text: /*
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License
   * as published by the Free Software Foundation; either version 2
   * of the License, or (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software  Foundation,
   * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
   *
   * The Original Code is Copyright (C) 2006 by Nicholas Bishop
   * All rights reserved.
   * Implements the Sculpt Mode tools
   */
  
  /** \file
   * \ingroup edsculpt
   */
  
  #include "MEM_guardedalloc.h"
  
  #include "BLI_math.h"
  #include "BLI_blenlib.h"
  #include "BLI_dial_2d.h"
  #include "BLI_task.h"
  #include "BLI_utildefines.h"
  #include "BLI_ghash.h"
  
  #include "BLT_translation.h"
  
  #include "DNA_customdata_types.h"
  #include "DNA_mesh_types.h"
  #include "DNA_meshdata_types.h"
  #include "DNA_node_types.h"
  #include "DNA_object_types.h"
  #include "DNA_scene_types.h"
  #include "DNA_brush_types.h"
  
  #include "BKE_brush.h"
  #include "BKE_ccg.h"
  #include "BKE_colortools.h"
  #include "BKE_context.h"
  #include "BKE_image.h"
  #include "BKE_key.h"
  #include "BKE_library.h"
  #include "BKE_main.h"
  #include "BKE_mesh.h"
  #include "BKE_mesh_mapping.h"
  #include "BKE_modifier.h"
  #include "BKE_multires.h"
  #include "BKE_node.h"
  #include "BKE_object.h"
  #include "BKE_paint.h"
  #include "BKE_particle.h"
  #include "BKE_pbvh.h"
  #include "BKE_pointcache.h"
  #include "BKE_report.h"
  #include "BKE_scene.h"
  #include "BKE_screen.h"
  #include "BKE_subsurf.h"
  
  #include "DEG_depsgraph.h"
  #include "DEG_depsgraph_query.h"
  
  #include "WM_api.h"
  #include "WM_types.h"
  #include "WM_message.h"
  #include "WM_toolsystem.h"
  
  #include "ED_sculpt.h"
  #include "ED_object.h"
  #include "ED_screen.h"
  #include "ED_view3d.h"
  #include "paint_intern.h"
  #include "sculpt_intern.h"
  
  #include "RNA_access.h"
  #include "RNA_define.h"
  
  #include "UI_interface.h"
  #include "UI_resources.h"
  
  #include "bmesh.h"
  #include "bmesh_tools.h"
  
  #include <math.h>
  #include <stdlib.h>
  #include <string.h>
  
  /** \name Tool Capabilities
   *
   * Avoid duplicate checks, internal logic only,
   * share logic with #rna_def_sculpt_capabilities where possible.
   *
   * \{ */
  
  /* Check if there are any active modifiers in stack
   * (used for flushing updates at enter/exit sculpt mode) */
  static bool sculpt_has_active_modifiers(Scene *scene, Object *ob)
  {
    ModifierData *md;
    VirtualModifierData virtualModifierData;
  
    md = modifiers_getVirtualModifierList(ob, &virtualModifierData);
  
    /* exception for shape keys because we can edit those */
    for (; md; md = md->next) {
      if (modifier_isEnabled(scene, md, eModifierMode_Realtime)) {
        return 1;
      }
    }
  
    return 0;
  }
  
  static bool sculpt_tool_needs_original(const char sculpt_tool)
  {
    return ELEM(
        sculpt_tool, SCULPT_TOOL_GRAB, SCULPT_TOOL_ROTATE, SCULPT_TOOL_THUMB, SCULPT_TOOL_LAYER);
  }
  
  static bool sculpt_tool_is_proxy_used(const char sculpt_tool)
  {
    return ELEM(sculpt_tool, SCULPT_TOOL_SMOOTH, SCULPT_TOOL_LAYER);
  }
  
  static bool sculpt_brush_use_topology_rake(const SculptSession *ss, const Brush *brush)
  {
    return SCULPT_TOOL_HAS_TOPOLOGY_RAKE(brush->sculpt_tool) &&
           (brush->topology_rake_factor > 0.0f) && (ss->bm != NULL);
  }
  
  /**
   * Test whether the #StrokeCache.sculpt_normal needs update in #do_brush_action
   */
  static int sculpt_brush_needs_normal(const SculptSession *ss, const Brush *brush)
  {
    return ((SCULPT_TOOL_HAS_NORMAL_WEIGHT(brush->sculpt_tool) &&
             (ss->cache->normal_weight > 0.0f)) ||
  
            ELEM(brush->sculpt_tool,
                 SCULPT_TOOL_BLOB,
                 SCULPT_TOOL_CREASE,
                 SCULPT_TOOL_DRAW,
                 SCULPT_TOOL_LAYER,
                 SCULPT_TOOL_NUDGE,
                 SCULPT_TOOL_ROTATE,
                 SCULPT_TOOL_THUMB) ||
  
            (brush->mtex.brush_map_mode == MTEX_MAP_MODE_AREA)) ||
           sculpt_brush_use_topology_rake(ss, brush);
  }
  /** \} */
  
  static bool sculpt_brush_needs_rake_rotation(const Brush *brush)
  {
    return SCULPT_TOOL_HAS_RAKE(brush->sculpt_tool) && (brush->rake_factor != 0.0f);
  }
  
  typedef enum StrokeFlags {
    CLIP_X = 1,
    CLIP_Y = 2,
    CLIP_Z = 4,
  } StrokeFlags;
  
  /************** Access to original unmodified vertex data *************/
  
  typedef struct {
    BMLog *bm_log;
  
    SculptUndoNode *unode;
    float (*coords)[3];
    short (*normals)[3];
    const float *vmasks;
  
    /* Original coordinate, normal, and mask */
    const float *co;
    const short *no;
    float mask;
  } SculptOrigVertData;
  
  /* Initialize a SculptOrigVertData for accessing original vertex data;
   * handles BMesh, mesh, and multires */
  static void sculpt_orig_vert_data_unode_init(SculptOrigVertData *data,
                                               Object *ob,
                                               SculptUndoNode *unode)
  {
    SculptSession *ss = ob->sculpt;
    BMesh *bm = ss->bm;
  
    memset(data, 0, sizeof(*data));
    data->unode = unode;
  
    if (bm) {
      data->bm_log = ss->bm_log;
    }
    else {
      data->coords = data->unode->co;
      data->normals = data->unode->no;
      data->vmasks = data->unode->mask;
    }
  }
  
  /* Initialize a SculptOrigVertData for accessing original vertex data;
   * handles BMesh, mesh, and multires */
  static void sculpt_orig_vert_data_init(SculptOrigVertData *data, Object *ob, PBVHNode *node)
  {
    SculptUndoNode *unode;
    unode = sculpt_undo_push_node(ob, node, SCULPT_UNDO_COORDS);
    sculpt_orig_vert_data_unode_init(data, ob, unode);
  }
  
  /* Update a SculptOrigVertData for a particular vertex from the PBVH
   * iterator */
  static void sculpt_orig_vert_data_update(SculptOrigVertData *orig_data, PBVHVertexIter *iter)
  {
    if (orig_data->unode->type == SCULPT_UNDO_COORDS) {
      if (orig_data->bm_log) {
        BM_log_original_vert_data(orig_data->bm_log, iter->bm_vert, &orig_data->co, &orig_data->no);
      }
      else {
        orig_data->co = orig_data->coords[iter->i];
        orig_data->no = orig_data->normals[iter->i];
      }
    }
    else if (orig_data->unode->type == SCULPT_UNDO_MASK) {
      if (orig_data->bm_log) {
        orig_data->mask = BM_log_original_mask(orig_data->bm_log, iter->bm_vert);
      }
      else {
        orig_data->mask = orig_data->vmasks[iter->i];
      }
    }
  }
  
  static void sculpt_rake_data_update(struct SculptRakeData *srd, const float co[3])
  {
    float rake_dist = len_v3v3(srd->follow_co, co);
    if (rake_dist > srd->follow_dist) {
      interp_v3_v3v3(srd->follow_co, srd->follow_co, co, rake_dist - srd->follow_dist);
    }
  }
  
  static void sculpt_rake_rotate(const SculptSession *ss,
                                 const float sculpt_co[3],
                                 const float v_co[3],
                                 float factor,
                                 float r_delta[3])
  {
    float vec_rot[3];
  
  #if 0
    /* lerp */
    sub_v3_v3v3(vec_rot, v_co, sculpt_co);
    mul_qt_v3(ss->cache->rake_rotation_symmetry, vec_rot);
    add_v3_v3(vec_rot, sculpt_co);
    sub_v3_v3v3(r_delta, vec_rot, v_co);
    mul_v3_fl(r_delta, factor);
  #else
    /* slerp */
    float q_interp[4];
    sub_v3_v3v3(vec_rot, v_co, sculpt_co);
  
    copy_qt_qt(q_interp, ss->cache->rake_rotation_symmetry);
    pow_qt_fl_normalized(q_interp, factor);
    mul_qt_v3(q_interp, vec_rot);
  
    add_v3_v3(vec_rot, sculpt_co);
    sub_v3_v3v3(r_delta, vec_rot, v_co);
  #endif
  }
  
  /**
   * Align the grab delta to the brush normal.
   *
   * \param grab_delta: Typically from `ss->cache->grab_delta_symmetry`.
   */
  static void sculpt_project_v3_normal_align(SculptSession *ss,
                                             const float normal_weight,
                                             float grab_delta[3])
  {
    /* signed to support grabbing in (to make a hole) as well as out. */
    const float len_signed = dot_v3v3(ss->cache->sculpt_normal_symm, grab_delta);
  
    /* this scale effectively projects the offset so dragging follows the cursor,
     * as the normal points towards the view, the scale increases. */
    float len_view_scale;
    {
      float view_aligned_normal[3];
      project_plane_v3_v3v3(
          view_aligned_normal, ss->cache->sculpt_normal_symm, ss->cache->view_normal);
      len_view_scale = fabsf(dot_v3v3(view_aligned_normal, ss->cache->sculpt_normal_symm));
      len_view_scale = (len_view_scale > FLT_EPSILON) ? 1.0f / len_view_scale : 1.0f;
    }
  
    mul_v3_fl(grab_delta, 1.0f - normal_weight);
    madd_v3_v3fl(
        grab_delta, ss->cache->sculpt_normal_symm, (len_signed * normal_weight) * len_view_scale);
  }
  
  /** \name SculptProjectVector
   *
   * Fast-path for #project_plane_v3_v3v3
   *
   * \{ */
  
  typedef struct SculptProjectVector {
    float plane[3];
    float len_sq;
    float len_sq_inv_neg;
    bool is_valid;
  
  } SculptProjectVector;
  
  /**
   * \param plane: Direction, can be any length.
   */
  static void sculpt_project_v3_cache_init(SculptProjectVector *spvc, const float plane[3])
  {
    copy_v3_v3(spvc->plane, plane);
    spvc->len_sq = len_squared_v3(spvc->plane);
    spvc->is_valid = (spvc->len_sq > FLT_EPSILON);
    spvc->len_sq_inv_neg = (spvc->is_valid) ? -1.0f / spvc->len_sq : 0.0f;
  }
  
  /**
   * Calculate the projection.
   */
  static void sculpt_project_v3(const SculptProjectVector *spvc, const float vec[3], float r_vec[3])
  {
  #if 0
    project_plane_v3_v3v3(r_vec, vec, spvc->plane);
  #else
    /* inline the projection, cache `-1.0 / dot_v3_v3(v_proj, v_proj)` */
    madd_v3_v3fl(r_vec, spvc->plane, dot_v3v3(vec, spvc->plane) * spvc->len_sq_inv_neg);
  #endif
  }
  
  /** \} */
  
  /**********************************************************************/
  
  /* Returns true if the stroke will use dynamic topology, false
   * otherwise.
   *
   * Factors: some brushes like grab cannot do dynamic topology.
   * Others, like smooth, are better without. Same goes for alt-
   * key smoothing. */
  static bool sculpt_stroke_is_dynamic_topology(const SculptSession *ss, const Brush *brush)
  {
    return ((BKE_pbvh_type(ss->pbvh) == PBVH_BMESH) &&
  
            (!ss->cache || (!ss->cache->alt_smooth)) &&
  
            /* Requires mesh restore, which doesn't work with
             * dynamic-topology */
            !(brush->flag & BRUSH_ANCHORED) && !(brush->flag & BRUSH_DRAG_DOT) &&
  
            SCULPT_TOOL_HAS_DYNTOPO(brush->sculpt_tool));
  }
  
  /*** paint mesh ***/
  
  static void paint_mesh_restore_co_task_cb(void *__restrict userdata,
                                            const int n,
                                            const TaskParallelTLS *__restrict UNUSED(tls))
  {
    SculptThreadedTaskData *data = userdata;
    SculptSession *ss = data->ob->sculpt;
  
    SculptUndoNode *unode;
    SculptUndoType type = (data->brush->sculpt_tool == SCULPT_TOOL_MASK ? SCULPT_UNDO_MASK :
                                                                          SCULPT_UNDO_COORDS);
  
    if (ss->bm) {
      unode = sculpt_undo_push_node(data->ob, data->nodes[n], type);
    }
    else {
      unode = sculpt_undo_get_node(data->nodes[n]);
    }
  
    if (unode) {
      PBVHVertexIter vd;
      SculptOrigVertData orig_data;
  
      sculpt_orig_vert_data_unode_init(&orig_data, data->ob, unode);
  
      BKE_pbvh_vertex_iter_begin(ss->pbvh, data->nodes[n], vd, PBVH_ITER_UNIQUE)
      {
        sculpt_orig_vert_data_update(&orig_data, &vd);
  
        if (orig_data.unode->type == SCULPT_UNDO_COORDS) {
          copy_v3_v3(vd.co, orig_data.co);
          if (vd.no) {
            copy_v3_v3_short(vd.no, orig_data.no);
          }
          else {
            normal_short_to_float_v3(vd.fno, orig_data.no);
          }
        }
        else if (orig_data.unode->type == SCULPT_UNDO_MASK) {
          *vd.mask = orig_data.mask;
        }
  
        if (vd.mvert) {
          vd.mvert->flag |= ME_VERT_PBVH_UPDATE;
        }
      }
      BKE_pbvh_vertex_iter_end;
  
      BKE_pbvh_node_mark_update(data->nodes[n]);
    }
  }
  
  static void paint_mesh_restore_co(Sculpt *sd, Object *ob)
  {
    SculptSession *ss = ob->sculpt;
    Brush *brush = BKE_paint_brush(&sd->paint);
  
    PBVHNode **nodes;
    int totnode;
  
    BKE_pbvh_search_gather(ss->pbvh, NULL, NULL, &nodes, &totnode);
  
    /**
     * Disable OpenMP when dynamic-topology is enabled. Otherwise, new entries might be inserted by
     * #sculpt_undo_push_node() into the GHash used internally by #BM_log_original_vert_co()
     * by a different thread. See T33787. */
    SculptThreadedTaskData data = {
        .sd = sd,
        .ob = ob,
        .brush = brush,
        .nodes = nodes,
    };
  
    TaskParallelSettings settings;
    BLI_parallel_range_settings_defaults(&settings);
    settings.use_threading = ((sd->flags & SCULPT_USE_OPENMP) && !ss->bm &&
                              totnode > SCULPT_THREADED_LIMIT);
    BLI_task_parallel_range(0, totnode, &data, paint_mesh_restore_co_task_cb, &settings);
  
    if (nodes) {
      MEM_freeN(nodes);
    }
  }
  
  /*** BVH Tree ***/
  
  static void sculpt_extend_redraw_rect_previous(Object *ob, rcti *rect)
  {
    /* expand redraw rect with redraw rect from previous step to
     * prevent partial-redraw issues caused by fast strokes. This is
     * needed here (not in sculpt_flush_update) as it was before
     * because redraw rectangle should be the same in both of
     * optimized PBVH draw function and 3d view redraw (if not -- some
     * mesh parts could disappear from screen (sergey) */
    SculptSession *ss = ob->sculpt;
  
    if (ss->cache) {
      if (!BLI_rcti_is_empty(&ss->cache->previous_r)) {
        BLI_rcti_union(rect, &ss->cache->previous_r);
      }
    }
  }
  
  /* Get a screen-space rectangle of the modified area */
  bool sculpt_get_redraw_rect(ARegion *ar, RegionView3D *rv3d, Object *ob, rcti *rect)
  {
    PBVH *pbvh = ob->sculpt->pbvh;
    float bb_min[3], bb_max[3];
  
    if (!pbvh) {
      return 0;
    }
  
    BKE_pbvh_redraw_BB(pbvh, bb_min, bb_max);
  
    /* convert 3D bounding box to screen space */
    if (!paint_convert_bb_to_rect(rect, bb_min, bb_max, ar, rv3d, ob)) {
      return 0;
    }
  
    return 1;
  }
  
  void ED_sculpt_redraw_planes_get(float planes[4][4], ARegion *ar, Object *ob)
  {
    PBVH *pbvh = ob->sculpt->pbvh;
    /* copy here, original will be used below */
    rcti rect = ob->sculpt->cache->current_r;
  
    sculpt_extend_redraw_rect_previous(ob, &rect);
  
    paint_calc_redraw_planes(planes, ar, ob, &rect);
  
    /* we will draw this rect, so now we can set it as the previous partial rect.
     * Note that we don't update with the union of previous/current (rect), only with
     * the current. Thus we avoid the rectangle needlessly growing to include
     * all the stroke area */
    ob->sculpt->cache->previous_r = ob->sculpt->cache->current_r;
  
    /* clear redraw flag from nodes */
    if (pbvh) {
      BKE_pbvh_update_bounds(pbvh, PBVH_UpdateRedraw);
    }
  }
  
  /************************ Brush Testing *******************/
  
  void sculpt_brush_test_init(SculptSession *ss, SculptBrushTest *test)
  {
    RegionView3D *rv3d = ss->cache->vc->rv3d;
  
    test->radius_squared = ss->cache->radius_squared;
    copy_v3_v3(test->location, ss->cache->location);
    test->dist = 0.0f; /* just for initialize */
  
    /* Only for 2D projection. */
    zero_v4(test->plane_view);
    zero_v4(test->plane_tool);
  
    test->mirror_symmetry_pass = ss->cache->mirror_symmetry_pass;
  
    if (rv3d->rflag & RV3D_CLIPPING) {
      test->clip_rv3d = rv3d;
    }
    else {
      test->clip_rv3d = NULL;
    }
  }
  
  BLI_INLINE bool sculpt_brush_test_clipping(const SculptBrushTest *test, const float co[3])
  {
    RegionView3D *rv3d = test->clip_rv3d;
    if (!rv3d) {
      return false;
    }
    float symm_co[3];
    flip_v3_v3(symm_co, co, test->mirror_symmetry_pass);
    return ED_view3d_clipping_test(rv3d, symm_co, true);
  }
  
  bool sculpt_brush_test_sphere(SculptBrushTest *test, const float co[3])
  {
    float distsq = len_squared_v3v3(co, test->location);
  
    if (distsq <= test->radius_squared) {
      if (sculpt_brush_test_clipping(test, co)) {
        return 0;
      }
      test->dist = sqrtf(distsq);
      return 1;
    }
    else {
      return 0;
    }
  }
  
  bool sculpt_brush_test_sphere_sq(SculptBrushTest *test, const float co[3])
  {
    float distsq = len_squared_v3v3(co, test->location);
  
    if (distsq <= test->radius_squared) {
      if (sculpt_brush_test_clipping(test, co)) {
        return 0;
      }
      test->dist = distsq;
      return 1;
    }
    else {
      return 0;
    }
  }
  
  bool sculpt_brush_test_sphere_fast(const SculptBrushTest *test, const float co[3])
  {
    if (sculpt_brush_test_clipping(test, co)) {
      return 0;
    }
    return len_squared_v3v3(co, test->location) <= test->radius_squared;
  }
  
  bool sculpt_brush_test_circle_sq(SculptBrushTest *test, const float co[3])
  {
    float co_proj[3];
    closest_to_plane_normalized_v3(co_proj, test->plane_view, co);
    float distsq = len_squared_v3v3(co_proj, test->location);
  
    if (distsq <= test->radius_squared) {
      if (sculpt_brush_test_clipping(test, co)) {
        return 0;
      }
      test->dist = distsq;
      return 1;
    }
    else {
      return 0;
    }
  }
  
  bool sculpt_brush_test_cube(SculptBrushTest *test, const float co[3], float local[4][4])
  {
    float side = M_SQRT1_2;
    float local_co[3];
  
    if (sculpt_brush_test_clipping(test, co)) {
      return 0;
    }
  
    mul_v3_m4v3(local_co, local, co);
  
    local_co[0] = fabsf(local_co[0]);
    local_co[1] = fabsf(local_co[1]);
    local_co[2] = fabsf(local_co[2]);
  
    if (local_co[0] <= side && local_co[1] <= side && local_co[2] <= side) {
      float p = 4.0f;
  
      test->dist = ((powf(local_co[0], p) + powf(local_co[1], p) + powf(local_co[2], p)) /
                    powf(side, p));
  
      return 1;
    }
    else {
      return 0;
    }
  }
  
  SculptBrushTestFn sculpt_brush_test_init_with_falloff_shape(SculptSession *ss,
                                                              SculptBrushTest *test,
                                                              char falloff_shape)
  {
    sculpt_brush_test_init(ss, test);
    SculptBrushTestFn sculpt_brush_test_sq_fn;
    if (falloff_shape == PAINT_FALLOFF_SHAPE_SPHERE) {
      sculpt_brush_test_sq_fn = sculpt_brush_test_sphere_sq;
    }
    else {
      /* PAINT_FALLOFF_SHAPE_TUBE */
      plane_from_point_normal_v3(test->plane_view, test->location, ss->cache->view_normal);
      sculpt_brush_test_sq_fn = sculpt_brush_test_circle_sq;
    }
    return sculpt_brush_test_sq_fn;
  }
  
  const float *sculpt_brush_frontface_normal_from_falloff_shape(SculptSession *ss,
                                                                char falloff_shape)
  {
    if (falloff_shape == PAINT_FALLOFF_SHAPE_SPHERE) {
      return ss->cache->sculpt_normal_symm;
    }
    else {
      /* PAINT_FALLOFF_SHAPE_TUBE */
      return ss->cache->view_normal;
    }
  }
  
  static float frontface(const Brush *br,
                         const float sculpt_normal[3],
                         const short no[3],
                         const float fno[3])
  {
    if (br->flag & BRUSH_FRONTFACE) {
      float dot;
  
      if (no) {
        float tmp[3];
  
        normal_short_to_float_v3(tmp, no);
        dot = dot_v3v3(tmp, sculpt_normal);
      }
      else {
        dot = dot_v3v3(fno, sculpt_normal);
      }
      return dot > 0 ? dot : 0;
    }
    else {
      return 1;
    }
  }
  
  #if 0
  
  static bool sculpt_brush_test_cyl(SculptBrushTest *test,
                                    float co[3],
                                    float location[3],
                                    const float area_no[3])
  {
    if (sculpt_brush_test_sphere_fast(test, co)) {
      float t1[3], t2[3], t3[3], dist;
  
      sub_v3_v3v3(t1, location, co);
      sub_v3_v3v3(t2, x2, location);
  
      cross_v3_v3v3(t3, area_no, t1);
  
      dist = len_v3(t3) / len_v3(t2);
  
      test->dist = dist;
  
      return 1;
    }
  
    return 0;
  }
  
  #endif
  
  /* ===== Sculpting =====
   */
  static void flip_v3(float v[3], const char symm)
  {
    flip_v3_v3(v, v, symm);
  }
  
  static float calc_overlap(StrokeCache *cache, const char symm, const char axis, const float angle)
  {
    float mirror[3];
    float distsq;
  
    /* flip_v3_v3(mirror, cache->traced_location, symm); */
    flip_v3_v3(mirror, cache->true_location, symm);
  
    if (axis != 0) {
      float mat[3][3];
      axis_angle_to_mat3_single(mat, axis, angle);
      mul_m3_v3(mat, mirror);
    }
  
    /* distsq = len_squared_v3v3(mirror, cache->traced_location); */
    distsq = len_squared_v3v3(mirror, cache->true_location);
  
    if (distsq <= 4.0f * (cache->radius_squared)) {
      return (2.0f * (cache->radius) - sqrtf(distsq)) / (2.0f * (cache->radius));
    }
    else {
      return 0;
    }
  }
  
  static float calc_radial_symmetry_feather(Sculpt *sd,
                                            StrokeCache *cache,
                                            const char symm,
                                            const char axis)
  {
    int i;
    float overlap;
  
    overlap = 0;
    for (i = 1; i < sd->radial_symm[axis - 'X']; ++i) {
      const float angle = 2 * M_PI * i / sd->radial_symm[axis - 'X'];
      overlap += calc_overlap(cache, symm, axis, angle);
    }
  
    return overlap;
  }
  
  static float calc_symmetry_feather(Sculpt *sd, StrokeCache *cache)
  {
    if (sd->paint.symmetry_flags & PAINT_SYMMETRY_FEATHER) {
      float overlap;
      int symm = cache->symmetry;
      int i;
  
      overlap = 0;
      for (i = 0; i <= symm; i++) {
        if (i == 0 || (symm & i && (symm != 5 || i != 3) && (symm != 6 || (i != 3 && i != 5)))) {
  
          overlap += calc_overlap(cache, i, 0, 0);
  
          overlap += calc_radial_symmetry_feather(sd, cache, i, 'X');
          overlap += calc_radial_symmetry_feather(sd, cache, i, 'Y');
          overlap += calc_radial_symmetry_feather(sd, cache, i, 'Z');
        }
      }
  
      return 1 / overlap;
    }
    else {
      return 1;
    }
  }
  
  /** \name Calculate Normal and Center
   *
   * Calculate geometry surrounding the brush center.
   * (optionally using original coordinates).
   *
   * Functions are:
   * - #calc_area_center
   * - #calc_area_normal
   * - #calc_area_normal_and_center
   *
   * \note These are all _very_ similar, when changing one, check others.
   * \{ */
  
  static void calc_area_normal_and_center_task_cb(void *__restrict userdata,
                                                  const int n,
                                                  const TaskParallelTLS *__restrict UNUSED(tls))
  {
    SculptThreadedTaskData *data = userdata;
    SculptSession *ss = data->ob->sculpt;
    float(*area_nos)[3] = data->area_nos;
    float(*area_cos)[3] = data->area_cos;
  
