Pixel Spaceships!

spaceships.py

#!/usr/bin/env python

import random

import pygame
from pygame.locals import *

#
# Pixel Spaceships!
# Original Idea: http://web.archive.org/web/20080228054410/http://www.davebollinger.com/works/pixelspaceships/
#

def pixel_spaceship(signature):
    small = [[' ' for x in range(16)] for y in range(16)]

    # always filled in pixels
    filled_pixels = [
        (6, 6), (6, 7), (7, 6), (7, 7), (8, 6), 
        (8, 7), (11, 6), (11, 7), (12, 6), (12, 7),
    ]

    for pos in filled_pixels:
        x, y = pos
        small[x][y] = 3

    # possible places to put a pixel
    possible_pixels = [
        (1, 6), (1, 7), 
        (2, 5), (2, 6), (2, 7),
        (3, 5), (3, 6), (3, 7), 
        (4, 4), (4, 5), (4, 6), (4, 7),
        (5, 4), (5, 5), (5, 6), (5, 7), 
        (6, 3), (6, 4), (6, 5), 
        (7, 3), (7, 4), (7, 5), 
        (8, 2), (8, 3), (8, 4), (8, 5), 
        (9, 2), (9, 3), (9, 4), (9, 5), (9, 6), (9, 7),
        (10, 1), (10, 2), (10, 3), (10, 4), (10, 5), (10, 6), (10, 7), 
        (11, 1), (11, 2), (11, 3), (11, 4), (11, 5), 
        (12, 1), (12, 2), (12, 3), (12, 4), (12, 5), 
        (13, 2), (13, 3), (13, 4), (13, 5), (13, 6), (13, 7), 
        (14, 3), (14, 4), (14, 5), (14, 6), (14, 7)
    ]

    # use the signature to create the ship
    for pos in possible_pixels:
        # if the smallest bit in the signature is true
        if (signature & 1 == 1):
            x, y = pos
            small[x][y] = 2
    
        # shift the signature
        signature >>= 1

    # mirror the left side to the right
    for row in small:
        for i in range(8):
            j = 15 - i
            row[j] = row[i]

    # expand the array to 32 x 32
    big = [[' ' for x in range(32)] for y in range(32)]

    ox = 0
    oy = 0

    for x in range(0, 32, 2):
        for y in range(0, 32, 2):
            value = small[ox][oy]
            big[x][y] = value
            big[x + 1][y] = value
            big[x][y + 1] = value
            big[x + 1][y + 1] = value
            oy += 1
        ox += 1
        oy = 0
    
    # wrap all the solid pixels twice
    colors = [2, 3]

    for x in range(32):
        for y in range(32):
        
            if big[x][y] in colors:
                continue
        
            if (x - 1 >= 0) and (big[x - 1][y] in colors):
                big[x][y] = 1
                continue
    
            if (x + 1 < 32) and (big[x + 1][y] in colors):
                big[x][y] = 1
                continue
        
            if (y - 1 >= 0) and (big[x][y - 1] in colors):
                big[x][y] = 1
                continue
        
            if (y + 1 < 32) and (big[x][y + 1] in colors):
                big[x][y] = 1
                continue
            
    colors = [1, 2, 3]

    for x in range(32):
        for y in range(32):

            if big[x][y] in colors:
                continue

            if (x - 1 >= 0) and (big[x - 1][y] in colors):
                big[x][y] = 0
                continue

            if (x + 1 < 32) and (big[x + 1][y] in colors):
                big[x][y] = 0
                continue

            if (y - 1 >= 0) and (big[x][y - 1] in colors):
                big[x][y] = 0
                continue

            if (y + 1 < 32) and (big[x][y + 1] in colors):
                big[x][y] = 0
                continue
    
    return big

def draw_spaceship(surface, array):
    surface.fill(pygame.Color('#999999FF'))
    pixelarray = None
    
    try:
        pixelarray = pygame.PixelArray(surface)

        color_map = {
            0: '#00000088',
            1: '#4E9A06FF',
            2: '#73D216FF',
            3: '#8AE234FF'
        }

        for x in range(32):
            for y in range(32):
                a = x + 48
                b = y + 48
        
                color = color_map.get(array[x][y], None)
        
                if color is None:
                    continue
        
                pixelarray[b][a] = surface.map_rgb(pygame.Color(color))
    finally:
        if pixelarray is not None:
            pixelarray = None
    
stop = False

pygame.init()
clock = pygame.time.Clock()

pygame.display.set_caption('Pixel Spaceship!')
surface = pygame.display.set_mode((128, 128))

signature = random.getrandbits(58)
array = pixel_spaceship(signature)
draw_spaceship(surface, array)

while not stop:
    events = pygame.event.get()
    
    for event in events:
        if event.type == QUIT:
            stop = True
            continue
            
        if event.type == MOUSEBUTTONUP:
            signature = random.getrandbits(58)
            array = pixel_spaceship(signature)            
            draw_spaceship(surface, array)
    
    pygame.display.flip()
    clock.tick(30)