Rigify: add more parent switching and 2.81 inherit scale features.

- Add a parent switch to the main spine control, to allow using the
  key baking operator to convert between moving and fixed root bone.
- Add hips, chest and head as parents for children of the spine.
- Use 'Fix Shear' Inherit Scale and 'Make Uniform' Copy Scale in limbs.
- Switch code to use the new inherit_scale parameter of set_bone_parent.
- Allow local matrices in adjust_widget_transform_mesh.

6 files changed, 60 insertions, 32 deletions

diff --git a/rigify/rigs/limbs/limb_rigs.py b/rigify/rigs/limbs/limb_rigs.py
index 30d475bb..81079c05 100644
--- a/rigify/rigs/limbs/limb_rigs.py
+++ b/rigify/rigs/limbs/limb_rigs.py
@@ -218,7 +218,7 @@ class BaseLimbRig(BaseRig):
     def parent_mch_follow_bone(self):
         mch = self.bones.mch.follow
         align_bone_orientation(self.obj, mch, 'root')
-        self.set_bone_parent(mch, self.rig_parent_bone)
+        self.set_bone_parent(mch, self.rig_parent_bone, inherit_scale='FIX_SHEAR')
 
     @stage.configure_bones
     def configure_mch_follow_bone(self):
@@ -232,8 +232,9 @@ class BaseLimbRig(BaseRig):
     def rig_mch_follow_bone(self):
         mch = self.bones.mch.follow
 
+        self.make_constraint(mch, 'COPY_SCALE', 'root', use_make_uniform=True)
+
         con = self.make_constraint(mch, 'COPY_ROTATION', 'root')
-        self.make_constraint(mch, 'COPY_SCALE', 'root')
 
         self.make_driver(con, 'influence', variables=[(self.prop_bone, 'FK_limb_follow')])
 
@@ -311,7 +312,7 @@ class BaseLimbRig(BaseRig):
 
     def parent_fk_parent_bone(self, i, parent_mch, prev_ctrl, org, prev_org):
         if i == 2:
-            self.set_bone_parent(parent_mch, prev_ctrl, use_connect=True)
+            self.set_bone_parent(parent_mch, prev_ctrl, use_connect=True, inherit_scale='NONE')
 
     @stage.rig_bones
     def rig_fk_parent_chain(self):
@@ -320,7 +321,7 @@ class BaseLimbRig(BaseRig):
 
     def rig_fk_parent_bone(self, i, parent_mch, org):
         if i == 2:
-            self.make_constraint(parent_mch, 'COPY_SCALE', 'root')
+            self.make_constraint(parent_mch, 'COPY_SCALE', 'root', use_make_uniform=True)
 
 
     ####################################################
@@ -691,7 +692,7 @@ class BaseLimbRig(BaseRig):
             self.make_constraint(tweak, 'DAMPED_TRACK', next_tweak)
 
         elif entry.seg_idx is not None:
-            self.make_constraint(tweak, 'COPY_SCALE', 'root')
+            self.make_constraint(tweak, 'COPY_SCALE', 'root', use_make_uniform=True)
 
 
     ####################################################
diff --git a/rigify/rigs/limbs/super_palm.py b/rigify/rigs/limbs/super_palm.py
index a7b322aa..8bcbabf8 100644
--- a/rigify/rigs/limbs/super_palm.py
+++ b/rigify/rigs/limbs/super_palm.py
@@ -115,17 +115,21 @@ class Rig(BaseRig):
 
     @stage.parent_bones
     def parent_master_control(self):
-        self.set_bone_parent(self.bones.ctrl.master, self.rig_parent_bone)
+        self.set_bone_parent(self.bones.ctrl.master, self.rig_parent_bone, inherit_scale='AVERAGE')
 
         if self.make_secondary:
-            self.set_bone_parent(self.bones.ctrl.secondary, self.rig_parent_bone)
+            self.set_bone_parent(self.bones.ctrl.secondary, self.rig_parent_bone, inherit_scale='AVERAGE')
 
