BlenderでボーンをSwing-Twist分解するリギングを行うためのアドオン

SwingTwistBone.py

"""
振り(swing)と捻じれ(twist)にボーンを分解してリグを組むための
機能を追加するアドオン。

Swing-Twist分解は、腕や足などのボーンによく使用されるが、
デフォルトの機能のみではこれをリギングできない。
・CopyRotationでEulerXZ/Yに分解する
　→ Swing-Twistではないので、角度が大きくなると破綻する
・DampedTrack & CopyRotation
　→ 一見再現できているように見えるが、実行順の影響か
　　 ワンテンポ回転の反映が遅れる
このアドオンでは、ちゃんとSwing-Twist分解した結果を
Driverから直接指定することで、Swing-Twistを実現する。
・・・が、結局1フレーム反映が遅れる

使い方
１．ポーズモードで、ハンドリング用ボーン・Swingボーン・Twistボーンの三つを選択した状態にする
２．ツールシェルフからSTBタブを選択
３．Src/Swing/Twistの項目に、候補となるボーン名が表示されているので、
    問題が無ければExecuteボタンを押す。
"""

import bpy
import os
import subprocess
import bmesh
import mathutils
import math
from bpy_extras.io_utils import ImportHelper
from bpy.app.handlers import persistent

from bpy.types import (
		Operator,
		Panel,
		PropertyGroup,
		OperatorFileListElement,
		)

from bpy.props import (
		BoolProperty,
		PointerProperty,
		StringProperty, 
		CollectionProperty,
		FloatProperty,
		EnumProperty,
		IntProperty,
		)



# プラグインに関する情報
bl_info = {
	"name" : "Swing Twist Bone",
	"author" : "Shu",
	"version" : (0,4),
    'blender': (2, 80, 0),
    "location": "View3D > Toolshelf",
	"description" : "Add the swing twist bone module",
	"warning" : "",
	"wiki_url" : "",
	"tracker_url" : "",
	"category" : "3D View"
}


#-------------------------------------------------------

# 現在選択しているボーンから、srcBone,swingBone,twistBone候補を抜き出して返す
def getSelectedSTBones():
	srcBone = None
	swingBone = None
	twistBone = None

	selectedPoseBones = bpy.context.selected_pose_bones
	for bone in selectedPoseBones:
		if bone.parent is not None and bone.parent in selectedPoseBones:
			twistBone = bone
	for bone in selectedPoseBones:
		if bone.parent is not None and not (bone.parent in selectedPoseBones):
			if twistBone is not None and twistBone.parent == bone:
				swingBone = bone
			else:
				srcBone = bone

	return srcBone, swingBone, twistBone

class Swing_Twist_Bone(Operator):
	bl_idname = "object.swing_twist_bone"
	bl_label = "SwingTwistBone"
	bl_options = {'REGISTER', 'UNDO'}

	def execute(self, context):
		srcBone,swingBone,twistBone = getSelectedSTBones()
		swingBone.rotation_mode = 'QUATERNION'
		twistBone.rotation_mode = 'XYZ'

		paramStr = '("' + bpy.context.active_object.name + '","' + srcBone.name + '")'

		# Locationのドライバーを設定
		d = swingBone.driver_add("location",0).driver
		d.expression = "getBoneLocX" + paramStr
		d = swingBone.driver_add("location",1).driver
		d.expression = "getBoneLocY" + paramStr
		d = swingBone.driver_add("location",2).driver
		d.expression = "getBoneLocZ" + paramStr
		
		# Scaleのドライバーを設定
		d = swingBone.driver_add("scale",0).driver
		d.expression = "getBoneSclX" + paramStr
		d = swingBone.driver_add("scale",1).driver
		d.expression = "getBoneSclY" + paramStr
		d = swingBone.driver_add("scale",2).driver
		d.expression = "getBoneSclZ" + paramStr
		
