

I would like speed improvements, code efficiency, and best practices. To detect which sprite is clicked on, I use a location attribute for every sprite, and not the built-in rect. I would like suggestions on this, is this a good practice?

The code:

import os
from tkinter.simpledialog import askfloat

import numpy as np
import pygame
from pygame.locals import K_ESCAPE, KEYDOWN, MOUSEBUTTONUP, QUIT, K_p

WHITE = (255, 255, 255)
BOARDCOLOR = (206, 148, 90)
BLACK = (0, 0, 0)
SHOW_HITBOXES = False

class Spot(pygame.sprite.Sprite):
    def __init__(self, array_indexes, location, size, color):
        super(Spot, self).__init__()
        self.surf = pygame.Surface(size)
        self.surf.fill(color)

        self.location = location
        self.array_indexes = array_indexes
        self.occupied = False
        self.color = None

class Main:
    def __init__(self, komi=2.5):
        pygame.init()

        SCREEN_WIDTH = 563
        SCREEN_HEIGHT = 563

        self.sprites = pygame.sprite.Group()
        self.sprite_array = [[0 for _ in range(19)] for _ in range(19)]

        self.screen = pygame.display.set_mode((SCREEN_WIDTH, SCREEN_HEIGHT))

        pygame.display.set_caption('Go Chess | It\'s Black\'s move!')
        pygame.display.set_allow_screensaver(True)

        if os.path.exists('./iconFile.png'):
            pygame.display.set_icon(pygame.image.load('./iconFile.png'))

        self.move = 0
        self.white_move = False

        self.passed_in_a_row = 0
        self.gameover = False
        
        self.komi = komi
    
    def printLog(self, message, message_type='info'):
        if self.gameover:
            msg = f'[INFO]    Game is over, stopping logging messages.'
        elif message_type == 'info':
            msg = f'[INFO]    {message}'
        elif message_type == 'error':
            msg = f'[ERROR]   {message}'
        elif message_type == 'config':
            msg = f'[CONFIG]  {message}'
        
        print(msg)

    def run(self):
        self.generateSpriteLocations()
        self.addSprites()

        running = True

        while running:
            for event in pygame.event.get():
                self.screen.fill(BOARDCOLOR)

                self.drawGrid()
                self.drawSprites()

                if event.type == MOUSEBUTTONUP:
                    pos = pygame.mouse.get_pos()
                    self.printLog(f'Position clicked: {pos}', 'info')

                    clicked_sprites = [sprite for sprite in self.sprites if self.spriteCollided(sprite.location, pos)]

                    if clicked_sprites and not self.gameover:
                        self.printLog('Sprite detected.', 'info')
                        clicked_sprite = clicked_sprites[0]

                        if not clicked_sprite.occupied:
                            self.move += 1
                            color = BLACK if self.move % 2 else WHITE

                            self.printLog(f'Clicked sprite\'s location: {clicked_sprite.location}', 'info')

                            x, y = clicked_sprite.location
                            loc = (x + 1, y)

                            pygame.draw.circle(self.screen, color, loc, 10, 0)

                            clicked_sprite.occupied = True
                            clicked_sprite.color = color
                            
                            self.capturePieces(*clicked_sprite.array_indexes)

                            if not clicked_sprite.occupied:
                                self.move -= 1
                                self.white_move = True if not self.white_move else False

                            else:
                                self.passed_in_a_row = 0

                                person = 'Black' if not self.move % 2 else 'White'
                                pygame.display.set_caption(f'Go Chess | It\'s {person}\'s move!')

                    else:
                        self.printLog('No sprite detected.', 'info')

                    print()

                elif event.type == KEYDOWN:
                    if event.key == K_ESCAPE:
                        running = False
                        
                    elif event.key == K_p:
                        player = 'White' if not self.move % 2 else 'Black'

                        self.printLog(f'{player} passed a move.', 'info')
                        self.passMove()

                elif event.type == QUIT:
                    running = False
            
            pygame.display.update()
        
        pygame.quit()

    def drawGrid(self):
        for y_pos in range(10, 551, 30):
            pygame.draw.line(self.screen, BLACK, (10, y_pos), (551, y_pos), width=2)
        
        for x_pos in range(10, 551, 30):
            pygame.draw.line(self.screen, BLACK, (x_pos, 10), (x_pos, 551), width=2)

        star_spots = \
            [
                (100, 100),
                (100, 280),
                (100, 460),        

