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# Copyright 2018-2019 The glTF-Blender-IO authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import struct
from ..com.gltf2_io import Accessor
class BinaryData():
"""Binary reader."""
def __new__(cls, *args, **kwargs):
raise RuntimeError("%s should not be instantiated" % cls)
# Note that this function is not used in Blender importer, but is kept in
# Source code to be used in any pipeline that want to manage gltf/glb file in python
@staticmethod
def get_binary_from_accessor(gltf, accessor_idx):
"""Get binary from accessor."""
accessor = gltf.data.accessors[accessor_idx]
if accessor.buffer_view is None:
return None
data = BinaryData.get_buffer_view(gltf, accessor.buffer_view)
accessor_offset = accessor.byte_offset
if accessor_offset is None:
accessor_offset = 0
return data[accessor_offset:]
@staticmethod
def get_buffer_view(gltf, buffer_view_idx):
"""Get binary data for buffer view."""
buffer_view = gltf.data.buffer_views[buffer_view_idx]
if buffer_view.buffer in gltf.buffers.keys():
buffer = gltf.buffers[buffer_view.buffer]
else:
# load buffer
gltf.load_buffer(buffer_view.buffer)
buffer = gltf.buffers[buffer_view.buffer]
byte_offset = buffer_view.byte_offset
if byte_offset is None:
byte_offset = 0
return buffer[byte_offset:byte_offset + buffer_view.byte_length]
@staticmethod
def get_data_from_accessor(gltf, accessor_idx, cache=False):
"""Get data from accessor."""
if accessor_idx in gltf.accessor_cache:
return gltf.accessor_cache[accessor_idx]
accessor = gltf.data.accessors[accessor_idx]
data = BinaryData.get_data_from_accessor_obj(gltf, accessor)
if cache:
gltf.accessor_cache[accessor_idx] = data
return data
@staticmethod
def get_data_from_accessor_obj(gltf, accessor):
if accessor.buffer_view is not None:
bufferView = gltf.data.buffer_views[accessor.buffer_view]
buffer_data = BinaryData.get_buffer_view(gltf, accessor.buffer_view)
accessor_offset = accessor.byte_offset or 0
buffer_data = buffer_data[accessor_offset:]
fmt_char = gltf.fmt_char_dict[accessor.component_type]
component_nb = gltf.component_nb_dict[accessor.type]
fmt = '<' + (fmt_char * component_nb)
default_stride = struct.calcsize(fmt)
# Special layouts for certain formats; see the section about
# data alignment in the glTF 2.0 spec.
component_size = struct.calcsize('<' + fmt_char)
if accessor.type == 'MAT2' and component_size == 1:
fmt = '<FFxxFF'.replace('F', fmt_char)
default_stride = 8
elif accessor.type == 'MAT3' and component_size == 1:
fmt = '<FFFxFFFxFFF'.replace('F', fmt_char)
default_stride = 12
elif accessor.type == 'MAT3' and component_size == 2:
fmt = '<FFFxxFFFxxFFF'.replace('F', fmt_char)
default_stride = 24
stride = bufferView.byte_stride or default_stride
# Decode
unpack_from = struct.Struct(fmt).unpack_from
data = [
unpack_from(buffer_data, offset)
for offset in range(0, accessor.count*stride, stride)
]
else:
# No buffer view; initialize to zeros
component_nb = gltf.component_nb_dict[accessor.type]
data = [
(0,) * component_nb
for i in range(accessor.count)
]
if accessor.sparse:
sparse_indices_obj = Accessor.from_dict({
'count': accessor.sparse.count,
'bufferView': accessor.sparse.indices.buffer_view,
'byteOffset': accessor.sparse.indices.byte_offset or 0,
'componentType': accessor.sparse.indices.component_type,
'type': 'SCALAR',
})
sparse_values_obj = Accessor.from_dict({
'count': accessor.sparse.count,
'bufferView': accessor.sparse.values.buffer_view,
'byteOffset': accessor.sparse.values.byte_offset or 0,
'componentType': accessor.component_type,
'type': accessor.type,
})
sparse_indices = BinaryData.get_data_from_accessor_obj(gltf, sparse_indices_obj)
sparse_values = BinaryData.get_data_from_accessor_obj(gltf, sparse_values_obj)
# Apply sparse
for i in range(accessor.sparse.count):
data[sparse_indices[i][0]] = sparse_values[i]
# Normalization
if accessor.normalized:
for idx, tuple in enumerate(data):
new_tuple = ()
for i in tuple:
if accessor.component_type == 5120:
new_tuple += (max(float(i / 127.0 ), -1.0),)
elif accessor.component_type == 5121:
new_tuple += (float(i / 255.0),)
elif accessor.component_type == 5122:
new_tuple += (max(float(i / 32767.0), -1.0),)
elif accessor.component_type == 5123:
new_tuple += (i / 65535.0,)
else:
new_tuple += (float(i),)
data[idx] = new_tuple
return data
@staticmethod
def get_image_data(gltf, img_idx):
"""Get data from image."""
pyimage = gltf.data.images[img_idx]
assert not (
pyimage.uri is not None and
pyimage.buffer_view is not None
)
if pyimage.uri is not None:
return gltf.load_uri(pyimage.uri)
if pyimage.buffer_view is not None:
return BinaryData.get_buffer_view(gltf, pyimage.buffer_view)
return None
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