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, 27 insertions, 0 deletions

diff --git a/source/blender/blenkernel/BKE_crazyspace.h b/source/blender/blenkernel/BKE_crazyspace.h
index c00e397f552..61c5b2ae29e 100644
--- a/source/blender/blenkernel/BKE_crazyspace.h
+++ b/source/blender/blenkernel/BKE_crazyspace.h
@@ -26,10 +26,12 @@
 #ifdef __cplusplus
 extern "C" {
 #endif
+
 struct BMEditMesh;
 struct Depsgraph;
 struct Mesh;
 struct Object;
+struct ReportList;
 struct Scene;
 
 /* crazyspace.c */
@@ -69,6 +71,31 @@ void BKE_crazyspace_build_sculpt(struct Depsgraph *depsgraph,
                                  float (**deformmats)[3][3],
                                  float (**deformcos)[3]);
 
+/* -------------------------------------------------------------------- */
+/** \name Crazyspace API
+ * \{ */
+
+void BKE_crazyspace_api_eval(struct Depsgraph *depsgraph,
+                             struct Scene *scene,
+                             struct Object *object,
+                             struct ReportList *reports);
+
+void BKE_crazyspace_api_displacement_to_deformed(struct Object *object,
+                                                 struct ReportList *reports,
+                                                 int vertex_index,
+                                                 float displacement[3],
+                                                 float r_displacement_deformed[3]);
+
+void BKE_crazyspace_api_displacement_to_original(struct Object *object,
+                                                 struct ReportList *reports,
+                                                 int vertex_index,
+                                                 float displacement_deformed[3],
+                                                 float r_displacement[3]);
+
+void BKE_crazyspace_api_eval_clear(struct Object *object);
+
+/** \} */
+
 #ifdef __cplusplus
 }
 #endif