    PBVHVertexIter vd;
    SculptUndoNode *unode = NULL;
  
    float private_co[2][3] = {{0.0f}};
    float private_no[2][3] = {{0.0f}};
    int private_count[2] = {0};
    bool use_original = false;
  
    if (ss->cache->original) {
      unode = sculpt_undo_push_node(data->ob, data->nodes[n], SCULPT_UNDO_COORDS);
      use_original = (unode->co || unode->bm_entry);
    }
  
    SculptBrushTest test;
    SculptBrushTestFn sculpt_brush_test_sq_fn = sculpt_brush_test_init_with_falloff_shape(
        ss, &test, data->brush->falloff_shape);
  
    /* when the mesh is edited we can't rely on original coords
     * (original mesh may not even have verts in brush radius) */
    if (use_original && data->has_bm_orco) {
      float(*orco_coords)[3];
      int(*orco_tris)[3];
      int orco_tris_num;
      int i;
  
      BKE_pbvh_node_get_bm_orco_data(data->nodes[n], &orco_tris, &orco_tris_num, &orco_coords);
  
      for (i = 0; i < orco_tris_num; i++) {
        const float *co_tri[3] = {
            orco_coords[orco_tris[i][0]],
            orco_coords[orco_tris[i][1]],
            orco_coords[orco_tris[i][2]],
        };
        float co[3];
  
        closest_on_tri_to_point_v3(co, test.location, UNPACK3(co_tri));
  
        if (sculpt_brush_test_sq_fn(&test, co)) {
          float no[3];
          int flip_index;
  
          normal_tri_v3(no, UNPACK3(co_tri));
  
          flip_index = (dot_v3v3(ss->cache->view_normal, no) <= 0.0f);
          if (area_cos) {
            add_v3_v3(private_co[flip_index], co);
          }
          if (area_nos) {
            add_v3_v3(private_no[flip_index], no);
          }
          private_count[flip_index] += 1;
        }
      }
    }
    else {
      BKE_pbvh_vertex_iter_begin(ss->pbvh, data->nodes[n], vd, PBVH_ITER_UNIQUE)
      {
        const float *co;
        const short *no_s; /* bm_vert only */
  
        if (use_original) {
          if (unode->bm_entry) {
            BM_log_original_vert_data(ss->bm_log, vd.bm_vert, &co, &no_s);
          }
          else {
            co = unode->co[vd.i];
            no_s = unode->no[vd.i];
          }
        }
        else {
          co = vd.co;
        }
  
        if (sculpt_brush_test_sq_fn(&test, co)) {
          float no_buf[3];
          const float *no;
          int flip_index;
  
          if (use_original) {
            normal_short_to_float_v3(no_buf, no_s);
            no = no_buf;
          }
          else {
            if (vd.no) {
              normal_short_to_float_v3(no_buf, vd.no);
              no = no_buf;
            }
            else {
              no = vd.fno;
            }
          }
  
          flip_index = (dot_v3v3(ss->cache->view_normal, no) <= 0.0f);
          if (area_cos) {
            add_v3_v3(private_co[flip_index], co);
          }
          if (area_nos) {
            add_v3_v3(private_no[flip_index], no);
          }
          private_count[flip_index] += 1;
        }
      }
      BKE_pbvh_vertex_iter_end;
    }
  
    BLI_mutex_lock(&data->mutex);
  
    /* for flatten center */
    if (area_cos) {
      add_v3_v3(area_cos[0], private_co[0]);
      add_v3_v3(area_cos[1], private_co[1]);
    }
  
    /* for area normal */
    if (area_nos) {
      add_v3_v3(area_nos[0], private_no[0]);
      add_v3_v3(area_nos[1], private_no[1]);
    }
  
    /* weights */
    data->count[0] += private_count[0];
    data->count[1] += private_count[1];
  
    BLI_mutex_unlock(&data->mutex);
  }
  
  static void calc_area_center(
      Sculpt *sd, Object *ob, PBVHNode **nodes, int totnode, float r_area_co[3])
  {
    const Brush *brush = BKE_paint_brush(&sd->paint);
    SculptSession *ss = ob->sculpt;
    const bool has_bm_orco = ss->bm && sculpt_stroke_is_dynamic_topology(ss, brush);
    int n;
  
    /* 0=towards view, 1=flipped */
    float area_cos[2][3] = {{0.0f}};
  
    int count[2] = {0};
  
    /* Intentionally set 'sd' to NULL since we share logic with vertex paint. */
    SculptThreadedTaskData data = {
        .sd = NULL,
        .ob = ob,
        .brush = brush,
        .nodes = nodes,
        .totnode = totnode,
        .has_bm_orco = has_bm_orco,
        .area_cos = area_cos,
        .area_nos = NULL,
        .count = count,
    };
    BLI_mutex_init(&data.mutex);
  
    TaskParallelSettings settings;
    BLI_parallel_range_settings_defaults(&settings);
    settings.use_threading = ((sd->flags & SCULPT_USE_OPENMP) && totnode > SCULPT_THREADED_LIMIT);
    BLI_task_parallel_range(0, totnode, &data, calc_area_normal_and_center_task_cb, &settings);
  
    BLI_mutex_end(&data.mutex);
  
    /* for flatten center */
    for (n = 0; n < ARRAY_SIZE(area_cos); n++) {
      if (count[n] != 0) {
        mul_v3_v3fl(r_area_co, area_cos[n], 1.0f / count[n]);
        break;
      }
    }
    if (n == 2) {
      zero_v3(r_area_co);
    }
  }
  
  static void calc_area_normal(
      Sculpt *sd, Object *ob, PBVHNode **nodes, int totnode, float r_area_no[3])
  {
    const Brush *brush = BKE_paint_brush(&sd->paint);
    bool use_threading = (sd->flags & SCULPT_USE_OPENMP) && totnode > SCULPT_THREADED_LIMIT;
    sculpt_pbvh_calc_area_normal(brush, ob, nodes, totnode, use_threading, r_area_no);
  }
  
  /* expose 'calc_area_normal' externally. */
  void sculpt_pbvh_calc_area_normal(const Brush *brush,
                                    Object *ob,
                                    PBVHNode **nodes,
                                    int totnode,
                                    bool use_threading,
                                    float r_area_no[3])
  {
    SculptSession *ss = ob->sculpt;
    const bool has_bm_orco = ss->bm && sculpt_stroke_is_dynamic_topology(ss, brush);
  
    /* 0=towards view, 1=flipped */
    float area_nos[2][3] = {{0.0f}};
  
    int count[2] = {0};
  
    /* Intentionally set 'sd' to NULL since this is used for vertex paint too. */
    SculptThreadedTaskData data = {
        .sd = NULL,
        .ob = ob,
        .brush = brush,
        .nodes = nodes,
        .totnode = totnode,
        .has_bm_orco = has_bm_orco,
        .area_cos = NULL,
        .area_nos = area_nos,
        .count = count,
    };
    BLI_mutex_init(&data.mutex);
  
    TaskParallelSettings settings;
    BLI_parallel_range_settings_defaults(&settings);
    settings.use_threading = use_threading;
    BLI_task_parallel_range(0, totnode, &data, calc_area_normal_and_center_task_cb, &settings);
  
    BLI_mutex_end(&data.mutex);
  
    /* for area normal */
    for (int i = 0; i < ARRAY_SIZE(area_nos); i++) {
      if (normalize_v3_v3(r_area_no, area_nos[i]) != 0.0f) {
        break;
      }
    }
  }
  
  /* this calculates flatten center and area normal together,
   * amortizing the memory bandwidth and loop overhead to calculate both at the same time */
  static void calc_area_normal_and_center(
      Sculpt *sd, Object *ob, PBVHNode **nodes, int totnode, float r_area_no[3], float r_area_co[3])
  {
    const Brush *brush = BKE_paint_brush(&sd->paint);
    SculptSession *ss = ob->sculpt;
    const bool has_bm_orco = ss->bm && sculpt_stroke_is_dynamic_topology(ss, brush);
    int n;
  
    /* 0=towards view, 1=flipped */
    float area_cos[2][3] = {{0.0f}};
    float area_nos[2][3] = {{0.0f}};
  
    int count[2] = {0};
  
    /* Intentionally set 'sd' to NULL since this is used for vertex paint too. */
    SculptThreadedTaskData data = {
        .sd = NULL,
        .ob = ob,
        .brush = brush,
        .nodes = nodes,
        .totnode = totnode,
        .has_bm_orco = has_bm_orco,
        .area_cos = area_cos,
        .area_nos = area_nos,
        .count = count,
    };
    BLI_mutex_init(&data.mutex);
  
    TaskParallelSettings settings;
    BLI_parallel_range_settings_defaults(&settings);
    settings.use_threading = ((sd->flags & SCULPT_USE_OPENMP) && totnode > SCULPT_THREADED_LIMIT);
    BLI_task_parallel_range(0, totnode, &data, calc_area_normal_and_center_task_cb, &settings);
  
    BLI_mutex_end(&data.mutex);
  
    /* for flatten center */
    for (n = 0; n < ARRAY_SIZE(area_cos); n++) {
      if (count[n] != 0) {
        mul_v3_v3fl(r_area_co, area_cos[n], 1.0f / count[n]);
        break;
      }
    }
    if (n == 2) {
      zero_v3(r_area_co);
    }
  
    /* for area normal */
    for (n = 0; n < ARRAY_SIZE(area_nos); n++) {
      if (normalize_v3_v3(r_area_no, area_nos[n]) != 0.0f) {
        break;
      }
    }
  }
  
  /** \} */
  
  /* Return modified brush strength. Includes the direction of the brush, positive
   * values pull vertices, negative values push. Uses tablet pressure and a
   * special multiplier found experimentally to scale the strength factor. */
  static float brush_strength(const Sculpt *sd,
                              const StrokeCache *cache,
                              const float feather,
                              const UnifiedPaintSettings *ups)
  {
    const Scene *scene = cache->vc->scene;
    const Brush *brush = BKE_paint_brush((Paint *)&sd->paint);
  
    /* Primary strength input; square it to make lower values more sensitive */
    const float root_alpha = BKE_brush_alpha_get(scene, brush);
    float alpha = root_alpha * root_alpha;
    float dir = (brush->flag & BRUSH_DIR_IN) ? -1 : 1;
    float pressure = BKE_brush_use_alpha_pressure(scene, brush) ? cache->pressure : 1;
    float pen_flip = cache->pen_flip ? -1 : 1;
    float invert = cache->invert ? -1 : 1;
    float overlap = ups->overlap_factor;
    /* spacing is integer percentage of radius, divide by 50 to get
     * normalized diameter */
  
    float flip = dir * invert * pen_flip;
  
    switch (brush->sculpt_tool) {
      case SCULPT_TOOL_CLAY:
      case SCULPT_TOOL_CLAY_STRIPS:
      case SCULPT_TOOL_DRAW:
      case SCULPT_TOOL_LAYER:
        return alpha * flip * pressure * overlap * feather;
  
      case SCULPT_TOOL_MASK:
        overlap = (1 + overlap) / 2;
        switch ((BrushMaskTool)brush->mask_tool) {
          case BRUSH_MASK_DRAW:
            return alpha * flip * pressure * overlap * feather;
          case BRUSH_MASK_SMOOTH:
            return alpha * pressure * feather;
        }
        BLI_assert(!"Not supposed to happen");
        return 0.0f;
  
      case SCULPT_TOOL_CREASE:
      case SCULPT_TOOL_BLOB:
        return alpha * flip * pressure * overlap * feather;
  
      case SCULPT_TOOL_INFLATE:
        if (flip > 0) {
          return 0.250f * alpha * flip * pressure * overlap * feather;
        }
        else {
          return 0.125f * alpha * flip * pressure * overlap * feather;
        }
  
      case SCULPT_TOOL_FILL:
      case SCULPT_TOOL_SCRAPE:
      case SCULPT_TOOL_FLATTEN:
        if (flip > 0) {
          overlap = (1 + overlap) / 2;
          return alpha * flip * pressure * overlap * feather;
        }
        else {
          /* reduce strength for DEEPEN, PEAKS, and CONTRAST */
          return 0.5f * alpha * flip * pressure * overlap * feather;
        }
  
      case SCULPT_TOOL_SMOOTH:
        return alpha * pressure * feather;
  
      case SCULPT_TOOL_PINCH:
        if (flip > 0) {
          return alpha * flip * pressure * overlap * feather;
        }
        else {
          return 0.25f * alpha * flip * pressure * overlap * feather;
        }
  
      case SCULPT_TOOL_NUDGE:
        overlap = (1 + overlap) / 2;
        return alpha * pressure * overlap * feather;
  
      case SCULPT_TOOL_THUMB:
        return alpha * pressure * feather;
  
      case SCULPT_TOOL_SNAKE_HOOK:
        return root_alpha * feather;
  
      case SCULPT_TOOL_GRAB:
        return root_alpha * feather;
  
      case SCULPT_TOOL_ROTATE:
        return alpha * pressure * feather;
  
      default:
        return 0;
    }
  }
  
  /* Return a multiplier for brush strength on a particular vertex. */
  float tex_strength(SculptSession *ss,
                     const Brush *br,
                     const float brush_point[3],
                     const float len,
                     const short vno[3],
                     const float fno[3],
                     const float mask,
                     const int thread_id)
  {
    StrokeCache *cache = ss->cache;
    const Scene *scene = cache->vc->scene;
    const MTex *mtex = &br->mtex;
    float avg = 1;
    float rgba[4];
    float point[3];
  
    sub_v3_v3v3(point, brush_point, cache->plane_offset);
  
    if (!mtex->tex) {
      avg = 1;
    }
    else if (mtex->brush_map_mode == MTEX_MAP_MODE_3D) {
      /* Get strength by feeding the vertex
       * location directly into a texture */
      avg = BKE_brush_sample_tex_3d(scene, br, point, rgba, 0, ss->tex_pool);
    }
    else if (ss->texcache) {
      float symm_point[3], point_2d[2];
      float x = 0.0f, y = 0.0f; /* Quite warnings */
  
      /* if the active area is being applied for symmetry, flip it
       * across the symmetry axis and rotate it back to the original
       * position in order to project it. This insures that the
       * brush texture will be oriented correctly. */
  
      flip_v3_v3(symm_point, point, cache->mirror_symmetry_pass);
  
      if (cache->radial_symmetry_pass) {
        mul_m4_v3(cache->symm_rot_mat_inv, symm_point);
      }
  
      ED_view3d_project_float_v2_m4(cache->vc->ar, symm_point, point_2d, cache->projection_mat);
  
      /* still no symmetry supported for other paint modes.
       * Sculpt does it DIY */
      if (mtex->brush_map_mode == MTEX_MAP_MODE_AREA) {
        /* Similar to fixed mode, but projects from brush angle
         * rather than view direction */
  
        mul_m4_v3(cache->brush_local_mat, symm_point);
  
        x = symm_point[0];
        y = symm_point[1];
  
        x *= br->mtex.size[0];
        y *= br->mtex.size[1];
  
        x += br->mtex.ofs[0];
        y += br->mtex.ofs[1];
  
        avg = paint_get_tex_pixel(&br->mtex, x, y, ss->tex_pool, thread_id);
  
        avg += br->texture_sample_bias;
      }
      else {
        const float point_3d[3] = {point_2d[0], point_2d[1], 0.0f};
        avg = BKE_brush_sample_tex_3d(scene, br, point_3d, rgba, 0, ss->tex_pool);
      }
    }
  
    /* Falloff curve */
    avg *= BKE_brush_curve_strength(br, len, cache->radius);
    avg *= frontface(br, cache->view_normal, vno, fno);
  
    /* Paint mask */
    avg *= 1.0f - mask;
  
    return avg;
  }
  
  /* Test AABB against sphere */
  bool sculpt_search_sphere_cb(PBVHNode *node, void *data_v)
  {
    SculptSearchSphereData *data = data_v;
    float *center = data->ss->cache->location, nearest[3];
    float t[3], bb_min[3], bb_max[3];
    int i;
  
    if (data->original) {
      BKE_pbvh_node_get_original_BB(node, bb_min, bb_max);
    }
    else {
      BKE_pbvh_node_get_BB(node, bb_min, bb_max);
    }
  
    for (i = 0; i < 3; ++i) {
      if (bb_min[i] > center[i]) {
        nearest[i] = bb_min[i];
      }
      else if (bb_max[i] < center[i]) {
        nearest[i] = bb_max[i];
      }
      else {
        nearest[i] = center[i];
      }
    }
  
    sub_v3_v3v3(t, center, nearest);
  
    return len_squared_v3(t) < data->radius_squared;
  }
  
  /* 2D projection (distance to line). */
  bool sculpt_search_circle_cb(PBVHNode *node, void *data_v)
  {
    SculptSearchCircleData *data = data_v;
    float bb_min[3], bb_max[3];
  
    if (data->original) {
      BKE_pbvh_node_get_original_BB(node, bb_min, bb_max);
    }
    else {
      BKE_pbvh_node_get_BB(node, bb_min, bb_min);
    }
  
    float dummy_co[3], dummy_depth;
    const float dist_sq = dist_squared_ray_to_aabb_v3(
        data->dist_ray_to_aabb_precalc, bb_min, bb_max, dummy_co, &dummy_depth);
  
    return dist_sq < data->radius_squared || 1;
  }
  
  /* Handles clipping against a mirror modifier and SCULPT_LOCK axis flags */
  static void sculpt_clip(Sculpt *sd, SculptSession *ss, float co[3], const float val[3])
  {
    int i;
  
    for (i = 0; i < 3; ++i) {
      if (sd->flags & (SCULPT_LOCK_X << i)) {
        continue;
      }
  
      if ((ss->cache->flag & (CLIP_X << i)) && (fabsf(co[i]) <= ss->cache->clip_tolerance[i])) {
        co[i] = 0.0f;
      }
      else {
        co[i] = val[i];
      }
    }
  }
  
  static PBVHNode **sculpt_pbvh_gather_generic(Object *ob,
                                               Sculpt *sd,
                                               const Brush *brush,
                                               bool use_original,
                                               float radius_scale,
                                               int *r_totnode)
  {
    SculptSession *ss = ob->sculpt;
    PBVHNode **nodes = NULL;
  
    /* Build a list of all nodes that are potentially within the brush's area of influence */
    if (brush->falloff_shape == PAINT_FALLOFF_SHAPE_SPHERE) {
      SculptSearchSphereData data = {
          .ss = ss,
          .sd = sd,
          .radius_squared = SQUARE(ss->cache->radius * radius_scale),
          .original = use_original,
      };
      BKE_pbvh_search_gather(ss->pbvh, sculpt_search_sphere_cb, &data, &nodes, r_totnode);
    }
    else {
      struct DistRayAABB_Precalc dist_ray_to_aabb_precalc;
      dist_squared_ray_to_aabb_v3_precalc(
          &dist_ray_to_aabb_precalc, ss->cache->location, ss->cache->view_normal);
      SculptSearchCircleData data = {
          .ss = ss,
          .sd = sd,
          .radius_squared = SQUARE(ss->cache->radius * radius_scale),
          .original = use_original,
          .dist_ray_to_aabb_precalc = &dist_ray_to_aabb_precalc,
      };
      BKE_pbvh_search_gather(ss->pbvh, sculpt_search_circle_cb, &data, &nodes, r_totnode);
    }
    return nodes;
  }
  
  /* Calculate primary direction of movement for many brushes */
  static void calc_sculpt_normal(
      Sculpt *sd, Object *ob, PBVHNode **nodes, int totnode, float r_area_no[3])
  {
    const Brush *brush = BKE_paint_brush(&sd->paint);
    const SculptSession *ss = ob->sculpt;
  
    switch (brush->sculpt_plane) {
      case SCULPT_DISP_DIR_VIEW:
        copy_v3_v3(r_area_no, ss->cache->true_view_normal);
        break;
  
      case SCULPT_DISP_DIR_X:
        ARRAY_SET_ITEMS(r_area_no, 1, 0, 0);
        break;
  
      case SCULPT_DISP_DIR_Y:
        ARRAY_SET_ITEMS(r_area_no, 0, 1, 0);
        break;
  
      case SCULPT_DISP_DIR_Z:
        ARRAY_SET_ITEMS(r_area_no, 0, 0, 1);
        break;
  
      case SCULPT_DISP_DIR_AREA:
        calc_area_normal(sd, ob, nodes, totnode, r_area_no);
        break;
  
      default:
        break;
    }
  }
  
  static void update_sculpt_normal(Sculpt *sd, Object *ob, PBVHNode **nodes, int totnode)
  {
    const Brush *brush = BKE_paint_brush(&sd->paint);
    StrokeCache *cache = ob->sculpt->cache;
  
    if (cache->mirror_symmetry_pass == 0 && cache->radial_symmetry_pass == 0 &&
        (cache->first_time || !(brush->flag & BRUSH_ORIGINAL_NORMAL))) {
      calc_sculpt_normal(sd, ob, nodes, totnode, cache->sculpt_normal);
      if (brush->falloff_shape == PAINT_FALLOFF_SHAPE_TUBE) {
        project_plane_v3_v3v3(cache->sculpt_normal, cache->sculpt_normal, cache->view_normal);
        normalize_v3(cache->sculpt_normal);
      }
      copy_v3_v3(cache->sculpt_normal_symm, cache->sculpt_normal);
    }
    else {
      copy_v3_v3(cache->sculpt_normal_symm, cache->sculpt_normal);
      flip_v3(cache->sculpt_normal_symm, cache->mirror_symmetry_pass);
      mul_m4_v3(cache->symm_rot_mat, cache->sculpt_normal_symm);
    }
  }
  
  static void calc_local_y(ViewContext *vc, const float center[3], float y[3])
  {
    Object *ob = vc->obact;
    float loc[3], mval_f[2] = {0.0f, 1.0f};
    float zfac;
  
    mul_v3_m4v3(loc, ob->imat, center);
    zfac = ED_view3d_calc_zfac(vc->rv3d, loc, NULL);
  
    ED_view3d_win_to_delta(vc->ar, mval_f, y, zfac);
    normalize_v3(y);
  
    add_v3_v3(y, ob->loc);
    mul_m4_v3(ob->imat, y);
  }
  
  static void calc_brush_local_mat(const Brush *brush, Object *ob, float local_mat[4][4])
  {
    const StrokeCache *cache = ob->sculpt->cache;
    float tmat[4][4];
    float mat[4][4];
    float scale[4][4];
    float angle, v[3];
    float up[3];
  
    /* Ensure ob->imat is up to date */
    invert_m4_m4(ob->imat, ob->obmat);
  
    /* Initialize last column of matrix */
    mat[0][3] = 0;
    mat[1][3] = 0;
    mat[2][3] = 0;
    mat[3][3] = 1;
  
    /* Get view's up vector in object-space */
    calc_local_y(cache->vc, cache->location, up);
  
    /* Calculate the X axis of the local matrix */
    cross_v3_v3v3(v, up, cache->sculpt_normal);
    /* Apply rotation (user angle, rake, etc.) to X axis */
    angle = brush->mtex.rot - cache->special_rotation;
    rotate_v3_v3v3fl(mat[0], v, cache->sculpt_normal, angle);
  
    /* Get other axes */
    cross_v3_v3v3(mat[1], cache->sculpt_normal, mat[0]);
    copy_v3_v3(mat[2], cache->sculpt_normal);
  
    /* Set location */
    copy_v3_v3(mat[3], cache->location);
  
    /* Scale by brush radius */
    normalize_m4(mat);
    scale_m4_fl(scale, cache->radius);
    mul_m4_m4m4(tmat, mat, scale);
  
    /* Return inverse (for converting from modelspace coords to local
     * area coords) */
    invert_m4_m4(local_mat, tmat);
  }
  
  static void update_brush_local_mat(Sculpt *sd, Object *ob)
  {
    StrokeCache *cache = ob->sculpt->cache;
  
    if (cache->mirror_symmetry_pass == 0 && cache->radial_symmetry_pass == 0) {
      calc_brush_local_mat(BKE_paint_brush(&sd->paint), ob, cache->brush_local_mat);
    }
  }
  
  /* For the smooth brush, uses the neighboring vertices around vert to calculate
   * a smoothed location for vert. Skips corner vertices (used by only one
   * polygon.) */
  static void neighbor_average(SculptSession *ss, float avg[3], unsigned vert)
  {
    const MeshElemMap *vert_map = &ss->pmap[vert];
    const MVert *mvert = ss->mvert;
    float(*deform_co)[3] = ss->deform_cos;
  
