Verify sprite type 4 in TWG

chkspr4.py

# -*- coding: utf-8 -*-

# Verity sprite file

import argparse
import struct
import os

parser = argparse.ArgumentParser(description='Check sprite file.')
parser.add_argument('-f', required=True, help='sprite file', dest='spr')
args = parser.parse_args()

with open(args.spr, 'rb') as f:
  f.seek(0, os.SEEK_END)
  file_len = f.tell()
  f.seek(0, os.SEEK_SET)

  bytes = f.read(0x40)
  assert b'New Fast&Compress Sprite Ver3.0 for 13h mode!!!. SOFTMAX(C)1994.' == bytes

  f.seek(2, os.SEEK_CUR)

  # number of sprites maybe
  bytes = f.read(2)
  bytes = struct.unpack('<H', bytes)
  num = bytes[0]

  # zero padding
  f.seek(60, os.SEEK_CUR)

  for n in range(num):
    bytes = f.read(4)
    bytes = struct.unpack('<I', bytes)
    len = bytes[0]

    # width maybe
    bytes = f.read(2)
    bytes = struct.unpack('<H', bytes)
    width = bytes[0]

    # height maybe
    bytes = f.read(2)
    bytes = struct.unpack('<H', bytes)
    height = bytes[0]

    assert (width * height + 4) == len

    f.seek(4, os.SEEK_CUR)

    # unknown
    f.read(2)
    f.read(2)

    f.seek(16, os.SEEK_CUR)

    bytes = f.read(2)
    bytes = struct.unpack('<H', bytes)
    assert bytes[0] == width

    bytes = f.read(2)
    bytes = struct.unpack('<H', bytes)
    assert bytes[0] == height

    f.read(len - 4)

  assert f.tell() == file_len