expre-gen/blender/3.4/scripts/addons/io_scene_fbx/encode_bin.py
2025-10-17 09:47:23 +08:00

304 lines
9.0 KiB
Python

# SPDX-License-Identifier: GPL-2.0-or-later
# Script copyright (C) 2013 Campbell Barton
try:
from . import data_types
except:
import data_types
from struct import pack
import array
import zlib
_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'
# fbx has very strict CRC rules, all based on file timestamp
# until we figure these out, write files at a fixed time. (workaround!)
# Assumes: CreationTime
_TIME_ID = b'1970-01-01 10:00:00:000'
_FILE_ID = b'\x28\xb3\x2a\xeb\xb6\x24\xcc\xc2\xbf\xc8\xb0\x2a\xa9\x2b\xfc\xf1'
_FOOT_ID = b'\xfa\xbc\xab\x09\xd0\xc8\xd4\x66\xb1\x76\xfb\x83\x1c\xf7\x26\x7e'
# Awful exceptions: those "classes" of elements seem to need block sentinel even when having no children and some props.
_ELEMS_ID_ALWAYS_BLOCK_SENTINEL = {b"AnimationStack", b"AnimationLayer"}
class FBXElem:
__slots__ = (
"id",
"props",
"props_type",
"elems",
"_props_length", # combine length of props
"_end_offset", # byte offset from the start of the file.
)
def __init__(self, id):
assert(len(id) < 256) # length must fit in a uint8
self.id = id
self.props = []
self.props_type = bytearray()
self.elems = []
self._end_offset = -1
self._props_length = -1
def add_bool(self, data):
assert(isinstance(data, bool))
data = pack('?', data)
self.props_type.append(data_types.BOOL)
self.props.append(data)
def add_int16(self, data):
assert(isinstance(data, int))
data = pack('<h', data)
self.props_type.append(data_types.INT16)
self.props.append(data)
def add_int32(self, data):
assert(isinstance(data, int))
data = pack('<i', data)
self.props_type.append(data_types.INT32)
self.props.append(data)
def add_int64(self, data):
assert(isinstance(data, int))
data = pack('<q', data)
self.props_type.append(data_types.INT64)
self.props.append(data)
def add_float32(self, data):
assert(isinstance(data, float))
data = pack('<f', data)
self.props_type.append(data_types.FLOAT32)
self.props.append(data)
def add_float64(self, data):
assert(isinstance(data, float))
data = pack('<d', data)
self.props_type.append(data_types.FLOAT64)
self.props.append(data)
def add_bytes(self, data):
assert(isinstance(data, bytes))
data = pack('<I', len(data)) + data
self.props_type.append(data_types.BYTES)
self.props.append(data)
def add_string(self, data):
assert(isinstance(data, bytes))
data = pack('<I', len(data)) + data
self.props_type.append(data_types.STRING)
self.props.append(data)
def add_string_unicode(self, data):
assert(isinstance(data, str))
data = data.encode('utf8')
data = pack('<I', len(data)) + data
self.props_type.append(data_types.STRING)
self.props.append(data)
def _add_array_helper(self, data, array_type, prop_type):
assert(isinstance(data, array.array))
assert(data.typecode == array_type)
length = len(data)
if _IS_BIG_ENDIAN:
data = data[:]
data.byteswap()
data = data.tobytes()
# mimic behavior of fbxconverter (also common sense)
# we could make this configurable.
encoding = 0 if len(data) <= 128 else 1
if encoding == 0:
pass
elif encoding == 1:
data = zlib.compress(data, 1)
comp_len = len(data)
data = pack('<3I', length, encoding, comp_len) + data
self.props_type.append(prop_type)
self.props.append(data)
def add_int32_array(self, data):
if not isinstance(data, array.array):
data = array.array(data_types.ARRAY_INT32, data)
self._add_array_helper(data, data_types.ARRAY_INT32, data_types.INT32_ARRAY)
def add_int64_array(self, data):
if not isinstance(data, array.array):
data = array.array(data_types.ARRAY_INT64, data)
self._add_array_helper(data, data_types.ARRAY_INT64, data_types.INT64_ARRAY)
def add_float32_array(self, data):
if not isinstance(data, array.array):
data = array.array(data_types.ARRAY_FLOAT32, data)
self._add_array_helper(data, data_types.ARRAY_FLOAT32, data_types.FLOAT32_ARRAY)
def add_float64_array(self, data):
if not isinstance(data, array.array):
data = array.array(data_types.ARRAY_FLOAT64, data)
self._add_array_helper(data, data_types.ARRAY_FLOAT64, data_types.FLOAT64_ARRAY)
def add_bool_array(self, data):
if not isinstance(data, array.array):
data = array.array(data_types.ARRAY_BOOL, data)
self._add_array_helper(data, data_types.ARRAY_BOOL, data_types.BOOL_ARRAY)
def add_byte_array(self, data):
if not isinstance(data, array.array):
data = array.array(data_types.ARRAY_BYTE, data)
self._add_array_helper(data, data_types.ARRAY_BYTE, data_types.BYTE_ARRAY)
# -------------------------
# internal helper functions
def _calc_offsets(self, offset, is_last):
"""
Call before writing, calculates fixed offsets.
