Cleanup: Sculpt: Add utility to duplicate mask data

Avoid the `PBVHVertRef` abstraction which is unnecesarily costly for
such a simple thing as copying data. Instead we can use abstractions
specific to each PBVH type (currently only `VArray` for meshes).

source/blender/editors/sculpt_paint/paint_intern.hh

@@ -468,6 +468,9 @@ void PAINT_OT_visibility_invert(wmOperatorType *ot);
 /* `paint_mask.cc` */
 
 namespace blender::ed::sculpt_paint::mask {
+
+Array<float> duplicate_mask(const Object &object);
+
 void PAINT_OT_mask_flood_fill(wmOperatorType *ot);
 void PAINT_OT_mask_lasso_gesture(wmOperatorType *ot);
 void PAINT_OT_mask_box_gesture(wmOperatorType *ot);

source/blender/editors/sculpt_paint/paint_mask.cc

@@ -62,6 +62,55 @@
 
 namespace blender::ed::sculpt_paint::mask {
 
+Array<float> duplicate_mask(const Object &object)
+{
+  const SculptSession &ss = *object.sculpt;
+  switch (BKE_pbvh_type(ss.pbvh)) {
+    case PBVH_FACES: {
+      const Mesh &mesh = *static_cast<const Mesh *>(object.data);
+      const bke::AttributeAccessor attributes = mesh.attributes();
+      const VArray mask = *attributes.lookup_or_default<float>(
+          ".sculpt_mask", bke::AttrDomain::Point, 0.0f);
+      Array<float> result(mask.size());
+      mask.materialize(result);
+      return result;
+    }
+    case PBVH_GRIDS: {
+      const SubdivCCG &subdiv_ccg = *ss.subdiv_ccg;
+      const CCGKey key = BKE_subdiv_ccg_key_top_level(subdiv_ccg);
+      const Span<CCGElem *> grids = subdiv_ccg.grids;
+
+      Array<float> result(grids.size() * key.grid_area);
+      int index = 0;
+      for (const int grid : grids.index_range()) {
+        CCGElem *elem = grids[grid];
+        for (const int i : IndexRange(key.grid_area)) {
+          result[index] = *CCG_elem_offset_mask(&key, elem, i);
+          index++;
+        }
+      }
+      return result;
+    }
+    case PBVH_BMESH: {
+      BMesh &bm = *ss.bm;
+      const int offset = CustomData_get_offset_named(&bm.vdata, CD_PROP_FLOAT, ".sculpt_mask");
+      Array<float> result(bm.totvert);
+      if (offset == -1) {
+        result.fill(0.0f);
+      }
+      else {
+        BM_mesh_elem_table_ensure(&bm, BM_VERT);
+        for (const int i : result.index_range()) {
+          result[i] = BM_ELEM_CD_GET_FLOAT(BM_vert_at_index(&bm, i), offset);
+        }
+      }
+      return result;
+    }
+  }
+  BLI_assert_unreachable();
+  return {};
+}
+
 /* The gesture API doesn't write to this enum type,
  * it writes to eSelectOp from ED_select_utils.hh.
  * We must thus map the modes here to the desired

source/blender/editors/sculpt_paint/sculpt_expand.cc

@@ -1143,7 +1143,6 @@ static void sculpt_expand_cache_data_free(Cache *expand_cache)
 {
   MEM_SAFE_FREE(expand_cache->vert_falloff);
   MEM_SAFE_FREE(expand_cache->face_falloff);
-  MEM_SAFE_FREE(expand_cache->original_mask);
   MEM_SAFE_FREE(expand_cache->original_colors);
   MEM_delete<Cache>(expand_cache);
 }
@@ -1240,7 +1239,7 @@ static void sculpt_expand_restore_original_state(bContext *C, Object *ob, Cache
   SculptSession *ss = ob->sculpt;
   switch (expand_cache->target) {
     case SCULPT_EXPAND_TARGET_MASK:
-      write_mask_data(ss, {expand_cache->original_mask, SCULPT_vertex_count_get(ss)});
+      write_mask_data(ss, expand_cache->original_mask);
       SCULPT_flush_update_step(C, SCULPT_UPDATE_MASK);
       SCULPT_flush_update_done(C, ob, SCULPT_UPDATE_MASK);
       SCULPT_tag_update_overlays(C);
@@ -1439,13 +1438,7 @@ static void sculpt_expand_original_state_store(Object *ob, Cache *expand_cache)
   expand_cache->original_face_sets = face_set::duplicate_face_sets(mesh);
 