    /* Don't modify corner vertices */
    if (vert_map->count > 1) {
      int i, total = 0;
  
      zero_v3(avg);
  
      for (i = 0; i < vert_map->count; i++) {
        const MPoly *p = &ss->mpoly[vert_map->indices[i]];
        unsigned f_adj_v[2];
  
        if (poly_get_adj_loops_from_vert(p, ss->mloop, vert, f_adj_v) != -1) {
          int j;
          for (j = 0; j < ARRAY_SIZE(f_adj_v); j += 1) {
            if (vert_map->count != 2 || ss->pmap[f_adj_v[j]].count <= 2) {
              add_v3_v3(avg, deform_co ? deform_co[f_adj_v[j]] : mvert[f_adj_v[j]].co);
  
              total++;
            }
          }
        }
      }
  
      if (total > 0) {
        mul_v3_fl(avg, 1.0f / total);
        return;
      }
    }
  
    copy_v3_v3(avg, deform_co ? deform_co[vert] : mvert[vert].co);
  }
  
  /* Similar to neighbor_average(), but returns an averaged mask value
   * instead of coordinate. Also does not restrict based on border or
   * corner vertices. */
  static float neighbor_average_mask(SculptSession *ss, unsigned vert)
  {
    const float *vmask = ss->vmask;
    float avg = 0;
    int i, total = 0;
  
    for (i = 0; i < ss->pmap[vert].count; i++) {
      const MPoly *p = &ss->mpoly[ss->pmap[vert].indices[i]];
      unsigned f_adj_v[2];
  
      if (poly_get_adj_loops_from_vert(p, ss->mloop, vert, f_adj_v) != -1) {
        int j;
        for (j = 0; j < ARRAY_SIZE(f_adj_v); j += 1) {
          avg += vmask[f_adj_v[j]];
          total++;
        }
      }
    }
  
    if (total > 0) {
      return avg / (float)total;
    }
    else {
      return vmask[vert];
    }
  }
  
  /* Same logic as neighbor_average(), but for bmesh rather than mesh */
  static void bmesh_neighbor_average(float avg[3], BMVert *v)
  {
    /* logic for 3 or more is identical */
    const int vfcount = BM_vert_face_count_at_most(v, 3);
  
    /* Don't modify corner vertices */
    if (vfcount > 1) {
      BMIter liter;
      BMLoop *l;
      int i, total = 0;
  
      zero_v3(avg);
  
      BM_ITER_ELEM (l, &liter, v, BM_LOOPS_OF_VERT) {
        const BMVert *adj_v[2] = {l->prev->v, l->next->v};
  
        for (i = 0; i < ARRAY_SIZE(adj_v); i++) {
          const BMVert *v_other = adj_v[i];
          if (vfcount != 2 || BM_vert_face_count_at_most(v_other, 2) <= 2) {
            add_v3_v3(avg, v_other->co);
            total++;
          }
        }
      }
  
      if (total > 0) {
        mul_v3_fl(avg, 1.0f / total);
        return;
      }
    }
  
    copy_v3_v3(avg, v->co);
  }
  
  /* For bmesh: average only the four most aligned (parallel and perpendicular) edges
   * relative to a direction. Naturally converges to a quad-like tessellation. */
  static void bmesh_four_neighbor_average(float avg[3], float direction[3], BMVert *v)
  {
    /* Logic for 3 or more is identical. */
    const int vfcount = BM_vert_face_count_at_most(v, 3);
  
    /* Don't modify corner vertices. */
    if (vfcount < 2) {
      copy_v3_v3(avg, v->co);
      return;
    }
  
    /* Project the direction to the vertex normal and create an additional
     * parallel vector. */
    float dir_a[3], dir_b[3];
    cross_v3_v3v3(dir_a, direction, v->no);
    cross_v3_v3v3(dir_b, dir_a, v->no);
  
    /* The four vectors which will be used for smoothing.
     * Occasionally less than 4 verts match the requirements in that case
     * use 'v' as fallback. */
    BMVert *pos_a = v;
    BMVert *neg_a = v;
    BMVert *pos_b = v;
    BMVert *neg_b = v;
  
    float pos_score_a = 0.0f;
    float neg_score_a = 0.0f;
    float pos_score_b = 0.0f;
    float neg_score_b = 0.0f;
  
    BMIter liter;
    BMLoop *l;
  
    BM_ITER_ELEM (l, &liter, v, BM_LOOPS_OF_VERT) {
      BMVert *adj_v[2] = {l->prev->v, l->next->v};
  
      for (int i = 0; i < ARRAY_SIZE(adj_v); i++) {
        BMVert *v_other = adj_v[i];
  
        if (vfcount != 2 || BM_vert_face_count_at_most(v_other, 2) <= 2) {
          float vec[3];
          sub_v3_v3v3(vec, v_other->co, v->co);
          normalize_v3(vec);
  
          /* The score is a measure of how orthogonal the edge is. */
          float score = dot_v3v3(vec, dir_a);
  
          if (score >= pos_score_a) {
            pos_a = v_other;
            pos_score_a = score;
          }
          else if (score < neg_score_a) {
            neg_a = v_other;
            neg_score_a = score;
          }
          /* The same scoring but for the perpendicular direction. */
          score = dot_v3v3(vec, dir_b);
  
          if (score >= pos_score_b) {
            pos_b = v_other;
            pos_score_b = score;
          }
          else if (score < neg_score_b) {
            neg_b = v_other;
            neg_score_b = score;
          }
        }
      }
    }
  
    /* Average everything together. */
    zero_v3(avg);
    add_v3_v3(avg, pos_a->co);
    add_v3_v3(avg, neg_a->co);
    add_v3_v3(avg, pos_b->co);
    add_v3_v3(avg, neg_b->co);
    mul_v3_fl(avg, 0.25f);
  
    /* Preserve volume. */
    float vec[3];
    sub_v3_v3(avg, v->co);
    mul_v3_v3fl(vec, v->no, dot_v3v3(avg, v->no));
    sub_v3_v3(avg, vec);
    add_v3_v3(avg, v->co);
  }
  
  /* Same logic as neighbor_average_mask(), but for bmesh rather than mesh */
  static float bmesh_neighbor_average_mask(BMVert *v, const int cd_vert_mask_offset)
  {
    BMIter liter;
    BMLoop *l;
    float avg = 0;
    int i, total = 0;
  
    BM_ITER_ELEM (l, &liter, v, BM_LOOPS_OF_VERT) {
      /* skip this vertex */
      const BMVert *adj_v[2] = {l->prev->v, l->next->v};
  
      for (i = 0; i < ARRAY_SIZE(adj_v); i++) {
        const BMVert *v_other = adj_v[i];
        const float *vmask = BM_ELEM_CD_GET_VOID_P(v_other, cd_vert_mask_offset);
        avg += (*vmask);
        total++;
      }
    }
  
    if (total > 0) {
      return avg / (float)total;
    }
    else {
      const float *vmask = BM_ELEM_CD_GET_VOID_P(v, cd_vert_mask_offset);
      return (*vmask);
    }
  }
  
  /* Note: uses after-struct allocated mem to store actual cache... */
  typedef struct SculptDoBrushSmoothGridDataChunk {
    size_t tmpgrid_size;
  } SculptDoBrushSmoothGridDataChunk;
  
  typedef struct {
    SculptSession *ss;
    const float *ray_start;
    bool hit;
    float depth;
    bool original;
  
    struct IsectRayPrecalc isect_precalc;
  } SculptRaycastData;
  
  typedef struct {
    const float *ray_start;
    bool hit;
    float depth;
    float edge_length;
  
    struct IsectRayPrecalc isect_precalc;
  } SculptDetailRaycastData;
  
  typedef struct {
    SculptSession *ss;
    const float *ray_start, *ray_normal;
    bool hit;
    float depth;
    float dist_sq_to_ray;
    bool original;
  } SculptFindNearestToRayData;
  
  static void do_smooth_brush_mesh_task_cb_ex(void *__restrict userdata,
                                              const int n,
                                              const TaskParallelTLS *__restrict tls)
  {
    SculptThreadedTaskData *data = userdata;
    SculptSession *ss = data->ob->sculpt;
    Sculpt *sd = data->sd;
    const Brush *brush = data->brush;
    const bool smooth_mask = data->smooth_mask;
    float bstrength = data->strength;
  
    PBVHVertexIter vd;
  
    CLAMP(bstrength, 0.0f, 1.0f);
  
    SculptBrushTest test;
    SculptBrushTestFn sculpt_brush_test_sq_fn = sculpt_brush_test_init_with_falloff_shape(
        ss, &test, data->brush->falloff_shape);
  
    BKE_pbvh_vertex_iter_begin(ss->pbvh, data->nodes[n], vd, PBVH_ITER_UNIQUE)
    {
      if (sculpt_brush_test_sq_fn(&test, vd.co)) {
        const float fade = bstrength * tex_strength(ss,
                                                    brush,
                                                    vd.co,
                                                    sqrtf(test.dist),
                                                    vd.no,
                                                    vd.fno,
                                                    smooth_mask ? 0.0f : (vd.mask ? *vd.mask : 0.0f),
                                                    tls->thread_id);
        if (smooth_mask) {
          float val = neighbor_average_mask(ss, vd.vert_indices[vd.i]) - *vd.mask;
          val *= fade * bstrength;
          *vd.mask += val;
          CLAMP(*vd.mask, 0.0f, 1.0f);
        }
        else {
          float avg[3], val[3];
  
          neighbor_average(ss, avg, vd.vert_indices[vd.i]);
          sub_v3_v3v3(val, avg, vd.co);
  
          madd_v3_v3v3fl(val, vd.co, val, fade);
  
          sculpt_clip(sd, ss, vd.co, val);
        }
  
        if (vd.mvert) {
          vd.mvert->flag |= ME_VERT_PBVH_UPDATE;
        }
      }
    }
    BKE_pbvh_vertex_iter_end;
  }
  
  static void do_smooth_brush_bmesh_task_cb_ex(void *__restrict userdata,
                                               const int n,
                                               const TaskParallelTLS *__restrict tls)
  {
    SculptThreadedTaskData *data = userdata;
    SculptSession *ss = data->ob->sculpt;
    Sculpt *sd = data->sd;
    const Brush *brush = data->brush;
    const bool smooth_mask = data->smooth_mask;
    float bstrength = data->strength;
  
    PBVHVertexIter vd;
  
    CLAMP(bstrength, 0.0f, 1.0f);
  
    SculptBrushTest test;
    SculptBrushTestFn sculpt_brush_test_sq_fn = sculpt_brush_test_init_with_falloff_shape(
        ss, &test, data->brush->falloff_shape);
  
    BKE_pbvh_vertex_iter_begin(ss->pbvh, data->nodes[n], vd, PBVH_ITER_UNIQUE)
    {
      if (sculpt_brush_test_sq_fn(&test, vd.co)) {
        const float fade = bstrength * tex_strength(ss,
                                                    brush,
                                                    vd.co,
                                                    sqrtf(test.dist),
                                                    vd.no,
                                                    vd.fno,
                                                    smooth_mask ? 0.0f : *vd.mask,
                                                    tls->thread_id);
        if (smooth_mask) {
          float val = bmesh_neighbor_average_mask(vd.bm_vert, vd.cd_vert_mask_offset) - *vd.mask;
          val *= fade * bstrength;
          *vd.mask += val;
          CLAMP(*vd.mask, 0.0f, 1.0f);
        }
        else {
          float avg[3], val[3];
  
          bmesh_neighbor_average(avg, vd.bm_vert);
          sub_v3_v3v3(val, avg, vd.co);
  
          madd_v3_v3v3fl(val, vd.co, val, fade);
  
          sculpt_clip(sd, ss, vd.co, val);
        }
  
        if (vd.mvert) {
          vd.mvert->flag |= ME_VERT_PBVH_UPDATE;
        }
      }
    }
    BKE_pbvh_vertex_iter_end;
  }
  
  static void do_topology_rake_bmesh_task_cb_ex(void *__restrict userdata,
                                                const int n,
                                                const TaskParallelTLS *__restrict tls)
  {
    SculptThreadedTaskData *data = userdata;
    SculptSession *ss = data->ob->sculpt;
    Sculpt *sd = data->sd;
    const Brush *brush = data->brush;
  
    float direction[3];
    copy_v3_v3(direction, ss->cache->grab_delta_symmetry);
  
    float tmp[3];
    mul_v3_v3fl(
        tmp, ss->cache->sculpt_normal_symm, dot_v3v3(ss->cache->sculpt_normal_symm, direction));
    sub_v3_v3(direction, tmp);
  
    /* Cancel if there's no grab data. */
    if (is_zero_v3(direction)) {
      return;
    }
  
    float bstrength = data->strength;
    CLAMP(bstrength, 0.0f, 1.0f);
  
    SculptBrushTest test;
    SculptBrushTestFn sculpt_brush_test_sq_fn = sculpt_brush_test_init_with_falloff_shape(
        ss, &test, data->brush->falloff_shape);
  
    PBVHVertexIter vd;
    BKE_pbvh_vertex_iter_begin(ss->pbvh, data->nodes[n], vd, PBVH_ITER_UNIQUE)
    {
      if (sculpt_brush_test_sq_fn(&test, vd.co)) {
        const float fade =
            bstrength *
            tex_strength(
                ss, brush, vd.co, sqrtf(test.dist), vd.no, vd.fno, *vd.mask, tls->thread_id) *
            ss->cache->pressure;
  
        float avg[3], val[3];
  
        bmesh_four_neighbor_average(avg, direction, vd.bm_vert);
  
        sub_v3_v3v3(val, avg, vd.co);
  
        madd_v3_v3v3fl(val, vd.co, val, fade);
  
        sculpt_clip(sd, ss, vd.co, val);
  
        if (vd.mvert) {
          vd.mvert->flag |= ME_VERT_PBVH_UPDATE;
        }
      }
    }
    BKE_pbvh_vertex_iter_end;
  }
  
  static void do_smooth_brush_multires_task_cb_ex(void *__restrict userdata,
                                                  const int n,
                                                  const TaskParallelTLS *__restrict tls)
  {
    SculptThreadedTaskData *data = userdata;
    SculptDoBrushSmoothGridDataChunk *data_chunk = tls->userdata_chunk;
    SculptSession *ss = data->ob->sculpt;
    Sculpt *sd = data->sd;
    const Brush *brush = data->brush;
    const bool smooth_mask = data->smooth_mask;
    float bstrength = data->strength;
  
    CCGElem **griddata, *gddata;
    CCGKey key;
  
    float(*tmpgrid_co)[3] = NULL;
    float tmprow_co[2][3];
    float *tmpgrid_mask = NULL;
    float tmprow_mask[2];
  
    BLI_bitmap *const *grid_hidden;
    int *grid_indices, totgrid, gridsize;
    int i, x, y;
  
    SculptBrushTest test;
    SculptBrushTestFn sculpt_brush_test_sq_fn = sculpt_brush_test_init_with_falloff_shape(
        ss, &test, data->brush->falloff_shape);
  
    CLAMP(bstrength, 0.0f, 1.0f);
  
    BKE_pbvh_node_get_grids(
        ss->pbvh, data->nodes[n], &grid_indices, &totgrid, NULL, &gridsize, &griddata);
    BKE_pbvh_get_grid_key(ss->pbvh, &key);
  
    grid_hidden = BKE_pbvh_grid_hidden(ss->pbvh);
  
    if (smooth_mask) {
      tmpgrid_mask = (void *)(data_chunk + 1);
    }
    else {
      tmpgrid_co = (void *)(data_chunk + 1);
    }
  
    for (i = 0; i < totgrid; i++) {
      int gi = grid_indices[i];
      const BLI_bitmap *gh = grid_hidden[gi];
      gddata = griddata[gi];
  
      if (smooth_mask) {
        memset(tmpgrid_mask, 0, data_chunk->tmpgrid_size);
      }
      else {
        memset(tmpgrid_co, 0, data_chunk->tmpgrid_size);
      }
  
      for (y = 0; y < gridsize - 1; y++) {
        const int v = y * gridsize;
        if (smooth_mask) {
          tmprow_mask[0] = (*CCG_elem_offset_mask(&key, gddata, v) +
                            *CCG_elem_offset_mask(&key, gddata, v + gridsize));
        }
        else {
          add_v3_v3v3(tmprow_co[0],
                      CCG_elem_offset_co(&key, gddata, v),
                      CCG_elem_offset_co(&key, gddata, v + gridsize));
        }
  
        for (x = 0; x < gridsize - 1; x++) {
          const int v1 = x + y * gridsize;
          const int v2 = v1 + 1;
          const int v3 = v1 + gridsize;
          const int v4 = v3 + 1;
  
          if (smooth_mask) {
            float tmp;
  
            tmprow_mask[(x + 1) % 2] = (*CCG_elem_offset_mask(&key, gddata, v2) +
                                        *CCG_elem_offset_mask(&key, gddata, v4));
            tmp = tmprow_mask[(x + 1) % 2] + tmprow_mask[x % 2];
  
            tmpgrid_mask[v1] += tmp;
            tmpgrid_mask[v2] += tmp;
            tmpgrid_mask[v3] += tmp;
            tmpgrid_mask[v4] += tmp;
          }
          else {
            float tmp[3];
  
            add_v3_v3v3(tmprow_co[(x + 1) % 2],
                        CCG_elem_offset_co(&key, gddata, v2),
                        CCG_elem_offset_co(&key, gddata, v4));
            add_v3_v3v3(tmp, tmprow_co[(x + 1) % 2], tmprow_co[x % 2]);
  
            add_v3_v3(tmpgrid_co[v1], tmp);
            add_v3_v3(tmpgrid_co[v2], tmp);
            add_v3_v3(tmpgrid_co[v3], tmp);
            add_v3_v3(tmpgrid_co[v4], tmp);
          }
        }
      }
  
      /* blend with existing coordinates */
      for (y = 0; y < gridsize; y++) {
        for (x = 0; x < gridsize; x++) {
          float *co;
          const float *fno;
          float *mask;
          const int index = y * gridsize + x;
  
          if (gh) {
            if (BLI_BITMAP_TEST(gh, index)) {
              continue;
            }
          }
  
          co = CCG_elem_offset_co(&key, gddata, index);
          fno = CCG_elem_offset_no(&key, gddata, index);
          mask = CCG_elem_offset_mask(&key, gddata, index);
  
          if (sculpt_brush_test_sq_fn(&test, co)) {
            const float strength_mask = (smooth_mask ? 0.0f : *mask);
            const float fade =
                bstrength *
                tex_strength(
                    ss, brush, co, sqrtf(test.dist), NULL, fno, strength_mask, tls->thread_id);
            float f = 1.0f / 16.0f;
  
            if (x == 0 || x == gridsize - 1) {
              f *= 2.0f;
            }
  
            if (y == 0 || y == gridsize - 1) {
              f *= 2.0f;
            }
  
            if (smooth_mask) {
              *mask += ((tmpgrid_mask[index] * f) - *mask) * fade;
            }
            else {
              float *avg = tmpgrid_co[index];
              float val[3];
  
              mul_v3_fl(avg, f);
              sub_v3_v3v3(val, avg, co);
              madd_v3_v3v3fl(val, co, val, fade);
  
              sculpt_clip(sd, ss, co, val);
            }
          }
        }
      }
    }
  }
  
  static void smooth(Sculpt *sd,
                     Object *ob,
                     PBVHNode **nodes,
                     const int totnode,
                     float bstrength,
                     const bool smooth_mask)
  {
    SculptSession *ss = ob->sculpt;
    Brush *brush = BKE_paint_brush(&sd->paint);
  
    const int max_iterations = 4;
    const float fract = 1.0f / max_iterations;
    PBVHType type = BKE_pbvh_type(ss->pbvh);
    int iteration, count;
    float last;
  
    CLAMP(bstrength, 0.0f, 1.0f);
  
    count = (int)(bstrength * max_iterations);
    last = max_iterations * (bstrength - count * fract);
  
    if (type == PBVH_FACES && !ss->pmap) {
      BLI_assert(!"sculpt smooth: pmap missing");
      return;
    }
  
    for (iteration = 0; iteration <= count; ++iteration) {
      const float strength = (iteration != count) ? 1.0f : last;
  
      SculptThreadedTaskData data = {
          .sd = sd,
          .ob = ob,
          .brush = brush,
          .nodes = nodes,
          .smooth_mask = smooth_mask,
          .strength = strength,
      };
  
      TaskParallelSettings settings;
      BLI_parallel_range_settings_defaults(&settings);
      settings.use_threading = ((sd->flags & SCULPT_USE_OPENMP) && totnode > SCULPT_THREADED_LIMIT);
  
      switch (type) {
        case PBVH_GRIDS: {
          int gridsize;
          size_t size;
          SculptDoBrushSmoothGridDataChunk *data_chunk;
  
          BKE_pbvh_node_get_grids(ss->pbvh, NULL, NULL, NULL, NULL, &gridsize, NULL);
          size = (size_t)gridsize;
          size = sizeof(float) * size * size * (smooth_mask ? 1 : 3);
          data_chunk = MEM_mallocN(sizeof(*data_chunk) + size, __func__);
          data_chunk->tmpgrid_size = size;
          size += sizeof(*data_chunk);
  
          settings.userdata_chunk = data_chunk;
          settings.userdata_chunk_size = size;
          BLI_task_parallel_range(0, totnode, &data, do_smooth_brush_multires_task_cb_ex, &settings);
  
          MEM_freeN(data_chunk);
          break;
        }
        case PBVH_FACES:
          BLI_task_parallel_range(0, totnode, &data, do_smooth_brush_mesh_task_cb_ex, &settings);
          break;
        case PBVH_BMESH:
          BLI_task_parallel_range(0, totnode, &data, do_smooth_brush_bmesh_task_cb_ex, &settings);
          break;
      }
  
      if (ss->multires) {
        multires_stitch_grids(ob);
      }
    }
  }
  
  static void bmesh_topology_rake(
      Sculpt *sd, Object *ob, PBVHNode **nodes, const int totnode, float bstrength)
  {
    Brush *brush = BKE_paint_brush(&sd->paint);
    CLAMP(bstrength, 0.0f, 1.0f);
  
    /* Interactions increase both strength and quality. */
    const int iterations = 3;
  
    int iteration;
    const int count = iterations * bstrength + 1;
    const float factor = iterations * bstrength / count;
  
    for (iteration = 0; iteration <= count; ++iteration) {
  
      SculptThreadedTaskData data = {
          .sd = sd,
          .ob = ob,
          .brush = brush,
          .nodes = nodes,
          .strength = factor,
      };
      TaskParallelSettings settings;
      BLI_parallel_range_settings_defaults(&settings);
      settings.use_threading = ((sd->flags & SCULPT_USE_OPENMP) && totnode > SCULPT_THREADED_LIMIT);
  
      BLI_task_parallel_range(0, totnode, &data, do_topology_rake_bmesh_task_cb_ex, &settings);
    }
  }
  
  static void do_smooth_brush(Sculpt *sd, Object *ob, PBVHNode **nodes, int totnode)
  {
    SculptSession *ss = ob->sculpt;
    smooth(sd, ob, nodes, totnode, ss->cache->bstrength, false);
  }
  
  static void do_mask_brush_draw_task_cb_ex(void *__restrict userdata,
                                            const int n,
                                            const TaskParallelTLS *__restrict tls)
  {
    SculptThreadedTaskData *data = userdata;
    SculptSession *ss = data->ob->sculpt;
    const Brush *brush = data->brush;
    const float bstrength = ss->cache->bstrength;
  
    PBVHVertexIter vd;
  
    SculptBrushTest test;
    SculptBrushTestFn sculpt_brush_test_sq_fn = sculpt_brush_test_init_with_falloff_shape(
        ss, &test, data->brush->falloff_shape);
  
    BKE_pbvh_vertex_iter_begin(ss->pbvh, data->nodes[n], vd, PBVH_ITER_UNIQUE)
    {
      if (sculpt_brush_test_sq_fn(&test, vd.co)) {
        const float fade = tex_strength(
            ss, brush, vd.co, sqrtf(test.dist), vd.no, vd.fno, 0.0f, tls->thread_id);
  
        (*vd.mask) += fade * bstrength;
        CLAMP(*vd.mask, 0, 1);
  
        if (vd.mvert) {
          vd.mvert->flag |= ME_VERT_PBVH_UPDATE;
        }
      }
      BKE_pbvh_vertex_iter_end;
    }
  }
  
  static void do_mask_brush_draw(Sculpt *sd, Object *ob, PBVHNode **nodes, int totnode)
  {
    Brush *brush = BKE_paint_brush(&sd->paint);
  
    /* threaded loop over nodes */
    SculptThreadedTaskData data = {
        .sd = sd,
        .ob = ob,
        .brush = brush,
        .nodes = nodes,
    };
  
    TaskParallelSettings settings;
    BLI_parallel_range_settings_defaults(&settings);
    settings.use_threading = ((sd->flags & SCULPT_USE_OPENMP) && totnode > SCULPT_THREADED_LIMIT);
    BLI_task_parallel_range(0, totnode, &data, do_mask_brush_draw_task_cb_ex, &settings);
  }
  
  static void do_mask_brush(Sculpt *sd, Object *ob, PBVHNode **nodes, int totnode)
  {
    SculptSession *ss = ob->sculpt;
    Brush *brush = BKE_paint_brush(&sd->paint);
  
    switch ((BrushMaskTool)brush->mask_tool) {
      case BRUSH_MASK_DRAW:
        do_mask_brush_draw(sd, ob, nodes, totnode);
        break;
      case BRUSH_MASK_SMOOTH:
        smooth(sd, ob, nodes, totnode, ss->cache->bstrength, true);
        break;
    }
  }
  
  static void do_draw_brush_task_cb_ex(void *__restrict userdata,
                                       const int n,
                                       const TaskParallelTLS *__restrict tls)
  {
    SculptThreadedTaskData *data = userdata;
    SculptSession *ss = data->ob->sculpt;
    const Brush *brush = data->brush;
    const float *offset = data->offset;
  
