Sculpt: Initial data oriented refactor for draw face sets brush

Part of #118145.

Performance after this change results in an 156% speedup. This is
measured on the function `stroke_update_step` on a mesh with 24k verts
across 20k instances of the function being timed. In absolute values,
this represents a 0.09ms speedup, from 0.16ms to 0.25ms.

For BMesh, the brush now takes mask values into consideration by
averaging all of the vert mask values for a face.

Co-authored-by: Hans Goudey <hans@blender.org>
Pull Request: https://projects.blender.org/blender/blender/pulls/123811

source/blender/editors/sculpt_paint/CMakeLists.txt

@@ -118,6 +118,7 @@ set(SRC
   brushes/clay_strips.cc
   brushes/clay_thumb.cc
   brushes/crease.cc
+  brushes/draw_face_sets.cc
   brushes/draw_vector_displacement.cc
   brushes/draw.cc
   brushes/fill.cc

source/blender/editors/sculpt_paint/brushes/draw_face_sets.cc

@@ -0,0 +1,457 @@
+/* SPDX-FileCopyrightText: 2024 Blender Authors
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include "editors/sculpt_paint/brushes/types.hh"
+#include "editors/sculpt_paint/mesh_brush_common.hh"
+
+#include "DNA_brush_types.h"
+
+#include "BKE_mesh.hh"
+#include "BKE_pbvh.hh"
+#include "BKE_subdiv_ccg.hh"
+
+#include "BLI_array_utils.hh"
+#include "BLI_enumerable_thread_specific.hh"
+#include "BLI_math_base.hh"
+#include "BLI_task.h"
+#include "BLI_task.hh"
+
+#include "editors/sculpt_paint/sculpt_intern.hh"
+
+namespace blender::ed::sculpt_paint {
+inline namespace draw_face_sets_cc {
+
+constexpr float FACE_SET_BRUSH_MIN_FADE = 0.05f;
+
+struct MeshLocalData {
+  Vector<int> face_indices;
+  Vector<float3> positions;
+  Vector<float3> normals;
+  Vector<float> factors;
+  Vector<float> distances;
+};
+
+static void calc_face_centers(const OffsetIndices<int> faces,
+                              const Span<int> corner_verts,
+                              const Span<float3> vert_positions,
+                              const Span<int> face_indices,
+                              const MutableSpan<float3> positions)
+{
+  BLI_assert(face_indices.size() == positions.size());
+
+  for (const int i : face_indices.index_range()) {
+    positions[i] = bke::mesh::face_center_calc(vert_positions,
+                                               corner_verts.slice(faces[face_indices[i]]));
+  }
+}
+
+static void calc_face_normals(const OffsetIndices<int> faces,
+                              const Span<int> corner_verts,
+                              const Span<float3> vert_positions,
+                              const Span<int> face_indices,
+                              const MutableSpan<float3> normals)
+{
+  BLI_assert(face_indices.size() == normals.size());
+
+  for (const int i : face_indices.index_range()) {
+    normals[i] = bke::mesh::face_normal_calc(vert_positions,
+                                             corner_verts.slice(faces[face_indices[i]]));
+  }
+}
+
+BLI_NOINLINE static void fill_factor_from_hide_and_mask(const Mesh &mesh,
+                                                        const Span<int> face_indices,
+                                                        const MutableSpan<float> r_factors)
+{
+  BLI_assert(face_indices.size() == r_factors.size());
+
+  const OffsetIndices<int> faces = mesh.faces();
+  const Span<int> corner_verts = mesh.corner_verts();
+
+  /* TODO: Avoid overhead of accessing attributes for every PBVH node. */
+  const bke::AttributeAccessor attributes = mesh.attributes();
+  if (const VArray mask = *attributes.lookup<float>(".sculpt_mask", bke::AttrDomain::Point)) {
+    const VArraySpan span(mask);
+    for (const int i : face_indices.index_range()) {
+      const Span<int> face_verts = corner_verts.slice(faces[face_indices[i]]);
+      const float inv_size = math::rcp(float(face_verts.size()));
+      float sum = 0.0f;
+      for (const int vert : face_verts) {
+        sum += span[vert];
+      }
+      r_factors[i] = 1.0f - sum * inv_size;
+    }
+  }
+  else {
+    r_factors.fill(1.0f);
+  }
+
+  if (const VArray hide_poly = *attributes.lookup<bool>(".hide_poly", bke::AttrDomain::Point)) {
+    const VArraySpan span(hide_poly);
+    for (const int i : face_indices.index_range()) {
+      if (span[face_indices[i]]) {
+        r_factors[i] = 0.0f;
+      }
+    }
+  }
+}
+
+BLI_NOINLINE static void apply_face_set(const int face_set_id,