                (280, 100),
                (280, 280),
                (280, 460),

                (460, 100),
                (460, 280),
                (460, 460)
            ]
        
        for location in star_spots:
            x, y = location
            loc = (x + 1, y)

            pygame.draw.circle(self.screen, BLACK, loc, 5, width=0)

    def drawSprites(self):
        for entity in self.sprites:
            if SHOW_HITBOXES:
                self.screen.blit(entity.surf, entity.location)
            if entity.occupied:
                x, y = entity.location
                loc = (x+1, y)
                pygame.draw.circle(self.screen, entity.color, loc, 10, 0)

    def generateSpriteLocations(self):
        locations = []

        for y_index, y_pos in enumerate(range(10, 551, 30)):
            for x_index, x_pos in enumerate(range(10, 551, 30)):
                locations.append([[y_index, x_index], [y_pos, x_pos]])
        
        self.locations = locations
    
    def addSprites(self):
        row = 0
        item = 0

        for location in self.locations:
            if item >= 19:
                row += 1
                item = 0
            if row > 18:
                break
            
            sprite = Spot(*location, (10, 10), (255, 32, 1))
            self.sprites.add(sprite)
            self.sprite_array[item][row] = sprite

            item += 1
        
    def spriteCollided(self, sprite_location, clicked_location):        
        sprite_y, sprite_x = sprite_location
        clicked_y, clicked_x = clicked_location

        if sprite_y - 10 < clicked_y < sprite_y + 10:
            if sprite_x - 10 < clicked_x < sprite_x + 10:
                return True
        
        return False
        
    def passMove(self):
        self.passed_in_a_row += 1
        if self.passed_in_a_row == 2:
            self.gameOver()
            return

        self.move += 1
        self.white_move = True if not self.white_move else False

        person = 'Black' if not self.move % 2 else 'White'
        pygame.display.set_caption(f'Go Chess | It\'s {person}\'s move!')
    
    def gameOver(self):
        person_won = self.calculateWhoWon()
        won_string = f'Go Chess | {person_won} won!'

        pygame.display.set_caption(won_string)

        self.gameover = True

    def calculateWhoWon(self):
        white_score = self.komi
        black_score = 0

        white_on_board, black_on_board = self.findPiecesOnBoard()
        white_surrounded, black_surrounded = self.calculateSurroundedSpots()

        white_score += white_on_board
        black_score += black_on_board

        white_score += white_surrounded
        black_score += black_surrounded
        
        print()
        self.printLog('ENDING SCORES:', 'info')
        self.printLog(f'{white_surrounded=}, {black_surrounded=}', 'info')
        self.printLog(f'{white_on_board=}, {black_on_board=}', 'info')
        self.printLog(f'{white_score=}, {black_score=}', 'info')
        print()

        if white_score > black_score:
            return 'White'
        else:
            return 'Black'
        
    def findPiecesOnBoard(self):
        white_count = 0
        black_count = 0

        for row in self.sprite_array:
            for item in row:
                if not item.occupied:
                    continue

                color = item.color

                if color == WHITE:
                    white_count += 1
                else:
                    black_count += 1

        return (white_count, black_count)
    
    def calculateSurroundedSpots(self):
        white_count = 0
        black_count = 0
        
        self.empty_groups = []
        self.empty_counts = []
        self.empty_colors = []

        self.visited = []        

        for y, row in enumerate(self.sprite_array):
            for x, sprite in enumerate(row):
                if sprite.occupied:
                    continue
                
                self.findEmptyLocations(y, x)

        for index in range(len(self.empty_colors)):
            empty_count = self.empty_counts[index]
            empty_colors = self.empty_colors[index]

            if BLACK not in empty_colors and WHITE in empty_colors:
                white_count += empty_count
            if WHITE not in empty_colors and BLACK in empty_colors:
                black_count += empty_count
        
        return (white_count, black_count)
    
    def findEmptyLocations(self, y, x, adding=False):
        if not adding:
            self.empty_groups.append([])
            self.empty_counts.append(0)
            self.empty_colors.append([])

        neighbors = self.getNeighbors(y, x, (19, 19))
        neighbors.append((y, x))

        for location in neighbors:
            sprite = self.sprite_array[location[0]][location[1]]
        
            if sprite.occupied or sprite in self.visited:
                continue

            self.visited.append(sprite)
            self.empty_groups[-1].append(location)
            self.empty_counts[-1] += 1
            self.empty_colors[-1] += self.getNonEmptyColorsOfNeighbors(y, x)

            self.findEmptyLocations(location[0], location[1], adding=True)
    
    def getNonEmptyColorsOfNeighbors(self, y, x):
        colors = []

        neighbors = self.getNeighbors(y, x, (19, 19))
        for location in neighbors:
            sprite = self.sprite_array[location[0]][location[1]]
            if not sprite.occupied:
                continue
            colors.append(sprite.color)
        
        return colors
    
    def testGroup(self, board, opponent_board, y, x, current_group):
        """ Assume the current group is captured. Find it via flood fill
        and if an empty neighboor is encountered, break (group is alive).

        board - 19x19 array of player's stones
        opponent_board - 19x19 array of opponent's stones
        x,y - position to test
        current_group - tested stones in player's color

