FBX: Add 'fbx2json.py' utils to convert binary FBX files into readable JSon ones.

From Campbell's repo.

io_scene_fbx/fbx2json.py

+#!/usr/bin/env python3
+# ##### BEGIN GPL LICENSE BLOCK #####
+#
+#  This program is free software; you can redistribute it and/or
+#  modify it under the terms of the GNU General Public License
+#  as published by the Free Software Foundation; either version 2
+#  of the License, or (at your option) any later version.
+#
+#  This program is distributed in the hope that it will be useful,
+#  but WITHOUT ANY WARRANTY; without even the implied warranty of
+#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#  GNU General Public License for more details.
+#
+#  You should have received a copy of the GNU General Public License
+#  along with this program; if not, write to the Free Software Foundation,
+#  Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+#
+# ##### END GPL LICENSE BLOCK #####
+
+# <pep8 compliant>
+
+# Script copyright (C) 2006-2012, assimp team
+# Script copyright (C) 2013 Blender Foundation
+
+"""
+Usage
+=====
+
+   fbx2json [FILES]...
+
+This script will write a JSON file for each FBX argument given.
+
+
+Output
+======
+
+The JSON data is formatted into a list of nested lists of 4 items:
+
+   ``[id, [data, ...], "data_types", [subtree, ...]]``
+
+Where each list may be empty, and the items in
+the subtree are formatted the same way.
+
+data_types is a string, aligned with data that spesifies a type
+for each property.
+
+The types are as follows:
+
+* 'Y': - INT16
+* 'C': - BOOL
+* 'I': - INT32
+* 'F': - FLOAT32
+* 'D': - FLOAT64
+* 'L': - INT64
+* 'R': - BYTES
+* 'S': - STRING
+* 'f': - FLOAT32_ARRAY
+* 'i': - INT32_ARRAY
+* 'd': - FLOAT64_ARRAY
+* 'l': - INT64_ARRAY
+* 'b': - BOOL ARRAY
+* 'c': - BYTE ARRAY
+
+Note that key:value pairs aren't used since the id's are not
+ensured to be unique.
+"""
+
+
+# ----------------------------------------------------------------------------
+# FBX Binary Parser
+
+from struct import unpack
+import array
+import zlib
+
+# at the end of each nested block, there is a NUL record to indicate
+# that the sub-scope exists (i.e. to distinguish between P: and P : {})
+# this NUL record is 13 bytes long.
+_BLOCK_SENTINEL_LENGTH = 13
+_BLOCK_SENTINEL_DATA = (b'\0' * _BLOCK_SENTINEL_LENGTH)
+_IS_BIG_ENDIAN = (__import__("sys").byteorder != 'little')
+_HEAD_MAGIC = b'Kaydara FBX Binary\x20\x20\x00\x1a\x00'
+from collections import namedtuple
+FBXElem = namedtuple("FBXElem", ("id", "props", "props_type", "elems"))
+del namedtuple
+
+
+def read_uint(read):
+    return unpack(b'<I', read(4))[0]
+
+
+def read_ubyte(read):
+    return unpack(b'B', read(1))[0]
+
+
+def read_string_ubyte(read):
+    size = read_ubyte(read)
+    data = read(size)
+    return data
+
+
+def unpack_array(read, array_type, array_stride, array_byteswap):
+    length = read_uint(read)
+    encoding = read_uint(read)
+    comp_len = read_uint(read)
+
+    data = read(comp_len)
+
+    if encoding == 0:
+        pass
+    elif encoding == 1:
+        data = zlib.decompress(data)
+
+    assert(length * array_stride == len(data))
+
+    data_array = array.array(array_type, data)
+    if array_byteswap and _IS_BIG_ENDIAN:
+        data_array.byteswap()
+    return data_array
+
+
+read_data_dict = {
+    b'Y'[0]: lambda read: unpack(b'<h', read(2))[0],  # 16 bit int
+    b'C'[0]: lambda read: unpack(b'?', read(1))[0],   # 1 bit bool (yes/no)
+    b'I'[0]: lambda read: unpack(b'<i', read(4))[0],  # 32 bit int
+    b'F'[0]: lambda read: unpack(b'<f', read(4))[0],  # 32 bit float
+    b'D'[0]: lambda read: unpack(b'<d', read(8))[0],  # 64 bit float
+    b'L'[0]: lambda read: unpack(b'<q', read(8))[0],  # 64 bit int
+    b'R'[0]: lambda read: read(read_uint(read)),      # binary data
+    b'S'[0]: lambda read: read(read_uint(read)),      # string data
+    b'f'[0]: lambda read: unpack_array(read, 'f', 4, False),  # array (float)
+    b'i'[0]: lambda read: unpack_array(read, 'i', 4, True),   # array (int)
+    b'd'[0]: lambda read: unpack_array(read, 'd', 8, False),  # array (double)
+    b'l'[0]: lambda read: unpack_array(read, 'q', 8, True),   # array (long)
+    b'b'[0]: lambda read: unpack_array(read, 'b', 1, False),  # array (bool)
+    b'c'[0]: lambda read: unpack_array(read, 'B', 1, False),  # array (ubyte)
+    }
+
+
+def read_elem(read, tell, use_namedtuple):
+    # [0] the offset at which this block ends
+    # [1] the number of properties in the scope
+    # [2] the length of the property list
+    end_offset = read_uint(read)
+    if end_offset == 0:
+        return None
+
+    prop_count = read_uint(read)
+    prop_length = read_uint(read)
+
+    elem_id = read_string_ubyte(read)        # elem name of the scope/key
+    elem_props_type = bytearray(prop_count)  # elem property types
+    elem_props_data = [None] * prop_count    # elem properties (if any)