+                                        const Span<int> face_indices,
+                                        const Span<float> factors,
+                                        const MutableSpan<int> face_sets)
+{
+  BLI_assert(face_indices.size() == factors.size());
+
+  for (const int i : face_indices.index_range()) {
+    if (factors[i] > FACE_SET_BRUSH_MIN_FADE) {
+      face_sets[face_indices[i]] = face_set_id;
+    }
+  }
+}
+
+static void calc_faces(Object &object,
+                       const Brush &brush,
+                       const float strength,
+                       const int face_set_id,
+                       Span<float3> positions_eval,
+                       const PBVHNode &node,
+                       const Span<int> face_indices,
+                       MeshLocalData &tls,
+                       const MutableSpan<int> face_sets)
+{
+  SculptSession &ss = *object.sculpt;
+  const StrokeCache &cache = *ss.cache;
+  Mesh &mesh = *static_cast<Mesh *>(object.data);
+  const OffsetIndices<int> faces = mesh.faces();
+  const Span<int> corner_verts = mesh.corner_verts();
+
+  tls.positions.reinitialize(face_indices.size());
+  const MutableSpan<float3> face_centers = tls.positions;
+  calc_face_centers(faces, corner_verts, positions_eval, face_indices, face_centers);
+
+  tls.normals.reinitialize(face_indices.size());
+  const MutableSpan<float3> face_normals = tls.normals;
+  calc_face_normals(faces, corner_verts, positions_eval, face_indices, face_normals);
+
+  tls.factors.reinitialize(face_indices.size());
+  const MutableSpan<float> factors = tls.factors;
+
+  fill_factor_from_hide_and_mask(mesh, face_indices, factors);
+
+  filter_region_clip_factors(ss, face_centers, factors);
+  if (brush.flag & BRUSH_FRONTFACE) {
+    calc_front_face(cache.view_normal, face_normals, factors);
+  }
+
+  tls.distances.reinitialize(face_indices.size());
+  const MutableSpan<float> distances = tls.distances;
+  calc_brush_distances(ss, face_centers, eBrushFalloffShape(brush.falloff_shape), distances);
+  filter_distances_with_radius(cache.radius, distances, factors);
+  apply_hardness_to_distances(cache, distances);
+  calc_brush_strength_factors(cache, brush, distances, factors);
+
+  if (cache.automasking) {
+    const OffsetIndices<int> faces = mesh.faces();
+    const Span<int> corner_verts = mesh.corner_verts();
+    auto_mask::calc_face_factors(
+        object, faces, corner_verts, *cache.automasking, node, face_indices, factors);
+  }
+
+  calc_brush_texture_factors(ss, brush, face_centers, factors);
+  scale_factors(factors, strength);
+
+  apply_face_set(face_set_id, face_indices, factors, face_sets);
+}
+
+static void do_draw_face_sets_brush_mesh(Object &object,
+                                         const Brush &brush,
+                                         const Span<PBVHNode *> nodes)
+{
+  const SculptSession &ss = *object.sculpt;
+  const PBVH &pbvh = *ss.pbvh;
+  const Span<float3> positions_eval = BKE_pbvh_get_vert_positions(pbvh);
+
+  Mesh &mesh = *static_cast<Mesh *>(object.data);
+  const Span<int> corner_tris = mesh.corner_tri_faces();
+
+  bke::SpanAttributeWriter<int> attribute = face_set::ensure_face_sets_mesh(object);
+  MutableSpan<int> face_sets = attribute.span;
+
+  threading::EnumerableThreadSpecific<MeshLocalData> all_tls;
+  threading::parallel_for(nodes.index_range(), 1, [&](const IndexRange range) {
+    MeshLocalData &tls = all_tls.local();
+    for (const int i : range) {
+      const Span<int> face_indices = bke::pbvh::node_face_indices_calc_mesh(
+          corner_tris, *nodes[i], tls.face_indices);
+
+      undo::push_node(object, nodes[i], undo::Type::FaceSet);
+
+      calc_faces(object,
+                 brush,
+                 ss.cache->bstrength,
+                 ss.cache->paint_face_set,
+                 positions_eval,
+                 *nodes[i],
+                 face_indices,
+                 tls,
+                 face_sets);
+    }
+  });
+
+  attribute.finish();
+}
+
+struct GridLocalData {
+  Vector<int> face_indices;
+  Vector<float3> positions;
+  Vector<float> factors;
+  Vector<float> distances;
+};
+
+BLI_NOINLINE static void calc_face_indices_grids(const SubdivCCG &subdiv_ccg,
+                                                 const Span<int> grids,
+                                                 const MutableSpan<int> face_indices)
+{
+  const CCGKey key = BKE_subdiv_ccg_key_top_level(subdiv_ccg);
