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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 bpy
import sys
from ctypes import c_void_p, c_uint32, c_uint64, c_bool, c_char_p, cdll
from pathlib import Path
import struct
from io_scene_gltf2.io.exp.gltf2_io_binary_data import BinaryData
from ...io.com.gltf2_io_debug import print_console
def dll_path() -> Path:
"""
Get the DLL path depending on the underlying platform.
:return: DLL path.
"""
lib_name = 'extern_draco'
blender_root = Path(bpy.app.binary_path).parent
python_lib = Path("{v[0]}.{v[1]}/python/lib".format(v=bpy.app.version))
python_version = "python{v[0]}.{v[1]}".format(v=sys.version_info)
paths = {
'win32': blender_root/python_lib/'site-packages'/'{}.dll'.format(lib_name),
'linux': blender_root/python_lib/python_version/'site-packages'/'lib{}.so'.format(lib_name),
'darwin': blender_root.parent/'Resources'/python_lib/python_version/'site-packages'/'lib{}.dylib'.format(lib_name)
}
path = paths.get(sys.platform)
return path if path is not None else ''
def dll_exists(quiet=False) -> bool:
"""
Checks whether the DLL path exists.
:return: True if the DLL exists.
"""
exists = dll_path().exists()
if quiet is False:
print("'{}' ".format(dll_path().absolute()) + ("exists, draco mesh compression is available" if exists else
"does not exist, draco mesh compression not available"))
return exists
def compress_scene_primitives(scenes, export_settings):
"""
Handles draco compression.
Invoked after data has been gathered, but before scenes get traversed.
Moves position, normal and texture coordinate attributes into a Draco compressed buffer.
"""
# Load DLL and setup function signatures.
# Nearly all functions take the compressor as the first argument.
dll = cdll.LoadLibrary(str(dll_path().resolve()))
# Initialization:
dll.create_compressor.restype = c_void_p
dll.create_compressor.argtypes = []
dll.destroy_compressor.restype = None
dll.destroy_compressor.argtypes = [c_void_p]
# Configuration:
dll.set_compression_level.restype = None
dll.set_compression_level.argtypes = [c_void_p, c_uint32]
dll.set_position_quantization.restype = None
dll.set_position_quantization.argtypes = [c_void_p, c_uint32]
dll.set_normal_quantization.restype = None
dll.set_normal_quantization.argtypes = [c_void_p, c_uint32]
dll.set_uv_quantization.restype = None
dll.set_uv_quantization.argtypes = [c_void_p, c_uint32]
dll.set_generic_quantization.restype = None
dll.set_generic_quantization.argtypes = [c_void_p, c_uint32]
# Data transfer:
dll.set_faces.restype = None
dll.set_faces.argtypes = [
c_void_p, # Compressor
c_uint32, # Index count
c_uint32, # Index byte length
c_char_p # Indices
]
add_attribute_fn_restype = c_uint32 # Draco id
add_attribute_fn_argtypes = [
c_void_p, # Compressor
c_uint32, # Attribute count
c_char_p # Values
]
dll.add_positions_f32.restype = add_attribute_fn_restype
dll.add_positions_f32.argtypes = add_attribute_fn_argtypes
dll.add_normals_f32.restype = add_attribute_fn_restype
dll.add_normals_f32.argtypes = add_attribute_fn_argtypes
dll.add_uvs_f32.restype = add_attribute_fn_restype
dll.add_uvs_f32.argtypes = add_attribute_fn_argtypes
dll.add_weights_f32.restype = add_attribute_fn_restype
dll.add_weights_f32.argtypes = add_attribute_fn_argtypes
dll.add_joints_u16.restype = add_attribute_fn_restype
dll.add_joints_u16.argtypes = add_attribute_fn_argtypes
# Compression:
dll.compress.restype = c_bool
dll.compress.argtypes = [
c_void_p # Compressor
]
dll.compress_morphed.restype = c_bool
dll.compress_morphed.argtypes = [
c_void_p # Compressor
]
dll.get_compressed_size.restype = c_uint64
dll.get_compressed_size.argtypes = [
c_void_p # Compressor
]
dll.copy_to_bytes.restype = None
dll.copy_to_bytes.argtypes = [
c_void_p, # Compressor
c_char_p # Destination pointer
]
# Traverse nodes.
for scene in scenes:
for node in scene.nodes:
__traverse_node(node, lambda node: __compress_node(node, dll, export_settings))
# Cleanup memory.
# May be shared amongst nodes because of non-unique primitive parents, so memory
# release happens delayed.
for scene in scenes:
for node in scene.nodes:
__traverse_node(node, __dispose_memory)
def __dispose_memory(node):
"""Remove buffers from attribute, since the data now resides inside the compressed Draco buffer."""
if not (node.mesh is None):
for primitive in node.mesh.primitives:
# Drop indices.
primitive.indices.buffer_view = None
# Drop attributes.
attributes = primitive.attributes
if 'NORMAL' in attributes:
attributes['NORMAL'].buffer_view = None
for attribute in [attributes[attr] for attr in attributes if attr.startswith('TEXCOORD_')]:
attribute.buffer_view = None
def __compress_node(node, dll, export_settings):
"""Compress a single node."""