     @stage.configure_bones
     def configure_master_control(self):
-        self.copy_bone_properties(self.bones.org[-1], self.bones.ctrl.master)
+        self.configure_control_bone(self.bones.ctrl.master, self.bones.org[-1])
 
         if self.make_secondary:
-            self.copy_bone_properties(self.bones.org[0], self.bones.ctrl.secondary)
+            self.configure_control_bone(self.bones.ctrl.secondary, self.bones.org[0])
+
+    def configure_control_bone(self, ctrl, org):
+        self.copy_bone_properties(org, ctrl)
+        self.get_bone(ctrl).lock_scale = (True, True, True)
 
     @stage.generate_widgets
     def make_master_control_widgets(self):
@@ -179,8 +183,7 @@ class Rig(BaseRig):
     @stage.parent_bones
     def parent_org_chain(self):
         for org in self.bones.org:
-            self.set_bone_parent(org, self.rig_parent_bone)
-            self.get_bone(org).inherit_scale = 'NONE'
+            self.set_bone_parent(org, self.rig_parent_bone, inherit_scale='NONE')
 
     @stage.rig_bones
     def rig_org_chain(self):
diff --git a/rigify/rigs/spines/spine_rigs.py b/rigify/rigs/spines/spine_rigs.py
index 34eefbf5..6628289f 100644
--- a/rigify/rigs/spines/spine_rigs.py
+++ b/rigify/rigs/spines/spine_rigs.py
@@ -64,11 +64,26 @@ class BaseSpineRig(TweakChainRig):
 
         align_bone_to_axis(self.obj, name, 'y', length=self.length * 0.6)
 
-        SwitchParentBuilder(self.generator).register_parent(self, name)
+        self.build_parent_switch(name)
+
+    def build_parent_switch(self, master_name):
+        pbuilder = SwitchParentBuilder(self.generator)
+        pbuilder.register_parent(self, master_name, name='Torso')
+        pbuilder.build_child(
+            self, master_name, exclude_self=True,
+            prop_id='torso_parent', prop_name='Torso Parent',
+            controls=lambda: self.bones.flatten('ctrl'),
+        )
+
+        self.register_parent_bones(pbuilder)
+
+    def register_parent_bones(self, pbuilder):
+        pbuilder.register_parent(self, self.bones.org[0], name='Hips', exclude_self=True)
+        pbuilder.register_parent(self, self.bones.org[-1], name='Chest', exclude_self=True)
 
     @stage.parent_bones
     def parent_master_control(self):
-        self.set_bone_parent(self.bones.ctrl.master, self.rig_parent_bone)
+        pass
 
     @stage.configure_bones
     def configure_master_control(self):
diff --git a/rigify/rigs/spines/super_head.py b/rigify/rigs/spines/super_head.py
index 422f3ad0..9b85e5b5 100644
--- a/rigify/rigs/spines/super_head.py
+++ b/rigify/rigs/spines/super_head.py
@@ -26,6 +26,7 @@ from ...utils.naming import make_derived_name
 from ...utils.bones import align_bone_orientation
 from ...utils.widgets_basic import create_circle_widget, create_cube_widget
 from ...utils.widgets_special import create_neck_bend_widget, create_neck_tweak_widget
+from ...utils.switch_parent import SwitchParentBuilder
 from ...utils.misc import map_list
 
 from ...base_rig import stage
@@ -253,8 +254,7 @@ class Rig(BaseHeadTailRig):
     def parent_mch_chain(self):
         mch = self.bones.mch
         for bone in mch.chain:
-            self.set_bone_parent(bone, mch.stretch)
-            self.get_bone(bone).inherit_scale = 'NONE'
+            self.set_bone_parent(bone, mch.stretch, inherit_scale='NONE')
 
     @stage.rig_bones
     def rig_mch_chain(self):
@@ -318,6 +318,12 @@ class Rig(BaseHeadTailRig):
     ####################################################
     # ORG and DEF bones
 
+    @stage.generate_bones
+    def register_parent_bones(self):
+        rig = self.rigify_parent or self
+        builder = SwitchParentBuilder(self.generator)
+        builder.register_parent(rig, self.bones.org[-1], name='Head', exclude_self=True)
+
     @stage.configure_bones
     def configure_bbone_chain(self):
         self.get_bone(self.bones.deform[-1]).bone.bbone_segments = 1
diff --git a/rigify/utils/switch_parent.py b/rigify/utils/switch_parent.py
index 85e6e130..463398fc 100644
--- a/rigify/utils/switch_parent.py
+++ b/rigify/utils/switch_parent.py
@@ -96,6 +96,7 @@ class SwitchParentBuilder(GeneratorPlugin, MechanismUtilityMixin):
           use_parent_mch    Create an intermediate MCH bone for the constraints and parent the child to it.
           select_parent     Select the specified bone instead of the last one.
           ignore_global     Ignore the is_global flag of potential parents.
+          exclude_self      Ignore parents registered by the rig itself.
           context_rig       Rig to use for selecting parents.
 
