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# Copyright 2018 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
from mathutils import Matrix
from ..com.gltf2_blender_conversion import loc_gltf_to_blender, quaternion_gltf_to_blender, scale_to_matrix
from ...io.imp.gltf2_io_binary import BinaryData
class BlenderBoneAnim():
"""Blender Bone Animation."""
def __new__(cls, *args, **kwargs):
raise RuntimeError("%s should not be instantiated" % cls)
@staticmethod
def set_interpolation(interpolation, kf):
"""Set interpolation."""
if interpolation == "LINEAR":
kf.interpolation = 'LINEAR'
elif interpolation == "STEP":
kf.interpolation = 'CONSTANT'
elif interpolation == "CUBICSPLINE":
kf.interpolation = 'BEZIER'
else:
kf.interpolation = 'LINEAR'
@staticmethod
def parse_translation_channel(gltf, node, obj, bone, channel, animation):
"""Manage Location animation."""
fps = bpy.context.scene.render.fps
blender_path = "location"
keys = BinaryData.get_data_from_accessor(gltf, animation.samplers[channel.sampler].input)
values = BinaryData.get_data_from_accessor(gltf, animation.samplers[channel.sampler].output)
inv_bind_matrix = node.blender_bone_matrix.to_quaternion().to_matrix().to_4x4().inverted() \
@ Matrix.Translation(node.blender_bone_matrix.to_translation()).inverted()
for idx, key in enumerate(keys):
if animation.samplers[channel.sampler].interpolation == "CUBICSPLINE":
# TODO manage tangent?
translation_keyframe = loc_gltf_to_blender(values[idx * 3 + 1])
else:
translation_keyframe = loc_gltf_to_blender(values[idx])
if node.parent is None:
parent_mat = Matrix()
else:
if not gltf.data.nodes[node.parent].is_joint:
parent_mat = Matrix()
else:
parent_mat = gltf.data.nodes[node.parent].blender_bone_matrix
# Pose is in object (armature) space and it's value if the offset from the bind pose
# (which is also in object space)
# Scale is not taken into account
final_trans = (parent_mat @ Matrix.Translation(translation_keyframe)).to_translation()
bone.location = inv_bind_matrix @ final_trans
bone.keyframe_insert(blender_path, frame=key[0] * fps, group="location")
for fcurve in [curve for curve in obj.animation_data.action.fcurves if curve.group.name == "location"]:
for kf in fcurve.keyframe_points:
BlenderBoneAnim.set_interpolation(animation.samplers[channel.sampler].interpolation, kf)
@staticmethod
def parse_rotation_channel(gltf, node, obj, bone, channel, animation):
"""Manage rotation animation."""
# Note: some operations lead to issue with quaternions. Converting to matrix and then back to quaternions breaks
# quaternion continuity
# (see antipodal quaternions). Blender interpolates between two antipodal quaternions, which causes glitches in
# animation.
# Converting to euler and then back to quaternion is a dirty fix preventing this issue in animation, until a
# better solution is found
# This fix is skipped when parent matrix is identity
fps = bpy.context.scene.render.fps
blender_path = "rotation_quaternion"
keys = BinaryData.get_data_from_accessor(gltf, animation.samplers[channel.sampler].input)
values = BinaryData.get_data_from_accessor(gltf, animation.samplers[channel.sampler].output)
bind_rotation = node.blender_bone_matrix.to_quaternion()
for idx, key in enumerate(keys):
if animation.samplers[channel.sampler].interpolation == "CUBICSPLINE":
