Sculpt: Separate hide status from face sets, use generic attribute

Whether faces are hidden and face sets are orthogonal concepts, but
currently sculpt mode stores them together in the face set array.
This means that if anything is hidden, there must be face sets,
and if there are face sets, we have to keep track of what is hidden.
In other words, it adds a bunch of redundant work and state tracking.

On the user level it's nice that face sets and hiding are consistent,
but we don't need to store them together to accomplish that.

This commit uses the `".hide_poly"` attribute from rB2480b55f216c to
read and change hiding in sculpt mode. Face sets don't need to be
negative anymore, and a bunch of "face set <-> hide status" conversion
can be removed. Plus some other benefits:
 - We don't need to allocate either array quite as much.
 - The hide status can be read from 1/4 the memory as face sets.
 - Updates when entering or exiting sculpt mode can be removed.
 - More opportunities for early-outs when nothing is hidden.
 - Separating concerns makes sculpt code more obvious.
 - It will be easier to convert face sets into a generic int attribute.

 Differential Revision: https://developer.blender.org/D15950

1 files changed, 6 insertions, 7 deletions

diff --git a/source/blender/editors/sculpt_paint/sculpt_intern.h b/source/blender/editors/sculpt_paint/sculpt_intern.h
index 7a72e5cc84b..681c90bafb6 100644
--- a/source/blender/editors/sculpt_paint/sculpt_intern.h
+++ b/source/blender/editors/sculpt_paint/sculpt_intern.h
@@ -1004,9 +1004,13 @@ void SCULPT_connected_components_ensure(Object *ob);
 
 void SCULPT_vertex_visible_set(SculptSession *ss, PBVHVertRef vertex, bool visible);
 bool SCULPT_vertex_visible_get(SculptSession *ss, PBVHVertRef vertex);
+bool SCULPT_vertex_all_faces_visible_get(const SculptSession *ss, PBVHVertRef vertex);
+bool SCULPT_vertex_any_face_visible_get(SculptSession *ss, PBVHVertRef vertex);
 
-void SCULPT_visibility_sync_all_face_sets_to_verts(struct Object *ob);
-void SCULPT_visibility_sync_all_vertex_to_face_sets(struct SculptSession *ss);
+void SCULPT_face_visibility_all_invert(SculptSession *ss);
+void SCULPT_face_visibility_all_set(SculptSession *ss, bool visible);
+
+void SCULPT_visibility_sync_all_from_faces(struct Object *ob);
 
 /** \} */
 
@@ -1024,11 +1028,6 @@ bool SCULPT_vertex_has_unique_face_set(SculptSession *ss, PBVHVertRef vertex);
 int SCULPT_face_set_next_available_get(SculptSession *ss);
 
 void SCULPT_face_set_visibility_set(SculptSession *ss, int face_set, bool visible);
-bool SCULPT_vertex_all_face_sets_visible_get(const SculptSession *ss, PBVHVertRef vertex);
-bool SCULPT_vertex_any_face_set_visible_get(SculptSession *ss, PBVHVertRef vertex);
-
-void SCULPT_face_sets_visibility_invert(SculptSession *ss);
-void SCULPT_face_sets_visibility_all_set(SculptSession *ss, bool visible);
 
 /** \} */