smooth.cc

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/* SPDX-FileCopyrightText: 2024 Blender Authors
 *
 * SPDX-License-Identifier: GPL-2.0-or-later */
 
#include "editors/sculpt_paint/brushes/types.hh"
 
#include "DNA_brush_types.h"
#include "DNA_mesh_types.h"
#include "DNA_object_types.h"
#include "DNA_scene_types.h"
 
#include "BKE_key.hh"
#include "BKE_mesh.hh"
#include "BKE_paint.hh"
#include "BKE_pbvh.hh"
#include "BKE_subdiv_ccg.hh"
 
#include "BLI_array.hh"
#include "BLI_enumerable_thread_specific.hh"
#include "BLI_task.hh"
#include "BLI_virtual_array.hh"
 
#include "editors/sculpt_paint/mesh_brush_common.hh"
#include "editors/sculpt_paint/sculpt_automask.hh"
#include "editors/sculpt_paint/sculpt_boundary.hh"
#include "editors/sculpt_paint/sculpt_intern.hh"
#include "editors/sculpt_paint/sculpt_smooth.hh"
 
namespace blender::ed::sculpt_paint {
 
inline namespace smooth_cc {
 
static Vector<float> iteration_strengths(const float strength)
{
  constexpr int max_iterations = 4;
 
  BLI_assert_msg(strength >= 0.0f,
                 "The smooth brush expects a non-negative strength to behave properly");
  const float clamped_strength = std::min(strength, 1.0f);
 
  const int count = int(clamped_strength * max_iterations);
  const float last = max_iterations * (clamped_strength - float(count) / max_iterations);
  Vector<float> result;
  result.append_n_times(1.0f, count);
  result.append(last);
  return result;
}
 
struct LocalData {
  Vector<float3> positions;
  Vector<float> factors;
  Vector<float> distances;
  Vector<Vector<int>> vert_neighbors;
  Vector<float3> new_positions;
  Vector<float3> translations;
};
 
BLI_NOINLINE static void apply_positions_faces(const Depsgraph &depsgraph,
                                               const Sculpt &sd,
                                               const Brush &brush,
                                               const MeshAttributeData &attribute_data,
                                               const Span<float3> vert_normals,
                                               const bke::pbvh::MeshNode &node,
                                               const float strength,
                                               Object &object,
                                               LocalData &tls,
                                               const Span<float3> new_positions,
                                               const PositionDeformData &position_data)
{
  SculptSession &ss = *object.sculpt;
 
  const Span<int> verts = node.verts();
 
  calc_factors_common_mesh_indexed(depsgraph,
                                   brush,
                                   object,
                                   attribute_data,
                                   position_data.eval,
                                   vert_normals,
                                   node,
                                   tls.factors,
                                   tls.distances);
 
  scale_factors(tls.factors, strength);
 
  tls.translations.resize(verts.size());
  const MutableSpan<float3> translations = tls.translations;
  translations_from_new_positions(new_positions, verts, position_data.eval, translations);
  scale_translations(translations, tls.factors);
 
  clip_and_lock_translations(sd, ss, position_data.eval, verts, translations);
  position_data.deform(translations, verts);
}
 
BLI_NOINLINE static void do_smooth_brush_mesh(const Depsgraph &depsgraph,
                                              const Sculpt &sd,
                                              const Brush &brush,
                                              Object &object,
                                              const IndexMask &node_mask,
                                              const float brush_strength)
{
  const SculptSession &ss = *object.sculpt;
  bke::pbvh::Tree &pbvh = *bke::object::pbvh_get(object);
  MutableSpan<bke::pbvh::MeshNode> nodes = pbvh.nodes<bke::pbvh::MeshNode>();
  Mesh &mesh = *static_cast<Mesh *>(object.data);
  const OffsetIndices faces = mesh.faces();
  const Span<int> corner_verts = mesh.corner_verts();
  const GroupedSpan<int> vert_to_face_map = mesh.vert_to_face_map();
  const MeshAttributeData attribute_data(mesh.attributes());
 
  const PositionDeformData position_data(depsgraph, object);
  const Span<float3> vert_normals = bke::pbvh::vert_normals_eval(depsgraph, object);
 
  Array<int> node_offset_data;
  const OffsetIndices<int> node_vert_offsets = create_node_vert_offsets(
      nodes, node_mask, node_offset_data);
  Array<float3> new_positions(node_vert_offsets.total_size());
 
  threading::EnumerableThreadSpecific<LocalData> all_tls;
 
  /* Calculate the new positions into a separate array in a separate loop because multiple loops
   * are updated in parallel. Without this there would be non-threadsafe access to changing
   * positions in other bke::pbvh::Tree nodes. */
  for (const float strength : iteration_strengths(brush_strength)) {
    node_mask.foreach_index(GrainSize(1), [&](const int i, const int pos) {
      LocalData &tls = all_tls.local();
      const Span<int> verts = nodes[i].verts();
      tls.vert_neighbors.resize(verts.size());
      calc_vert_neighbors_interior(faces,
                                   corner_verts,
                                   vert_to_face_map,
                                   ss.vertex_info.boundary,
                                   attribute_data.hide_poly,
                                   verts,
                                   tls.vert_neighbors);
      smooth::neighbor_data_average_mesh_check_loose(
          position_data.eval,
          verts,
          tls.vert_neighbors,
          new_positions.as_mutable_span().slice(node_vert_offsets[pos]));
    });
 
