import pygame                
import random

WIDTH = 640                  #width of screen
HEIGHT = 480                 #height of screen

LIFE_WIDTH=64
LIFE_HEIGHT=48

DENSITY = 0.5

def init_random_life_world():
    new_life_world = []
    for y in range(0, LIFE_HEIGHT):
        c_row = []
        for x in range(0, LIFE_WIDTH):
            cur_random = random.random()
            if cur_random > DENSITY:
                c_row.append(1)
            else:
                c_row.append(0)
                
        new_life_world.append(c_row)
        
    return new_life_world

def update_life_world(life_world_passed):
    new_life_world = []
    for y in range(0, LIFE_HEIGHT):
        c_row = []
        for x in range(0, LIFE_WIDTH):
            # get number of neighbors on in 8 surrounding cells
            number_on = life_world_passed[y][ (x-1)%LIFE_WIDTH  ] + \
                        life_world_passed[y][ (x+1)%LIFE_WIDTH  ] + \
                        life_world_passed[ (y-1)%LIFE_HEIGHT ][x] + \
                        life_world_passed[ (y+1)%LIFE_HEIGHT ][x] + \
                        life_world_passed[ (y-1)%LIFE_HEIGHT ][(x-1)%LIFE_WIDTH] + \
                        life_world_passed[ (y-1)%LIFE_HEIGHT ][(x+1)%LIFE_WIDTH] + \
                        life_world_passed[ (y+1)%LIFE_HEIGHT ][(x-1)%LIFE_WIDTH] + \
                        life_world_passed[ (y+1)%LIFE_HEIGHT ][(x+1)%LIFE_WIDTH]
                        
            # RULES:
            # dead cell w/ 3 neighbors wakes up
            # live cell w/ 2 or 3 neighbors stays alive
            if (life_world_passed[y][x] == 0 and number_on == 3) or \
               (life_world_passed[y][x] == 1 and number_on in (2,3) ):
                c_row.append(1)
            else:
                c_row.append(0)
        new_life_world.append(c_row)
    return new_life_world

def show_life_world(life_world):
    for y in range(0, LIFE_HEIGHT):
        for x in range(0, LIFE_WIDTH):
            if life_world[y][x] == 1:
                color = (0, 255, 0)
            else:
                color = (0, 0, 0)
            pygame.draw.rect(screen, color, (x*10, y*10, 9, 9))
    pygame.display.flip()   

screen = pygame.display.set_mode((WIDTH, HEIGHT)) #make screen

life_world = init_random_life_world()

for iteration in range(1, 10000):
    show_life_world(life_world)
    life_world = update_life_world(life_world)
    # print "GENERATION: ", iteration

raw_input("DONE! Press any key to continue")

pygame.display.quit()