if not (node.mesh is None):
print_console('INFO', 'Draco exporter: Compressing mesh "%s".' % node.name)
for primitive in node.mesh.primitives:
__compress_primitive(primitive, dll, export_settings)
def __traverse_node(node, f):
"""Calls f for each node and all child nodes, recursively."""
f(node)
if not (node.children is None):
for child in node.children:
__traverse_node(child, f)
def __compress_primitive(primitive, dll, export_settings):
attributes = primitive.attributes
indices = primitive.indices
# Maps component types to their byte length.
component_type_byte_length = {
'Byte': 1,
'UnsignedByte': 1,
'Short': 2,
'UnsignedShort': 2,
'UnsignedInt': 4,
}
# Positions are the only attribute type required to be present.
if 'POSITION' not in attributes:
print_console('WARNING', 'Draco exporter: Primitive without positions encountered. Skipping.')
return
positions = attributes['POSITION']
normals = attributes['NORMAL'] if 'NORMAL' in attributes else None
uvs = [attributes[attr] for attr in attributes if attr.startswith('TEXCOORD_')]
weights = [attributes[attr] for attr in attributes if attr.startswith('WEIGHTS_')]
joints = [attributes[attr] for attr in attributes if attr.startswith('JOINTS_')]
print_console('INFO', 'Draco exporter: %s normals, %d uvs, %d weights, %d joints' %
('without' if normals is None else 'with', len(uvs), len(weights), len(joints)))
# Begin mesh.
compressor = dll.create_compressor()
# Each attribute must have the same count of elements.
count = positions.count
# Add attributes to mesh compressor, remembering each attribute's Draco id.
position_id = dll.add_positions_f32(compressor, count, positions.buffer_view.data)
normal_id = None
if normals is not None:
if normals.count != count:
print_console('INFO', 'Draco exporter: Mismatching normal count. Skipping.')
dll.disposeCompressor(compressor)
return
normal_id = dll.add_normals_f32(compressor, normals.count, normals.buffer_view.data)
uv_ids = []
for uv in uvs:
if uv.count != count:
print_console('INFO', 'Draco exporter: Mismatching uv count. Skipping.')
dll.disposeCompressor(compressor)
return
uv_ids.append(dll.add_uvs_f32(compressor, uv.count, uv.buffer_view.data))
weight_ids = []
for weight in weights:
if weight.count != count:
print_console('INFO', 'Draco exporter: Mismatching weight count. Skipping.')
dll.disposeCompressor(compressor)
return
weight_ids.append(dll.add_weights_f32(compressor, weight.count, weight.buffer_view.data))
joint_ids = []
for joint in joints:
if joint.count != count:
print_console('INFO', 'Draco exporter: Mismatching joint count. Skipping.')
dll.disposeCompressor(compressor)
return
joint_ids.append(dll.add_joints_u16(compressor, joint.count, joint.buffer_view.data))
# Add face indices to mesh compressor.
dll.set_faces(compressor, indices.count, component_type_byte_length[indices.component_type.name], indices.buffer_view.data)
# Set compression parameters.
dll.set_compression_level(compressor, export_settings['gltf_draco_mesh_compression_level'])
dll.set_position_quantization(compressor, export_settings['gltf_draco_position_quantization'])
dll.set_normal_quantization(compressor, export_settings['gltf_draco_normal_quantization'])
dll.set_uv_quantization(compressor, export_settings['gltf_draco_texcoord_quantization'])
dll.set_generic_quantization(compressor, export_settings['gltf_draco_generic_quantization'])
compress_fn = dll.compress if not primitive.targets else dll.compress_morphed
# After all point and connectivity data has been written to the compressor,
# it can finally be compressed.
if dll.compress(compressor):
# Compression was successful.
# Move compressed data into a bytes object,
# which is referenced by a 'gltf2_io_binary_data.BinaryData':
#
# "KHR_draco_mesh_compression": {
# ....
# "buffer_view": Compressed data inside a 'gltf2_io_binary_data.BinaryData'.
# }
# Query size necessary to hold all the compressed data.
compression_size = dll.get_compressed_size(compressor)
# Allocate byte buffer and write compressed data to it.
compressed_data = bytes(compression_size)
dll.copy_to_bytes(compressor, compressed_data)
if primitive.extensions is None:
primitive.extensions = {}
# Write Draco extension into primitive, including attribute ids:
extension = {
'bufferView': BinaryData(compressed_data),
'attributes': {
'POSITION': position_id
}
}
if normals is not None:
extension['attributes']['NORMAL'] = normal_id
for (k, id) in enumerate(uvs):
extension['attributes']['TEXCOORD_' + str(k)] = id
for (k, id) in enumerate(weight_ids):
extension['attributes']['WEIGHTS_' + str(k)] = id
for (k, id) in enumerate(joint_ids):
extension['attributes']['JOINTS_' + str(k)] = id
primitive.extensions['KHR_draco_mesh_compression'] = extension
# Remove buffer views from the accessors of the attributes which compressed:
positions.buffer_view = None
if normals is not None:
normals.buffer_view = None
for uv in uvs:
uv.buffer_view = None
for weight in weights:
weight.buffer_view = None
for joint in joints:
joint.buffer_view = None
# Set to triangle list mode.
primitive.mode = 4
# Afterwards, the compressor can be released.
dll.destroy_compressor(compressor)
return
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