+  BLI_assert(grids.size() * key.grid_area == face_indices.size());
+
+  for (const int i : grids.index_range()) {
+    const int start = i * key.grid_area;
+    for (const int offset : IndexRange(key.grid_area)) {
+      face_indices[start + offset] = BKE_subdiv_ccg_grid_to_face_index(subdiv_ccg, grids[i]);
+    }
+  }
+}
+
+static void calc_grids(Object &object,
+                       const Brush &brush,
+                       const float strength,
+                       const int face_set_id,
+                       const PBVHNode &node,
+                       GridLocalData &tls,
+                       const MutableSpan<int> face_sets)
+{
+  SculptSession &ss = *object.sculpt;
+  const StrokeCache &cache = *ss.cache;
+  SubdivCCG &subdiv_ccg = *ss.subdiv_ccg;
+  const CCGKey key = BKE_subdiv_ccg_key_top_level(subdiv_ccg);
+
+  const Span<int> grids = bke::pbvh::node_grid_indices(node);
+  const int grid_verts_num = grids.size() * key.grid_area;
+
+  tls.positions.reinitialize(grid_verts_num);
+  MutableSpan<float3> positions = tls.positions;
+  gather_grids_positions(subdiv_ccg, grids, positions);
+
+  tls.factors.reinitialize(grid_verts_num);
+  const MutableSpan<float> factors = tls.factors;
+  blender::ed::sculpt_paint::fill_factor_from_hide_and_mask(subdiv_ccg, grids, factors);
+  filter_region_clip_factors(ss, positions, factors);
+  if (brush.flag & BRUSH_FRONTFACE) {
+    calc_front_face(cache.view_normal, subdiv_ccg, grids, factors);
+  }
+
+  tls.distances.reinitialize(grid_verts_num);
+  const MutableSpan<float> distances = tls.distances;
+  calc_brush_distances(ss, positions, eBrushFalloffShape(brush.falloff_shape), distances);
+  filter_distances_with_radius(cache.radius, distances, factors);
+  apply_hardness_to_distances(cache, distances);
+  calc_brush_strength_factors(cache, brush, distances, factors);
+
+  if (cache.automasking) {
+    auto_mask::calc_grids_factors(object, *cache.automasking, node, grids, factors);
+  }
+
+  calc_brush_texture_factors(ss, brush, positions, factors);
+  scale_factors(factors, strength);
+
+  tls.face_indices.reinitialize(grid_verts_num);
+  MutableSpan<int> face_indices = tls.face_indices;
+
+  calc_face_indices_grids(subdiv_ccg, grids, face_indices);
+  apply_face_set(face_set_id, face_indices, factors, face_sets);
+}
+
+static void do_draw_face_sets_brush_grids(Object &object,
+                                          const Brush &brush,
+                                          const Span<PBVHNode *> nodes)
+{
+  SculptSession &ss = *object.sculpt;
+
+  bke::SpanAttributeWriter<int> attribute = face_set::ensure_face_sets_mesh(object);
+  MutableSpan<int> face_sets = attribute.span;
+
+  threading::EnumerableThreadSpecific<GridLocalData> all_tls;
+  threading::parallel_for(nodes.index_range(), 1, [&](const IndexRange range) {
+    GridLocalData &tls = all_tls.local();
+    for (PBVHNode *node : nodes.slice(range)) {
+      for (const int i : range) {
+        undo::push_node(object, node, undo::Type::FaceSet);
+
+        calc_grids(object,
+                   brush,
+                   ss.cache->bstrength,
+                   ss.cache->paint_face_set,
+                   *nodes[i],
+                   tls,
+                   face_sets);
+      }
+    }
+  });
+  attribute.finish();
+}
+struct BMeshLocalData {
+  Vector<float3> positions;
+  Vector<float> factors;
+  Vector<float> distances;
+};
+
+BLI_NOINLINE static void fill_factor_from_hide_and_mask(const BMesh &bm,
+                                                        const Set<BMFace *, 0L> &faces,
+                                                        const MutableSpan<float> r_factors)
+{
+  BLI_assert(faces.size() == r_factors.size());
+
+  /* TODO: Avoid overhead of accessing attributes for every PBVH node. */
+  const int mask_offset = CustomData_get_offset_named(&bm.vdata, CD_PROP_FLOAT, ".sculpt_mask");
+  int i = 0;
+  for (BMFace *f : faces) {
+    if (BM_elem_flag_test(f, BM_ELEM_HIDDEN)) {
+      r_factors[i] = 0.0f;
+      continue;
+    }
+    if (mask_offset == -1) {
+      r_factors[i] = 1.0f;
+      continue;
+    }
+
+    const BMLoop *l_iter = f->l_first = BM_FACE_FIRST_LOOP(f);
+    int total_verts = 0;
+    float sum;
+    do {
+      BMVert *vert = l_iter->v;
+      sum += BM_ELEM_CD_GET_FLOAT(vert, mask_offset);
+      total_verts++;
+    } while ((l_iter = l_iter->next) != f->l_first);
