glTF is a format for distribution of 3D models optimized for being used in software
This page hosts a formal specification of GL Transmission Format, binary container using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.
All parsing code for Python generated by Kaitai Struct depends on the Python runtime library. You have to install it before you can parse data.
The Python runtime library can be installed from PyPI:
python3 -m pip install kaitaistructParse a local file and get structure in memory:
data = GltfBinary.from_file("path/to/local/file.glb")
Or parse structure from a bytes:
from kaitaistruct import KaitaiStream, BytesIO
raw = b"\x00\x01\x02..."
data = GltfBinary(KaitaiStream(BytesIO(raw)))
After that, one can get various attributes from the structure by invoking getter methods like:
data.header # => get header
# This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild
# type: ignore
import kaitaistruct
from kaitaistruct import KaitaiStruct, KaitaiStream, BytesIO
from enum import IntEnum
if getattr(kaitaistruct, 'API_VERSION', (0, 9)) < (0, 11):
raise Exception("Incompatible Kaitai Struct Python API: 0.11 or later is required, but you have %s" % (kaitaistruct.__version__))
class GltfBinary(KaitaiStruct):
"""glTF is a format for distribution of 3D models optimized for being used in software
.. seealso::
Source - https://github.com/KhronosGroup/glTF/tree/2354846/specification/2.0#binary-gltf-layout
"""
class ChunkType(IntEnum):
bin = 5130562
json = 1313821514
def __init__(self, _io, _parent=None, _root=None):
super(GltfBinary, self).__init__(_io)
self._parent = _parent
self._root = _root or self
self._read()
def _read(self):
self.header = GltfBinary.Header(self._io, self, self._root)
self.chunks = []
i = 0
while not self._io.is_eof():
self.chunks.append(GltfBinary.Chunk(self._io, self, self._root))
i += 1
def _fetch_instances(self):
pass
self.header._fetch_instances()
for i in range(len(self.chunks)):
pass
self.chunks[i]._fetch_instances()
class Bin(KaitaiStruct):
def __init__(self, _io, _parent=None, _root=None):
super(GltfBinary.Bin, self).__init__(_io)
self._parent = _parent
self._root = _root
self._read()
def _read(self):
self.data = self._io.read_bytes_full()
def _fetch_instances(self):
pass
class Chunk(KaitaiStruct):
def __init__(self, _io, _parent=None, _root=None):
super(GltfBinary.Chunk, self).__init__(_io)
self._parent = _parent
self._root = _root
self._read()
def _read(self):
self.len_data = self._io.read_u4le()
self.type = KaitaiStream.resolve_enum(GltfBinary.ChunkType, self._io.read_u4le())
_on = self.type
if _on == GltfBinary.ChunkType.bin:
pass
self._raw_data = self._io.read_bytes(self.len_data)
_io__raw_data = KaitaiStream(BytesIO(self._raw_data))
self.data = GltfBinary.Bin(_io__raw_data, self, self._root)
elif _on == GltfBinary.ChunkType.json:
pass
self._raw_data = self._io.read_bytes(self.len_data)
_io__raw_data = KaitaiStream(BytesIO(self._raw_data))
self.data = GltfBinary.Json(_io__raw_data, self, self._root)
else:
pass
self.data = self._io.read_bytes(self.len_data)
def _fetch_instances(self):
pass
_on = self.type
if _on == GltfBinary.ChunkType.bin:
pass
self.data._fetch_instances()
elif _on == GltfBinary.ChunkType.json:
pass
self.data._fetch_instances()
else:
pass
class Header(KaitaiStruct):
def __init__(self, _io, _parent=None, _root=None):
super(GltfBinary.Header, self).__init__(_io)
self._parent = _parent
self._root = _root
self._read()
def _read(self):
self.magic = self._io.read_bytes(4)
if not self.magic == b"\x67\x6C\x54\x46":
raise kaitaistruct.ValidationNotEqualError(b"\x67\x6C\x54\x46", self.magic, self._io, u"/types/header/seq/0")
self.version = self._io.read_u4le()
self.length = self._io.read_u4le()
def _fetch_instances(self):
pass
class Json(KaitaiStruct):
def __init__(self, _io, _parent=None, _root=None):
super(GltfBinary.Json, self).__init__(_io)
self._parent = _parent
self._root = _root
self._read()
def _read(self):
self.data = (self._io.read_bytes_full()).decode(u"UTF-8")
def _fetch_instances(self):
pass