# TODO manage tangent?
quat_keyframe = quaternion_gltf_to_blender(values[idx * 3 + 1])
else:
quat_keyframe = quaternion_gltf_to_blender(values[idx])
if not node.parent:
bone.rotation_quaternion = bind_rotation.inverted() @ quat_keyframe
else:
if not gltf.data.nodes[node.parent].is_joint:
parent_mat = Matrix()
else:
parent_mat = gltf.data.nodes[node.parent].blender_bone_matrix
if parent_mat != parent_mat.inverted():
final_rot = (parent_mat @ quat_keyframe.to_matrix().to_4x4()).to_quaternion()
bone.rotation_quaternion = bind_rotation.rotation_difference(final_rot).to_euler().to_quaternion()
else:
bone.rotation_quaternion = \
bind_rotation.rotation_difference(quat_keyframe).to_euler().to_quaternion()
bone.keyframe_insert(blender_path, frame=key[0] * fps, group='rotation')
for fcurve in [curve for curve in obj.animation_data.action.fcurves if curve.group.name == "rotation"]:
for kf in fcurve.keyframe_points:
BlenderBoneAnim.set_interpolation(animation.samplers[channel.sampler].interpolation, kf)
@staticmethod
def parse_scale_channel(gltf, node, obj, bone, channel, animation):
"""Manage scaling animation."""
fps = bpy.context.scene.render.fps
blender_path = "scale"
keys = BinaryData.get_data_from_accessor(gltf, animation.samplers[channel.sampler].input)
values = BinaryData.get_data_from_accessor(gltf, animation.samplers[channel.sampler].output)
bind_scale = scale_to_matrix(node.blender_bone_matrix.to_scale())
for idx, key in enumerate(keys):
if animation.samplers[channel.sampler].interpolation == "CUBICSPLINE":
# TODO manage tangent?
scale_mat = scale_to_matrix(loc_gltf_to_blender(values[idx * 3 + 1]))
else:
scale_mat = scale_to_matrix(loc_gltf_to_blender(values[idx]))
if not node.parent:
bone.scale = (bind_scale.inverted() @ scale_mat).to_scale()
else:
if not gltf.data.nodes[node.parent].is_joint:
parent_mat = Matrix()
else:
parent_mat = gltf.data.nodes[node.parent].blender_bone_matrix
bone.scale = (
bind_scale.inverted() @ scale_to_matrix(parent_mat.to_scale()) @ scale_mat
).to_scale()
bone.keyframe_insert(blender_path, frame=key[0] * fps, group='scale')
for fcurve in [curve for curve in obj.animation_data.action.fcurves if curve.group.name == "scale"]:
for kf in fcurve.keyframe_points:
BlenderBoneAnim.set_interpolation(animation.samplers[channel.sampler].interpolation, kf)
@staticmethod
def anim(gltf, anim_idx, node_idx):
"""Manage animation."""
node = gltf.data.nodes[node_idx]
obj = bpy.data.objects[gltf.data.skins[node.skin_id].blender_armature_name]
bone = obj.pose.bones[node.blender_bone_name]
if anim_idx not in node.animations.keys():
return
animation = gltf.data.animations[anim_idx]
if animation.name:
name = animation.name + "_" + obj.name
else:
name = "Animation_" + str(anim_idx) + "_" + obj.name
if name not in bpy.data.actions:
action = bpy.data.actions.new(name)
else:
action = bpy.data.actions[name]
# Check if this action has some users.
# If no user (only 1 indeed), that means that this action must be deleted
# (is an action from a deleted object)
if action.users == 1:
bpy.data.actions.remove(action)
action = bpy.data.actions.new(name)
if not obj.animation_data:
obj.animation_data_create()
obj.animation_data.action = bpy.data.actions[action.name]
for channel_idx in node.animations[anim_idx]:
channel = animation.channels[channel_idx]
if channel.target.path == "translation":
BlenderBoneAnim.parse_translation_channel(gltf, node, obj, bone, channel, animation)
elif channel.target.path == "rotation":
BlenderBoneAnim.parse_rotation_channel(gltf, node, obj, bone, channel, animation)
elif channel.target.path == "scale":
BlenderBoneAnim.parse_scale_channel(gltf, node, obj, bone, channel, animation)
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