+    r_factors[i] = 1.0f - sum * math::rcp(float(total_verts));
+    i++;
+  }
+}
+
+static void calc_face_centers(const Set<BMFace *, 0L> &faces, const MutableSpan<float3> centers)
+{
+  BLI_assert(faces.size() == centers.size());
+
+  int i = 0;
+  for (const BMFace *f : faces) {
+    float3 face_center;
+    BM_face_calc_center_median(f, face_center);
+
+    centers[i] = face_center;
+    i++;
+  }
+}
+
+BLI_NOINLINE static void apply_face_set(const int face_set_id,
+                                        const Set<BMFace *, 0> &faces,
+                                        const MutableSpan<float> factors,
+                                        const int cd_offset)
+{
+  int i = 0;
+  for (BMFace *face : faces) {
+    if (factors[i] > FACE_SET_BRUSH_MIN_FADE) {
+      BM_ELEM_CD_SET_INT(face, cd_offset, face_set_id);
+    }
+    i++;
+  }
+}
+
+static void calc_bmesh(Object &object,
+                       const Brush &brush,
+                       const float strength,
+                       const int face_set_id,
+                       PBVHNode &node,
+                       BMeshLocalData &tls,
+                       const int cd_offset)
+{
+  SculptSession &ss = *object.sculpt;
+  const StrokeCache &cache = *ss.cache;
+
+  const Set<BMFace *, 0> &faces = BKE_pbvh_bmesh_node_faces(&node);
+  tls.positions.reinitialize(faces.size());
+  const MutableSpan<float3> positions = tls.positions;
+  calc_face_centers(faces, positions);
+
+  tls.factors.reinitialize(faces.size());
+  const MutableSpan<float> factors = tls.factors;
+  fill_factor_from_hide_and_mask(*ss.bm, faces, factors);
+  filter_region_clip_factors(ss, positions, factors);
+  if (brush.flag & BRUSH_FRONTFACE) {
+    calc_front_face(cache.view_normal, faces, factors);
+  }
+
+  tls.distances.reinitialize(faces.size());
+  const MutableSpan<float> distances = tls.distances;
+  calc_brush_distances(ss, positions, eBrushFalloffShape(brush.falloff_shape), distances);
+  filter_distances_with_radius(cache.radius, distances, factors);
+  apply_hardness_to_distances(cache, distances);
+  calc_brush_strength_factors(cache, brush, distances, factors);
+
+  /* Disable auto-masking code path which rely on an undo step to access original data.
+   *
+   * This is because the dynamic topology uses BMesh Log based undo system, which creates a
+   * single node for the undo step, and its type could be different for the needs of the
+   * brush undo and the original data access.
+   *
+   * For the brushes like Draw the ss.cache->automasking is set to nullptr at the first step
+   * of the brush, as there is an explicit check there for the brushes which support dynamic
+   * topology. Do it locally here for the Draw Face Set brush here, to mimic the behavior of
+   * the other brushes but without marking the brush as supporting dynamic topology. */
+  auto_mask::node_begin(object, nullptr, node);
+
+  calc_brush_texture_factors(ss, brush, positions, factors);
+  scale_factors(factors, strength);
+
+  apply_face_set(face_set_id, faces, factors, cd_offset);
+}
+
+static void do_draw_face_sets_brush_bmesh(Object &object,
+                                          const Brush &brush,
+                                          const Span<PBVHNode *> nodes)
+{
+  SculptSession &ss = *object.sculpt;
+  const int cd_offset = face_set::ensure_face_sets_bmesh(object);
+
+  threading::EnumerableThreadSpecific<BMeshLocalData> all_tls;
+  threading::parallel_for(nodes.index_range(), 1, [&](const IndexRange range) {
+    BMeshLocalData &tls = all_tls.local();
+    for (const int i : range) {
+      undo::push_node(object, nodes[i], undo::Type::FaceSet);
+      calc_bmesh(
+          object, brush, ss.cache->bstrength, ss.cache->paint_face_set, *nodes[i], tls, cd_offset);
+    }
+  });
+}
+
+}  // namespace draw_face_sets_cc
+
+void do_draw_face_sets_brush(const Sculpt &sd, Object &object, Span<PBVHNode *> nodes)
+{
+  SculptSession &ss = *object.sculpt;
+  const Brush &brush = *BKE_paint_brush_for_read(&sd.paint);
+
+  switch (BKE_pbvh_type(*ss.pbvh)) {
+    case PBVH_FACES:
+      do_draw_face_sets_brush_mesh(object, brush, nodes);
+      break;
+    case PBVH_GRIDS:
+      do_draw_face_sets_brush_grids(object, brush, nodes);
+      break;
+    case PBVH_BMESH:
+      do_draw_face_sets_brush_bmesh(object, brush, nodes);
+      break;
+  }
+}
+}  // namespace blender::ed::sculpt_paint