    PBVHVertexIter vd;
    float(*proxy)[3];
  
    proxy = BKE_pbvh_node_add_proxy(ss->pbvh, data->nodes[n])->co;
  
    SculptBrushTest test;
    SculptBrushTestFn sculpt_brush_test_sq_fn = sculpt_brush_test_init_with_falloff_shape(
        ss, &test, data->brush->falloff_shape);
  
    BKE_pbvh_vertex_iter_begin(ss->pbvh, data->nodes[n], vd, PBVH_ITER_UNIQUE)
    {
      if (sculpt_brush_test_sq_fn(&test, vd.co)) {
        /* offset vertex */
        const float fade = tex_strength(ss,
                                        brush,
                                        vd.co,
                                        sqrtf(test.dist),
                                        vd.no,
                                        vd.fno,
                                        vd.mask ? *vd.mask : 0.0f,
                                        tls->thread_id);
  
        mul_v3_v3fl(proxy[vd.i], offset, fade);
  
        if (vd.mvert) {
          vd.mvert->flag |= ME_VERT_PBVH_UPDATE;
        }
      }
    }
    BKE_pbvh_vertex_iter_end;
  }
  
  static void do_draw_brush(Sculpt *sd, Object *ob, PBVHNode **nodes, int totnode)
  {
    SculptSession *ss = ob->sculpt;
    Brush *brush = BKE_paint_brush(&sd->paint);
    float offset[3];
    const float bstrength = ss->cache->bstrength;
  
    /* offset with as much as possible factored in already */
    mul_v3_v3fl(offset, ss->cache->sculpt_normal_symm, ss->cache->radius);
    mul_v3_v3(offset, ss->cache->scale);
    mul_v3_fl(offset, bstrength);
  
    /* XXX - this shouldn't be necessary, but sculpting crashes in blender2.8 otherwise
     * initialize before threads so they can do curve mapping */
    BKE_curvemapping_initialize(brush->curve);
  
    /* threaded loop over nodes */
    SculptThreadedTaskData data = {
        .sd = sd,
        .ob = ob,
        .brush = brush,
        .nodes = nodes,
        .offset = offset,
    };
  
    TaskParallelSettings settings;
    BLI_parallel_range_settings_defaults(&settings);
    settings.use_threading = ((sd->flags & SCULPT_USE_OPENMP) && totnode > SCULPT_THREADED_LIMIT);
    BLI_task_parallel_range(0, totnode, &data, do_draw_brush_task_cb_ex, &settings);
  }
  
  /**
   * Used for 'SCULPT_TOOL_CREASE' and 'SCULPT_TOOL_BLOB'
   */
  static void do_crease_brush_task_cb_ex(void *__restrict userdata,
                                         const int n,
                                         const TaskParallelTLS *__restrict tls)
  {
    SculptThreadedTaskData *data = userdata;
    SculptSession *ss = data->ob->sculpt;
    const Brush *brush = data->brush;
    SculptProjectVector *spvc = data->spvc;
    const float flippedbstrength = data->flippedbstrength;
    const float *offset = data->offset;
  
    PBVHVertexIter vd;
    float(*proxy)[3];
  
    proxy = BKE_pbvh_node_add_proxy(ss->pbvh, data->nodes[n])->co;
  
    SculptBrushTest test;
    SculptBrushTestFn sculpt_brush_test_sq_fn = sculpt_brush_test_init_with_falloff_shape(
        ss, &test, data->brush->falloff_shape);
  
    BKE_pbvh_vertex_iter_begin(ss->pbvh, data->nodes[n], vd, PBVH_ITER_UNIQUE)
    {
      if (sculpt_brush_test_sq_fn(&test, vd.co)) {
        /* offset vertex */
        const float fade = tex_strength(ss,
                                        brush,
                                        vd.co,
                                        sqrtf(test.dist),
                                        vd.no,
                                        vd.fno,
                                        vd.mask ? *vd.mask : 0.0f,
                                        tls->thread_id);
        float val1[3];
        float val2[3];
  
        /* first we pinch */
        sub_v3_v3v3(val1, test.location, vd.co);
        if (brush->falloff_shape == PAINT_FALLOFF_SHAPE_TUBE) {
          project_plane_v3_v3v3(val1, val1, ss->cache->view_normal);
        }
  
        mul_v3_fl(val1, fade * flippedbstrength);
  
        sculpt_project_v3(spvc, val1, val1);
  
        /* then we draw */
        mul_v3_v3fl(val2, offset, fade);
  
        add_v3_v3v3(proxy[vd.i], val1, val2);
  
        if (vd.mvert) {
          vd.mvert->flag |= ME_VERT_PBVH_UPDATE;
        }
      }
    }
    BKE_pbvh_vertex_iter_end;
  }
  
  static void do_crease_brush(Sculpt *sd, Object *ob, PBVHNode **nodes, int totnode)
  {
    SculptSession *ss = ob->sculpt;
    const Scene *scene = ss->cache->vc->scene;
    Brush *brush = BKE_paint_brush(&sd->paint);
    float offset[3];
    float bstrength = ss->cache->bstrength;
    float flippedbstrength, crease_correction;
    float brush_alpha;
  
    SculptProjectVector spvc;
  
    /* offset with as much as possible factored in already */
    mul_v3_v3fl(offset, ss->cache->sculpt_normal_symm, ss->cache->radius);
    mul_v3_v3(offset, ss->cache->scale);
    mul_v3_fl(offset, bstrength);
  
    /* We divide out the squared alpha and multiply by the squared crease
     * to give us the pinch strength. */
    crease_correction = brush->crease_pinch_factor * brush->crease_pinch_factor;
    brush_alpha = BKE_brush_alpha_get(scene, brush);
    if (brush_alpha > 0.0f) {
      crease_correction /= brush_alpha * brush_alpha;
    }
  
    /* we always want crease to pinch or blob to relax even when draw is negative */
    flippedbstrength = (bstrength < 0) ? -crease_correction * bstrength :
                                         crease_correction * bstrength;
  
    if (brush->sculpt_tool == SCULPT_TOOL_BLOB) {
      flippedbstrength *= -1.0f;
    }
  
    /* Use surface normal for 'spvc',
     * so the vertices are pinched towards a line instead of a single point.
     * Without this we get a 'flat' surface surrounding the pinch */
    sculpt_project_v3_cache_init(&spvc, ss->cache->sculpt_normal_symm);
  
    /* threaded loop over nodes */
    SculptThreadedTaskData data = {
        .sd = sd,
        .ob = ob,
        .brush = brush,
        .nodes = nodes,
        .spvc = &spvc,
        .offset = offset,
        .flippedbstrength = flippedbstrength,
    };
  
    TaskParallelSettings settings;
    BLI_parallel_range_settings_defaults(&settings);
    settings.use_threading = ((sd->flags & SCULPT_USE_OPENMP) && totnode > SCULPT_THREADED_LIMIT);
    BLI_task_parallel_range(0, totnode, &data, do_crease_brush_task_cb_ex, &settings);
  }
  
  static void do_pinch_brush_task_cb_ex(void *__restrict userdata,
                                        const int n,
                                        const TaskParallelTLS *__restrict tls)
  {
    SculptThreadedTaskData *data = userdata;
    SculptSession *ss = data->ob->sculpt;
    const Brush *brush = data->brush;
  
    PBVHVertexIter vd;
    float(*proxy)[3];
    const float bstrength = ss->cache->bstrength;
  
    proxy = BKE_pbvh_node_add_proxy(ss->pbvh, data->nodes[n])->co;
  
    SculptBrushTest test;
    SculptBrushTestFn sculpt_brush_test_sq_fn = sculpt_brush_test_init_with_falloff_shape(
        ss, &test, data->brush->falloff_shape);
  
    BKE_pbvh_vertex_iter_begin(ss->pbvh, data->nodes[n], vd, PBVH_ITER_UNIQUE)
    {
      if (sculpt_brush_test_sq_fn(&test, vd.co)) {
        const float fade = bstrength * tex_strength(ss,
                                                    brush,
                                                    vd.co,
                                                    sqrtf(test.dist),
                                                    vd.no,
                                                    vd.fno,
                                                    vd.mask ? *vd.mask : 0.0f,
                                                    tls->thread_id);
        float val[3];
  
        sub_v3_v3v3(val, test.location, vd.co);
        if (brush->falloff_shape == PAINT_FALLOFF_SHAPE_TUBE) {
          project_plane_v3_v3v3(val, val, ss->cache->view_normal);
        }
        mul_v3_v3fl(proxy[vd.i], val, fade);
  
        if (vd.mvert) {
          vd.mvert->flag |= ME_VERT_PBVH_UPDATE;
        }
      }
    }
    BKE_pbvh_vertex_iter_end;
  }
  
  static void do_pinch_brush(Sculpt *sd, Object *ob, PBVHNode **nodes, int totnode)
  {
    Brush *brush = BKE_paint_brush(&sd->paint);
  
    SculptThreadedTaskData data = {
        .sd = sd,
        .ob = ob,
        .brush = brush,
        .nodes = nodes,
    };
  
    TaskParallelSettings settings;
    BLI_parallel_range_settings_defaults(&settings);
    settings.use_threading = ((sd->flags & SCULPT_USE_OPENMP) && totnode > SCULPT_THREADED_LIMIT);
    BLI_task_parallel_range(0, totnode, &data, do_pinch_brush_task_cb_ex, &settings);
  }
  
  static void do_grab_brush_task_cb_ex(void *__restrict userdata,
                                       const int n,
                                       const TaskParallelTLS *__restrict tls)
  {
    SculptThreadedTaskData *data = userdata;
    SculptSession *ss = data->ob->sculpt;
    const Brush *brush = data->brush;
    const float *grab_delta = data->grab_delta;
  
    PBVHVertexIter vd;
    SculptOrigVertData orig_data;
    float(*proxy)[3];
    const float bstrength = ss->cache->bstrength;
  
    sculpt_orig_vert_data_init(&orig_data, data->ob, data->nodes[n]);
  
    proxy = BKE_pbvh_node_add_proxy(ss->pbvh, data->nodes[n])->co;
  
    SculptBrushTest test;
    SculptBrushTestFn sculpt_brush_test_sq_fn = sculpt_brush_test_init_with_falloff_shape(
        ss, &test, data->brush->falloff_shape);
  
    BKE_pbvh_vertex_iter_begin(ss->pbvh, data->nodes[n], vd, PBVH_ITER_UNIQUE)
    {
      sculpt_orig_vert_data_update(&orig_data, &vd);
  
      if (sculpt_brush_test_sq_fn(&test, orig_data.co)) {
        const float fade = bstrength * tex_strength(ss,
                                                    brush,
                                                    orig_data.co,
                                                    sqrtf(test.dist),
                                                    orig_data.no,
                                                    NULL,
                                                    vd.mask ? *vd.mask : 0.0f,
                                                    tls->thread_id);
  
        mul_v3_v3fl(proxy[vd.i], grab_delta, fade);
  
        if (vd.mvert) {
          vd.mvert->flag |= ME_VERT_PBVH_UPDATE;
        }
      }
    }
    BKE_pbvh_vertex_iter_end;
  }
  
  static void do_grab_brush(Sculpt *sd, Object *ob, PBVHNode **nodes, int totnode)
  {
    SculptSession *ss = ob->sculpt;
    Brush *brush = BKE_paint_brush(&sd->paint);
    float grab_delta[3];
  
    copy_v3_v3(grab_delta, ss->cache->grab_delta_symmetry);
  
    if (ss->cache->normal_weight > 0.0f) {
      sculpt_project_v3_normal_align(ss, ss->cache->normal_weight, grab_delta);
    }
  
    SculptThreadedTaskData data = {
        .sd = sd,
        .ob = ob,
        .brush = brush,
        .nodes = nodes,
        .grab_delta = grab_delta,
    };
  
    TaskParallelSettings settings;
    BLI_parallel_range_settings_defaults(&settings);
    settings.use_threading = ((sd->flags & SCULPT_USE_OPENMP) && totnode > SCULPT_THREADED_LIMIT);
    BLI_task_parallel_range(0, totnode, &data, do_grab_brush_task_cb_ex, &settings);
  }
  
  static void do_nudge_brush_task_cb_ex(void *__restrict userdata,
                                        const int n,
                                        const TaskParallelTLS *__restrict tls)
  {
    SculptThreadedTaskData *data = userdata;
    SculptSession *ss = data->ob->sculpt;
    const Brush *brush = data->brush;
    const float *cono = data->cono;
  
    PBVHVertexIter vd;
    float(*proxy)[3];
    const float bstrength = ss->cache->bstrength;
  
    proxy = BKE_pbvh_node_add_proxy(ss->pbvh, data->nodes[n])->co;
  
    SculptBrushTest test;
    SculptBrushTestFn sculpt_brush_test_sq_fn = sculpt_brush_test_init_with_falloff_shape(
        ss, &test, data->brush->falloff_shape);
  
    BKE_pbvh_vertex_iter_begin(ss->pbvh, data->nodes[n], vd, PBVH_ITER_UNIQUE)
    {
      if (sculpt_brush_test_sq_fn(&test, vd.co)) {
        const float fade = bstrength * tex_strength(ss,
                                                    brush,
                                                    vd.co,
                                                    sqrtf(test.dist),
                                                    vd.no,
                                                    vd.fno,
                                                    vd.mask ? *vd.mask : 0.0f,
                                                    tls->thread_id);
  
        mul_v3_v3fl(proxy[vd.i], cono, fade);
  
        if (vd.mvert) {
          vd.mvert->flag |= ME_VERT_PBVH_UPDATE;
        }
      }
    }
    BKE_pbvh_vertex_iter_end;
  }
  
  static void do_nudge_brush(Sculpt *sd, Object *ob, PBVHNode **nodes, int totnode)
  {
    SculptSession *ss = ob->sculpt;
    Brush *brush = BKE_paint_brush(&sd->paint);
    float grab_delta[3];
    float tmp[3], cono[3];
  
    copy_v3_v3(grab_delta, ss->cache->grab_delta_symmetry);
  
    cross_v3_v3v3(tmp, ss->cache->sculpt_normal_symm, grab_delta);
    cross_v3_v3v3(cono, tmp, ss->cache->sculpt_normal_symm);
  
    SculptThreadedTaskData data = {
        .sd = sd,
        .ob = ob,
        .brush = brush,
        .nodes = nodes,
        .cono = cono,
    };
  
    TaskParallelSettings settings;
    BLI_parallel_range_settings_defaults(&settings);
    settings.use_threading = ((sd->flags & SCULPT_USE_OPENMP) && totnode > SCULPT_THREADED_LIMIT);
    BLI_task_parallel_range(0, totnode, &data, do_nudge_brush_task_cb_ex, &settings);
  }
  
  static void do_snake_hook_brush_task_cb_ex(void *__restrict userdata,
                                             const int n,
                                             const TaskParallelTLS *__restrict tls)
  {
    SculptThreadedTaskData *data = userdata;
    SculptSession *ss = data->ob->sculpt;
    const Brush *brush = data->brush;
    SculptProjectVector *spvc = data->spvc;
    const float *grab_delta = data->grab_delta;
  
    PBVHVertexIter vd;
    float(*proxy)[3];
    const float bstrength = ss->cache->bstrength;
    const bool do_rake_rotation = ss->cache->is_rake_rotation_valid;
    const bool do_pinch = (brush->crease_pinch_factor != 0.5f);
    const float pinch = do_pinch ? (2.0f * (0.5f - brush->crease_pinch_factor) *
                                    (len_v3(grab_delta) / ss->cache->radius)) :
                                   0.0f;
  
    proxy = BKE_pbvh_node_add_proxy(ss->pbvh, data->nodes[n])->co;
  
    SculptBrushTest test;
    SculptBrushTestFn sculpt_brush_test_sq_fn = sculpt_brush_test_init_with_falloff_shape(
        ss, &test, data->brush->falloff_shape);
  
    BKE_pbvh_vertex_iter_begin(ss->pbvh, data->nodes[n], vd, PBVH_ITER_UNIQUE)
    {
      if (sculpt_brush_test_sq_fn(&test, vd.co)) {
        const float fade = bstrength * tex_strength(ss,
                                                    brush,
                                                    vd.co,
                                                    sqrtf(test.dist),
                                                    vd.no,
                                                    vd.fno,
                                                    vd.mask ? *vd.mask : 0.0f,
                                                    tls->thread_id);
  
        mul_v3_v3fl(proxy[vd.i], grab_delta, fade);
  
        /* negative pinch will inflate, helps maintain volume */
        if (do_pinch) {
          float delta_pinch_init[3], delta_pinch[3];
  
          sub_v3_v3v3(delta_pinch, vd.co, test.location);
          if (brush->falloff_shape == PAINT_FALLOFF_SHAPE_TUBE) {
            project_plane_v3_v3v3(delta_pinch, delta_pinch, ss->cache->true_view_normal);
          }
  
          /* important to calculate based on the grabbed location
           * (intentionally ignore fade here). */
          add_v3_v3(delta_pinch, grab_delta);
  
          sculpt_project_v3(spvc, delta_pinch, delta_pinch);
  
          copy_v3_v3(delta_pinch_init, delta_pinch);
  
          float pinch_fade = pinch * fade;
          /* when reducing, scale reduction back by how close to the center we are,
           * so we don't pinch into nothingness */
          if (pinch > 0.0f) {
            /* square to have even less impact for close vertices */
            pinch_fade *= pow2f(min_ff(1.0f, len_v3(delta_pinch) / ss->cache->radius));
          }
          mul_v3_fl(delta_pinch, 1.0f + pinch_fade);
          sub_v3_v3v3(delta_pinch, delta_pinch_init, delta_pinch);
          add_v3_v3(proxy[vd.i], delta_pinch);
        }
  
        if (do_rake_rotation) {
          float delta_rotate[3];
          sculpt_rake_rotate(ss, test.location, vd.co, fade, delta_rotate);
          add_v3_v3(proxy[vd.i], delta_rotate);
        }
  
        if (vd.mvert) {
          vd.mvert->flag |= ME_VERT_PBVH_UPDATE;
        }
      }
    }
    BKE_pbvh_vertex_iter_end;
  }
  
  static void do_snake_hook_brush(Sculpt *sd, Object *ob, PBVHNode **nodes, int totnode)
  {
    SculptSession *ss = ob->sculpt;
    Brush *brush = BKE_paint_brush(&sd->paint);
    const float bstrength = ss->cache->bstrength;
    float grab_delta[3];
  
    SculptProjectVector spvc;
  
    copy_v3_v3(grab_delta, ss->cache->grab_delta_symmetry);
  
    if (bstrength < 0) {
      negate_v3(grab_delta);
    }
  
    if (ss->cache->normal_weight > 0.0f) {
      sculpt_project_v3_normal_align(ss, ss->cache->normal_weight, grab_delta);
    }
  
    /* optionally pinch while painting */
    if (brush->crease_pinch_factor != 0.5f) {
      sculpt_project_v3_cache_init(&spvc, grab_delta);
    }
  
    SculptThreadedTaskData data = {
        .sd = sd,
        .ob = ob,
        .brush = brush,
        .nodes = nodes,
        .spvc = &spvc,
        .grab_delta = grab_delta,
    };
  
    TaskParallelSettings settings;
    BLI_parallel_range_settings_defaults(&settings);
    settings.use_threading = ((sd->flags & SCULPT_USE_OPENMP) && totnode > SCULPT_THREADED_LIMIT);
    BLI_task_parallel_range(0, totnode, &data, do_snake_hook_brush_task_cb_ex, &settings);
  }
  
  static void do_thumb_brush_task_cb_ex(void *__restrict userdata,
                                        const int n,
                                        const TaskParallelTLS *__restrict tls)
  {
    SculptThreadedTaskData *data = userdata;
    SculptSession *ss = data->ob->sculpt;
    const Brush *brush = data->brush;
    const float *cono = data->cono;
  
    PBVHVertexIter vd;
    SculptOrigVertData orig_data;
    float(*proxy)[3];
    const float bstrength = ss->cache->bstrength;
  
    sculpt_orig_vert_data_init(&orig_data, data->ob, data->nodes[n]);
  
    proxy = BKE_pbvh_node_add_proxy(ss->pbvh, data->nodes[n])->co;
  
    SculptBrushTest test;
    SculptBrushTestFn sculpt_brush_test_sq_fn = sculpt_brush_test_init_with_falloff_shape(
        ss, &test, data->brush->falloff_shape);
  
    BKE_pbvh_vertex_iter_begin(ss->pbvh, data->nodes[n], vd, PBVH_ITER_UNIQUE)
    {
      sculpt_orig_vert_data_update(&orig_data, &vd);
  
      if (sculpt_brush_test_sq_fn(&test, orig_data.co)) {
        const float fade = bstrength * tex_strength(ss,
                                                    brush,
                                                    orig_data.co,
                                                    sqrtf(test.dist),
                                                    orig_data.no,
                                                    NULL,
                                                    vd.mask ? *vd.mask : 0.0f,
                                                    tls->thread_id);
  
        mul_v3_v3fl(proxy[vd.i], cono, fade);
  
        if (vd.mvert) {
          vd.mvert->flag |= ME_VERT_PBVH_UPDATE;
        }
      }
    }
    BKE_pbvh_vertex_iter_end;
  }
  
  static void do_thumb_brush(Sculpt *sd, Object *ob, PBVHNode **nodes, int totnode)
  {
    SculptSession *ss = ob->sculpt;
    Brush *brush = BKE_paint_brush(&sd->paint);
    float grab_delta[3];
    float tmp[3], cono[3];
  
    copy_v3_v3(grab_delta, ss->cache->grab_delta_symmetry);
  
    cross_v3_v3v3(tmp, ss->cache->sculpt_normal_symm, grab_delta);
    cross_v3_v3v3(cono, tmp, ss->cache->sculpt_normal_symm);
  
    SculptThreadedTaskData data = {
        .sd = sd,
        .ob = ob,
        .brush = brush,
        .nodes = nodes,
        .cono = cono,
    };
  
    TaskParallelSettings settings;
    BLI_parallel_range_settings_defaults(&settings);
    settings.use_threading = ((sd->flags & SCULPT_USE_OPENMP) && totnode > SCULPT_THREADED_LIMIT);
    BLI_task_parallel_range(0, totnode, &data, do_thumb_brush_task_cb_ex, &settings);
  }
  
  static void do_rotate_brush_task_cb_ex(void *__restrict userdata,
                                         const int n,
                                         const TaskParallelTLS *__restrict tls)
  {
    SculptThreadedTaskData *data = userdata;
    SculptSession *ss = data->ob->sculpt;
    const Brush *brush = data->brush;
    const float angle = data->angle;
  
    PBVHVertexIter vd;
    SculptOrigVertData orig_data;
    float(*proxy)[3];
    const float bstrength = ss->cache->bstrength;
  
    sculpt_orig_vert_data_init(&orig_data, data->ob, data->nodes[n]);
  
    proxy = BKE_pbvh_node_add_proxy(ss->pbvh, data->nodes[n])->co;
  
    SculptBrushTest test;
    SculptBrushTestFn sculpt_brush_test_sq_fn = sculpt_brush_test_init_with_falloff_shape(
        ss, &test, data->brush->falloff_shape);
  
    BKE_pbvh_vertex_iter_begin(ss->pbvh, data->nodes[n], vd, PBVH_ITER_UNIQUE)
    {
      sculpt_orig_vert_data_update(&orig_data, &vd);
  
      if (sculpt_brush_test_sq_fn(&test, orig_data.co)) {
        float vec[3], rot[3][3];
        const float fade = bstrength * tex_strength(ss,
                                                    brush,
                                                    orig_data.co,
                                                    sqrtf(test.dist),
                                                    orig_data.no,
                                                    NULL,
                                                    vd.mask ? *vd.mask : 0.0f,
                                                    tls->thread_id);
  
        sub_v3_v3v3(vec, orig_data.co, ss->cache->location);
        axis_angle_normalized_to_mat3(rot, ss->cache->sculpt_normal_symm, angle * fade);
        mul_v3_m3v3(proxy[vd.i], rot, vec);
        add_v3_v3(proxy[vd.i], ss->cache->location);
        sub_v3_v3(proxy[vd.i], orig_data.co);
  
        if (vd.mvert) {
          vd.mvert->flag |= ME_VERT_PBVH_UPDATE;
        }
      }
    }
    BKE_pbvh_vertex_iter_end;
  }
  
  static void do_rotate_brush(Sculpt *sd, Object *ob, PBVHNode **nodes, int totnode)
  {
    SculptSession *ss = ob->sculpt;
    Brush *brush = BKE_paint_brush(&sd->paint);
  
    static const int flip[8] = {1, -1, -1, 1, -1, 1, 1, -1};
    const float angle = ss->cache->vertex_rotation * flip[ss->cache->mirror_symmetry_pass];
  
    SculptThreadedTaskData data = {
        .sd = sd,
        .ob = ob,
        .brush = brush,
        .nodes = nodes,
        .angle = angle,
    };
  
    TaskParallelSettings settings;
    BLI_parallel_range_settings_defaults(&settings);
    settings.use_threading = ((sd->flags & SCULPT_USE_OPENMP) && totnode > SCULPT_THREADED_LIMIT);
    BLI_task_parallel_range(0, totnode, &data, do_rotate_brush_task_cb_ex, &settings);
  }
  
  static void do_layer_brush_task_cb_ex(void *__restrict userdata,
                                        const int n,
                                        const TaskParallelTLS *__restrict tls)
  {
    SculptThreadedTaskData *data = userdata;
    SculptSession *ss = data->ob->sculpt;
    Sculpt *sd = data->sd;
    const Brush *brush = data->brush;
    const float *offset = data->offset;
  
