Python: Expose crazyspace correction functionality via RNA

Allows to perform correction of coordinate delta/displacement in a
similar way of how sculpt mode handles sculpting on a deformed mesh.
An example of usecase of this is allowing riggers and sciprters to
improve corrective shapekey workflow.

The usage consists of pre-processing and access. For example:

  object.crazyspace_eval(depsgraph, scene)

  # When we have a difference between two vertices and want to convert
  # it to a space to be stored, say, in shapekey:
  delta_in_orig_space = rigged_ob.crazyspace_displacement_to_original(
      vertex_index=i, displacement=delta)

  # The reverse of above.
  delta_in_deformed_space = rigged_ob.crazyspace_displacement_to_deformed(
      vertex_index=i, displacement=delta)

  object.crazyspace_eval_clear()

Fuller explanation with actual usecases and studio examples are written in
the comment:

  https://developer.blender.org/D13892#368898

Differential Revision: https://developer.blender.org/D13892

1 files changed, 6 insertions, 0 deletions

diff --git a/source/blender/blenkernel/intern/object.cc b/source/blender/blenkernel/intern/object.cc
index 3fa380d2519..ed0174bd592 100644
--- a/source/blender/blenkernel/intern/object.cc
+++ b/source/blender/blenkernel/intern/object.cc
@@ -87,6 +87,7 @@
 #include "BKE_camera.h"
 #include "BKE_collection.h"
 #include "BKE_constraint.h"
+#include "BKE_crazyspace.h"
 #include "BKE_curve.h"
 #include "BKE_deform.h"
 #include "BKE_displist.h"
@@ -1881,6 +1882,8 @@ void BKE_object_free_derived_caches(Object *ob)
   BKE_object_to_curve_clear(ob);
   BKE_object_free_curve_cache(ob);
 
+  BKE_crazyspace_api_eval_clear(ob);
+
   /* Clear grease pencil data. */
   if (ob->runtime.gpd_eval != nullptr) {
     BKE_gpencil_eval_delete(ob->runtime.gpd_eval);
@@ -5219,6 +5222,9 @@ void BKE_object_runtime_reset_on_copy(Object *object, const int UNUSED(flag))
   runtime->object_as_temp_mesh = nullptr;
   runtime->object_as_temp_curve = nullptr;
   runtime->geometry_set_eval = nullptr;
+
+  runtime->crazyspace_deform_imats = nullptr;
+  runtime->crazyspace_deform_cos = nullptr;
 }
 
 void BKE_object_runtime_free_data(Object *object)