source/blender/editors/sculpt_paint/brushes/types.hh

@@ -20,6 +20,7 @@ void do_crease_brush(const Scene &scene, const Sculpt &sd, Object &ob, Span<PBVH
 void do_blob_brush(const Scene &scene, const Sculpt &sd, Object &ob, Span<PBVHNode *> nodes);
 void do_displacement_eraser_brush(const Sculpt &sd, Object &ob, Span<PBVHNode *> nodes);
 void do_displacement_smear_brush(const Sculpt &sd, Object &ob, Span<PBVHNode *> nodes);
+void do_draw_face_sets_brush(const Sculpt &sd, Object &object, Span<PBVHNode *> nodes);
 /** A simple normal-direction displacement. */
 void do_draw_brush(const Sculpt &sd, Object &object, Span<PBVHNode *> nodes);
 /** A simple normal-direction displacement based on image texture RGB/XYZ values. */

source/blender/editors/sculpt_paint/mesh_brush_common.hh

@@ -34,6 +34,7 @@
 
 struct BMesh;
 struct BMVert;
+struct BMFace;
 struct Brush;
 struct Mesh;
 struct Object;
@@ -115,6 +116,9 @@ void calc_front_face(const float3 &view_normal,
 void calc_front_face(const float3 &view_normal,
                      const Set<BMVert *, 0> &verts,
                      const MutableSpan<float> factors);
+void calc_front_face(const float3 &view_normal,
+                     const Set<BMFace *, 0> &faces,
+                     const MutableSpan<float> factors);
 
 /**
  * When the 3D view's clipping planes are enabled, brushes shouldn't have any effect on vertices
@@ -217,6 +221,17 @@ void calc_vert_factors(const Object &object,
                        const Set<BMVert *, 0> &verts,
                        MutableSpan<float> factors);
 
+/**
+ * Calculate all auto-masking influence on each face.
+ */
+void calc_face_factors(const Object &object,
+                       const OffsetIndices<int> faces,
+                       const Span<int> corner_verts,
+                       const Cache &cache,
+                       const PBVHNode &node,
+                       const Span<int> face_indices,
+                       const MutableSpan<float> factors);
+
 }  // namespace auto_mask
 
 /**

source/blender/editors/sculpt_paint/sculpt.cc

@@ -3893,7 +3893,12 @@ static void do_brush_action(const Scene &scene,
       cloth::do_cloth_brush(sd, ob, nodes);
       break;
     case SCULPT_TOOL_DRAW_FACE_SETS:
-      face_set::do_draw_face_sets_brush(sd, ob, nodes);
+      if (!ss.cache->alt_smooth) {
+        do_draw_face_sets_brush(sd, ob, nodes);
+      }
+      else {
+        face_set::do_relax_face_sets_brush(sd, ob, nodes);
+      }
       break;
     case SCULPT_TOOL_DISPLACEMENT_ERASER:
       do_displacement_eraser_brush(sd, ob, nodes);
@@ -6859,6 +6864,20 @@ void calc_front_face(const float3 &view_normal,
   }
 }
 
+void calc_front_face(const float3 &view_normal,
+                     const Set<BMFace *, 0> &faces,
+                     const MutableSpan<float> factors)
+{
+  BLI_assert(faces.size() == factors.size());
+
+  int i = 0;
+  for (const BMFace *face : faces) {
+    const float dot = math::dot(view_normal, float3(face->no));
+    factors[i] *= std::max(dot, 0.0f);
+    i++;
+  }
+}
+
 void filter_region_clip_factors(const SculptSession &ss,
                                 const Span<float3> positions,
                                 const Span<int> verts,
@@ -6892,6 +6911,8 @@ void filter_region_clip_factors(const SculptSession &ss,
                                 const Span<float3> positions,
                                 const MutableSpan<float> factors)
 {
+  BLI_assert(positions.size() == factors.size());
+
   const RegionView3D *rv3d = ss.cache ? ss.cache->vc->rv3d : ss.rv3d;
   const View3D *v3d = ss.cache ? ss.cache->vc->v3d : ss.v3d;
   if (!RV3D_CLIPPING_ENABLED(v3d, rv3d)) {