    PBVHVertexIter vd;
    SculptOrigVertData orig_data;
    float *layer_disp;
    const float bstrength = ss->cache->bstrength;
    const float lim = (bstrength < 0) ? -data->brush->height : data->brush->height;
    /* XXX: layer brush needs conversion to proxy but its more complicated */
    /* proxy = BKE_pbvh_node_add_proxy(ss->pbvh, nodes[n])->co; */
  
    sculpt_orig_vert_data_init(&orig_data, data->ob, data->nodes[n]);
  
    /* Why does this have to be thread-protected? */
    BLI_mutex_lock(&data->mutex);
    layer_disp = BKE_pbvh_node_layer_disp_get(ss->pbvh, data->nodes[n]);
    BLI_mutex_unlock(&data->mutex);
  
    SculptBrushTest test;
    SculptBrushTestFn sculpt_brush_test_sq_fn = sculpt_brush_test_init_with_falloff_shape(
        ss, &test, data->brush->falloff_shape);
  
    BKE_pbvh_vertex_iter_begin(ss->pbvh, data->nodes[n], vd, PBVH_ITER_UNIQUE)
    {
      sculpt_orig_vert_data_update(&orig_data, &vd);
  
      if (sculpt_brush_test_sq_fn(&test, orig_data.co)) {
        const float fade = bstrength * tex_strength(ss,
                                                    brush,
                                                    vd.co,
                                                    sqrtf(test.dist),
                                                    vd.no,
                                                    vd.fno,
                                                    vd.mask ? *vd.mask : 0.0f,
                                                    tls->thread_id);
        float *disp = &layer_disp[vd.i];
        float val[3];
  
        *disp += fade;
  
        /* Don't let the displacement go past the limit */
        if ((lim < 0.0f && *disp < lim) || (lim >= 0.0f && *disp > lim)) {
          *disp = lim;
        }
  
        mul_v3_v3fl(val, offset, *disp);
  
        if (!ss->multires && !ss->bm && ss->layer_co && (brush->flag & BRUSH_PERSISTENT)) {
          int index = vd.vert_indices[vd.i];
  
          /* persistent base */
          add_v3_v3(val, ss->layer_co[index]);
        }
        else {
          add_v3_v3(val, orig_data.co);
        }
  
        sculpt_clip(sd, ss, vd.co, val);
  
        if (vd.mvert) {
          vd.mvert->flag |= ME_VERT_PBVH_UPDATE;
        }
      }
    }
    BKE_pbvh_vertex_iter_end;
  }
  
  static void do_layer_brush(Sculpt *sd, Object *ob, PBVHNode **nodes, int totnode)
  {
    SculptSession *ss = ob->sculpt;
    Brush *brush = BKE_paint_brush(&sd->paint);
    float offset[3];
  
    mul_v3_v3v3(offset, ss->cache->scale, ss->cache->sculpt_normal_symm);
  
    SculptThreadedTaskData data = {
        .sd = sd,
        .ob = ob,
        .brush = brush,
        .nodes = nodes,
        .offset = offset,
    };
    BLI_mutex_init(&data.mutex);
  
    TaskParallelSettings settings;
    BLI_parallel_range_settings_defaults(&settings);
    settings.use_threading = ((sd->flags & SCULPT_USE_OPENMP) && totnode > SCULPT_THREADED_LIMIT);
    BLI_task_parallel_range(0, totnode, &data, do_layer_brush_task_cb_ex, &settings);
  
    BLI_mutex_end(&data.mutex);
  }
  
  static void do_inflate_brush_task_cb_ex(void *__restrict userdata,
                                          const int n,
                                          const TaskParallelTLS *__restrict tls)
  {
    SculptThreadedTaskData *data = userdata;
    SculptSession *ss = data->ob->sculpt;
    const Brush *brush = data->brush;
  
    PBVHVertexIter vd;
    float(*proxy)[3];
    const float bstrength = ss->cache->bstrength;
  
    proxy = BKE_pbvh_node_add_proxy(ss->pbvh, data->nodes[n])->co;
  
    SculptBrushTest test;
    SculptBrushTestFn sculpt_brush_test_sq_fn = sculpt_brush_test_init_with_falloff_shape(
        ss, &test, data->brush->falloff_shape);
  
    BKE_pbvh_vertex_iter_begin(ss->pbvh, data->nodes[n], vd, PBVH_ITER_UNIQUE)
    {
      if (sculpt_brush_test_sq_fn(&test, vd.co)) {
        const float fade = bstrength * tex_strength(ss,
                                                    brush,
                                                    vd.co,
                                                    sqrtf(test.dist),
                                                    vd.no,
                                                    vd.fno,
                                                    vd.mask ? *vd.mask : 0.0f,
                                                    tls->thread_id);
        float val[3];
  
        if (vd.fno) {
          copy_v3_v3(val, vd.fno);
        }
        else {
          normal_short_to_float_v3(val, vd.no);
        }
  
        mul_v3_fl(val, fade * ss->cache->radius);
        mul_v3_v3v3(proxy[vd.i], val, ss->cache->scale);
  
        if (vd.mvert) {
          vd.mvert->flag |= ME_VERT_PBVH_UPDATE;
        }
      }
    }
    BKE_pbvh_vertex_iter_end;
  }
  
  static void do_inflate_brush(Sculpt *sd, Object *ob, PBVHNode **nodes, int totnode)
  {
    Brush *brush = BKE_paint_brush(&sd->paint);
  
    SculptThreadedTaskData data = {
        .sd = sd,
        .ob = ob,
        .brush = brush,
        .nodes = nodes,
    };
  
    TaskParallelSettings settings;
    BLI_parallel_range_settings_defaults(&settings);
    settings.use_threading = ((sd->flags & SCULPT_USE_OPENMP) && totnode > SCULPT_THREADED_LIMIT);
    BLI_task_parallel_range(0, totnode, &data, do_inflate_brush_task_cb_ex, &settings);
  }
  
  static void calc_sculpt_plane(
      Sculpt *sd, Object *ob, PBVHNode **nodes, int totnode, float r_area_no[3], float r_area_co[3])
  {
    SculptSession *ss = ob->sculpt;
    Brush *brush = BKE_paint_brush(&sd->paint);
  
    if (ss->cache->mirror_symmetry_pass == 0 && ss->cache->radial_symmetry_pass == 0 &&
        ss->cache->tile_pass == 0 &&
        (ss->cache->first_time || !(brush->flag & BRUSH_ORIGINAL_NORMAL))) {
      switch (brush->sculpt_plane) {
        case SCULPT_DISP_DIR_VIEW:
          copy_v3_v3(r_area_no, ss->cache->true_view_normal);
          break;
  
        case SCULPT_DISP_DIR_X:
          ARRAY_SET_ITEMS(r_area_no, 1, 0, 0);
          break;
  
        case SCULPT_DISP_DIR_Y:
          ARRAY_SET_ITEMS(r_area_no, 0, 1, 0);
          break;
  
        case SCULPT_DISP_DIR_Z:
          ARRAY_SET_ITEMS(r_area_no, 0, 0, 1);
          break;
  
        case SCULPT_DISP_DIR_AREA:
          calc_area_normal_and_center(sd, ob, nodes, totnode, r_area_no, r_area_co);
          if (brush->falloff_shape == PAINT_FALLOFF_SHAPE_TUBE) {
            project_plane_v3_v3v3(r_area_no, r_area_no, ss->cache->view_normal);
            normalize_v3(r_area_no);
          }
          break;
  
        default:
          break;
      }
  
      /* for flatten center */
      /* flatten center has not been calculated yet if we are not using the area normal */
      if (brush->sculpt_plane != SCULPT_DISP_DIR_AREA) {
        calc_area_center(sd, ob, nodes, totnode, r_area_co);
      }
  
      /* for area normal */
      copy_v3_v3(ss->cache->sculpt_normal, r_area_no);
  
      /* for flatten center */
      copy_v3_v3(ss->cache->last_center, r_area_co);
    }
    else {
      /* for area normal */
      copy_v3_v3(r_area_no, ss->cache->sculpt_normal);
  
      /* for flatten center */
      copy_v3_v3(r_area_co, ss->cache->last_center);
  
      /* for area normal */
      flip_v3(r_area_no, ss->cache->mirror_symmetry_pass);
  
      /* for flatten center */
      flip_v3(r_area_co, ss->cache->mirror_symmetry_pass);
  
      /* for area normal */
      mul_m4_v3(ss->cache->symm_rot_mat, r_area_no);
  
      /* for flatten center */
      mul_m4_v3(ss->cache->symm_rot_mat, r_area_co);
  
      /* shift the plane for the current tile */
      add_v3_v3(r_area_co, ss->cache->plane_offset);
    }
  }
  
  static int plane_trim(const StrokeCache *cache, const Brush *brush, const float val[3])
  {
    return (!(brush->flag & BRUSH_PLANE_TRIM) ||
            ((dot_v3v3(val, val) <= cache->radius_squared * cache->plane_trim_squared)));
  }
  
  static bool plane_point_side_flip(const float co[3], const float plane[4], const bool flip)
  {
    float d = plane_point_side_v3(plane, co);
    if (flip) {
      d = -d;
    }
    return d <= 0.0f;
  }
  
  static int plane_point_side(const float co[3], const float plane[4])
  {
    float d = plane_point_side_v3(plane, co);
    return d <= 0.0f;
  }
  
  static float get_offset(Sculpt *sd, SculptSession *ss)
  {
    Brush *brush = BKE_paint_brush(&sd->paint);
  
    float rv = brush->plane_offset;
  
    if (brush->flag & BRUSH_OFFSET_PRESSURE) {
      rv *= ss->cache->pressure;
    }
  
    return rv;
  }
  
  static void do_flatten_brush_task_cb_ex(void *__restrict userdata,
                                          const int n,
                                          const TaskParallelTLS *__restrict tls)
  {
    SculptThreadedTaskData *data = userdata;
    SculptSession *ss = data->ob->sculpt;
    const Brush *brush = data->brush;
    const float *area_no = data->area_no;
    const float *area_co = data->area_co;
  
    PBVHVertexIter vd;
    float(*proxy)[3];
    const float bstrength = ss->cache->bstrength;
  
    proxy = BKE_pbvh_node_add_proxy(ss->pbvh, data->nodes[n])->co;
  
    SculptBrushTest test;
    SculptBrushTestFn sculpt_brush_test_sq_fn = sculpt_brush_test_init_with_falloff_shape(
        ss, &test, data->brush->falloff_shape);
  
    plane_from_point_normal_v3(test.plane_tool, area_co, area_no);
  
    BKE_pbvh_vertex_iter_begin(ss->pbvh, data->nodes[n], vd, PBVH_ITER_UNIQUE)
    {
      if (sculpt_brush_test_sq_fn(&test, vd.co)) {
        float intr[3];
        float val[3];
  
        closest_to_plane_normalized_v3(intr, test.plane_tool, vd.co);
  
        sub_v3_v3v3(val, intr, vd.co);
  
        if (plane_trim(ss->cache, brush, val)) {
          const float fade = bstrength * tex_strength(ss,
                                                      brush,
                                                      vd.co,
                                                      sqrtf(test.dist),
                                                      vd.no,
                                                      vd.fno,
                                                      vd.mask ? *vd.mask : 0.0f,
                                                      tls->thread_id);
  
          mul_v3_v3fl(proxy[vd.i], val, fade);
  
          if (vd.mvert) {
            vd.mvert->flag |= ME_VERT_PBVH_UPDATE;
          }
        }
      }
    }
    BKE_pbvh_vertex_iter_end;
  }
  
  static void do_flatten_brush(Sculpt *sd, Object *ob, PBVHNode **nodes, int totnode)
  {
    SculptSession *ss = ob->sculpt;
    Brush *brush = BKE_paint_brush(&sd->paint);
  
    const float radius = ss->cache->radius;
  
    float area_no[3];
    float area_co[3];
  
    float offset = get_offset(sd, ss);
    float displace;
    float temp[3];
  
    calc_sculpt_plane(sd, ob, nodes, totnode, area_no, area_co);
  
    displace = radius * offset;
  
    mul_v3_v3v3(temp, area_no, ss->cache->scale);
    mul_v3_fl(temp, displace);
    add_v3_v3(area_co, temp);
  
    SculptThreadedTaskData data = {
        .sd = sd,
        .ob = ob,
        .brush = brush,
        .nodes = nodes,
        .area_no = area_no,
        .area_co = area_co,
    };
  
    TaskParallelSettings settings;
    BLI_parallel_range_settings_defaults(&settings);
    settings.use_threading = ((sd->flags & SCULPT_USE_OPENMP) && totnode > SCULPT_THREADED_LIMIT);
    BLI_task_parallel_range(0, totnode, &data, do_flatten_brush_task_cb_ex, &settings);
  }
  
  static void do_clay_brush_task_cb_ex(void *__restrict userdata,
                                       const int n,
                                       const TaskParallelTLS *__restrict tls)
  {
    SculptThreadedTaskData *data = userdata;
    SculptSession *ss = data->ob->sculpt;
    const Brush *brush = data->brush;
    const float *area_no = data->area_no;
    const float *area_co = data->area_co;
  
    PBVHVertexIter vd;
    float(*proxy)[3];
    const bool flip = (ss->cache->bstrength < 0);
    const float bstrength = flip ? -ss->cache->bstrength : ss->cache->bstrength;
  
    proxy = BKE_pbvh_node_add_proxy(ss->pbvh, data->nodes[n])->co;
  
    SculptBrushTest test;
    SculptBrushTestFn sculpt_brush_test_sq_fn = sculpt_brush_test_init_with_falloff_shape(
        ss, &test, data->brush->falloff_shape);
  
    plane_from_point_normal_v3(test.plane_tool, area_co, area_no);
  
    BKE_pbvh_vertex_iter_begin(ss->pbvh, data->nodes[n], vd, PBVH_ITER_UNIQUE)
    {
      if (sculpt_brush_test_sq_fn(&test, vd.co)) {
        if (plane_point_side_flip(vd.co, test.plane_tool, flip)) {
          float intr[3];
          float val[3];
  
          closest_to_plane_normalized_v3(intr, test.plane_tool, vd.co);
  
          sub_v3_v3v3(val, intr, vd.co);
  
          if (plane_trim(ss->cache, brush, val)) {
            /* note, the normal from the vertices is ignored,
             * causes glitch with planes, see: T44390 */
            const float fade = bstrength * tex_strength(ss,
                                                        brush,
                                                        vd.co,
                                                        sqrtf(test.dist),
                                                        vd.no,
                                                        vd.fno,
                                                        vd.mask ? *vd.mask : 0.0f,
                                                        tls->thread_id);
  
            mul_v3_v3fl(proxy[vd.i], val, fade);
  
            if (vd.mvert) {
              vd.mvert->flag |= ME_VERT_PBVH_UPDATE;
            }
          }
        }
      }
    }
    BKE_pbvh_vertex_iter_end;
  }
  
  static void do_clay_brush(Sculpt *sd, Object *ob, PBVHNode **nodes, int totnode)
  {
    SculptSession *ss = ob->sculpt;
    Brush *brush = BKE_paint_brush(&sd->paint);
  
    const bool flip = (ss->cache->bstrength < 0);
    const float radius = flip ? -ss->cache->radius : ss->cache->radius;
  
    float offset = get_offset(sd, ss);
    float displace;
  
    float area_no[3];
    float area_co[3];
    float temp[3];
  
    calc_sculpt_plane(sd, ob, nodes, totnode, area_no, area_co);
  
    displace = radius * (0.25f + offset);
  
    mul_v3_v3v3(temp, area_no, ss->cache->scale);
    mul_v3_fl(temp, displace);
    add_v3_v3(area_co, temp);
  
    /* add_v3_v3v3(p, ss->cache->location, area_no); */
  
    SculptThreadedTaskData data = {
        .sd = sd,
        .ob = ob,
        .brush = brush,
        .nodes = nodes,
        .area_no = area_no,
        .area_co = area_co,
    };
  
    TaskParallelSettings settings;
    BLI_parallel_range_settings_defaults(&settings);
    settings.use_threading = ((sd->flags & SCULPT_USE_OPENMP) && totnode > SCULPT_THREADED_LIMIT);
    BLI_task_parallel_range(0, totnode, &data, do_clay_brush_task_cb_ex, &settings);
  }
  
  static void do_clay_strips_brush_task_cb_ex(void *__restrict userdata,
                                              const int n,
                                              const TaskParallelTLS *__restrict tls)
  {
    SculptThreadedTaskData *data = userdata;
    SculptSession *ss = data->ob->sculpt;
    const Brush *brush = data->brush;
    float(*mat)[4] = data->mat;
    const float *area_no_sp = data->area_no_sp;
    const float *area_co = data->area_co;
  
    PBVHVertexIter vd;
    SculptBrushTest test;
    float(*proxy)[3];
    const bool flip = (ss->cache->bstrength < 0);
    const float bstrength = flip ? -ss->cache->bstrength : ss->cache->bstrength;
  
    proxy = BKE_pbvh_node_add_proxy(ss->pbvh, data->nodes[n])->co;
  
    sculpt_brush_test_init(ss, &test);
    plane_from_point_normal_v3(test.plane_tool, area_co, area_no_sp);
  
    BKE_pbvh_vertex_iter_begin(ss->pbvh, data->nodes[n], vd, PBVH_ITER_UNIQUE)
    {
      if (sculpt_brush_test_cube(&test, vd.co, mat)) {
        if (plane_point_side_flip(vd.co, test.plane_tool, flip)) {
          float intr[3];
          float val[3];
  
          closest_to_plane_normalized_v3(intr, test.plane_tool, vd.co);
  
          sub_v3_v3v3(val, intr, vd.co);
  
          if (plane_trim(ss->cache, brush, val)) {
            /* note, the normal from the vertices is ignored,
             * causes glitch with planes, see: T44390 */
            const float fade = bstrength * tex_strength(ss,
                                                        brush,
                                                        vd.co,
                                                        ss->cache->radius * test.dist,
                                                        vd.no,
                                                        vd.fno,
                                                        vd.mask ? *vd.mask : 0.0f,
                                                        tls->thread_id);
  
            mul_v3_v3fl(proxy[vd.i], val, fade);
  
            if (vd.mvert) {
              vd.mvert->flag |= ME_VERT_PBVH_UPDATE;
            }
          }
        }
      }
    }
    BKE_pbvh_vertex_iter_end;
  }
  
  static void do_clay_strips_brush(Sculpt *sd, Object *ob, PBVHNode **nodes, int totnode)
  {
    SculptSession *ss = ob->sculpt;
    Brush *brush = BKE_paint_brush(&sd->paint);
  
    const bool flip = (ss->cache->bstrength < 0);
    const float radius = flip ? -ss->cache->radius : ss->cache->radius;
    const float offset = get_offset(sd, ss);
    const float displace = radius * (0.25f + offset);
  
    float area_no_sp[3]; /* the sculpt-plane normal (whatever its set to) */
    float area_no[3];    /* geometry normal */
    float area_co[3];
  
    float temp[3];
    float mat[4][4];
    float scale[4][4];
    float tmat[4][4];
  
    calc_sculpt_plane(sd, ob, nodes, totnode, area_no_sp, area_co);
  
    if (brush->sculpt_plane != SCULPT_DISP_DIR_AREA || (brush->flag & BRUSH_ORIGINAL_NORMAL)) {
      calc_area_normal(sd, ob, nodes, totnode, area_no);
    }
    else {
      copy_v3_v3(area_no, area_no_sp);
    }
  
    /* delay the first daub because grab delta is not setup */
    if (ss->cache->first_time) {
      return;
    }
  
    if (is_zero_v3(ss->cache->grab_delta_symmetry)) {
      return;
    }
  
    mul_v3_v3v3(temp, area_no_sp, ss->cache->scale);
    mul_v3_fl(temp, displace);
    add_v3_v3(area_co, temp);
  
    /* init mat */
    cross_v3_v3v3(mat[0], area_no, ss->cache->grab_delta_symmetry);
    mat[0][3] = 0;
    cross_v3_v3v3(mat[1], area_no, mat[0]);
    mat[1][3] = 0;
    copy_v3_v3(mat[2], area_no);
    mat[2][3] = 0;
    copy_v3_v3(mat[3], ss->cache->location);
    mat[3][3] = 1;
    normalize_m4(mat);
  
    /* scale mat */
    scale_m4_fl(scale, ss->cache->radius);
    mul_m4_m4m4(tmat, mat, scale);
    invert_m4_m4(mat, tmat);
  
    SculptThreadedTaskData data = {
        .sd = sd,
        .ob = ob,
        .brush = brush,
        .nodes = nodes,
        .area_no_sp = area_no_sp,
        .area_co = area_co,
        .mat = mat,
    };
  
    TaskParallelSettings settings;
    BLI_parallel_range_settings_defaults(&settings);
    settings.use_threading = ((sd->flags & SCULPT_USE_OPENMP) && totnode > SCULPT_THREADED_LIMIT);
    BLI_task_parallel_range(0, totnode, &data, do_clay_strips_brush_task_cb_ex, &settings);
  }
  
  static void do_fill_brush_task_cb_ex(void *__restrict userdata,
                                       const int n,
                                       const TaskParallelTLS *__restrict tls)
  {
    SculptThreadedTaskData *data = userdata;
    SculptSession *ss = data->ob->sculpt;
    const Brush *brush = data->brush;
    const float *area_no = data->area_no;
    const float *area_co = data->area_co;
  
    PBVHVertexIter vd;
    float(*proxy)[3];
    const float bstrength = ss->cache->bstrength;
  
    proxy = BKE_pbvh_node_add_proxy(ss->pbvh, data->nodes[n])->co;
  
    SculptBrushTest test;
    SculptBrushTestFn sculpt_brush_test_sq_fn = sculpt_brush_test_init_with_falloff_shape(
        ss, &test, data->brush->falloff_shape);
  
    plane_from_point_normal_v3(test.plane_tool, area_co, area_no);
  
    BKE_pbvh_vertex_iter_begin(ss->pbvh, data->nodes[n], vd, PBVH_ITER_UNIQUE)
    {
      if (sculpt_brush_test_sq_fn(&test, vd.co)) {
        if (plane_point_side(vd.co, test.plane_tool)) {
          float intr[3];
          float val[3];
  
          closest_to_plane_normalized_v3(intr, test.plane_tool, vd.co);
  
          sub_v3_v3v3(val, intr, vd.co);
  
          if (plane_trim(ss->cache, brush, val)) {
            const float fade = bstrength * tex_strength(ss,
                                                        brush,
                                                        vd.co,
                                                        sqrtf(test.dist),
                                                        vd.no,
                                                        vd.fno,
                                                        vd.mask ? *vd.mask : 0.0f,
                                                        tls->thread_id);
  
            mul_v3_v3fl(proxy[vd.i], val, fade);
  
            if (vd.mvert) {
              vd.mvert->flag |= ME_VERT_PBVH_UPDATE;
            }
          }
        }
      }
    }
    BKE_pbvh_vertex_iter_end;
  }
  
  static void do_fill_brush(Sculpt *sd, Object *ob, PBVHNode **nodes, int totnode)
  {
    SculptSession *ss = ob->sculpt;
    Brush *brush = BKE_paint_brush(&sd->paint);
  
    const float radius = ss->cache->radius;
  
    float area_no[3];
    float area_co[3];
    float offset = get_offset(sd, ss);
  
    float displace;
  
    float temp[3];
  
    calc_sculpt_plane(sd, ob, nodes, totnode, area_no, area_co);
  
    displace = radius * offset;
  
    mul_v3_v3v3(temp, area_no, ss->cache->scale);
    mul_v3_fl(temp, displace);
    add_v3_v3(area_co, temp);
  
    SculptThreadedTaskData data = {
        .sd = sd,
        .ob = ob,
        .brush = brush,
        .nodes = nodes,
        .area_no = area_no,
        .area_co = area_co,
    };
  
    TaskParallelSettings settings;
    BLI_parallel_range_settings_defaults(&settings);
    settings.use_threading = ((sd->flags & SCULPT_USE_OPENMP) && totnode > SCULPT_THREADED_LIMIT);
    BLI_task_parallel_range(0, totnode, &data, do_fill_brush_task_cb_ex, &settings);
  }
  
  static void do_scrape_brush_task_cb_ex(void *__restrict userdata,
                                         const int n,
                                         const TaskParallelTLS *__restrict tls)
  {
    SculptThreadedTaskData *data = userdata;
    SculptSession *ss = data->ob->sculpt;
    const Brush *brush = data->brush;
    const float *area_no = data->area_no;
    const float *area_co = data->area_co;
  
    PBVHVertexIter vd;
    float(*proxy)[3];
    const float bstrength = ss->cache->bstrength;
  
    proxy = BKE_pbvh_node_add_proxy(ss->pbvh, data->nodes[n])->co;
  
    SculptBrushTest test;
    SculptBrushTestFn sculpt_brush_test_sq_fn = sculpt_brush_test_init_with_falloff_shape(
        ss, &test, data->brush->falloff_shape);
    plane_from_point_normal_v3(test.plane_tool, area_co, area_no);
  