"""
assert(self._end_offset == -1)
assert(self._props_length == -1)
offset += 12 # 3 uints
offset += 1 + len(self.id) # len + idname
props_length = 0
for data in self.props:
# 1 byte for the prop type
props_length += 1 + len(data)
self._props_length = props_length
offset += props_length
offset = self._calc_offsets_children(offset, is_last)
self._end_offset = offset
return offset
def _calc_offsets_children(self, offset, is_last):
if self.elems:
elem_last = self.elems[-1]
for elem in self.elems:
offset = elem._calc_offsets(offset, (elem is elem_last))
offset += _BLOCK_SENTINEL_LENGTH
elif not self.props or self.id in _ELEMS_ID_ALWAYS_BLOCK_SENTINEL:
if not is_last:
offset += _BLOCK_SENTINEL_LENGTH
return offset
def _write(self, write, tell, is_last):
assert(self._end_offset != -1)
assert(self._props_length != -1)
write(pack('<3I', self._end_offset, len(self.props), self._props_length))
write(bytes((len(self.id),)))
write(self.id)
for i, data in enumerate(self.props):
write(bytes((self.props_type[i],)))
write(data)
self._write_children(write, tell, is_last)
if tell() != self._end_offset:
raise IOError("scope length not reached, "
"something is wrong (%d)" % (end_offset - tell()))
def _write_children(self, write, tell, is_last):
if self.elems:
elem_last = self.elems[-1]
for elem in self.elems:
assert(elem.id != b'')
elem._write(write, tell, (elem is elem_last))
write(_BLOCK_SENTINEL_DATA)
elif not self.props or self.id in _ELEMS_ID_ALWAYS_BLOCK_SENTINEL:
if not is_last:
write(_BLOCK_SENTINEL_DATA)
def _write_timedate_hack(elem_root):
# perform 2 changes
# - set the FileID
# - set the CreationTime
ok = 0
for elem in elem_root.elems:
if elem.id == b'FileId':
assert(elem.props_type[0] == b'R'[0])
assert(len(elem.props_type) == 1)
elem.props.clear()
elem.props_type.clear()
elem.add_bytes(_FILE_ID)
ok += 1
elif elem.id == b'CreationTime':
assert(elem.props_type[0] == b'S'[0])
assert(len(elem.props_type) == 1)
elem.props.clear()
elem.props_type.clear()
elem.add_string(_TIME_ID)
ok += 1
if ok == 2:
break
if ok != 2:
print("Missing fields!")
def write(fn, elem_root, version):
assert(elem_root.id == b'')
with open(fn, 'wb') as f:
write = f.write
tell = f.tell
write(_HEAD_MAGIC)
write(pack('<I', version))
# hack since we don't decode time.
# ideally we would _not_ modify this data.
_write_timedate_hack(elem_root)
elem_root._calc_offsets_children(tell(), False)
elem_root._write_children(write, tell, False)
write(_FOOT_ID)
write(b'\x00' * 4)
# padding for alignment (values between 1 & 16 observed)
# if already aligned to 16, add a full 16 bytes padding.
ofs = tell()
pad = ((ofs + 15) & ~15) - ofs
if pad == 0:
pad = 16
write(b'\0' * pad)
write(pack('<I', version))
# unknown magic (always the same)
write(b'\0' * 120)
write(b'\xf8\x5a\x8c\x6a\xde\xf5\xd9\x7e\xec\xe9\x0c\xe3\x75\x8f\x29\x0b')