source/blender/editors/sculpt_paint/sculpt_automasking.cc

@@ -11,6 +11,7 @@
 #include "BLI_array.hh"
 #include "BLI_hash.h"
 #include "BLI_index_range.hh"
+#include "BLI_math_base.hh"
 #include "BLI_math_base_safe.h"
 #include "BLI_math_vector.h"
 #include "BLI_math_vector_types.hh"
@@ -613,6 +614,34 @@ void calc_vert_factors(const Object &object,
   }
 }
 
+void calc_face_factors(const Object &object,
+                       const OffsetIndices<int> faces,
+                       const Span<int> corner_verts,
+                       const Cache &cache,
+                       const PBVHNode &node,
+                       const Span<int> face_indices,
+                       const MutableSpan<float> factors)
+{
+  SculptSession &ss = *object.sculpt;
+
+  NodeData data = node_begin(object, &cache, node);
+  /* NOTE: We explicitly nullify data.orig_data here as we currently cannot go from mesh vert index
+   * to the undo node array index. The only brush this method is currently used for is the Draw
+   * Face Set brush, which never modifies the position of the vertices in a brush stroke. This
+   * needs to be implemented in the future if brushes that iterate over faces need original
+   * position and normal data. */
+  data.orig_data = std::nullopt;
+
+  for (const int i : face_indices.index_range()) {
+    const Span<int> face_verts = corner_verts.slice(faces[face_indices[i]]);
+    float sum = 0.0f;
+    for (const int vert : face_verts) {
+      sum += factor_get(&cache, ss, BKE_pbvh_make_vref(vert), &data);
+    }
+    factors[i] *= sum * math::rcp(float(face_verts.size()));
+  }
+}
+
 void calc_grids_factors(const Object &object,
                         const Cache &cache,
                         const PBVHNode &node,

source/blender/editors/sculpt_paint/sculpt_face_set.cc

@@ -211,222 +211,6 @@ Array<int> duplicate_face_sets(const Mesh &mesh)
 /** \name Draw Face Sets Brush
  * \{ */
 