    BKE_pbvh_vertex_iter_begin(ss->pbvh, data->nodes[n], vd, PBVH_ITER_UNIQUE)
    {
      if (sculpt_brush_test_sq_fn(&test, vd.co)) {
        if (!plane_point_side(vd.co, test.plane_tool)) {
          float intr[3];
          float val[3];
  
          closest_to_plane_normalized_v3(intr, test.plane_tool, vd.co);
  
          sub_v3_v3v3(val, intr, vd.co);
  
          if (plane_trim(ss->cache, brush, val)) {
            const float fade = bstrength * tex_strength(ss,
                                                        brush,
                                                        vd.co,
                                                        sqrtf(test.dist),
                                                        vd.no,
                                                        vd.fno,
                                                        vd.mask ? *vd.mask : 0.0f,
                                                        tls->thread_id);
  
            mul_v3_v3fl(proxy[vd.i], val, fade);
  
            if (vd.mvert) {
              vd.mvert->flag |= ME_VERT_PBVH_UPDATE;
            }
          }
        }
      }
    }
    BKE_pbvh_vertex_iter_end;
  }
  
  static void do_scrape_brush(Sculpt *sd, Object *ob, PBVHNode **nodes, int totnode)
  {
    SculptSession *ss = ob->sculpt;
    Brush *brush = BKE_paint_brush(&sd->paint);
  
    const float radius = ss->cache->radius;
  
    float area_no[3];
    float area_co[3];
    float offset = get_offset(sd, ss);
  
    float displace;
  
    float temp[3];
  
    calc_sculpt_plane(sd, ob, nodes, totnode, area_no, area_co);
  
    displace = -radius * offset;
  
    mul_v3_v3v3(temp, area_no, ss->cache->scale);
    mul_v3_fl(temp, displace);
    add_v3_v3(area_co, temp);
  
    SculptThreadedTaskData data = {
        .sd = sd,
        .ob = ob,
        .brush = brush,
        .nodes = nodes,
        .area_no = area_no,
        .area_co = area_co,
    };
  
    TaskParallelSettings settings;
    BLI_parallel_range_settings_defaults(&settings);
    settings.use_threading = ((sd->flags & SCULPT_USE_OPENMP) && totnode > SCULPT_THREADED_LIMIT);
    BLI_task_parallel_range(0, totnode, &data, do_scrape_brush_task_cb_ex, &settings);
  }
  
  static void do_gravity_task_cb_ex(void *__restrict userdata,
                                    const int n,
                                    const TaskParallelTLS *__restrict tls)
  {
    SculptThreadedTaskData *data = userdata;
    SculptSession *ss = data->ob->sculpt;
    const Brush *brush = data->brush;
    float *offset = data->offset;
  
    PBVHVertexIter vd;
    float(*proxy)[3];
  
    proxy = BKE_pbvh_node_add_proxy(ss->pbvh, data->nodes[n])->co;
  
    SculptBrushTest test;
    SculptBrushTestFn sculpt_brush_test_sq_fn = sculpt_brush_test_init_with_falloff_shape(
        ss, &test, data->brush->falloff_shape);
  
    BKE_pbvh_vertex_iter_begin(ss->pbvh, data->nodes[n], vd, PBVH_ITER_UNIQUE)
    {
      if (sculpt_brush_test_sq_fn(&test, vd.co)) {
        const float fade = tex_strength(ss,
                                        brush,
                                        vd.co,
                                        sqrtf(test.dist),
                                        vd.no,
                                        vd.fno,
                                        vd.mask ? *vd.mask : 0.0f,
                                        tls->thread_id);
  
        mul_v3_v3fl(proxy[vd.i], offset, fade);
  
        if (vd.mvert) {
          vd.mvert->flag |= ME_VERT_PBVH_UPDATE;
        }
      }
    }
    BKE_pbvh_vertex_iter_end;
  }
  
  static void do_gravity(Sculpt *sd, Object *ob, PBVHNode **nodes, int totnode, float bstrength)
  {
    SculptSession *ss = ob->sculpt;
    Brush *brush = BKE_paint_brush(&sd->paint);
  
    float offset[3] /*, area_no[3]*/;
    float gravity_vector[3];
  
    mul_v3_v3fl(gravity_vector, ss->cache->gravity_direction, -ss->cache->radius_squared);
  
    /* offset with as much as possible factored in already */
    mul_v3_v3v3(offset, gravity_vector, ss->cache->scale);
    mul_v3_fl(offset, bstrength);
  
    /* threaded loop over nodes */
    SculptThreadedTaskData data = {
        .sd = sd,
        .ob = ob,
        .brush = brush,
        .nodes = nodes,
        .offset = offset,
    };
  
    TaskParallelSettings settings;
    BLI_parallel_range_settings_defaults(&settings);
    settings.use_threading = ((sd->flags & SCULPT_USE_OPENMP) && totnode > SCULPT_THREADED_LIMIT);
    BLI_task_parallel_range(0, totnode, &data, do_gravity_task_cb_ex, &settings);
  }
  
  void sculpt_vertcos_to_key(Object *ob, KeyBlock *kb, float (*vertCos)[3])
  {
    Mesh *me = (Mesh *)ob->data;
    float(*ofs)[3] = NULL;
    int a;
    const int kb_act_idx = ob->shapenr - 1;
    KeyBlock *currkey;
  
    /* for relative keys editing of base should update other keys */
    if (BKE_keyblock_is_basis(me->key, kb_act_idx)) {
      ofs = BKE_keyblock_convert_to_vertcos(ob, kb);
  
      /* calculate key coord offsets (from previous location) */
      for (a = 0; a < me->totvert; a++) {
        sub_v3_v3v3(ofs[a], vertCos[a], ofs[a]);
      }
  
      /* apply offsets on other keys */
      for (currkey = me->key->block.first; currkey; currkey = currkey->next) {
        if ((currkey != kb) && (currkey->relative == kb_act_idx)) {
          BKE_keyblock_update_from_offset(ob, currkey, ofs);
        }
      }
  
      MEM_freeN(ofs);
    }
  
    /* modifying of basis key should update mesh */
    if (kb == me->key->refkey) {
      MVert *mvert = me->mvert;
  
      for (a = 0; a < me->totvert; a++, mvert++) {
        copy_v3_v3(mvert->co, vertCos[a]);
      }
  
      BKE_mesh_calc_normals(me);
    }
  
    /* apply new coords on active key block, no need to re-allocate kb->data here! */
    BKE_keyblock_update_from_vertcos(ob, kb, vertCos);
  }
  
  /* Note: we do the topology update before any brush actions to avoid
   * issues with the proxies. The size of the proxy can't change, so
   * topology must be updated first. */
  static void sculpt_topology_update(Sculpt *sd,
                                     Object *ob,
                                     Brush *brush,
                                     UnifiedPaintSettings *UNUSED(ups))
  {
    SculptSession *ss = ob->sculpt;
  
    int n, totnode;
    /* Build a list of all nodes that are potentially within the brush's area of influence */
    const bool use_original = sculpt_tool_needs_original(brush->sculpt_tool) ? true :
                                                                               ss->cache->original;
    const float radius_scale = 1.25f;
    PBVHNode **nodes = sculpt_pbvh_gather_generic(
        ob, sd, brush, use_original, radius_scale, &totnode);
  
    /* Only act if some verts are inside the brush area */
    if (totnode) {
      PBVHTopologyUpdateMode mode = 0;
      float location[3];
  
      if (!(sd->flags & SCULPT_DYNTOPO_DETAIL_MANUAL)) {
        if (sd->flags & SCULPT_DYNTOPO_SUBDIVIDE) {
          mode |= PBVH_Subdivide;
        }
  
        if ((sd->flags & SCULPT_DYNTOPO_COLLAPSE) || (brush->sculpt_tool == SCULPT_TOOL_SIMPLIFY)) {
          mode |= PBVH_Collapse;
        }
      }
  
      for (n = 0; n < totnode; n++) {
        sculpt_undo_push_node(ob,
                              nodes[n],
                              brush->sculpt_tool == SCULPT_TOOL_MASK ? SCULPT_UNDO_MASK :
                                                                       SCULPT_UNDO_COORDS);
        BKE_pbvh_node_mark_update(nodes[n]);
  
        if (BKE_pbvh_type(ss->pbvh) == PBVH_BMESH) {
          BKE_pbvh_node_mark_topology_update(nodes[n]);
          BKE_pbvh_bmesh_node_save_orig(nodes[n]);
        }
      }
  
      if (BKE_pbvh_type(ss->pbvh) == PBVH_BMESH) {
        BKE_pbvh_bmesh_update_topology(ss->pbvh,
                                       mode,
                                       ss->cache->location,
                                       ss->cache->view_normal,
                                       ss->cache->radius,
                                       (brush->flag & BRUSH_FRONTFACE) != 0,
                                       (brush->falloff_shape != PAINT_FALLOFF_SHAPE_SPHERE));
      }
  
      MEM_freeN(nodes);
  
      /* update average stroke position */
      copy_v3_v3(location, ss->cache->true_location);
      mul_m4_v3(ob->obmat, location);
    }
  }
  
  static void do_brush_action_task_cb(void *__restrict userdata,
                                      const int n,
                                      const TaskParallelTLS *__restrict UNUSED(tls))
  {
    SculptThreadedTaskData *data = userdata;
  
    sculpt_undo_push_node(data->ob,
                          data->nodes[n],
                          data->brush->sculpt_tool == SCULPT_TOOL_MASK ? SCULPT_UNDO_MASK :
                                                                         SCULPT_UNDO_COORDS);
    BKE_pbvh_node_mark_update(data->nodes[n]);
  }
  
  static void do_brush_action(Sculpt *sd, Object *ob, Brush *brush, UnifiedPaintSettings *ups)
  {
    SculptSession *ss = ob->sculpt;
    int totnode;
  
    /* Build a list of all nodes that are potentially within the brush's area of influence */
    const bool use_original = sculpt_tool_needs_original(brush->sculpt_tool) ? true :
                                                                               ss->cache->original;
    const float radius_scale = 1.0f;
    PBVHNode **nodes = sculpt_pbvh_gather_generic(
        ob, sd, brush, use_original, radius_scale, &totnode);
  
    /* Only act if some verts are inside the brush area */
    if (totnode) {
      float location[3];
  
      SculptThreadedTaskData task_data = {
          .sd = sd,
          .ob = ob,
          .brush = brush,
          .nodes = nodes,
      };
  
      TaskParallelSettings settings;
      BLI_parallel_range_settings_defaults(&settings);
      settings.use_threading = ((sd->flags & SCULPT_USE_OPENMP) && totnode > SCULPT_THREADED_LIMIT);
      BLI_task_parallel_range(0, totnode, &task_data, do_brush_action_task_cb, &settings);
  
      if (sculpt_brush_needs_normal(ss, brush)) {
        update_sculpt_normal(sd, ob, nodes, totnode);
      }
  
      if (brush->mtex.brush_map_mode == MTEX_MAP_MODE_AREA) {
        update_brush_local_mat(sd, ob);
      }
  
      /* Apply one type of brush action */
      switch (brush->sculpt_tool) {
        case SCULPT_TOOL_DRAW:
          do_draw_brush(sd, ob, nodes, totnode);
          break;
        case SCULPT_TOOL_SMOOTH:
          do_smooth_brush(sd, ob, nodes, totnode);
          break;
        case SCULPT_TOOL_CREASE:
          do_crease_brush(sd, ob, nodes, totnode);
          break;
        case SCULPT_TOOL_BLOB:
          do_crease_brush(sd, ob, nodes, totnode);
          break;
        case SCULPT_TOOL_PINCH:
          do_pinch_brush(sd, ob, nodes, totnode);
          break;
        case SCULPT_TOOL_INFLATE:
          do_inflate_brush(sd, ob, nodes, totnode);
          break;
        case SCULPT_TOOL_GRAB:
          do_grab_brush(sd, ob, nodes, totnode);
          break;
        case SCULPT_TOOL_ROTATE:
          do_rotate_brush(sd, ob, nodes, totnode);
          break;
        case SCULPT_TOOL_SNAKE_HOOK:
          do_snake_hook_brush(sd, ob, nodes, totnode);
          break;
        case SCULPT_TOOL_NUDGE:
          do_nudge_brush(sd, ob, nodes, totnode);
          break;
        case SCULPT_TOOL_THUMB:
          do_thumb_brush(sd, ob, nodes, totnode);
          break;
        case SCULPT_TOOL_LAYER:
          do_layer_brush(sd, ob, nodes, totnode);
          break;
        case SCULPT_TOOL_FLATTEN:
          do_flatten_brush(sd, ob, nodes, totnode);
          break;
        case SCULPT_TOOL_CLAY:
          do_clay_brush(sd, ob, nodes, totnode);
          break;
        case SCULPT_TOOL_CLAY_STRIPS:
          do_clay_strips_brush(sd, ob, nodes, totnode);
          break;
        case SCULPT_TOOL_FILL:
          do_fill_brush(sd, ob, nodes, totnode);
          break;
        case SCULPT_TOOL_SCRAPE:
          do_scrape_brush(sd, ob, nodes, totnode);
          break;
        case SCULPT_TOOL_MASK:
          do_mask_brush(sd, ob, nodes, totnode);
          break;
      }
  
      if (!ELEM(brush->sculpt_tool, SCULPT_TOOL_SMOOTH, SCULPT_TOOL_MASK) &&
          brush->autosmooth_factor > 0) {
        if (brush->flag & BRUSH_INVERSE_SMOOTH_PRESSURE) {
          smooth(
              sd, ob, nodes, totnode, brush->autosmooth_factor * (1 - ss->cache->pressure), false);
        }
        else {
          smooth(sd, ob, nodes, totnode, brush->autosmooth_factor, false);
        }
      }
  
      if (sculpt_brush_use_topology_rake(ss, brush)) {
        bmesh_topology_rake(sd, ob, nodes, totnode, brush->topology_rake_factor);
      }
  
      if (ss->cache->supports_gravity) {
        do_gravity(sd, ob, nodes, totnode, sd->gravity_factor);
      }
  
      MEM_freeN(nodes);
  
      /* update average stroke position */
      copy_v3_v3(location, ss->cache->true_location);
      mul_m4_v3(ob->obmat, location);
  
      add_v3_v3(ups->average_stroke_accum, location);
      ups->average_stroke_counter++;
      /* update last stroke position */
      ups->last_stroke_valid = true;
    }
  }
  
  /* flush displacement from deformed PBVH vertex to original mesh */
  static void sculpt_flush_pbvhvert_deform(Object *ob, PBVHVertexIter *vd)
  {
    SculptSession *ss = ob->sculpt;
    Mesh *me = ob->data;
    float disp[3], newco[3];
    int index = vd->vert_indices[vd->i];
  
    sub_v3_v3v3(disp, vd->co, ss->deform_cos[index]);
    mul_m3_v3(ss->deform_imats[index], disp);
    add_v3_v3v3(newco, disp, ss->orig_cos[index]);
  
    copy_v3_v3(ss->deform_cos[index], vd->co);
    copy_v3_v3(ss->orig_cos[index], newco);
  
    if (!ss->kb) {
      copy_v3_v3(me->mvert[index].co, newco);
    }
  }
  
  static void sculpt_combine_proxies_task_cb(void *__restrict userdata,
                                             const int n,
                                             const TaskParallelTLS *__restrict UNUSED(tls))
  {
    SculptThreadedTaskData *data = userdata;
    SculptSession *ss = data->ob->sculpt;
    Sculpt *sd = data->sd;
    Object *ob = data->ob;
  
    /* these brushes start from original coordinates */
    const bool use_orco = ELEM(
        data->brush->sculpt_tool, SCULPT_TOOL_GRAB, SCULPT_TOOL_ROTATE, SCULPT_TOOL_THUMB);
  
    PBVHVertexIter vd;
    PBVHProxyNode *proxies;
    int proxy_count;
    float(*orco)[3] = NULL;
  
    if (use_orco && !ss->bm) {
      orco = sculpt_undo_push_node(data->ob, data->nodes[n], SCULPT_UNDO_COORDS)->co;
    }
  
    BKE_pbvh_node_get_proxies(data->nodes[n], &proxies, &proxy_count);
  
    BKE_pbvh_vertex_iter_begin(ss->pbvh, data->nodes[n], vd, PBVH_ITER_UNIQUE)
    {
      float val[3];
      int p;
  
      if (use_orco) {
        if (ss->bm) {
          copy_v3_v3(val, BM_log_original_vert_co(ss->bm_log, vd.bm_vert));
        }
        else {
          copy_v3_v3(val, orco[vd.i]);
        }
      }
      else {
        copy_v3_v3(val, vd.co);
      }
  
      for (p = 0; p < proxy_count; p++) {
        add_v3_v3(val, proxies[p].co[vd.i]);
      }
  
      sculpt_clip(sd, ss, vd.co, val);
  
      if (ss->modifiers_active) {
        sculpt_flush_pbvhvert_deform(ob, &vd);
      }
    }
    BKE_pbvh_vertex_iter_end;
  
    BKE_pbvh_node_free_proxies(data->nodes[n]);
  }
  
  static void sculpt_combine_proxies(Sculpt *sd, Object *ob)
  {
    SculptSession *ss = ob->sculpt;
    Brush *brush = BKE_paint_brush(&sd->paint);
    PBVHNode **nodes;
    int totnode;
  
    BKE_pbvh_gather_proxies(ss->pbvh, &nodes, &totnode);
  
    /* first line is tools that don't support proxies */
    if (ss->cache->supports_gravity || (sculpt_tool_is_proxy_used(brush->sculpt_tool) == false)) {
      SculptThreadedTaskData data = {
          .sd = sd,
          .ob = ob,
          .brush = brush,
          .nodes = nodes,
      };
  
      TaskParallelSettings settings;
      BLI_parallel_range_settings_defaults(&settings);
      settings.use_threading = ((sd->flags & SCULPT_USE_OPENMP) && totnode > SCULPT_THREADED_LIMIT);
      BLI_task_parallel_range(0, totnode, &data, sculpt_combine_proxies_task_cb, &settings);
    }
  
    if (nodes) {
      MEM_freeN(nodes);
    }
  }
  
  /* copy the modified vertices from bvh to the active key */
  static void sculpt_update_keyblock(Object *ob)
  {
    SculptSession *ss = ob->sculpt;
    float(*vertCos)[3];
  
    /* Keyblock update happens after handling deformation caused by modifiers,
     * so ss->orig_cos would be updated with new stroke */
    if (ss->orig_cos) {
      vertCos = ss->orig_cos;
    }
    else {
      vertCos = BKE_pbvh_get_vertCos(ss->pbvh);
    }
  
    if (vertCos) {
      sculpt_vertcos_to_key(ob, ss->kb, vertCos);
  
      if (vertCos != ss->orig_cos) {
        MEM_freeN(vertCos);
      }
    }
  }
  
  static void sculpt_flush_stroke_deform_task_cb(void *__restrict userdata,
                                                 const int n,
                                                 const TaskParallelTLS *__restrict UNUSED(tls))
  {
    SculptThreadedTaskData *data = userdata;
    SculptSession *ss = data->ob->sculpt;
    Object *ob = data->ob;
    float(*vertCos)[3] = data->vertCos;
  
    PBVHVertexIter vd;
  
    BKE_pbvh_vertex_iter_begin(ss->pbvh, data->nodes[n], vd, PBVH_ITER_UNIQUE)
    {
      sculpt_flush_pbvhvert_deform(ob, &vd);
  
      if (vertCos) {
        int index = vd.vert_indices[vd.i];
        copy_v3_v3(vertCos[index], ss->orig_cos[index]);
      }
    }
    BKE_pbvh_vertex_iter_end;
  }
  
  /* flush displacement from deformed PBVH to original layer */
  static void sculpt_flush_stroke_deform(Sculpt *sd, Object *ob)
  {
    SculptSession *ss = ob->sculpt;
    Brush *brush = BKE_paint_brush(&sd->paint);
  
    if (sculpt_tool_is_proxy_used(brush->sculpt_tool)) {
      /* this brushes aren't using proxies, so sculpt_combine_proxies() wouldn't
       * propagate needed deformation to original base */
  
      int totnode;
      Mesh *me = (Mesh *)ob->data;
      PBVHNode **nodes;
      float(*vertCos)[3] = NULL;
  
      if (ss->kb) {
        vertCos = MEM_mallocN(sizeof(*vertCos) * me->totvert, "flushStrokeDeofrm keyVerts");
  
        /* mesh could have isolated verts which wouldn't be in BVH,
         * to deal with this we copy old coordinates over new ones
         * and then update coordinates for all vertices from BVH
         */
        memcpy(vertCos, ss->orig_cos, sizeof(*vertCos) * me->totvert);
      }
  
      BKE_pbvh_search_gather(ss->pbvh, NULL, NULL, &nodes, &totnode);
  
      SculptThreadedTaskData data = {
          .sd = sd,
          .ob = ob,
          .brush = brush,
          .nodes = nodes,
          .vertCos = vertCos,
      };
  
      TaskParallelSettings settings;
      BLI_parallel_range_settings_defaults(&settings);
      settings.use_threading = ((sd->flags & SCULPT_USE_OPENMP) && totnode > SCULPT_THREADED_LIMIT);
      BLI_task_parallel_range(0, totnode, &data, sculpt_flush_stroke_deform_task_cb, &settings);
  
      if (vertCos) {
        sculpt_vertcos_to_key(ob, ss->kb, vertCos);
        MEM_freeN(vertCos);
      }
  
      MEM_freeN(nodes);
  
      /* Modifiers could depend on mesh normals, so we should update them/
       * Note, then if sculpting happens on locked key, normals should be re-calculated
       * after applying coords from keyblock on base mesh */
      BKE_mesh_calc_normals(me);
    }
    else if (ss->kb) {
      sculpt_update_keyblock(ob);
    }
  }
  
  /* Flip all the editdata across the axis/axes specified by symm. Used to
   * calculate multiple modifications to the mesh when symmetry is enabled. */
  void sculpt_cache_calc_brushdata_symm(StrokeCache *cache,
                                        const char symm,
                                        const char axis,
                                        const float angle)
  {
    flip_v3_v3(cache->location, cache->true_location, symm);
    flip_v3_v3(cache->last_location, cache->true_last_location, symm);
    flip_v3_v3(cache->grab_delta_symmetry, cache->grab_delta, symm);
    flip_v3_v3(cache->view_normal, cache->true_view_normal, symm);
  
    /* XXX This reduces the length of the grab delta if it approaches the line of symmetry
     * XXX However, a different approach appears to be needed */
  #if 0
    if (sd->paint.symmetry_flags & PAINT_SYMMETRY_FEATHER) {
      float frac = 1.0f / max_overlap_count(sd);
      float reduce = (feather - frac) / (1 - frac);
  
      printf("feather: %f frac: %f reduce: %f\n", feather, frac, reduce);
  
      if (frac < 1) {
        mul_v3_fl(cache->grab_delta_symmetry, reduce);
      }
    }
  #endif
  
    unit_m4(cache->symm_rot_mat);
    unit_m4(cache->symm_rot_mat_inv);
    zero_v3(cache->plane_offset);
  
    if (axis) { /* expects XYZ */
      rotate_m4(cache->symm_rot_mat, axis, angle);
      rotate_m4(cache->symm_rot_mat_inv, axis, -angle);
    }
  
    mul_m4_v3(cache->symm_rot_mat, cache->location);
    mul_m4_v3(cache->symm_rot_mat, cache->grab_delta_symmetry);
  
    if (cache->supports_gravity) {
      flip_v3_v3(cache->gravity_direction, cache->true_gravity_direction, symm);
      mul_m4_v3(cache->symm_rot_mat, cache->gravity_direction);
    }
  
    if (cache->is_rake_rotation_valid) {
      flip_qt_qt(cache->rake_rotation_symmetry, cache->rake_rotation, symm);
    }
  }
  
  typedef void (*BrushActionFunc)(Sculpt *sd, Object *ob, Brush *brush, UnifiedPaintSettings *ups);
  
  static void do_tiled(
      Sculpt *sd, Object *ob, Brush *brush, UnifiedPaintSettings *ups, BrushActionFunc action)
  {
    SculptSession *ss = ob->sculpt;
    StrokeCache *cache = ss->cache;
    const float radius = cache->radius;
    BoundBox *bb = BKE_object_boundbox_get(ob);
    const float *bbMin = bb->vec[0];
    const float *bbMax = bb->vec[6];
    const float *step = sd->paint.tile_offset;
    int dim;
  
    /* These are integer locations, for real location: multiply with step and add orgLoc.
     * So 0,0,0 is at orgLoc. */
    int start[3];
    int end[3];
    int cur[3];
  
    float orgLoc[3]; /* position of the "prototype" stroke for tiling */
    copy_v3_v3(orgLoc, cache->location);
  
    for (dim = 0; dim < 3; ++dim) {
      if ((sd->paint.symmetry_flags & (PAINT_TILE_X << dim)) && step[dim] > 0) {
        start[dim] = (bbMin[dim] - orgLoc[dim] - radius) / step[dim];
        end[dim] = (bbMax[dim] - orgLoc[dim] + radius) / step[dim];
      }
      else {
        start[dim] = end[dim] = 0;
      }
    }
  
    /* first do the "untiled" position to initialize the stroke for this location */
    cache->tile_pass = 0;
    action(sd, ob, brush, ups);
  
    /* now do it for all the tiles */
    copy_v3_v3_int(cur, start);
    for (cur[0] = start[0]; cur[0] <= end[0]; ++cur[0]) {
      for (cur[1] = start[1]; cur[1] <= end[1]; ++cur[1]) {
        for (cur[2] = start[2]; cur[2] <= end[2]; ++cur[2]) {
          if (!cur[0] && !cur[1] && !cur[2]) {
            continue; /* skip tile at orgLoc, this was already handled before all others */
          }
  
