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# SPDX-License-Identifier: Apache-2.0
# Copyright 2018-2021 The glTF-Blender-IO authors.
from ..com.gltf2_io import gltf_from_dict
from ..com.gltf2_io_debug import Log
import logging
import json
import struct
import base64
from os.path import dirname, join, isfile
from urllib.parse import unquote
# Raise this error to have the importer report an error message.
class ImportError(RuntimeError):
pass
class glTFImporter():
"""glTF Importer class."""
def __init__(self, filename, import_settings):
"""initialization."""
self.filename = filename
self.import_settings = import_settings
self.glb_buffer = None
self.buffers = {}
self.accessor_cache = {}
self.decode_accessor_cache = {}
self.import_user_extensions = import_settings['import_user_extensions']
self.variant_mapping = {} # Used to map between mgltf material idx and blender material, for Variants
if 'loglevel' not in self.import_settings.keys():
self.import_settings['loglevel'] = logging.ERROR
log = Log(import_settings['loglevel'])
self.log = log.logger
self.log_handler = log.hdlr
# TODO: move to a com place?
self.extensions_managed = [
'KHR_materials_pbrSpecularGlossiness',
'KHR_lights_punctual',
'KHR_materials_unlit',
'KHR_texture_transform',
'KHR_materials_clearcoat',
'KHR_mesh_quantization',
'KHR_draco_mesh_compression',
'KHR_materials_variants',
'KHR_materials_emissive_strength',
'KHR_materials_transmission',
'KHR_materials_specular',
'KHR_materials_sheen',
'KHR_materials_ior'
]
# Add extensions required supported by custom import extensions
for import_extension in self.import_user_extensions:
if hasattr(import_extension, "extensions"):
for custom_extension in import_extension.extensions:
if custom_extension.required:
self.extensions_managed.append(custom_extension.name)
@staticmethod
def load_json(content):
def bad_constant(val):
raise ImportError('Bad glTF: json contained %s' % val)
try:
text = str(content, encoding='utf-8')
return json.loads(text, parse_constant=bad_constant)
except ValueError as e:
raise ImportError('Bad glTF: json error: %s' % e.args[0])
@staticmethod
def check_version(gltf):
"""Check version. This is done *before* gltf_from_dict."""
if not isinstance(gltf, dict) or 'asset' not in gltf:
raise ImportError("Bad glTF: no asset in json")
if 'version' not in gltf['asset']:
raise ImportError("Bad glTF: no version")
if gltf['asset']['version'] != "2.0":
raise ImportError("glTF version must be 2.0; got %s" % gltf['asset']['version'])
def checks(self):
"""Some checks."""
if self.data.extensions_required is not None:
for extension in self.data.extensions_required:
if extension not in self.data.extensions_used:
raise ImportError("Extension required must be in Extension Used too")
if extension not in self.extensions_managed:
raise ImportError("Extension %s is not available on this addon version" % extension)
if self.data.extensions_used is not None:
for extension in self.data.extensions_used:
if extension not in self.extensions_managed:
# Non blocking error #TODO log
pass
def load_glb(self, content):
"""Load binary glb."""
magic = content[:4]
if magic != b'glTF':
raise ImportError("This file is not a glTF/glb file")
version, file_size = struct.unpack_from('<II', content, offset=4)
if version != 2:
raise ImportError("GLB version must be 2; got %d" % version)
if file_size != len(content):
raise ImportError("Bad GLB: file size doesn't match")
glb_buffer = None
offset = 12 # header size = 12
# JSON chunk is first
type_, len_, json_bytes, offset = self.load_chunk(content, offset)
if type_ != b"JSON":
raise ImportError("Bad GLB: first chunk not JSON")
if len_ != len(json_bytes):
raise ImportError("Bad GLB: length of json chunk doesn't match")
gltf = glTFImporter.load_json(json_bytes)
# BIN chunk is second (if it exists)
if offset < len(content):
type_, len_, data, offset = self.load_chunk(content, offset)
if type_ == b"BIN\0":
if len_ != len(data):
raise ImportError("Bad GLB: length of BIN chunk doesn't match")
glb_buffer = data
return gltf, glb_buffer
def load_chunk(self, content, offset):
"""Load chunk."""
chunk_header = struct.unpack_from('<I4s', content, offset)
data_length = chunk_header[0]
data_type = chunk_header[1]
data = content[offset + 8: offset + 8 + data_length]
return data_type, data_length, data, offset + 8 + data_length
def read(self):
"""Read file."""
if not isfile(self.filename):
raise ImportError("Please select a file")
with open(self.filename, 'rb') as f:
content = memoryview(f.read())
if content[:4] == b'glTF':
gltf, self.glb_buffer = self.load_glb(content)
else:
gltf = glTFImporter.load_json(content)
self.glb_buffer = None
glTFImporter.check_version(gltf)
try:
self.data = gltf_from_dict(gltf)
except AssertionError:
import traceback
traceback.print_exc()
raise ImportError("Couldn't parse glTF. Check that the file is valid")
def load_buffer(self, buffer_idx):
"""Load buffer."""
buffer = self.data.buffers[buffer_idx]
if buffer.uri:
data = self.load_uri(buffer.uri)
if data is None:
raise ImportError("Missing resource, '" + buffer.uri + "'.")
self.buffers[buffer_idx] = data
else:
# GLB-stored buffer
if buffer_idx == 0 and self.glb_buffer is not None:
self.buffers[buffer_idx] = self.glb_buffer
def load_uri(self, uri):
"""Loads a URI."""
sep = ';base64,'
if uri.startswith('data:'):
idx = uri.find(sep)
if idx != -1:
data = uri[idx + len(sep):]
return memoryview(base64.b64decode(data))
path = join(dirname(self.filename), unquote(uri))
try:
with open(path, 'rb') as f_:
return memoryview(f_.read())
except Exception:
self.log.error("Couldn't read file: " + path)
return None
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