           prop_bone         Name of the bone to add the property to.
@@ -158,7 +159,7 @@ class SwitchParentBuilder(GeneratorPlugin, MechanismUtilityMixin):
     child_option_table = {
         'extra_parents': None,
         'prop_bone': None, 'prop_id': None, 'prop_name': None, 'controls': None,
-        'select_parent': None, 'ignore_global': False, 'context_rig': None,
+        'select_parent': None, 'ignore_global': False, 'exclude_self': False, 'context_rig': None,
         'ctrl_bone': None,
         'no_fix_location': False, 'no_fix_rotation': False, 'no_fix_scale': False,
         'copy_location': None, 'copy_rotation': None, 'copy_scale': None,
@@ -186,7 +187,7 @@ class SwitchParentBuilder(GeneratorPlugin, MechanismUtilityMixin):
 
             for parent in self.parent_list:
                 if parent['rig'] is child_rig:
-                    if parent['exclude_self']:
+                    if parent['exclude_self'] or child['exclude_self']:
                         continue
                 elif parent['is_global'] and not child['ignore_global']:
                     # Can't use parents from own children, even if global (cycle risk)
@@ -218,8 +219,7 @@ class SwitchParentBuilder(GeneratorPlugin, MechanismUtilityMixin):
 
             # Parent child to the MCH proxy
             if mch != child['bone']:
-                rig.set_bone_parent(child['bone'], mch)
-                rig.get_bone(child['bone']).inherit_scale = child['inherit_scale']
+                rig.set_bone_parent(child['bone'], mch, inherit_scale=child['inherit_scale'])
 
     def configure_bones(self):
         for child in self.child_list:
diff --git a/rigify/utils/widgets.py b/rigify/utils/widgets.py
index f7e796b6..f4713372 100644
--- a/rigify/utils/widgets.py
+++ b/rigify/utils/widgets.py
@@ -50,16 +50,8 @@ def obj_to_bone(obj, rig, bone_name, bone_transform_name=None):
     elif bone.custom_shape_transform:
         bone = bone.custom_shape_transform
 
-    mat = rig.matrix_world @ bone.bone.matrix_local
-
-    obj.location = mat.to_translation()
-
     obj.rotation_mode = 'XYZ'
-    obj.rotation_euler = mat.to_euler()
-
-    scl = mat.to_scale()
-    scl_avg = (scl[0] + scl[1] + scl[2]) / 3
-    obj.scale = (scale * scl_avg), (scale * scl_avg), (scale * scl_avg)
+    obj.matrix_basis = rig.matrix_world @ bone.bone.matrix_local @ Matrix.Scale(scale, 4)
 
 
 def create_widget(rig, bone_name, bone_transform_name=None):
@@ -159,11 +151,22 @@ def adjust_widget_axis(obj, axis='y', offset=0.0):
         vert.co = matrix @ vert.co
 
 
-def adjust_widget_transform(obj, matrix):
-    """Adjust the generated widget by applying a world space correction matrix to the mesh."""
+def adjust_widget_transform_mesh(obj, matrix, local=None):
+    """Adjust the generated widget by applying a correction matrix to the mesh.
+       If local is false, the matrix is in world space.
+       If local is True, it's in the local space of the widget.
+       If local is a bone, it's in the local space of the bone.
+    """
     if obj:
-        obmat = obj.matrix_basis
-        matrix = obmat.inverted() @ matrix @ obmat
+        if local is not True:
+            if local:
+                assert isinstance(local, bpy.types.PoseBone)
+                bonemat = local.id_data.matrix_world @ local.bone.matrix_local
+                matrix = bonemat @ matrix @ bonemat.inverted()
+
+            obmat = obj.matrix_basis
+            matrix = obmat.inverted() @ matrix @ obmat
+
         obj.data.transform(matrix)