          ++cache->tile_pass;
  
          for (dim = 0; dim < 3; ++dim) {
            cache->location[dim] = cur[dim] * step[dim] + orgLoc[dim];
            cache->plane_offset[dim] = cur[dim] * step[dim];
          }
          action(sd, ob, brush, ups);
        }
      }
    }
  }
  
  static void do_radial_symmetry(Sculpt *sd,
                                 Object *ob,
                                 Brush *brush,
                                 UnifiedPaintSettings *ups,
                                 BrushActionFunc action,
                                 const char symm,
                                 const int axis,
                                 const float UNUSED(feather))
  {
    SculptSession *ss = ob->sculpt;
    int i;
  
    for (i = 1; i < sd->radial_symm[axis - 'X']; ++i) {
      const float angle = 2 * M_PI * i / sd->radial_symm[axis - 'X'];
      ss->cache->radial_symmetry_pass = i;
      sculpt_cache_calc_brushdata_symm(ss->cache, symm, axis, angle);
      do_tiled(sd, ob, brush, ups, action);
    }
  }
  
  /* noise texture gives different values for the same input coord; this
   * can tear a multires mesh during sculpting so do a stitch in this
   * case */
  static void sculpt_fix_noise_tear(Sculpt *sd, Object *ob)
  {
    SculptSession *ss = ob->sculpt;
    Brush *brush = BKE_paint_brush(&sd->paint);
    MTex *mtex = &brush->mtex;
  
    if (ss->multires && mtex->tex && mtex->tex->type == TEX_NOISE) {
      multires_stitch_grids(ob);
    }
  }
  
  static void do_symmetrical_brush_actions(Sculpt *sd,
                                           Object *ob,
                                           BrushActionFunc action,
                                           UnifiedPaintSettings *ups)
  {
    Brush *brush = BKE_paint_brush(&sd->paint);
    SculptSession *ss = ob->sculpt;
    StrokeCache *cache = ss->cache;
    const char symm = sd->paint.symmetry_flags & PAINT_SYMM_AXIS_ALL;
    int i;
  
    float feather = calc_symmetry_feather(sd, ss->cache);
  
    cache->bstrength = brush_strength(sd, cache, feather, ups);
    cache->symmetry = symm;
  
    /* symm is a bit combination of XYZ -
     * 1 is mirror X; 2 is Y; 3 is XY; 4 is Z; 5 is XZ; 6 is YZ; 7 is XYZ */
    for (i = 0; i <= symm; ++i) {
      if (i == 0 || (symm & i && (symm != 5 || i != 3) && (symm != 6 || (i != 3 && i != 5)))) {
        cache->mirror_symmetry_pass = i;
        cache->radial_symmetry_pass = 0;
  
        sculpt_cache_calc_brushdata_symm(cache, i, 0, 0);
        do_tiled(sd, ob, brush, ups, action);
  
        do_radial_symmetry(sd, ob, brush, ups, action, i, 'X', feather);
        do_radial_symmetry(sd, ob, brush, ups, action, i, 'Y', feather);
        do_radial_symmetry(sd, ob, brush, ups, action, i, 'Z', feather);
      }
    }
  }
  
  static void sculpt_update_tex(const Scene *scene, Sculpt *sd, SculptSession *ss)
  {
    Brush *brush = BKE_paint_brush(&sd->paint);
    const int radius = BKE_brush_size_get(scene, brush);
  
    if (ss->texcache) {
      MEM_freeN(ss->texcache);
      ss->texcache = NULL;
    }
  
    if (ss->tex_pool) {
      BKE_image_pool_free(ss->tex_pool);
      ss->tex_pool = NULL;
    }
  
    /* Need to allocate a bigger buffer for bigger brush size */
    ss->texcache_side = 2 * radius;
    if (!ss->texcache || ss->texcache_side > ss->texcache_actual) {
      ss->texcache = BKE_brush_gen_texture_cache(brush, radius, false);
      ss->texcache_actual = ss->texcache_side;
      ss->tex_pool = BKE_image_pool_new();
    }
  }
  
  bool sculpt_mode_poll(bContext *C)
  {
    Object *ob = CTX_data_active_object(C);
    return ob && ob->mode & OB_MODE_SCULPT;
  }
  
  bool sculpt_mode_poll_view3d(bContext *C)
  {
    return (sculpt_mode_poll(C) && CTX_wm_region_view3d(C));
  }
  
  bool sculpt_poll_view3d(bContext *C)
  {
    return (sculpt_poll(C) && CTX_wm_region_view3d(C));
  }
  
  bool sculpt_poll(bContext *C)
  {
    return sculpt_mode_poll(C) && paint_poll(C);
  }
  
  static const char *sculpt_tool_name(Sculpt *sd)
  {
    Brush *brush = BKE_paint_brush(&sd->paint);
  
    switch ((eBrushSculptTool)brush->sculpt_tool) {
      case SCULPT_TOOL_DRAW:
        return "Draw Brush";
      case SCULPT_TOOL_SMOOTH:
        return "Smooth Brush";
      case SCULPT_TOOL_CREASE:
        return "Crease Brush";
      case SCULPT_TOOL_BLOB:
        return "Blob Brush";
      case SCULPT_TOOL_PINCH:
        return "Pinch Brush";
      case SCULPT_TOOL_INFLATE:
        return "Inflate Brush";
      case SCULPT_TOOL_GRAB:
        return "Grab Brush";
      case SCULPT_TOOL_NUDGE:
        return "Nudge Brush";
      case SCULPT_TOOL_THUMB:
        return "Thumb Brush";
      case SCULPT_TOOL_LAYER:
        return "Layer Brush";
      case SCULPT_TOOL_FLATTEN:
        return "Flatten Brush";
      case SCULPT_TOOL_CLAY:
        return "Clay Brush";
      case SCULPT_TOOL_CLAY_STRIPS:
        return "Clay Strips Brush";
      case SCULPT_TOOL_FILL:
        return "Fill Brush";
      case SCULPT_TOOL_SCRAPE:
        return "Scrape Brush";
      case SCULPT_TOOL_SNAKE_HOOK:
        return "Snake Hook Brush";
      case SCULPT_TOOL_ROTATE:
        return "Rotate Brush";
      case SCULPT_TOOL_MASK:
        return "Mask Brush";
      case SCULPT_TOOL_SIMPLIFY:
        return "Simplify Brush";
    }
  
    return "Sculpting";
  }
  
  /**
   * Operator for applying a stroke (various attributes including mouse path)
   * using the current brush. */
  
  void sculpt_cache_free(StrokeCache *cache)
  {
    if (cache->dial) {
      MEM_freeN(cache->dial);
    }
    MEM_freeN(cache);
  }
  
  /* Initialize mirror modifier clipping */
  static void sculpt_init_mirror_clipping(Object *ob, SculptSession *ss)
  {
    ModifierData *md;
    int i;
  
    for (md = ob->modifiers.first; md; md = md->next) {
      if (md->type == eModifierType_Mirror && (md->mode & eModifierMode_Realtime)) {
        MirrorModifierData *mmd = (MirrorModifierData *)md;
  
        if (mmd->flag & MOD_MIR_CLIPPING) {
          /* check each axis for mirroring */
          for (i = 0; i < 3; ++i) {
            if (mmd->flag & (MOD_MIR_AXIS_X << i)) {
              /* enable sculpt clipping */
              ss->cache->flag |= CLIP_X << i;
  
              /* update the clip tolerance */
              if (mmd->tolerance > ss->cache->clip_tolerance[i]) {
                ss->cache->clip_tolerance[i] = mmd->tolerance;
              }
            }
          }
        }
      }
    }
  }
  
  /* Initialize the stroke cache invariants from operator properties */
  static void sculpt_update_cache_invariants(
      bContext *C, Sculpt *sd, SculptSession *ss, wmOperator *op, const float mouse[2])
  {
    StrokeCache *cache = MEM_callocN(sizeof(StrokeCache), "stroke cache");
    Main *bmain = CTX_data_main(C);
    Scene *scene = CTX_data_scene(C);
    UnifiedPaintSettings *ups = &CTX_data_tool_settings(C)->unified_paint_settings;
    Brush *brush = BKE_paint_brush(&sd->paint);
    ViewContext *vc = paint_stroke_view_context(op->customdata);
    Object *ob = CTX_data_active_object(C);
    float mat[3][3];
    float viewDir[3] = {0.0f, 0.0f, 1.0f};
    float max_scale;
    int i;
    int mode;
  
    ss->cache = cache;
  
    /* Set scaling adjustment */
    if (brush->sculpt_tool == SCULPT_TOOL_LAYER) {
      max_scale = 1.0f;
    }
    else {
      max_scale = 0.0f;
      for (i = 0; i < 3; i++) {
        max_scale = max_ff(max_scale, fabsf(ob->scale[i]));
      }
    }
    cache->scale[0] = max_scale / ob->scale[0];
    cache->scale[1] = max_scale / ob->scale[1];
    cache->scale[2] = max_scale / ob->scale[2];
  
    cache->plane_trim_squared = brush->plane_trim * brush->plane_trim;
  
    cache->flag = 0;
  
    sculpt_init_mirror_clipping(ob, ss);
  
    /* Initial mouse location */
    if (mouse) {
      copy_v2_v2(cache->initial_mouse, mouse);
    }
    else {
      zero_v2(cache->initial_mouse);
    }
  
    mode = RNA_enum_get(op->ptr, "mode");
    cache->invert = mode == BRUSH_STROKE_INVERT;
    cache->alt_smooth = mode == BRUSH_STROKE_SMOOTH;
    cache->normal_weight = brush->normal_weight;
  
    /* interpret invert as following normal, for grab brushes */
    if (SCULPT_TOOL_HAS_NORMAL_WEIGHT(brush->sculpt_tool)) {
      if (cache->invert) {
        cache->invert = false;
        cache->normal_weight = (cache->normal_weight == 0.0f);
      }
    }
  
    /* not very nice, but with current events system implementation
     * we can't handle brush appearance inversion hotkey separately (sergey) */
    if (cache->invert) {
      ups->draw_inverted = true;
    }
    else {
      ups->draw_inverted = false;
    }
  
    /* Alt-Smooth */
    if (cache->alt_smooth) {
      if (brush->sculpt_tool == SCULPT_TOOL_MASK) {
        cache->saved_mask_brush_tool = brush->mask_tool;
        brush->mask_tool = BRUSH_MASK_SMOOTH;
      }
      else {
        Paint *p = &sd->paint;
        Brush *br;
        int size = BKE_brush_size_get(scene, brush);
  
        BLI_strncpy(cache->saved_active_brush_name,
                    brush->id.name + 2,
                    sizeof(cache->saved_active_brush_name));
  
        br = (Brush *)BKE_libblock_find_name(bmain, ID_BR, "Smooth");
        if (br) {
          BKE_paint_brush_set(p, br);
          brush = br;
          cache->saved_smooth_size = BKE_brush_size_get(scene, brush);
          BKE_brush_size_set(scene, brush, size);
          BKE_curvemapping_initialize(brush->curve);
        }
      }
    }
  
    copy_v2_v2(cache->mouse, cache->initial_mouse);
    copy_v2_v2(ups->tex_mouse, cache->initial_mouse);
  
    /* Truly temporary data that isn't stored in properties */
  
    cache->vc = vc;
  
    cache->brush = brush;
  
    /* cache projection matrix */
    ED_view3d_ob_project_mat_get(cache->vc->rv3d, ob, cache->projection_mat);
  
    invert_m4_m4(ob->imat, ob->obmat);
    copy_m3_m4(mat, cache->vc->rv3d->viewinv);
    mul_m3_v3(mat, viewDir);
    copy_m3_m4(mat, ob->imat);
    mul_m3_v3(mat, viewDir);
    normalize_v3_v3(cache->true_view_normal, viewDir);
  
    cache->supports_gravity =
        (!ELEM(brush->sculpt_tool, SCULPT_TOOL_MASK, SCULPT_TOOL_SMOOTH, SCULPT_TOOL_SIMPLIFY) &&
         (sd->gravity_factor > 0.0f));
    /* get gravity vector in world space */
    if (cache->supports_gravity) {
      if (sd->gravity_object) {
        Object *gravity_object = sd->gravity_object;
  
        copy_v3_v3(cache->true_gravity_direction, gravity_object->obmat[2]);
      }
      else {
        cache->true_gravity_direction[0] = cache->true_gravity_direction[1] = 0.0;
        cache->true_gravity_direction[2] = 1.0;
      }
  
      /* transform to sculpted object space */
      mul_m3_v3(mat, cache->true_gravity_direction);
      normalize_v3(cache->true_gravity_direction);
    }
  
    /* Initialize layer brush displacements and persistent coords */
    if (brush->sculpt_tool == SCULPT_TOOL_LAYER) {
      /* not supported yet for multires or dynamic topology */
      if (!ss->multires && !ss->bm && !ss->layer_co && (brush->flag & BRUSH_PERSISTENT)) {
        if (!ss->layer_co) {
          ss->layer_co = MEM_mallocN(sizeof(float) * 3 * ss->totvert, "sculpt mesh vertices copy");
        }
  
        if (ss->deform_cos) {
          memcpy(ss->layer_co, ss->deform_cos, ss->totvert);
        }
        else {
          for (i = 0; i < ss->totvert; ++i) {
            copy_v3_v3(ss->layer_co[i], ss->mvert[i].co);
          }
        }
      }
  
      if (ss->bm) {
        /* Free any remaining layer displacements from nodes. If not and topology changes
         * from using another tool, then next layer toolstroke
         * can access past disp array bounds */
        BKE_pbvh_free_layer_disp(ss->pbvh);
      }
    }
  
    /* Make copies of the mesh vertex locations and normals for some tools */
    if (brush->flag & BRUSH_ANCHORED) {
      cache->original = 1;
    }
  
    if (SCULPT_TOOL_HAS_ACCUMULATE(brush->sculpt_tool)) {
      if (!(brush->flag & BRUSH_ACCUMULATE)) {
        cache->original = 1;
      }
    }
  
    cache->first_time = 1;
  
  #define PIXEL_INPUT_THRESHHOLD 5
    if (brush->sculpt_tool == SCULPT_TOOL_ROTATE) {
      cache->dial = BLI_dial_initialize(cache->initial_mouse, PIXEL_INPUT_THRESHHOLD);
    }
  
  #undef PIXEL_INPUT_THRESHHOLD
  }
  
  static void sculpt_update_brush_delta(UnifiedPaintSettings *ups, Object *ob, Brush *brush)
  {
    SculptSession *ss = ob->sculpt;
    StrokeCache *cache = ss->cache;
    const float mouse[2] = {
        cache->mouse[0],
        cache->mouse[1],
    };
    int tool = brush->sculpt_tool;
  
    if (ELEM(tool,
             SCULPT_TOOL_GRAB,
             SCULPT_TOOL_NUDGE,
             SCULPT_TOOL_CLAY_STRIPS,
             SCULPT_TOOL_SNAKE_HOOK,
             SCULPT_TOOL_THUMB) ||
        sculpt_brush_use_topology_rake(ss, brush)) {
      float grab_location[3], imat[4][4], delta[3], loc[3];
  
      if (cache->first_time) {
        copy_v3_v3(cache->orig_grab_location, cache->true_location);
      }
      else if (tool == SCULPT_TOOL_SNAKE_HOOK) {
        add_v3_v3(cache->true_location, cache->grab_delta);
      }
  
      /* compute 3d coordinate at same z from original location + mouse */
      mul_v3_m4v3(loc, ob->obmat, cache->orig_grab_location);
      ED_view3d_win_to_3d(cache->vc->v3d, cache->vc->ar, loc, mouse, grab_location);
  
      /* compute delta to move verts by */
      if (!cache->first_time) {
        switch (tool) {
          case SCULPT_TOOL_GRAB:
          case SCULPT_TOOL_THUMB:
            sub_v3_v3v3(delta, grab_location, cache->old_grab_location);
            invert_m4_m4(imat, ob->obmat);
            mul_mat3_m4_v3(imat, delta);
            add_v3_v3(cache->grab_delta, delta);
            break;
          case SCULPT_TOOL_CLAY_STRIPS:
          case SCULPT_TOOL_NUDGE:
          case SCULPT_TOOL_SNAKE_HOOK:
            if (brush->flag & BRUSH_ANCHORED) {
              float orig[3];
              mul_v3_m4v3(orig, ob->obmat, cache->orig_grab_location);
              sub_v3_v3v3(cache->grab_delta, grab_location, orig);
            }
            else {
              sub_v3_v3v3(cache->grab_delta, grab_location, cache->old_grab_location);
            }
            invert_m4_m4(imat, ob->obmat);
            mul_mat3_m4_v3(imat, cache->grab_delta);
            break;
          default:
            /* Use for 'Brush.topology_rake_factor'. */
            sub_v3_v3v3(cache->grab_delta, grab_location, cache->old_grab_location);
            break;
        }
      }
      else {
        zero_v3(cache->grab_delta);
      }
  
      if (brush->falloff_shape == PAINT_FALLOFF_SHAPE_TUBE) {
        project_plane_v3_v3v3(cache->grab_delta, cache->grab_delta, ss->cache->true_view_normal);
      }
  
      copy_v3_v3(cache->old_grab_location, grab_location);
  
      if (tool == SCULPT_TOOL_GRAB) {
        copy_v3_v3(cache->anchored_location, cache->true_location);
      }
      else if (tool == SCULPT_TOOL_THUMB) {
        copy_v3_v3(cache->anchored_location, cache->orig_grab_location);
      }
  
      if (ELEM(tool, SCULPT_TOOL_GRAB, SCULPT_TOOL_THUMB)) {
        /* location stays the same for finding vertices in brush radius */
        copy_v3_v3(cache->true_location, cache->orig_grab_location);
  
        ups->draw_anchored = true;
        copy_v2_v2(ups->anchored_initial_mouse, cache->initial_mouse);
        ups->anchored_size = ups->pixel_radius;
      }
  
      /* handle 'rake' */
      cache->is_rake_rotation_valid = false;
  
      if (cache->first_time) {
        copy_v3_v3(cache->rake_data.follow_co, grab_location);
      }
  
      if (sculpt_brush_needs_rake_rotation(brush)) {
        cache->rake_data.follow_dist = cache->radius * SCULPT_RAKE_BRUSH_FACTOR;
  
        if (!is_zero_v3(cache->grab_delta)) {
          const float eps = 0.00001f;
  
          float v1[3], v2[3];
  
          copy_v3_v3(v1, cache->rake_data.follow_co);
          copy_v3_v3(v2, cache->rake_data.follow_co);
          sub_v3_v3(v2, cache->grab_delta);
  
          sub_v3_v3(v1, grab_location);
          sub_v3_v3(v2, grab_location);
  
          if ((normalize_v3(v2) > eps) && (normalize_v3(v1) > eps) &&
              (len_squared_v3v3(v1, v2) > eps)) {
            const float rake_dist_sq = len_squared_v3v3(cache->rake_data.follow_co, grab_location);
            const float rake_fade = (rake_dist_sq > SQUARE(cache->rake_data.follow_dist)) ?
                                        1.0f :
                                        sqrtf(rake_dist_sq) / cache->rake_data.follow_dist;
  
            float axis[3], angle;
            float tquat[4];
  
            rotation_between_vecs_to_quat(tquat, v1, v2);
  
            /* use axis-angle to scale rotation since the factor may be above 1 */
            quat_to_axis_angle(axis, &angle, tquat);
            normalize_v3(axis);
  
            angle *= brush->rake_factor * rake_fade;
            axis_angle_normalized_to_quat(cache->rake_rotation, axis, angle);
            cache->is_rake_rotation_valid = true;
          }
        }
        sculpt_rake_data_update(&cache->rake_data, grab_location);
      }
    }
  }
  
  /* Initialize the stroke cache variants from operator properties */
  static void sculpt_update_cache_variants(bContext *C, Sculpt *sd, Object *ob, PointerRNA *ptr)
  {
    Scene *scene = CTX_data_scene(C);
    UnifiedPaintSettings *ups = &scene->toolsettings->unified_paint_settings;
    SculptSession *ss = ob->sculpt;
    StrokeCache *cache = ss->cache;
    Brush *brush = BKE_paint_brush(&sd->paint);
  
    /* RNA_float_get_array(ptr, "location", cache->traced_location); */
  
    if (cache->first_time ||
        !((brush->flag & BRUSH_ANCHORED) || (brush->sculpt_tool == SCULPT_TOOL_SNAKE_HOOK) ||
          (brush->sculpt_tool == SCULPT_TOOL_ROTATE))) {
      RNA_float_get_array(ptr, "location", cache->true_location);
    }
  
    cache->pen_flip = RNA_boolean_get(ptr, "pen_flip");
    RNA_float_get_array(ptr, "mouse", cache->mouse);
  
    /* XXX: Use pressure value from first brush step for brushes which don't
     *      support strokes (grab, thumb). They depends on initial state and
     *      brush coord/pressure/etc.
     *      It's more an events design issue, which doesn't split coordinate/pressure/angle
     *      changing events. We should avoid this after events system re-design */
    if (paint_supports_dynamic_size(brush, PAINT_MODE_SCULPT) || cache->first_time) {
      cache->pressure = RNA_float_get(ptr, "pressure");
    }
  
    /* Truly temporary data that isn't stored in properties */
    if (cache->first_time) {
      if (!BKE_brush_use_locked_size(scene, brush)) {
        cache->initial_radius = paint_calc_object_space_radius(
            cache->vc, cache->true_location, BKE_brush_size_get(scene, brush));
        BKE_brush_unprojected_radius_set(scene, brush, cache->initial_radius);
      }
      else {
        cache->initial_radius = BKE_brush_unprojected_radius_get(scene, brush);
      }
    }
  
    if (BKE_brush_use_size_pressure(scene, brush) &&
        paint_supports_dynamic_size(brush, PAINT_MODE_SCULPT)) {
      cache->radius = cache->initial_radius * cache->pressure;
    }
    else {
      cache->radius = cache->initial_radius;
    }
  
    cache->radius_squared = cache->radius * cache->radius;
  
    if (brush->flag & BRUSH_ANCHORED) {
      /* true location has been calculated as part of the stroke system already here */
      if (brush->flag & BRUSH_EDGE_TO_EDGE) {
        RNA_float_get_array(ptr, "location", cache->true_location);
      }
  
      cache->radius = paint_calc_object_space_radius(
          cache->vc, cache->true_location, ups->pixel_radius);
      cache->radius_squared = cache->radius * cache->radius;
  
      copy_v3_v3(cache->anchored_location, cache->true_location);
    }
  
    sculpt_update_brush_delta(ups, ob, brush);
  
    if (brush->sculpt_tool == SCULPT_TOOL_ROTATE) {
      cache->vertex_rotation = -BLI_dial_angle(cache->dial, cache->mouse) * cache->bstrength;
  
      ups->draw_anchored = true;
      copy_v2_v2(ups->anchored_initial_mouse, cache->initial_mouse);
      copy_v3_v3(cache->anchored_location, cache->true_location);
      ups->anchored_size = ups->pixel_radius;
    }
  
    cache->special_rotation = ups->brush_rotation;
  }
  
  /* Returns true if any of the smoothing modes are active (currently
   * one of smooth brush, autosmooth, mask smooth, or shift-key
   * smooth) */
  static bool sculpt_any_smooth_mode(const Brush *brush, StrokeCache *cache, int stroke_mode)
  {
    return ((stroke_mode == BRUSH_STROKE_SMOOTH) || (cache && cache->alt_smooth) ||
            (brush->sculpt_tool == SCULPT_TOOL_SMOOTH) || (brush->autosmooth_factor > 0) ||
            ((brush->sculpt_tool == SCULPT_TOOL_MASK) && (brush->mask_tool == BRUSH_MASK_SMOOTH)));
  }
  
  static void sculpt_stroke_modifiers_check(const bContext *C, Object *ob, const Brush *brush)
  {
    SculptSession *ss = ob->sculpt;
  
    if (ss->kb || ss->modifiers_active) {
      Depsgraph *depsgraph = CTX_data_depsgraph_pointer(C);
      bool need_pmap = sculpt_any_smooth_mode(brush, ss->cache, 0);
      BKE_sculpt_update_object_for_edit(depsgraph, ob, need_pmap, false);
    }
  }
  
  static void sculpt_raycast_cb(PBVHNode *node, void *data_v, float *tmin)
  {
    if (BKE_pbvh_node_get_tmin(node) < *tmin) {
      SculptRaycastData *srd = data_v;
      float(*origco)[3] = NULL;
      bool use_origco = false;
  
      if (srd->original && srd->ss->cache) {
        if (BKE_pbvh_type(srd->ss->pbvh) == PBVH_BMESH) {
          use_origco = true;
        }
        else {
          /* intersect with coordinates from before we started stroke */
          SculptUndoNode *unode = sculpt_undo_get_node(node);
          origco = (unode) ? unode->co : NULL;
          use_origco = origco ? true : false;
        }
      }
  
      if (BKE_pbvh_node_raycast(srd->ss->pbvh,
                                node,
                                origco,
                                use_origco,
                                srd->ray_start,
                                &srd->isect_precalc,
                                &srd->depth)) {
        srd->hit = 1;
        *tmin = srd->depth;
      }
    }
  }
  
  static void sculpt_find_nearest_to_ray_cb(PBVHNode *node, void *data_v, float *tmin)
  {
    if (BKE_pbvh_node_get_tmin(node) < *tmin) {
      SculptFindNearestToRayData *srd = data_v;
      float(*origco)[3] = NULL;
      bool use_origco = false;
  
      if (srd->original && srd->ss->cache) {
        if (BKE_pbvh_type(srd->ss->pbvh) == PBVH_BMESH) {
          use_origco = true;
        }
        else {
          /* intersect with coordinates from before we started stroke */
          SculptUndoNode *unode = sculpt_undo_get_node(node);
          origco = (unode) ? unode->co : NULL;
          use_origco = origco ? true : false;
        }
      }
  
      if (BKE_pbvh_node_find_nearest_to_ray(srd->ss->pbvh,
                                            node,
                                            origco,
                                            use_origco,
                                            srd->ray_start,
                                            srd->ray_normal,
                                            &srd->depth,
                                            &srd->dist_sq_to_ray)) {
        srd->hit = 1;
        *tmin = srd->dist_sq_to_ray;
      }
    }
  }
  
  static void sculpt_raycast_detail_cb(PBVHNode *node, void *data_v, float *tmin)
  {
    if (BKE_pbvh_node_get_tmin(node) < *tmin) {
      SculptDetailRaycastData *srd = data_v;
      if (BKE_pbvh_bmesh_node_raycast_detail(
              node, srd->ray_start, &srd->isect_precalc, &srd->depth, &srd->edge_length)) {
        srd->hit = 1;
        *tmin = srd->depth;
      }
    }
  }
  
  static float sculpt_raycast_init(ViewContext *vc,
                                   const float mouse[2],
                                   float ray_start[3],
                                   float ray_end[3],
                                   float ray_normal[3],
                                   bool original)
  {
    float obimat[4][4];
    float dist;
    Object *ob = vc->obact;
    RegionView3D *rv3d = vc->ar->regiondata;
  