        """

        pos = (y,x)

        if current_group[pos]:
            # already tested stones are no liberties
            return False

        if opponent_board[pos]:
            current_group[pos] = True
            neighbors = self.getNeighbors(y,x,board.shape)

            for yn, xn in neighbors:
                has_liberties = self.testGroup(board, opponent_board, yn, xn, current_group)
                if has_liberties:
                    return True
            return False

        return not board[pos]

    def floodfill(self, liberties, y, x):
        """
        flood fill a region that is now known to have liberties. 1.0 signals a liberty, 0.0 signals
        undecided and -1.0 a known non-liberty (black stone)
        liberties is an np.array of currently known liberties and non-liberties
        """

        if not liberties[y][x]:
            liberties[y][x] = 1.0 
            if y > 0:
                self.floodfill(liberties, y-1, x)
            if y < liberties.shape[0] - 1:
                self.floodfill(liberties, y+1, x)
            if x > 0:
                self.floodfill(liberties, y, x-1)
            if x < liberties.shape[1] - 1:
                self.floodfill(liberties, y, x+1)

    def capturePieces(self, y, x):
        white_board = np.array([[1.0 if item.color == WHITE and item.occupied else 0.0 for item in row] for row in self.sprite_array], dtype=int)
        black_board = np.array([[1.0 if item.color == BLACK and item.occupied else 0.0 for item in row] for row in self.sprite_array], dtype=int)

        white_move = self.white_move
        self.white_move = True if not self.white_move else False

        resulting_board = self.fastCapturePieces(black_board, white_board, white_move, y, x)

        for index1, row in enumerate(resulting_board):
            for index2, item in enumerate(row):
                color = WHITE if item == 1 else BLACK
                occupied = True if item != 0 else False

                self.sprite_array[index1][index2].occupied = occupied
                self.sprite_array[index1][index2].color = color

    def fastCapturePieces(self, black_board_, white_board_, turn_white, y,x):
        """Remove all pieces from the board that have no liberties.
        black_board is a 19x19 np.array with value 1.0 if a black stone is
        present and 0.0 otherwise.

        white_board is a 19x19 np.array similar to black_board.

        active_player - the player that made a move
        (x,y) - position of the move

        """

        black_board, white_board = black_board_.copy(), white_board_.copy()

        # only test neighbors of current move (other's will have unchanged
        # liberties)
        neighbors = self.getNeighbors(y, x, black_board.shape)

        board = white_board if turn_white else black_board
        opponent_board = black_board if turn_white else white_board

        original_opponent_board = opponent_board.copy()

        # to test suicidal moves
        original_pos = (y, x)
        original_pos = original_pos[::-1]

        # testing suicides

        current_group = np.zeros((19,19), dtype=bool)
        original_pos_has_liberties = self.testGroup(opponent_board, board, *original_pos, current_group)

        # only test adjacent stones in opponent's color
        for pos in neighbors:
            pos = pos[::-1]

            if not opponent_board[pos]:
                continue

            current_group = np.zeros((19,19), dtype=bool)
            has_liberties = self.testGroup(board, opponent_board, *pos, current_group)

            if not has_liberties:
                opponent_board[current_group] = False

        same = True
        break_out = False

        for row_index, row in enumerate(original_opponent_board):
            for item_index, item in enumerate(row):
                if opponent_board[row_index, item_index] != item:
                    same = False
                    break_out = True
                    break
            if break_out:
                break

        out_board = [[i for i in range(19)] for v in range(19)]
        for i in range(19):
            for v in range(19):
                if white_board[i][v]:
                    out_board[i][v] = 1
                elif black_board[i][v]:
                    out_board[i][v] = -1
                else:
                    out_board[i][v] = 0

        if same and not original_pos_has_liberties:
            out_board[original_pos[0]][original_pos[1]] = 0

            return out_board
        else:       
            return out_board

    def getNeighbors(self, y, x, board_shape):
        neighbors = list()

        if y > 0:
            neighbors.append((y-1,x))
        if y < board_shape[0] - 1:
            neighbors.append((y+1,x))
        if x > 0:
            neighbors.append((y,x-1))
        if x < board_shape[1] - 1:
            neighbors.append((y,x+1))

        return neighbors

if __name__ == '__main__':
    komi = askfloat(title='Go Chess', prompt='Enter a komi value:', minvalue=0, maxvalue=100, initialvalue=2.5)
    app = Main(komi=komi)
    app.run()
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1 Answer 1

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Your program has a bug, that may make it seem slow, which it is not: It redraws the screen before it process an event.

If you click to place a stone to kill a group, and do not move your mouse or touch your keyboard, the display will never update. Not until you move your mouse cursor a pixel.

In general, you should update your screen AFTER processing events. The code below is your main loop. Your drawing code is at location (1), but it should be at location (2)

while running:
  for event in pygame.event.get():
    # (1)
    # process event
  # (2)
  pygame.display.update()

I recommend you use smaller functions, so this kind of patterns will be more obvious. It is a warning sign if a single function contains more than a couple of indentation levels and cannot fit on your screen.

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