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NES blocky graphics converter - Details: https://www.patreon.com/posts/22735126
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#!/usr/bin/env python3 | |
# nes_blocky.py | |
# Brad Smith, 2018 | |
# http://rainwarrior.ca | |
# | |
# Finds .NES ROM files in the current folder, | |
# and generates "blocky" pixellated versions of each, | |
# if the game does not use CHR-RAM. | |
import sys | |
import os | |
import random | |
assert sys.version_info[0] >= 3, "Python 3 required." | |
# make this true to overwrite existing files | |
overwrite = False | |
# turn 16 byte CHR tile into 64 pixels, valued 0-3 | |
def chr_to_pixel(tile): | |
pixels = bytearray([0]*64) | |
for y in range(0,8): | |
for x in range(0,8): | |
plane0 = ((tile[y+0] << x) & 0x80) >> 7 | |
plane1 = ((tile[y+8] << x) & 0x80) >> 6 | |
pixel = plane0 | plane1 | |
pixels[(y*8)+x] = pixel | |
return pixels | |
# turn 64 pixels into 16 byte CHR tile | |
def pixel_to_chr(pixels): | |
tile = bytearray([0]*16) | |
for y in range(0,8): | |
plane0 = 0 | |
plane1 = 0 | |
for x in range(0,8): | |
pixel = pixels[(y*8)+x] | |
plane0 <<= 1 | |
plane1 <<= 1 | |
plane0 |= (pixel & 1) | |
plane1 |= (pixel & 2) >> 1 | |
tile[y+0] = plane0 | |
tile[y+8] = plane1 | |
return tile | |
# blockify an 8x8 pixel tile | |
def blocky(pixels,block): | |
# blockify tile | |
y = 0 | |
while y < 8: | |
x = 0 | |
while x < 8: | |
# count the pixels of each colour in the block | |
freq = [0,0,0,0] | |
seed = 0 | |
for by in range(0,block): | |
for bx in range(0,block): | |
p = pixels[((y+by)*8)+(x+bx)] | |
freq[p] += 1 | |
seed += (p * (bx+7) * (by+13)) # simple hash random seed | |
random.seed(seed) # keep randomized tie-breaking consistent | |
# determine the most common colour | |
most = 0 | |
#most_freq = freq[0] | |
most_freq = 0.75 # only choose 0 if no other coloured pixel | |
freq[1] += 0.1 | |
freq[2] += 0.2 | |
freq[3] += 0.3 # favour colour 3 in ties | |
for i in range(1,4): | |
if freq[i] > most_freq: | |
most = i | |
most_freq = freq[i] | |
# fill the block | |
for by in range(0,block): | |
for bx in range(0,block): | |
pixels[((y+by)*8)+(x+bx)] = most | |
# next block | |
x += block | |
y += block | |
# for debugging | |
def print_pixel(pixels): | |
for y in range(0,8): | |
s = "%d:" % y | |
for x in range(0,8): | |
s += " %d" % pixels[(y*8)+x] | |
print(s) | |
# blockify a CHR=ROM | |
def blocky_chr(chr_rom,block): | |
for i in range(0,len(chr_rom),16): | |
tile = chr_rom[i:i+16] | |
pixels = chr_to_pixel(tile) | |
#print("Tile %d" % (i/16)) | |
#print_pixel(pixels) | |
blocky(pixels,block) | |
#print("Blocky %d" % (i/16)) | |
#print_pixel(pixels) | |
tile = pixel_to_chr(pixels) | |
for j in range(0,16): | |
chr_rom[i+j] = tile[j] | |
return | |
# create a blocky version of a ROM | |
def blocky_nes(rom,filename,block): | |
filename_out = "%s (%dx%d)%s" % (os.path.splitext(filename)[0],8/block,8/block,os.path.splitext(filename)[1]) | |
if not overwrite and os.path.exists(filename_out): | |
print("File already exists: "+filename_out) | |
return | |
prg_size = rom[4] * 16 * 1024 | |
chr_size = rom[5] * 8 * 1024 | |
chr_rom = bytearray(rom[16+prg_size:16+prg_size+chr_size]) | |
blocky_chr(chr_rom,block) | |
f = open(filename_out,"wb") | |
f.write(rom[0:16+prg_size]) | |
f.write(chr_rom) | |
f.close() | |
print("Saved: "+filename_out) | |
return | |
# create 2x2, 4x4, and 8x8 blocky versions of a ROM | |
def blocky_nes_group(filename): | |
if not os.path.exists(filename): | |
print("Error! File not found: " + filename) | |
return | |
print("Processing: "+filename) | |
rom = open(filename,"rb").read() | |
prg_size = rom[4] * 16 * 1024 | |
chr_size = rom[5] * 8 * 1024 | |
if chr_size < 1: | |
print("Error! No CHR-ROM present.") | |
return | |
if len(rom) < (16+prg_size+chr_size): | |
print("Error! ROM is missing data.") | |
return | |
if len(rom) > (16+prg_size+chr_size): | |
print("Error! ROM has extra data.") | |
return | |
blocky_nes(rom,filename,2) | |
blocky_nes(rom,filename,4) | |
blocky_nes(rom,filename,8) | |
# to remove generated files | |
def cleanup(): | |
for f in os.listdir(): | |
if ("(4x4)" in f) or ("(2x2)" in f) or ("(1x1)" in f): | |
print("Deleting: %s" % f) | |
os.remove(f) | |
# main program | |
# find all .NES files in the current directory and blockify them | |
random.seed() | |
for filename in os.listdir(): | |
f = filename.lower() | |
if ("(4x4)" in f) or ("(2x2)" in f) or ("(1x1)" in f): | |
continue | |
if (f.endswith(".nes")): | |
blocky_nes_group(filename) | |
# end of file |
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