Multires: Initial work to get sculpting to work with OpenSubdiv

Allows to go to sculpt mode, do brush strokes, get out of sculpt mode
and have deformation preserved.

The issues currently is that the current implementation of CCG
storage is created from the limit surface, without displacement
taken into account. It is trivial to get displaced coordinates,
but it is more tricky to get displaced normals. This is something
to be solved next.

Another limitation is that this only works for sculpting at a maximal
multires level. There is code to be done to support propagation
of displacement onto a higher levels.

1 files changed, 2 insertions, 0 deletions

diff --git a/source/blender/blenkernel/BKE_pbvh.h b/source/blender/blenkernel/BKE_pbvh.h
index 3838474381c..47fedb565fc 100644
--- a/source/blender/blenkernel/BKE_pbvh.h
+++ b/source/blender/blenkernel/BKE_pbvh.h
@@ -155,6 +155,8 @@ int BKE_pbvh_count_grid_quads(BLI_bitmap **grid_hidden,
 /* multires level, only valid for type == PBVH_GRIDS */
 void BKE_pbvh_get_grid_key(const PBVH *pbvh, struct CCGKey *key);
 
+struct CCGElem **BKE_pbvh_get_grids(const PBVH *pbvh, int *num_grids);
+
 /* Only valid for type == PBVH_BMESH */
 struct BMesh *BKE_pbvh_get_bmesh(PBVH *pbvh);
 void BKE_pbvh_bmesh_detail_size_set(PBVH *pbvh, float detail_size);