Fix T74761: Reimplement vertex to face sets visibility sync

This fixes multiple issues:
- Adds tag to update shading when changing vertex visibiliyt. This makes the mesh visibility update when the operator ends.
- Sync vertex to face sets no longer requires the pmap, so it does not crash. (Maybe we can initialize the pmap on undo to avoid these problems in the future).
- Sync vertex to face sets now works in a coherent way with the rest of visibility operations. Hide Box and Hide mask now sync the visibility changes to the face sets, so the all the operations are now getting a correct visibility state.

Reviewed By: brecht

Maniphest Tasks: T74761

Differential Revision: https://developer.blender.org/D7187

source/blender/editors/sculpt_paint/paint_hide.c

@@ -403,6 +403,9 @@ static int hide_show_exec(bContext *C, wmOperator *op)
     BKE_mesh_flush_hidden_from_verts(me);
   }
 
+  SCULPT_visibility_sync_all_vertex_to_face_sets(ob->sculpt);
+
+  DEG_id_tag_update(&ob->id, ID_RECALC_SHADING);
   ED_region_tag_redraw(region);
 
   return OPERATOR_FINISHED;

source/blender/editors/sculpt_paint/sculpt.c

@@ -435,8 +435,23 @@ static void sculpt_visibility_sync_vertex_to_face_sets(SculptSession *ss, int in
 
 void SCULPT_visibility_sync_all_vertex_to_face_sets(SculptSession *ss)
 {
-  for (int i = 0; i < ss->totvert; i++) {
-    sculpt_visibility_sync_vertex_to_face_sets(ss, i);
+  if (BKE_pbvh_type(ss->pbvh) == PBVH_FACES) {
+    for (int i = 0; i < ss->totpoly; i++) {
+      MPoly *poly = &ss->mpoly[i];
+      bool poly_visible = true;
+      for (int l = 0; l < poly->totloop; l++) {
+        MLoop *loop = &ss->mloop[poly->loopstart + l];
+        if (!SCULPT_vertex_visible_get(ss, (int)loop->v)) {
+          poly_visible = false;
+        }
+      }
+      if (poly_visible) {
+        ss->face_sets[i] = abs(ss->face_sets[i]);
+      }
+      else {
+        ss->face_sets[i] = -abs(ss->face_sets[i]);
+      }
+    }
   }
 }