xkcd_tictactoe.py

#!/usr/bin/env python3
#
# Attempts to play Tic Tac Toe following https://imgs.xkcd.com/comics/tic_tac_toe.png
# Does so by trying to read off the image.
# Requires the file to be located in the same folder.

import cv2
import numpy as np

DEBUG = False

image = cv2.imread("tic_tac_toe.png")

print("Welcome to Tic Tac Toe - XKCD edition.")

player = None
while player not in ['X', 'O']:
    player = input("Do you want to play as X or O? ")

if player == 'O':
    image = image[155:878,9:730]
    offset = 0
else:
    image = image[939:1666,9:730]
    offset = 2

# remove spaces
image = np.delete(image, slice(477+offset, 483+offset), 0)
image = np.delete(image, slice(236+offset, 242+offset), 0)
image = np.delete(image, slice(480, 486), 1)
image = np.delete(image, slice(235, 241), 1)

turn = 'X'
gameState = [None] * 9

def winner():
    checks = [[0,1,2], [3,4,5], [6,7,8], [0,4,8], [2,4,6], [0,3,6], [1,4,7], [2,5,8]]
    for check in checks:
        elements = [gameState[i] for i in check]
        first = elements[0]
        if first is None: continue
        if all(x == first for x in elements): return first
    return False

def gameOver():
    return winner() or None not in gameState

def showBoard():
    for i in [0, 3, 6]:
        elms = zip(gameState[i:i+3], range(i, i+3))
        print("|".join(e if e else str(i) for (e, i) in elms))
        if i < 6: print("-"*5)

def validMove(move):
    return move is not None and move >= 0 and gameState[move] is None

def imageSegment(i):
    global image
    (h, w, d) = image.shape

    dh = h // 3
    dw = w // 3
    newH = dh * (i // 3)
    newW = dw * (i % 3)

    return image[newH:newH+dh, newW:newW+dw]

while not gameOver():
    if turn == player:
        move = None
        while not validMove(move):
            showBoard()
            move = input(f"Where do you want to place an {player}? ")
            if not move.isnumeric():
                move = None
            else:
                move = int(move)
        gameState[move] = player

        image = imageSegment(move)
        if DEBUG:
            cv2.imshow("image", image)
            cv2.waitKey(0)
    else:
        bestScore = -999999
        bestSegment = None
        for i in range(9):
            if gameState[i] is not None: continue
            segment = imageSegment(i)

            # Count red/black/white pixels in segment to deduce where the next move is intended to be.
            (b, g, r) = cv2.split(segment)
            blackCount = 0
            redCount = 0
            whiteCount = 0
            for y in range(r.shape[0]):
                for x in range(r.shape[1]):
                    if r[y,x] < 150: blackCount += 1
                    if r[y,x] > 150 and b[y,x] < 150: redCount += 1
                    if r[y,x] > 150 and b[y,x] > 150 and g[y,x] > 150: whiteCount += 1

            score = 10*redCount + 0.25*whiteCount - 3*blackCount
            if DEBUG:
                print(f"segment {i}: redCount {redCount}, blackCount {blackCount}, whiteCount {whiteCount}, score {score}")
            if score > bestScore:
                bestScore = score
                bestSegment = i
            if DEBUG:
                cv2.imshow(f"segment {i}", imageSegment(i))
                cv2.waitKey(0)

        print(f"AI places piece in spot {bestSegment}")
        gameState[bestSegment] = 'X' if player == 'O' else 'O'

    turn = 'X' if turn == 'O' else 'O'

showBoard()
won = winner()
if won:
    print(f"Game over. Winner is {won}.")
else:
    print("Game over. Game is a draw!")