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# SPDX-License-Identifier: Apache-2.0
# Copyright 2018-2021 The glTF-Blender-IO authors.
import mathutils
from . import gltf2_blender_export_keys
from io_scene_gltf2.blender.exp.gltf2_blender_gather_cache import cached
from io_scene_gltf2.io.com import gltf2_io
from io_scene_gltf2.io.exp import gltf2_io_binary_data
from io_scene_gltf2.io.com import gltf2_io_constants
from io_scene_gltf2.blender.exp import gltf2_blender_gather_accessors
from io_scene_gltf2.blender.exp import gltf2_blender_gather_joints
from io_scene_gltf2.io.exp.gltf2_io_user_extensions import export_user_extensions
@cached
def gather_skin(blender_object, export_settings):
"""
Gather armatures, bones etc into a glTF2 skin object.
:param blender_object: the object which may contain a skin
:param export_settings:
:return: a glTF2 skin object
"""
if not __filter_skin(blender_object, export_settings):
return None
skin = gltf2_io.Skin(
extensions=__gather_extensions(blender_object, export_settings),
extras=__gather_extras(blender_object, export_settings),
inverse_bind_matrices=__gather_inverse_bind_matrices(blender_object, export_settings),
joints=__gather_joints(blender_object, export_settings),
name=__gather_name(blender_object, export_settings),
skeleton=__gather_skeleton(blender_object, export_settings)
)
export_user_extensions('gather_skin_hook', export_settings, skin, blender_object)
return skin
def __filter_skin(blender_object, export_settings):
if not export_settings[gltf2_blender_export_keys.SKINS]:
return False
if blender_object.type != 'ARMATURE' or len(blender_object.pose.bones) == 0:
return False
return True
def __gather_extensions(blender_object, export_settings):
return None
def __gather_extras(blender_object, export_settings):
return None
def __gather_inverse_bind_matrices(blender_object, export_settings):
axis_basis_change = mathutils.Matrix.Identity(4)
if export_settings[gltf2_blender_export_keys.YUP]:
axis_basis_change = mathutils.Matrix(
((1.0, 0.0, 0.0, 0.0), (0.0, 0.0, 1.0, 0.0), (0.0, -1.0, 0.0, 0.0), (0.0, 0.0, 0.0, 1.0)))
if export_settings['gltf_def_bones'] is False:
# build the hierarchy of nodes out of the bones
root_bones = []
for blender_bone in blender_object.pose.bones:
if not blender_bone.parent:
root_bones.append(blender_bone)
else:
_, children_, root_bones = get_bone_tree(None, blender_object)
matrices = []
# traverse the matrices in the same order as the joints and compute the inverse bind matrix
def __collect_matrices(bone):
inverse_bind_matrix = (
axis_basis_change @
(
blender_object.matrix_world @
bone.bone.matrix_local
)
).inverted_safe()
matrices.append(inverse_bind_matrix)
if export_settings['gltf_def_bones'] is False:
for child in bone.children:
__collect_matrices(child)
else:
if bone.name in children_.keys():
for child in children_[bone.name]:
__collect_matrices(blender_object.pose.bones[child])
# start with the "root" bones and recurse into children, in the same ordering as the how joints are gathered
for root_bone in root_bones:
__collect_matrices(root_bone)
# flatten the matrices
inverse_matrices = []
for matrix in matrices:
for column in range(0, 4):
for row in range(0, 4):
inverse_matrices.append(matrix[row][column])
binary_data = gltf2_io_binary_data.BinaryData.from_list(inverse_matrices, gltf2_io_constants.ComponentType.Float)
return gltf2_blender_gather_accessors.gather_accessor(
binary_data,
gltf2_io_constants.ComponentType.Float,
len(inverse_matrices) // gltf2_io_constants.DataType.num_elements(gltf2_io_constants.DataType.Mat4),
None,
None,
gltf2_io_constants.DataType.Mat4,
export_settings
)
def __gather_joints(blender_object, export_settings):
root_joints = []
if export_settings['gltf_def_bones'] is False:
# build the hierarchy of nodes out of the bones
for blender_bone in blender_object.pose.bones:
if not blender_bone.parent:
root_joints.append(gltf2_blender_gather_joints.gather_joint(blender_object, blender_bone, export_settings))
else:
_, children_, root_joints = get_bone_tree(None, blender_object)
root_joints = [gltf2_blender_gather_joints.gather_joint(blender_object, i, export_settings) for i in root_joints]
# joints is a flat list containing all nodes belonging to the skin
joints = []
def __collect_joints(node):
joints.append(node)
if export_settings['gltf_def_bones'] is False:
for child in node.children:
__collect_joints(child)
else:
if node.name in children_.keys():
for child in children_[node.name]:
__collect_joints(gltf2_blender_gather_joints.gather_joint(blender_object, blender_object.pose.bones[child], export_settings))
for joint in root_joints:
__collect_joints(joint)
return joints
def __gather_name(blender_object, export_settings):
return blender_object.name
def __gather_skeleton(blender_object, export_settings):
# In the future support the result of https://github.com/KhronosGroup/glTF/pull/1195
return None # gltf2_blender_gather_nodes.gather_node(blender_object, blender_scene, export_settings)
@cached
def get_bone_tree(blender_dummy, blender_object):
bones = []
children = {}
root_bones = []
def get_parent(bone):
bones.append(bone.name)
if bone.parent is not None:
if bone.parent.name not in children.keys():
children[bone.parent.name] = []
children[bone.parent.name].append(bone.name)
get_parent(bone.parent)
else:
root_bones.append(bone.name)
for bone in [b for b in blender_object.data.bones if b.use_deform is True]:
get_parent(bone)
# remove duplicates
for k, v in children.items():
children[k] = list(set(v))
list_ = list(set(bones))
root_ = list(set(root_bones))
return [blender_object.data.bones[b] for b in list_], children, [blender_object.pose.bones[b] for b in root_]
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