Verify sprite type 5 in TWG(The War of Genesis 2).

chkspr5.py

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

import argparse
import struct
import os

parser = argparse.ArgumentParser(description='Verify sprites.')
parser.add_argument('-f', required=True, help='sprites 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)

  # header
  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)

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

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

  for n in range(num):
    # total length of compressed pixel data
    buf = f.read(4)
    buf = struct.unpack('<I', buf)
    length = buf[0]

    # width
    buf = f.read(2)
    buf = struct.unpack('<H', buf)
    width = buf[0]
    assert 320 >= width

    # height
    buf = f.read(2)
    buf = struct.unpack('<H', buf)
    height = buf[0]
    assert 200 >= height

    # unknown
    f.seek(24, os.SEEK_CUR)

    # number of compressed chunks
    buf = f.read(2)
    buf = struct.unpack('<H', buf)
    chunks = buf[0]

    l = 0
    for c in range(chunks):
      assert f.tell() < file_len
      buf = f.read(2)
      buf = struct.unpack('<H', buf)
      blanks = buf[0]

      assert f.tell() < file_len
      buf = f.read(1)
      buf = struct.unpack('<B', buf)
      i = buf[0]

      assert f.tell() < file_len
      buf = f.read(1)
      buf = struct.unpack('<B', buf)
      j = buf[0]
    
      f.read(4 * i + j)

      l = l + 2 + 1 + 1 + 4 * i + j

    assert (l + 2) == length

  assert f.tell() == file_len