-constexpr float FACE_SET_BRUSH_MIN_FADE = 0.05f;
-
-static void do_draw_face_sets_brush_faces(Object &ob,
-                                          const Brush &brush,
-                                          const Span<PBVHNode *> nodes)
-{
-  SculptSession &ss = *ob.sculpt;
-  const Span<float3> positions = SCULPT_mesh_deformed_positions_get(ss);
-
-  Mesh &mesh = *static_cast<Mesh *>(ob.data);
-  const OffsetIndices<int> faces = mesh.faces();
-  const Span<int> corner_verts = mesh.corner_verts();
-  const bke::AttributeAccessor attributes = mesh.attributes();
-  const VArraySpan<bool> hide_poly = *attributes.lookup<bool>(".hide_poly", bke::AttrDomain::Face);
-
-  bke::SpanAttributeWriter<int> attribute = ensure_face_sets_mesh(ob);
-  MutableSpan<int> face_sets = attribute.span;
-
-  threading::parallel_for(nodes.index_range(), 1, [&](const IndexRange range) {
-    const float bstrength = ss.cache->bstrength;
-    const int thread_id = BLI_task_parallel_thread_id(nullptr);
-    for (PBVHNode *node : nodes.slice(range)) {
-      SculptBrushTest test;
-      SculptBrushTestFn sculpt_brush_test_sq_fn = SCULPT_brush_test_init_with_falloff_shape(
-          ss, test, brush.falloff_shape);
-
-      auto_mask::NodeData automask_data = auto_mask::node_begin(
-          ob, ss.cache->automasking.get(), *node);
-
-      bool changed = false;
-
-      PBVHVertexIter vd;
-      BKE_pbvh_vertex_iter_begin (*ss.pbvh, node, vd, PBVH_ITER_UNIQUE) {
-        auto_mask::node_update(automask_data, vd);
-
-        for (const int face_i : ss.vert_to_face_map[vd.index]) {
-          const IndexRange face = faces[face_i];
-          const float3 center = bke::mesh::face_center_calc(positions, corner_verts.slice(face));
-
-          if (!sculpt_brush_test_sq_fn(test, center)) {
-            continue;
-          }
-          if (!hide_poly.is_empty() && hide_poly[face_i]) {
-            continue;
-          }
-          const float fade = bstrength * SCULPT_brush_strength_factor(ss,
-                                                                      brush,
-                                                                      vd.co,
-                                                                      sqrtf(test.dist),
-                                                                      vd.no,
-                                                                      vd.fno,
-                                                                      vd.mask,
-                                                                      vd.vertex,
-                                                                      thread_id,
-                                                                      &automask_data);
-
-          if (fade > FACE_SET_BRUSH_MIN_FADE) {
-            face_sets[face_i] = ss.cache->paint_face_set;
-            changed = true;
-          }
-        }
-      }
-      BKE_pbvh_vertex_iter_end;
-
-      if (changed) {
-        undo::push_node(ob, node, undo::Type::FaceSet);
-      }
-    }
-  });
-  attribute.finish();
-}
-
-static void do_draw_face_sets_brush_grids(Object &ob,
-                                          const Brush &brush,
-                                          const Span<PBVHNode *> nodes)
-{
-  SculptSession &ss = *ob.sculpt;
-  const float bstrength = ss.cache->bstrength;
-  SubdivCCG &subdiv_ccg = *ss.subdiv_ccg;
-
-  bke::SpanAttributeWriter<int> attribute = ensure_face_sets_mesh(ob);
-  MutableSpan<int> face_sets = attribute.span;
-
-  threading::parallel_for(nodes.index_range(), 1, [&](const IndexRange range) {
-    const int thread_id = BLI_task_parallel_thread_id(nullptr);
-    for (PBVHNode *node : nodes.slice(range)) {
-      SculptBrushTest test;
-      SculptBrushTestFn sculpt_brush_test_sq_fn = SCULPT_brush_test_init_with_falloff_shape(
-          ss, test, brush.falloff_shape);
-
-      auto_mask::NodeData automask_data = auto_mask::node_begin(
-          ob, ss.cache->automasking.get(), *node);
-
-      bool changed = false;
-
-      PBVHVertexIter vd;
-      BKE_pbvh_vertex_iter_begin (*ss.pbvh, node, vd, PBVH_ITER_UNIQUE) {
-        auto_mask::node_update(automask_data, vd);
-
-        if (!sculpt_brush_test_sq_fn(test, vd.co)) {
-          continue;
-        }
-        const float fade = bstrength * SCULPT_brush_strength_factor(ss,
-                                                                    brush,
-                                                                    vd.co,
-                                                                    sqrtf(test.dist),
-                                                                    vd.no,
-                                                                    vd.fno,
-                                                                    vd.mask,
-                                                                    vd.vertex,
-                                                                    thread_id,
-                                                                    &automask_data);
-
-        if (fade > FACE_SET_BRUSH_MIN_FADE) {
-          const int face_index = BKE_subdiv_ccg_grid_to_face_index(subdiv_ccg,
-                                                                   vd.grid_indices[vd.g]);
-          face_sets[face_index] = ss.cache->paint_face_set;
-          changed = true;
-        }
-      }
-      BKE_pbvh_vertex_iter_end;
-
-      if (changed) {
-        undo::push_node(ob, node, undo::Type::FaceSet);
-      }
-    }
-  });
-  attribute.finish();
-}
-
-static void do_draw_face_sets_brush_bmesh(Object &ob,
-                                          const Brush &brush,
-                                          const Span<PBVHNode *> nodes)
-{
-  SculptSession &ss = *ob.sculpt;
-  const float bstrength = ss.cache->bstrength;
-  const int cd_offset = ensure_face_sets_bmesh(ob);
-
-  threading::parallel_for(nodes.index_range(), 1, [&](const IndexRange range) {
-    const int thread_id = BLI_task_parallel_thread_id(nullptr);
-    for (PBVHNode *node : nodes.slice(range)) {
-
-      SculptBrushTest test;
-      SculptBrushTestFn sculpt_brush_test_sq_fn = SCULPT_brush_test_init_with_falloff_shape(
-          ss, test, brush.falloff_shape);
-
-      /* Disable auto-masking code path which rely on an undo step to access original data.
-       *
-       * This is because the dynamic topology uses BMesh Log based undo system, which creates a
-       * single node for the undo step, and its type could be different for the needs of the brush
-       * undo and the original data access.
-       *
-       * For the brushes like Draw the ss.cache->automasking is set to nullptr at the first step
-       * of the brush, as there is an explicit check there for the brushes which support dynamic
-       * topology. Do it locally here for the Draw Face Set brush here, to mimic the behavior of
-       * the other brushes but without marking the brush as supporting dynamic topology. */
-      auto_mask::NodeData automask_data = auto_mask::node_begin(ob, nullptr, *node);
-
-      bool changed = false;
-
-      for (BMFace *f : BKE_pbvh_bmesh_node_faces(node)) {
-        if (BM_elem_flag_test(f, BM_ELEM_HIDDEN)) {
-          continue;
-        }
-
-        float3 face_center;
-        BM_face_calc_center_median(f, face_center);
-
-        const BMLoop *l_iter = f->l_first = BM_FACE_FIRST_LOOP(f);
-        do {
-          if (!sculpt_brush_test_sq_fn(test, l_iter->v->co)) {
-            continue;
-          }
-
-          BMVert *vert = l_iter->v;
-
-          /* There is no need to update the automasking data as it is disabled above. Additionally,
-           * there is no access to the PBVHVertexIter as iteration happens over faces.
-           *
-           * The full auto-masking support would be very good to be implemented here, so keeping
-           * the typical code flow for it here for the reference, and ease of looking at what needs
-           * to be done for such integration.
-           *
-           * auto_mask::node_update(automask_data, vd); */
-
-          const float fade = bstrength *
-                             SCULPT_brush_strength_factor(ss,
-                                                          brush,
-                                                          face_center,
-                                                          sqrtf(test.dist),
-                                                          f->no,
-                                                          f->no,
-                                                          0.0f,
-                                                          BKE_pbvh_make_vref(intptr_t(vert)),
-                                                          thread_id,
-                                                          &automask_data);
-
-          if (fade <= FACE_SET_BRUSH_MIN_FADE) {
-            continue;
-          }
-
-          int &fset = *static_cast<int *>(POINTER_OFFSET(f->head.data, cd_offset));
-          fset = ss.cache->paint_face_set;
-          changed = true;
-          break;
-
-        } while ((l_iter = l_iter->next) != f->l_first);
-      }
-
-      if (changed) {
-        undo::push_node(ob, node, undo::Type::FaceSet);
-      }
-    }
-  });
-}
-
 static void do_relax_face_sets_brush_task(Object &ob,
                                           const Brush &brush,
                                           const float strength,
@@ -483,38 +267,24 @@ static std::array<float, 4> iteration_strengths(const float strength, const int
   return {modified_strength, modified_strength, strength, strength};
 }
 