   if (expand_cache->target == SCULPT_EXPAND_TARGET_MASK) {
-    expand_cache->original_mask = static_cast<float *>(
-        MEM_malloc_arrayN(totvert, sizeof(float), "initial mask"));
-    for (int i = 0; i < totvert; i++) {
-      PBVHVertRef vertex = BKE_pbvh_index_to_vertex(ss->pbvh, i);
-
-      expand_cache->original_mask[i] = SCULPT_vertex_mask_get(ss, vertex);
-    }
+    expand_cache->original_mask = mask::duplicate_mask(*ob);
   }
 
   if (expand_cache->target == SCULPT_EXPAND_TARGET_COLORS) {

source/blender/editors/sculpt_paint/sculpt_filter_mask.cc

@@ -23,6 +23,7 @@
 #include "WM_api.hh"
 #include "WM_types.hh"
 
+#include "paint_intern.hh"
 #include "sculpt_intern.hh"
 
 #include "RNA_access.hh"
@@ -64,7 +65,7 @@ static EnumPropertyItem prop_mask_filter_types[] = {
 
 static void mask_filter_task(SculptSession *ss,
                              const int mode,
-                             float *prev_mask,
+                             const Span<float> prev_mask,
                              const SculptMaskWriteInfo mask_write,
                              PBVHNode *node)
 {
@@ -184,7 +185,7 @@ static int sculpt_mask_filter_exec(bContext *C, wmOperator *op)
     undo::push_node(ob, node, undo::Type::Mask);
   }
 
-  float *prev_mask = nullptr;
+  Array<float> prev_mask;
   int iterations = RNA_int_get(op->ptr, "iterations");
 
   /* Auto iteration count calculates the number of iteration based on the vertices of the mesh to
@@ -199,11 +200,7 @@ static int sculpt_mask_filter_exec(bContext *C, wmOperator *op)
 
   for (int i = 0; i < iterations; i++) {
     if (ELEM(filter_type, MASK_FILTER_GROW, MASK_FILTER_SHRINK)) {
-      prev_mask = static_cast<float *>(MEM_mallocN(num_verts * sizeof(float), __func__));
-      for (int j = 0; j < num_verts; j++) {
-        PBVHVertRef vertex = BKE_pbvh_index_to_vertex(ss->pbvh, j);
-        prev_mask[j] = SCULPT_vertex_mask_get(ss, vertex);
-      }
+      prev_mask = duplicate_mask(*ob);
     }
 
     threading::parallel_for(nodes.index_range(), 1, [&](const IndexRange range) {
@@ -211,10 +208,6 @@ static int sculpt_mask_filter_exec(bContext *C, wmOperator *op)
         mask_filter_task(ss, filter_type, prev_mask, mask_write, nodes[i]);
       }
     });
-
-    if (ELEM(filter_type, MASK_FILTER_GROW, MASK_FILTER_SHRINK)) {
-      MEM_freeN(prev_mask);
-    }
   }
 
   undo::push_end(ob);

source/blender/editors/sculpt_paint/sculpt_intern.hh

@@ -709,7 +709,7 @@ struct Cache {
   Array<int> initial_face_sets;
 
   /* Original data of the sculpt as it was before running the Expand operator. */
-  float *original_mask;
+  Array<float> original_mask;
   Array<int> original_face_sets;
   float (*original_colors)[4];