		# Swingのドライバーを設定
		d = swingBone.driver_add("rotation_quaternion",0).driver
		d.expression = "getBoneSwingW" + paramStr
		d = swingBone.driver_add("rotation_quaternion",1).driver
		d.expression = "getBoneSwingX" + paramStr
		d = swingBone.driver_add("rotation_quaternion",2).driver
		d.expression = "getBoneSwingY" + paramStr
		d = swingBone.driver_add("rotation_quaternion",3).driver
		d.expression = "getBoneSwingZ" + paramStr

		# Twistのドライバーを設定
		d = twistBone.driver_add("rotation_euler",1).driver
		d.expression = "getBoneTwist" + paramStr

		return {'FINISHED'}


# 現在選択しているボーンを、とりあえずSwingBoneとしてのDriverを設定する機能。
# 命名規則は HDL_ボーン名が元になるというので固定。
class Quick_Make_Swing_Bone(Operator):
	bl_idname = "object.quick_make_swing_bone"
	bl_label = "QuickMakeSwingBone"
	bl_options = {'REGISTER', 'UNDO'}

	def execute(self, context):
		srcBone,swingBone,twistBone = getSelectedSTBones()
		swingBone = srcBone
		swingBone.rotation_mode = 'QUATERNION'

		paramStr = '("' + bpy.context.active_object.name + '","HDL_"+self.name)'

		d = swingBone.driver_add("rotation_quaternion",0).driver
		d.expression = "getBoneSwingW" + paramStr
		d.use_self = True
		d = swingBone.driver_add("rotation_quaternion",1).driver
		d.expression = "getBoneSwingX" + paramStr
		d.use_self = True
		d = swingBone.driver_add("rotation_quaternion",2).driver
		d.expression = "getBoneSwingY" + paramStr
		d.use_self = True
		d = swingBone.driver_add("rotation_quaternion",3).driver
		d.expression = "getBoneSwingZ" + paramStr
		d.use_self = True

		return {'FINISHED'}


class VIEW3D_PT_Swing_Twist_Bone_panel(Panel):
	bl_label = "Swing Twist Bone"
	bl_space_type = "VIEW_3D"
	bl_region_type = "UI"
	bl_category = "STB"

	@classmethod
	def poll(self, context):
		return (context.object is not None and (context.object.mode == 'POSE') and (context.active_object.type == 'ARMATURE'))

	def draw(self, context):
		layout = self.layout
		if context.object is not None:
			srcBone,swingBone,twistBone = getSelectedSTBones()
			column = layout.column()
			column.label(text="src : "   + ("" if srcBone   is None else srcBone.name))
			column.label(text="swing : " + ("" if swingBone is None else swingBone.name))
			column.label(text="twist : " + ("" if twistBone is None else twistBone.name))
			row = column.row()
			row.enabled = srcBone is not None and swingBone is not None and twistBone is not None
			row.operator("object.swing_twist_bone", text="Execute")
			layout.separator()

			column = layout.column()
			column.label(text="quick make swing bone")
			column.label(text="tgt : "   + ("" if srcBone   is None else srcBone.name))
			row = column.row()
			row.enabled = srcBone is not None
			row.operator("object.quick_make_swing_bone", text="Execute")
			layout.separator()

		else:
			row = layout.row()
			row.label(text=" ")

classes = (
    VIEW3D_PT_Swing_Twist_Bone_panel,
	Swing_Twist_Bone,
	Quick_Make_Swing_Bone,
)


#-------------------------------------------------------		

# Constraint適応後の最終的なローカル変換マトリクスを得る
def getLocalMtx(amtName, boneName):
	amt = bpy.data.objects[amtName]
	# rotation_quaternionなどでは、Constraint適応後の角度が取れないため、
	# 全適応後のmatrixを直接参照して、そこからボーン回転量を算出する
	mtxPP = amt.pose.bones[boneName].parent.matrix.copy()
	mtxPD = amt.data.bones[boneName].parent.matrix_local.copy()
	mtxPP.invert()
	mtxPD.invert()
	mtxP = mtxPP @ amt.pose.bones[boneName].matrix.copy()
	mtxD = mtxPD @ amt.data.bones[boneName].matrix_local.copy()
	mtxD.invert()
	mtx = mtxD @ mtxP
	return mtx