-void do_draw_face_sets_brush(const Sculpt &sd, Object &ob, Span<PBVHNode *> nodes)
+void do_relax_face_sets_brush(const Sculpt &sd, Object &ob, Span<PBVHNode *> nodes)
 {
-  SculptSession &ss = *ob.sculpt;
   const Brush &brush = *BKE_paint_brush_for_read(&sd.paint);
 
   BKE_curvemapping_init(brush.curve);
 
-  if (ss.cache->alt_smooth) {
-    SCULPT_boundary_info_ensure(ob);
-    const SculptSession &ss = *ob.sculpt;
-    const std::array<float, 4> strengths = iteration_strengths(ss.cache->bstrength,
-                                                               ss.cache->iteration_count);
-    for (const float strength : strengths) {
-      threading::parallel_for(nodes.index_range(), 1, [&](const IndexRange range) {
-        for (const int i : range) {
-          do_relax_face_sets_brush_task(ob, brush, strength, nodes[i]);
-        }
-      });
-    }
-  }
-  else {
-    switch (BKE_pbvh_type(*ss.pbvh)) {
-      case PBVH_FACES:
-        do_draw_face_sets_brush_faces(ob, brush, nodes);
-        break;
-      case PBVH_GRIDS:
-        do_draw_face_sets_brush_grids(ob, brush, nodes);
-        break;
-      case PBVH_BMESH:
-        do_draw_face_sets_brush_bmesh(ob, brush, nodes);
-        break;
-    }
+  SCULPT_boundary_info_ensure(ob);
+
+  const SculptSession &ss = *ob.sculpt;
+  const std::array<float, 4> strengths = iteration_strengths(ss.cache->bstrength,
+                                                             ss.cache->iteration_count);
+  for (const float strength : strengths) {
+
+    threading::parallel_for(nodes.index_range(), 1, [&](const IndexRange range) {
+      for (const int i : range) {
+        do_relax_face_sets_brush_task(ob, brush, strength, nodes[i]);
+      }
+    });
   }
 }
 

source/blender/editors/sculpt_paint/sculpt_intern.hh

@@ -1968,7 +1968,7 @@ void multiplane_scrape_preview_draw(uint gpuattr,
 
 namespace face_set {
 
-void do_draw_face_sets_brush(const Sculpt &sd, Object &ob, Span<PBVHNode *> nodes);
+void do_relax_face_sets_brush(const Sculpt &sd, Object &ob, Span<PBVHNode *> nodes);
 
 }