+    elem_subtree = []                        # elem children (if any)
+
+    for i in range(prop_count):
+        data_type = read(1)[0]
+        elem_props_data[i] = read_data_dict[data_type](read)
+        elem_props_type[i] = data_type
+
+    if tell() < end_offset:
+        while tell() < (end_offset - _BLOCK_SENTINEL_LENGTH):
+            elem_subtree.append(read_elem(read, tell, use_namedtuple))
+
+        if read(_BLOCK_SENTINEL_LENGTH) != _BLOCK_SENTINEL_DATA:
+            raise IOError("failed to read nested block sentinel, "
+                          "expected all bytes to be 0")
+
+    if tell() != end_offset:
+        raise IOError("scope length not reached, something is wrong")
+
+    args = (elem_id, elem_props_data, elem_props_type, elem_subtree)
+    return FBXElem(*args) if use_namedtuple else args
+
+
+def parse_version(fn):
+    """
+    Return the FBX version,
+    if the file isn't a binary FBX return zero.
+    """
+    with open(fn, 'rb') as f:
+        read = f.read
+
+        if read(len(_HEAD_MAGIC)) != _HEAD_MAGIC:
+            return 0
+
+        return read_uint(read)
+
+
+def parse(fn, use_namedtuple=True):
+    root_elems = []
+
+    with open(fn, 'rb') as f:
+        read = f.read
+        tell = f.tell
+
+        if read(len(_HEAD_MAGIC)) != _HEAD_MAGIC:
+            raise IOError("Invalid header")
+
+        fbx_version = read_uint(read)
+
+        while True:
+            elem = read_elem(read, tell, use_namedtuple)
+            if elem is None:
+                break
+            root_elems.append(elem)
+
+    args = (b'', [], bytearray(0), root_elems)
+    return FBXElem(*args) if use_namedtuple else args, fbx_version
+
+
+# ----------------------------------------------------------------------------
+# Inline Modules
+
+# pyfbx.data_types
+data_types = type(array)("data_types")
+data_types.__dict__.update(
+dict(
+INT16 = b'Y'[0],
+BOOL = b'C'[0],
+INT32 = b'I'[0],
+FLOAT32 = b'F'[0],
+FLOAT64 = b'D'[0],
+INT64 = b'L'[0],
+BYTES = b'R'[0],
+STRING = b'S'[0],
+FLOAT32_ARRAY = b'f'[0],
+INT32_ARRAY = b'i'[0],
+FLOAT64_ARRAY = b'd'[0],
+INT64_ARRAY = b'l'[0],
+BOOL_ARRAY = b'b'[0],
+BYTE_ARRAY = b'c'[0],
+))
+
+# pyfbx.parse_bin
+parse_bin = type(array)("parse_bin")
+parse_bin.__dict__.update(
+dict(
+parse = parse
+))
+
+
+# ----------------------------------------------------------------------------
+# JSON Converter
+# from pyfbx import parse_bin, data_types
+import json
+import array
+
+
+def fbx2json_property_as_string(prop, prop_type):
+    if prop_type == data_types.STRING:
+        prop_str = prop.decode('utf-8')
+        prop_str = prop_str.replace('\x00\x01', '::')
+        return json.dumps(prop_str)
+    else:
+        prop_py_type = type(prop)
+        if prop_py_type == bytes:
+            return json.dumps(repr(prop)[2:-1])
+        elif prop_py_type == bool:
+            return json.dumps(prop)
+        elif prop_py_type == array.array:
+            return repr(list(prop))
+
+    return repr(prop)
+
+
+def fbx2json_properties_as_string(fbx_elem):
+    return ", ".join(fbx2json_property_as_string(*prop_item)
+                     for prop_item in zip(fbx_elem.props,
+                                          fbx_elem.props_type))
+
+
+def fbx2json_recurse(fw, fbx_elem, ident, is_last):
+    fbx_elem_id = fbx_elem.id.decode('utf-8')
+    fw('%s["%s", ' % (ident, fbx_elem_id))
+    fw('[%s], ' % fbx2json_properties_as_string(fbx_elem))
+    fw('"%s", ' % (fbx_elem.props_type.decode('ascii')))
+
+    fw('[')
+    if fbx_elem.elems:
+        fw('\n')
+        ident_sub = ident + "    "
+        for fbx_elem_sub in fbx_elem.elems:
+            fbx2json_recurse(fw, fbx_elem_sub, ident_sub,
+                             fbx_elem_sub is fbx_elem.elems[-1])
+    fw(']')
+
+    fw(']%s' % ('' if is_last else ',\n'))
+
+
+def fbx2json(fn):
+    import os
+
+    fn_json = "%s.json" % os.path.splitext(fn)[0]
+    print("Writing: %r " % fn_json, end="")
+    fbx_root_elem, fbx_version = parse(fn, use_namedtuple=True)
+    print("(Version %d) ..." % fbx_version)
+
+    with open(fn_json, 'w', encoding="ascii", errors='xmlcharrefreplace') as f:
+        fw = f.write
+        fw('[\n')
+        ident_sub = "    "
+        for fbx_elem_sub in fbx_root_elem.elems:
+            fbx2json_recurse(f.write, fbx_elem_sub, ident_sub,
+                             fbx_elem_sub is fbx_root_elem.elems[-1])
+        fw(']\n')
+
+
+# ----------------------------------------------------------------------------
+# Command Line
+
+def main():
+    import sys
+
+    if "--help" in sys.argv:
+        print(__doc__)
+        return
+
+    for arg in sys.argv[1:]:
+        try:
+            fbx2json(arg)
+        except:
+            print("Failed to convert %r, error:" % arg)
+
+            import traceback
+            traceback.print_exc()
+
+
+if __name__ == "__main__":
+    main()