Conway's Game of Life - using Pygame

conway_game_of_life.py

'''
Conway's Game of Life

Install Pygame:
```
pip install pygame
```
'''

# game configuration

RULE      = ((3, ), (2, 3))  # game rule: B3/S23
                             # see: https://en.wikipedia.org/wiki/Life-like_cellular_automaton#A_selection_of_Life-like_rules
RAND_PCT  = 25               # cell seeding chance (25%)
WIDTH     = 100              # board width
HEIGHT    = 50               # board height
DRAW_SIZE = 8                # size of a "pixel"
DELAY     = 0.05             # cycle delay


# to create a Gosper glider gun instead, set to True
glider_gun = False


import random, time, gc, pygame

gc.enable()
pygame.init()
screen = pygame.display.set_mode([WIDTH * DRAW_SIZE, HEIGHT * DRAW_SIZE])
TOTAL = WIDTH * HEIGHT


def init():
    global board, glider_gun
    board = [0] * TOTAL
    if not glider_gun:
        for i in range(TOTAL):
            if random.randint(0, (100 // RAND_PCT) - 1) == 0:
                board[i] = 1
    else:
        glider_gun = [
            WIDTH*1+25,
            WIDTH*2+23,
            WIDTH*2+25,
            WIDTH*3+13,
            WIDTH*3+14,
            WIDTH*3+21,
            WIDTH*3+22,
            WIDTH*3+35,
            WIDTH*3+36,
            WIDTH*4+12,
            WIDTH*4+16,
            WIDTH*4+21,
            WIDTH*4+22,
            WIDTH*4+35,
            WIDTH*4+36,
            WIDTH*5+1,
            WIDTH*5+2,
            WIDTH*5+11,
            WIDTH*5+17,
            WIDTH*5+21,
            WIDTH*5+22,
            WIDTH*6+1,
            WIDTH*6+2,
            WIDTH*6+11,
            WIDTH*6+15,
            WIDTH*6+17,
            WIDTH*6+18,
            WIDTH*6+23,
            WIDTH*6+25,
            WIDTH*7+11,
            WIDTH*7+17,
            WIDTH*7+25,
            WIDTH*8+12,
            WIDTH*8+16,
            WIDTH*9+13,
            WIDTH*9+14,
        ]
        for i in glider_gun:
            board[i] = 1


def next_gen():
    global board
    buffer = [0] * TOTAL
    
    for i in range(TOTAL):
        i1 = (i - 1) if (i % WIDTH) - 1 >= 0 else (i - 1) + WIDTH
        i3 = (i + 1) if (i % WIDTH) + 1 < WIDTH else (i + 1) - WIDTH
        cells = board[i1] + board[i3] + \
                board[i1 - WIDTH] + board[i - WIDTH] + board[i3 - WIDTH] + \
                board[(i1 + WIDTH) % TOTAL] + board[(i + WIDTH) % TOTAL] + board[(i3 + WIDTH) % TOTAL]
        
        if cells in RULE[board[i]]:
            buffer[i] = 1
        
        pygame.draw.circle(screen,
                           (255, 255, 255) if buffer[i] else (0, 0, 0),
                           (i % WIDTH * DRAW_SIZE, i // WIDTH * DRAW_SIZE), DRAW_SIZE // 2)
    
    board = buffer
    pygame.display.flip()
    pygame.display.set_caption(f'Conway\'s Game of Life [{sum(board)} cells]')


init()
running = True

while running:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False
    
    next_gen()
    time.sleep(DELAY)

pygame.quit()