    node_mask.foreach_index(GrainSize(1), [&](const int i, const int pos) {
      LocalData &tls = all_tls.local();
      apply_positions_faces(depsgraph,
                            sd,
                            brush,
                            attribute_data,
                            vert_normals,
                            nodes[i],
                            strength,
                            object,
                            tls,
                            new_positions.as_span().slice(node_vert_offsets[pos]),
                            position_data);
    });
  }
}
 
static void calc_grids(const Depsgraph &depsgraph,
                       const Sculpt &sd,
                       const OffsetIndices<int> faces,
                       const Span<int> corner_verts,
                       const BitSpan boundary_verts,
                       Object &object,
                       const Brush &brush,
                       const float strength,
                       const bke::pbvh::GridsNode &node,
                       LocalData &tls)
{
  SculptSession &ss = *object.sculpt;
  SubdivCCG &subdiv_ccg = *ss.subdiv_ccg;
 
  const Span<int> grids = node.grids();
  const MutableSpan positions = gather_grids_positions(subdiv_ccg, grids, tls.positions);
 
  calc_factors_common_grids(depsgraph, brush, object, positions, node, tls.factors, tls.distances);
 
  scale_factors(tls.factors, strength);
 
  tls.new_positions.resize(positions.size());
  const MutableSpan<float3> new_positions = tls.new_positions;
  smooth::neighbor_position_average_interior_grids(
      faces, corner_verts, boundary_verts, subdiv_ccg, grids, new_positions);
 
  tls.translations.resize(positions.size());
  const MutableSpan<float3> translations = tls.translations;
  translations_from_new_positions(new_positions, positions, translations);
  scale_translations(translations, tls.factors);
 
  clip_and_lock_translations(sd, ss, positions, translations);
  apply_translations(translations, grids, subdiv_ccg);
}
 
static void calc_bmesh(const Depsgraph &depsgraph,
                       const Sculpt &sd,
                       Object &object,
                       const Brush &brush,
                       const float strength,
                       bke::pbvh::BMeshNode &node,
                       LocalData &tls)
{
  SculptSession &ss = *object.sculpt;
 
  const Set<BMVert *, 0> &verts = BKE_pbvh_bmesh_node_unique_verts(&node);
  const MutableSpan positions = gather_bmesh_positions(verts, tls.positions);
 
  calc_factors_common_bmesh(depsgraph, brush, object, positions, node, tls.factors, tls.distances);
 
  scale_factors(tls.factors, strength);
 
  tls.new_positions.resize(verts.size());
  const MutableSpan<float3> new_positions = tls.new_positions;
  smooth::neighbor_position_average_interior_bmesh(verts, new_positions);
 
  tls.translations.resize(verts.size());
  const MutableSpan<float3> translations = tls.translations;
  translations_from_new_positions(new_positions, positions, translations);
  scale_translations(translations, tls.factors);
 
  clip_and_lock_translations(sd, ss, positions, translations);
  apply_translations(translations, verts);
}
 
}  // namespace smooth_cc
 
void do_smooth_brush(const Depsgraph &depsgraph,
                     const Sculpt &sd,
                     Object &object,
                     const IndexMask &node_mask,
                     const float brush_strength)
{
  SculptSession &ss = *object.sculpt;
  bke::pbvh::Tree &pbvh = *bke::object::pbvh_get(object);
  const Brush &brush = *BKE_paint_brush_for_read(&sd.paint);
 
  boundary::ensure_boundary_info(object);
 
  switch (pbvh.type()) {
    case bke::pbvh::Type::Mesh:
      do_smooth_brush_mesh(depsgraph, sd, brush, object, node_mask, brush_strength);
      break;
    case bke::pbvh::Type::Grids: {
      const Mesh &base_mesh = *static_cast<const Mesh *>(object.data);
      const OffsetIndices faces = base_mesh.faces();
      const Span<int> corner_verts = base_mesh.corner_verts();
 
      threading::EnumerableThreadSpecific<LocalData> all_tls;
      for (const float strength : iteration_strengths(brush_strength)) {
        MutableSpan<bke::pbvh::GridsNode> nodes = pbvh.nodes<bke::pbvh::GridsNode>();
        node_mask.foreach_index(GrainSize(1), [&](const int i) {
          LocalData &tls = all_tls.local();
          calc_grids(depsgraph,
                     sd,
                     faces,
                     corner_verts,
                     ss.vertex_info.boundary,
                     object,
                     brush,
                     strength,
                     nodes[i],
                     tls);
        });
      }
      break;
    }
    case bke::pbvh::Type::BMesh: {
      BM_mesh_elem_index_ensure(ss.bm, BM_VERT);
      BM_mesh_elem_table_ensure(ss.bm, BM_VERT);
      threading::EnumerableThreadSpecific<LocalData> all_tls;
      for (const float strength : iteration_strengths(brush_strength)) {
        MutableSpan<bke::pbvh::BMeshNode> nodes = pbvh.nodes<bke::pbvh::BMeshNode>();
        node_mask.foreach_index(GrainSize(1), [&](const int i) {
          LocalData &tls = all_tls.local();
          calc_bmesh(depsgraph, sd, object, brush, strength, nodes[i], tls);
        });
      }
      break;
    }
  }
  pbvh.tag_positions_changed(node_mask);
  bke::pbvh::update_bounds(depsgraph, object, pbvh);
}
 
}  // namespace blender::ed::sculpt_paint