def getBoneSwingTwist(amtName, boneName, rate):
	mtx = getLocalMtx(amtName, boneName)
	rot = mtx.to_quaternion()
	rot = mathutils.Quaternion().slerp(rot, rate)
	return rot.to_swing_twist("Y")

def getBoneLocX(amtName, boneName):
    return getLocalMtx(amtName, boneName).to_translation().x
def getBoneLocY(amtName, boneName):
    return getLocalMtx(amtName, boneName).to_translation().y
def getBoneLocZ(amtName, boneName):
    return getLocalMtx(amtName, boneName).to_translation().z
def getBoneSclX(amtName, boneName):
    return getLocalMtx(amtName, boneName).to_scale().x
def getBoneSclY(amtName, boneName):
    return getLocalMtx(amtName, boneName).to_scale().y
def getBoneSclZ(amtName, boneName):
    return getLocalMtx(amtName, boneName).to_scale().z
def getBoneSwingX(amtName, boneName):
    return getBoneSwingTwist(amtName, boneName, 1)[0].x
def getBoneSwingY(amtName, boneName):
    return getBoneSwingTwist(amtName, boneName, 1)[0].y
def getBoneSwingZ(amtName, boneName):
    return getBoneSwingTwist(amtName, boneName, 1)[0].z
def getBoneSwingW(amtName, boneName):
    return getBoneSwingTwist(amtName, boneName, 1)[0].w
def getBoneTwist(amtName, boneName):
    return getBoneSwingTwist(amtName, boneName, 1)[1]
def getBoneSwingX2(amtName, boneName, rate):
    return getBoneSwingTwist(amtName, boneName, rate)[0].x
def getBoneSwingY2(amtName, boneName, rate):
    return getBoneSwingTwist(amtName, boneName, rate)[0].y
def getBoneSwingZ2(amtName, boneName, rate):
    return getBoneSwingTwist(amtName, boneName, rate)[0].z
def getBoneSwingW2(amtName, boneName, rate):
    return getBoneSwingTwist(amtName, boneName, rate)[0].w
def getBoneTwist2(amtName, boneName, rate):
    return getBoneSwingTwist(amtName, boneName, rate)[1]

@persistent
def load_handler(dummy):
	# Add variable defined in this script into the drivers namespace.
	bpy.app.driver_namespace["getBoneLocX"] = getBoneLocX
	bpy.app.driver_namespace["getBoneLocY"] = getBoneLocY
	bpy.app.driver_namespace["getBoneLocZ"] = getBoneLocZ
	bpy.app.driver_namespace["getBoneSclX"] = getBoneSclX
	bpy.app.driver_namespace["getBoneSclY"] = getBoneSclY
	bpy.app.driver_namespace["getBoneSclZ"] = getBoneSclZ
	bpy.app.driver_namespace["getBoneSwingX"] = getBoneSwingX
	bpy.app.driver_namespace["getBoneSwingY"] = getBoneSwingY
	bpy.app.driver_namespace["getBoneSwingZ"] = getBoneSwingZ
	bpy.app.driver_namespace["getBoneSwingW"] = getBoneSwingW
	bpy.app.driver_namespace["getBoneTwist"] = getBoneTwist
	bpy.app.driver_namespace["getBoneSwingX2"] = getBoneSwingX2
	bpy.app.driver_namespace["getBoneSwingY2"] = getBoneSwingY2
	bpy.app.driver_namespace["getBoneSwingZ2"] = getBoneSwingZ2
	bpy.app.driver_namespace["getBoneSwingW2"] = getBoneSwingW2
	bpy.app.driver_namespace["getBoneTwist2"] = getBoneTwist2


#-------------------------------------------------------		

# プラグインをインストールしたときの処理
def register():
	for cls in classes:
		bpy.utils.register_class(cls)
	bpy.app.handlers.load_post.append(load_handler)

# プラグインをアンインストールしたときの処理
def unregister():
	for cls in reversed(classes):
		bpy.utils.unregister_class(cls)
	bpy.app.handlers.load_post.remove(load_handler)

if __name__ == "__main__":
	register()