Rigify: port the ability to generate Action constraints from CloudRig.

CloudRig has a feature that allows the user to automatically generate
Action constraints that move bones of the rig based on the position
of other bones. This is done by adding and configuring the actions
in a UI panel of the metarig. The feature also supports corrective
actions that activate based on the state of two other actions.

This ports the feature to base Rigify with the necessary changes in
code organization and style, and replacing CloudRig-specific code.

There are also some functional changes:

- The order of action constraints is reversed.
- The way symmetry of LOCATION_X is handed is changed to
  match how Paste Pose Flipped works.
- The action slot UI is shown even without a generated rig.
- More alerts in the UI, e.g. for duplicate rows.

Differential Revision: https://developer.blender.org/D16336

1 files changed, 3 insertions, 0 deletions

diff --git a/rigify/generate.py b/rigify/generate.py
index 4f30adff..7060c448 100644
--- a/rigify/generate.py
+++ b/rigify/generate.py
@@ -16,6 +16,7 @@ from .utils.misc import gamma_correct, select_object, ArmatureObject, verify_arm
 from .utils.collections import (ensure_collection, list_layer_collections,
                                 filter_layer_collections_by_object)
 from .utils.rig import get_rigify_type, get_rigify_layers
+from .utils.action_layers import ActionLayerBuilder
 
 from . import base_generate
 from . import rig_ui_template
@@ -37,6 +38,7 @@ class Timer:
 
 class Generator(base_generate.BaseGenerator):
     usable_collections: list[bpy.types.LayerCollection]
+    action_layers: ActionLayerBuilder
 
     def __init__(self, context, metarig):
         super().__init__(context, metarig)
@@ -456,6 +458,7 @@ class Generator(base_generate.BaseGenerator):
         obj.data["rig_id"] = self.rig_id
 
         self.script = rig_ui_template.ScriptGenerator(self)
+        self.action_layers = ActionLayerBuilder(self)
 
         ###########################################
         bpy.ops.object.mode_set(mode='OBJECT')