add script to unpack .pak-formatted texture packs

tools/unpak.py

@@ -0,0 +1,95 @@
+#!/usr/bin/env python3
+
+# requires Pillow and zstandard for Python
+# on msys, install Pillow with
+#   pacman -S mingw-w64-x86_64-python-pillow
+# zstd needs to be compiled, because the one in pip3 fails to do so:
+#   pacman -S mingw-w64-x86_64-python-setuptools mingw-w64-x86_64-zstd
+#   git clone https://github.com/indygreg/python-zstandard.git --recursive && cd python-zstandard
+#   python setup.py build_ext --external clean
+# run like this:
+#   ./unpak.py pakfile.pak outdir tools/default_crcmap.txt
+# any files not found in crcmap will go to the "nonmatching" folder
+
+import os
+import sys
+import zstd
+import struct
+from PIL import Image
+
+PAK_MAGIC = b'\x11\xde\x37\x10\x68\x75\xb6\xe8'
+
+if len(sys.argv) < 3:
+    print('usage: unpak <input.pak> <outdir> [<crcmap>]')
+    sys.exit(1)
+
+pakfname = sys.argv[1]
+outpath = sys.argv[2]
+mapfname = "crcmap.txt"
+if len(sys.argv) > 3:
+    mapfname = sys.argv[3]
+
+# load the CRC map
+crcmap = dict()
+try:
+    with open(mapfname, 'r') as f:
+        for line in f:
+            line = line.strip()
+            if line == '' or line[0] == '#':
+                continue
+            tok = line.split(',')
+            crcstr = tok[0].strip()
+            if crcstr.startswith('0x'):
+                crc = int(crcstr[2:], 16)
+            else:
+                crc = int(crcstr)
+            path = os.path.join(outpath, tok[1].strip())
+            if crc in crcmap:
+                crcmap[crc].append(path)
+            else:
+                crcmap[crc] = [path]
+except OSError as e:
+    print('could not open {0}: {1}'.format(mapfname, e))
+    sys.exit(2)
+except ValueError as e:
+    print('invalid integer in {0}: {1}'.format(mapfname, e))
+    sys.exit(2)
+
+unmatchdir = os.path.join(outpath, "nonmatching")
+if not os.path.exists(unmatchdir):
+    os.makedirs(unmatchdir)
+
+# read the PAK
+try:
+    texlist = []
+    with open(pakfname, "rb") as f:
+        magic = f.read(len(PAK_MAGIC))
+        if magic != PAK_MAGIC:
+            print('invalid magic in PAK ' + pakfname)
+            sys.exit(3)
+        texcount = int.from_bytes(f.read(8), byteorder='little')
+        print('reading {0} textures from {1}'.format(texcount, pakfname))
+        for i in range(texcount):
+            crc = int.from_bytes(f.read(4), byteorder='little')
+            size = int.from_bytes(f.read(4), byteorder='little')
+            offset = int.from_bytes(f.read(8), byteorder='little')
+            width = int.from_bytes(f.read(8), byteorder='little')
+            height = int.from_bytes(f.read(8), byteorder='little')
+            texlist.append((crc, size, offset, width, height))
+        for (crc, size, ofs, w, h) in texlist:
+            f.seek(ofs)
+            data = f.read(size)
+            img = Image.frombytes('RGBA', (w, h), zstd.decompress(data))
+            if crc in crcmap:
+                for path in crcmap[crc]:
+                    [fpath, fname] = os.path.split(path)
+                    if not os.path.exists(fpath):
+                        os.makedirs(fpath)
+                    img.save(path)
+            else:
+                print('unknown crc: {0:08x}'.format(crc))
+                path = os.path.join(unmatchdir, "{0:08x}.png".format(crc))
+                img.save(path)
+except OSError as e:
+    print('could not open {0}: {1}'.format(pakfname, e))
+    sys.exit(3)