    /* TODO: what if the segment is totally clipped? (return == 0) */
    ED_view3d_win_to_segment_clipped(
        vc->depsgraph, vc->ar, vc->v3d, mouse, ray_start, ray_end, true);
  
    invert_m4_m4(obimat, ob->obmat);
    mul_m4_v3(obimat, ray_start);
    mul_m4_v3(obimat, ray_end);
  
    sub_v3_v3v3(ray_normal, ray_end, ray_start);
    dist = normalize_v3(ray_normal);
  
    if ((rv3d->is_persp == false) &&
        /* if the ray is clipped, don't adjust its start/end */
        ((rv3d->rflag & RV3D_CLIPPING) == 0)) {
      BKE_pbvh_raycast_project_ray_root(ob->sculpt->pbvh, original, ray_start, ray_end, ray_normal);
  
      /* recalculate the normal */
      sub_v3_v3v3(ray_normal, ray_end, ray_start);
      dist = normalize_v3(ray_normal);
    }
  
    return dist;
  }
  
  /* Do a raycast in the tree to find the 3d brush location
   * (This allows us to ignore the GL depth buffer)
   * Returns 0 if the ray doesn't hit the mesh, non-zero otherwise
   */
  bool sculpt_stroke_get_location(bContext *C, float out[3], const float mouse[2])
  {
    Object *ob;
    SculptSession *ss;
    StrokeCache *cache;
    float ray_start[3], ray_end[3], ray_normal[3], depth;
    bool original;
    ViewContext vc;
  
    ED_view3d_viewcontext_init(C, &vc);
  
    ob = vc.obact;
  
    ss = ob->sculpt;
    cache = ss->cache;
    original = (cache) ? cache->original : 0;
  
    const Brush *brush = BKE_paint_brush(BKE_paint_get_active_from_context(C));
  
    sculpt_stroke_modifiers_check(C, ob, brush);
  
    depth = sculpt_raycast_init(&vc, mouse, ray_start, ray_end, ray_normal, original);
  
    bool hit = false;
    {
      SculptRaycastData srd;
      srd.ss = ob->sculpt;
      srd.ray_start = ray_start;
      srd.hit = 0;
      srd.depth = depth;
      srd.original = original;
      isect_ray_tri_watertight_v3_precalc(&srd.isect_precalc, ray_normal);
  
      BKE_pbvh_raycast(ss->pbvh, sculpt_raycast_cb, &srd, ray_start, ray_normal, srd.original);
      if (srd.hit) {
        hit = true;
        copy_v3_v3(out, ray_normal);
        mul_v3_fl(out, srd.depth);
        add_v3_v3(out, ray_start);
      }
    }
  
    if (hit == false) {
      if (ELEM(brush->falloff_shape, PAINT_FALLOFF_SHAPE_TUBE)) {
        SculptFindNearestToRayData srd = {
            .original = original,
            .ss = ob->sculpt,
            .hit = 0,
            .ray_start = ray_start,
            .ray_normal = ray_normal,
            .depth = FLT_MAX,
            .dist_sq_to_ray = FLT_MAX,
        };
        BKE_pbvh_find_nearest_to_ray(
            ss->pbvh, sculpt_find_nearest_to_ray_cb, &srd, ray_start, ray_normal, srd.original);
        if (srd.hit) {
          hit = true;
          copy_v3_v3(out, ray_normal);
          mul_v3_fl(out, srd.depth);
          add_v3_v3(out, ray_start);
        }
      }
    }
  
    if (cache && hit) {
      copy_v3_v3(cache->true_location, out);
    }
  
    return hit;
  }
  
  static void sculpt_brush_init_tex(const Scene *scene, Sculpt *sd, SculptSession *ss)
  {
    Brush *brush = BKE_paint_brush(&sd->paint);
    MTex *mtex = &brush->mtex;
  
    /* init mtex nodes */
    if (mtex->tex && mtex->tex->nodetree) {
      /* has internal flag to detect it only does it once */
      ntreeTexBeginExecTree(mtex->tex->nodetree);
    }
  
    /* TODO: Shouldn't really have to do this at the start of every
     * stroke, but sculpt would need some sort of notification when
     * changes are made to the texture. */
    sculpt_update_tex(scene, sd, ss);
  }
  
  static void sculpt_brush_stroke_init(bContext *C, wmOperator *op)
  {
    Depsgraph *depsgraph = CTX_data_ensure_evaluated_depsgraph(C);
    Scene *scene = CTX_data_scene(C);
    Object *ob = CTX_data_active_object(C);
    Sculpt *sd = CTX_data_tool_settings(C)->sculpt;
    SculptSession *ss = CTX_data_active_object(C)->sculpt;
    Brush *brush = BKE_paint_brush(&sd->paint);
    int mode = RNA_enum_get(op->ptr, "mode");
    bool is_smooth;
    bool need_mask = false;
  
    if (brush->sculpt_tool == SCULPT_TOOL_MASK) {
      need_mask = true;
    }
  
    view3d_operator_needs_opengl(C);
    sculpt_brush_init_tex(scene, sd, ss);
  
    is_smooth = sculpt_any_smooth_mode(brush, NULL, mode);
    BKE_sculpt_update_object_for_edit(depsgraph, ob, is_smooth, need_mask);
  }
  
  static void sculpt_restore_mesh(Sculpt *sd, Object *ob)
  {
    SculptSession *ss = ob->sculpt;
    Brush *brush = BKE_paint_brush(&sd->paint);
  
    /* Restore the mesh before continuing with anchored stroke */
    if ((brush->flag & BRUSH_ANCHORED) ||
        (brush->sculpt_tool == SCULPT_TOOL_GRAB &&
         BKE_brush_use_size_pressure(ss->cache->vc->scene, brush)) ||
        (brush->flag & BRUSH_DRAG_DOT)) {
      paint_mesh_restore_co(sd, ob);
    }
  }
  
  /* Copy the PBVH bounding box into the object's bounding box */
  void sculpt_update_object_bounding_box(Object *ob)
  {
    if (ob->runtime.bb) {
      float bb_min[3], bb_max[3];
  
      BKE_pbvh_bounding_box(ob->sculpt->pbvh, bb_min, bb_max);
      BKE_boundbox_init_from_minmax(ob->runtime.bb, bb_min, bb_max);
    }
  }
  
  static void sculpt_flush_update_step(bContext *C)
  {
    Depsgraph *depsgraph = CTX_data_depsgraph_pointer(C);
    Object *ob = CTX_data_active_object(C);
    SculptSession *ss = ob->sculpt;
    ARegion *ar = CTX_wm_region(C);
    MultiresModifierData *mmd = ss->multires;
    View3D *v3d = CTX_wm_view3d(C);
  
    if (mmd != NULL) {
      multires_mark_as_modified(depsgraph, ob, MULTIRES_COORDS_MODIFIED);
    }
  
    DEG_id_tag_update(&ob->id, ID_RECALC_SHADING);
  
    /* Only current viewport matters, slower update for all viewports will
     * be done in sculpt_flush_update_done. */
    if (!BKE_sculptsession_use_pbvh_draw(ob, v3d)) {
      /* Slow update with full dependency graph update and all that comes with it.
       * Needed when there are modifiers or full shading in the 3D viewport. */
      DEG_id_tag_update(&ob->id, ID_RECALC_GEOMETRY);
      ED_region_tag_redraw(ar);
    }
    else {
      /* Fast path where we just update the BVH nodes that changed, and redraw
       * only the part of the 3D viewport where changes happened. */
      rcti r;
  
      BKE_pbvh_update_bounds(ss->pbvh, PBVH_UpdateBB);
      /* Update the object's bounding box too so that the object
       * doesn't get incorrectly clipped during drawing in
       * draw_mesh_object(). [#33790] */
      sculpt_update_object_bounding_box(ob);
  
      if (sculpt_get_redraw_rect(ar, CTX_wm_region_view3d(C), ob, &r)) {
        if (ss->cache) {
          ss->cache->current_r = r;
        }
  
        /* previous is not set in the current cache else
         * the partial rect will always grow */
        sculpt_extend_redraw_rect_previous(ob, &r);
  
        r.xmin += ar->winrct.xmin - 2;
        r.xmax += ar->winrct.xmin + 2;
        r.ymin += ar->winrct.ymin - 2;
        r.ymax += ar->winrct.ymin + 2;
        ED_region_tag_redraw_partial(ar, &r, true);
      }
    }
  }
  
  static void sculpt_flush_update_done(const bContext *C, Object *ob)
  {
    /* After we are done drawing the stroke, check if we need to do a more
     * expensive depsgraph tag to update geometry. */
    wmWindowManager *wm = CTX_wm_manager(C);
    View3D *current_v3d = CTX_wm_view3d(C);
    SculptSession *ss = ob->sculpt;
    Mesh *mesh = ob->data;
    bool need_tag = (mesh->id.us > 1); /* Always needed for linked duplicates. */
  
    for (wmWindow *win = wm->windows.first; win; win = win->next) {
      bScreen *screen = WM_window_get_active_screen(win);
      for (ScrArea *sa = screen->areabase.first; sa; sa = sa->next) {
        SpaceLink *sl = sa->spacedata.first;
        if (sl->spacetype == SPACE_VIEW3D) {
          View3D *v3d = (View3D *)sl;
          if (v3d != current_v3d) {
            need_tag |= !BKE_sculptsession_use_pbvh_draw(ob, v3d);
          }
        }
      }
    }
  
    BKE_pbvh_update_bounds(ss->pbvh, PBVH_UpdateOriginalBB);
  
    if (BKE_pbvh_type(ss->pbvh) == PBVH_BMESH) {
      BKE_pbvh_bmesh_after_stroke(ss->pbvh);
    }
  
    /* optimization: if there is locked key and active modifiers present in */
    /* the stack, keyblock is updating at each step. otherwise we could update */
    /* keyblock only when stroke is finished */
    if (ss->kb && !ss->modifiers_active) {
      sculpt_update_keyblock(ob);
    }
  
    if (need_tag) {
      DEG_id_tag_update(&ob->id, ID_RECALC_GEOMETRY);
    }
  }
  
  /* Returns whether the mouse/stylus is over the mesh (1)
   * or over the background (0) */
  static bool over_mesh(bContext *C, struct wmOperator *UNUSED(op), float x, float y)
  {
    float mouse[2], co[3];
  
    mouse[0] = x;
    mouse[1] = y;
  
    return sculpt_stroke_get_location(C, co, mouse);
  }
  
  static bool sculpt_stroke_test_start(bContext *C, struct wmOperator *op, const float mouse[2])
  {
    /* Don't start the stroke until mouse goes over the mesh.
     * note: mouse will only be null when re-executing the saved stroke.
     * We have exception for 'exec' strokes since they may not set 'mouse',
     * only 'location', see: T52195. */
    if (((op->flag & OP_IS_INVOKE) == 0) || (mouse == NULL) ||
        over_mesh(C, op, mouse[0], mouse[1])) {
      Object *ob = CTX_data_active_object(C);
      SculptSession *ss = ob->sculpt;
      Sculpt *sd = CTX_data_tool_settings(C)->sculpt;
  
      ED_view3d_init_mats_rv3d(ob, CTX_wm_region_view3d(C));
  
      sculpt_update_cache_invariants(C, sd, ss, op, mouse);
  
      sculpt_undo_push_begin(sculpt_tool_name(sd));
  
      return 1;
    }
    else {
      return 0;
    }
  }
  
  static void sculpt_stroke_update_step(bContext *C,
                                        struct PaintStroke *UNUSED(stroke),
                                        PointerRNA *itemptr)
  {
    UnifiedPaintSettings *ups = &CTX_data_tool_settings(C)->unified_paint_settings;
    Sculpt *sd = CTX_data_tool_settings(C)->sculpt;
    Object *ob = CTX_data_active_object(C);
    SculptSession *ss = ob->sculpt;
    const Brush *brush = BKE_paint_brush(&sd->paint);
  
    sculpt_stroke_modifiers_check(C, ob, brush);
    sculpt_update_cache_variants(C, sd, ob, itemptr);
    sculpt_restore_mesh(sd, ob);
  
    if (sd->flags & (SCULPT_DYNTOPO_DETAIL_CONSTANT | SCULPT_DYNTOPO_DETAIL_MANUAL)) {
      float object_space_constant_detail = 1.0f / (sd->constant_detail * mat4_to_scale(ob->obmat));
      BKE_pbvh_bmesh_detail_size_set(ss->pbvh, object_space_constant_detail);
    }
    else if (sd->flags & SCULPT_DYNTOPO_DETAIL_BRUSH) {
      BKE_pbvh_bmesh_detail_size_set(ss->pbvh, ss->cache->radius * sd->detail_percent / 100.0f);
    }
    else {
      BKE_pbvh_bmesh_detail_size_set(ss->pbvh,
                                     (ss->cache->radius / (float)ups->pixel_radius) *
                                         (float)(sd->detail_size * U.pixelsize) / 0.4f);
    }
  
    if (sculpt_stroke_is_dynamic_topology(ss, brush)) {
      do_symmetrical_brush_actions(sd, ob, sculpt_topology_update, ups);
    }
  
    do_symmetrical_brush_actions(sd, ob, do_brush_action, ups);
  
    sculpt_combine_proxies(sd, ob);
  
    /* hack to fix noise texture tearing mesh */
    sculpt_fix_noise_tear(sd, ob);
  
    /* TODO(sergey): This is not really needed for the solid shading,
     * which does use pBVH drawing anyway, but texture and wireframe
     * requires this.
     *
     * Could be optimized later, but currently don't think it's so
     * much common scenario.
     *
     * Same applies to the DEG_id_tag_update() invoked from
     * sculpt_flush_update_step().
     */
    if (ss->modifiers_active) {
      sculpt_flush_stroke_deform(sd, ob);
    }
    else if (ss->kb) {
      sculpt_update_keyblock(ob);
    }
  
    ss->cache->first_time = false;
  
    /* Cleanup */
    sculpt_flush_update_step(C);
  }
  
  static void sculpt_brush_exit_tex(Sculpt *sd)
  {
    Brush *brush = BKE_paint_brush(&sd->paint);
    MTex *mtex = &brush->mtex;
  
    if (mtex->tex && mtex->tex->nodetree) {
      ntreeTexEndExecTree(mtex->tex->nodetree->execdata);
    }
  }
  
  static void sculpt_stroke_done(const bContext *C, struct PaintStroke *UNUSED(stroke))
  {
    Main *bmain = CTX_data_main(C);
    Object *ob = CTX_data_active_object(C);
    Scene *scene = CTX_data_scene(C);
    SculptSession *ss = ob->sculpt;
    Sculpt *sd = CTX_data_tool_settings(C)->sculpt;
  
    /* Finished */
    if (ss->cache) {
      UnifiedPaintSettings *ups = &CTX_data_tool_settings(C)->unified_paint_settings;
      Brush *brush = BKE_paint_brush(&sd->paint);
      BLI_assert(brush == ss->cache->brush); /* const, so we shouldn't change. */
      ups->draw_inverted = false;
  
      sculpt_stroke_modifiers_check(C, ob, brush);
  
      /* Alt-Smooth */
      if (ss->cache->alt_smooth) {
        if (brush->sculpt_tool == SCULPT_TOOL_MASK) {
          brush->mask_tool = ss->cache->saved_mask_brush_tool;
        }
        else {
          BKE_brush_size_set(scene, brush, ss->cache->saved_smooth_size);
          brush = (Brush *)BKE_libblock_find_name(bmain, ID_BR, ss->cache->saved_active_brush_name);
          if (brush) {
            BKE_paint_brush_set(&sd->paint, brush);
          }
        }
      }
  
      sculpt_cache_free(ss->cache);
      ss->cache = NULL;
  
      sculpt_undo_push_end();
  
      sculpt_flush_update_done(C, ob);
  
      WM_event_add_notifier(C, NC_OBJECT | ND_DRAW, ob);
    }
  
    sculpt_brush_exit_tex(sd);
  }
  
  static int sculpt_brush_stroke_invoke(bContext *C, wmOperator *op, const wmEvent *event)
  {
    struct PaintStroke *stroke;
    int ignore_background_click;
    int retval;
  
    sculpt_brush_stroke_init(C, op);
  
    stroke = paint_stroke_new(C,
                              op,
                              sculpt_stroke_get_location,
                              sculpt_stroke_test_start,
                              sculpt_stroke_update_step,
                              NULL,
                              sculpt_stroke_done,
                              event->type);
  
    op->customdata = stroke;
  
    /* For tablet rotation */
    ignore_background_click = RNA_boolean_get(op->ptr, "ignore_background_click");
  
    if (ignore_background_click && !over_mesh(C, op, event->x, event->y)) {
      paint_stroke_data_free(op);
      return OPERATOR_PASS_THROUGH;
    }
  
    if ((retval = op->type->modal(C, op, event)) == OPERATOR_FINISHED) {
      paint_stroke_data_free(op);
      return OPERATOR_FINISHED;
    }
    /* add modal handler */
    WM_event_add_modal_handler(C, op);
  
    OPERATOR_RETVAL_CHECK(retval);
    BLI_assert(retval == OPERATOR_RUNNING_MODAL);
  
    return OPERATOR_RUNNING_MODAL;
  }
  
  static int sculpt_brush_stroke_exec(bContext *C, wmOperator *op)
  {
    sculpt_brush_stroke_init(C, op);
  
    op->customdata = paint_stroke_new(C,
                                      op,
                                      sculpt_stroke_get_location,
                                      sculpt_stroke_test_start,
                                      sculpt_stroke_update_step,
                                      NULL,
                                      sculpt_stroke_done,
                                      0);
  
    /* frees op->customdata */
    paint_stroke_exec(C, op);
  
    return OPERATOR_FINISHED;
  }
  
  static void sculpt_brush_stroke_cancel(bContext *C, wmOperator *op)
  {
    Object *ob = CTX_data_active_object(C);
    SculptSession *ss = ob->sculpt;
    Sculpt *sd = CTX_data_tool_settings(C)->sculpt;
    const Brush *brush = BKE_paint_brush(&sd->paint);
  
    /* XXX Canceling strokes that way does not work with dynamic topology,
     *     user will have to do real undo for now. See T46456. */
    if (ss->cache && !sculpt_stroke_is_dynamic_topology(ss, brush)) {
      paint_mesh_restore_co(sd, ob);
    }
  
    paint_stroke_cancel(C, op);
  
    if (ss->cache) {
      sculpt_cache_free(ss->cache);
      ss->cache = NULL;
    }
  
    sculpt_brush_exit_tex(sd);
  }
  
  static void SCULPT_OT_brush_stroke(wmOperatorType *ot)
  {
    /* identifiers */
    ot->name = "Sculpt";
    ot->idname = "SCULPT_OT_brush_stroke";
    ot->description = "Sculpt a stroke into the geometry";
  
    /* api callbacks */
    ot->invoke = sculpt_brush_stroke_invoke;
    ot->modal = paint_stroke_modal;
    ot->exec = sculpt_brush_stroke_exec;
    ot->poll = sculpt_poll;
    ot->cancel = sculpt_brush_stroke_cancel;
  
    /* flags (sculpt does own undo? (ton) */
    ot->flag = OPTYPE_BLOCKING;
  
    /* properties */
  
    paint_stroke_operator_properties(ot);
  
    RNA_def_boolean(ot->srna,
                    "ignore_background_click",
                    0,
                    "Ignore Background Click",
                    "Clicks on the background do not start the stroke");
  }
  
  /* Reset the copy of the mesh that is being sculpted on (currently just for the layer brush) */
  
  static int sculpt_set_persistent_base_exec(bContext *C, wmOperator *UNUSED(op))
  {
    SculptSession *ss = CTX_data_active_object(C)->sculpt;
  
    if (ss) {
      if (ss->layer_co) {
        MEM_freeN(ss->layer_co);
      }
      ss->layer_co = NULL;
    }
  
    return OPERATOR_FINISHED;
  }
  
  static void SCULPT_OT_set_persistent_base(wmOperatorType *ot)
  {
    /* identifiers */
    ot->name = "Set Persistent Base";
    ot->idname = "SCULPT_OT_set_persistent_base";
    ot->description = "Reset the copy of the mesh that is being sculpted on";
  
    /* api callbacks */
    ot->exec = sculpt_set_persistent_base_exec;
    ot->poll = sculpt_mode_poll;
  
    ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
  }
  
  /************************** Dynamic Topology **************************/
  
  static void sculpt_dynamic_topology_triangulate(BMesh *bm)
  {
    if (bm->totloop != bm->totface * 3) {
      BM_mesh_triangulate(
          bm, MOD_TRIANGULATE_QUAD_BEAUTY, MOD_TRIANGULATE_NGON_EARCLIP, 4, false, NULL, NULL, NULL);
    }
  }
  
  void sculpt_pbvh_clear(Object *ob)
  {
    SculptSession *ss = ob->sculpt;
  
    /* Clear out any existing DM and PBVH */
    if (ss->pbvh) {
      BKE_pbvh_free(ss->pbvh);
    }
    ss->pbvh = NULL;
    BKE_object_free_derived_caches(ob);
  
    /* Tag to rebuild PBVH in depsgraph. */
    DEG_id_tag_update(&ob->id, ID_RECALC_GEOMETRY);
  }
  
  void sculpt_dyntopo_node_layers_add(SculptSession *ss)
  {
    int cd_node_layer_index;
  
    char layer_id[] = "_dyntopo_node_id";
  
    cd_node_layer_index = CustomData_get_named_layer_index(&ss->bm->vdata, CD_PROP_INT, layer_id);
    if (cd_node_layer_index == -1) {
      BM_data_layer_add_named(ss->bm, &ss->bm->vdata, CD_PROP_INT, layer_id);
      cd_node_layer_index = CustomData_get_named_layer_index(&ss->bm->vdata, CD_PROP_INT, layer_id);
    }
  
    ss->cd_vert_node_offset = CustomData_get_n_offset(
        &ss->bm->vdata,
        CD_PROP_INT,
        cd_node_layer_index - CustomData_get_layer_index(&ss->bm->vdata, CD_PROP_INT));
  
    ss->bm->vdata.layers[cd_node_layer_index].flag |= CD_FLAG_TEMPORARY;
  
    cd_node_layer_index = CustomData_get_named_layer_index(&ss->bm->pdata, CD_PROP_INT, layer_id);
    if (cd_node_layer_index == -1) {
      BM_data_layer_add_named(ss->bm, &ss->bm->pdata, CD_PROP_INT, layer_id);
      cd_node_layer_index = CustomData_get_named_layer_index(&ss->bm->pdata, CD_PROP_INT, layer_id);
    }
  
    ss->cd_face_node_offset = CustomData_get_n_offset(
        &ss->bm->pdata,
        CD_PROP_INT,
        cd_node_layer_index - CustomData_get_layer_index(&ss->bm->pdata, CD_PROP_INT));
  
    ss->bm->pdata.layers[cd_node_layer_index].flag |= CD_FLAG_TEMPORARY;
  }
  
  static void sculpt_dynamic_topology_enable_ex(Main *bmain,
                                                Depsgraph *depsgraph,
                                                Scene *scene,
                                                Object *ob)
  {
    SculptSession *ss = ob->sculpt;
    Mesh *me = ob->data;
    const BMAllocTemplate allocsize = BMALLOC_TEMPLATE_FROM_ME(me);
  
    sculpt_pbvh_clear(ob);
  
    ss->bm_smooth_shading = (scene->toolsettings->sculpt->flags & SCULPT_DYNTOPO_SMOOTH_SHADING) !=
                            0;
  
    /* Dynamic topology doesn't ensure selection state is valid, so remove [#36280] */
    BKE_mesh_mselect_clear(me);
  
    /* Create triangles-only BMesh */
    ss->bm = BM_mesh_create(&allocsize,
                            &((struct BMeshCreateParams){
                                .use_toolflags = false,
                            }));
  
    BM_mesh_bm_from_me(ss->bm,
                       me,
                       (&(struct BMeshFromMeshParams){
                           .calc_face_normal = true,
                           .use_shapekey = true,
                           .active_shapekey = ob->shapenr,
                       }));
    sculpt_dynamic_topology_triangulate(ss->bm);
    BM_data_layer_add(ss->bm, &ss->bm->vdata, CD_PAINT_MASK);
    sculpt_dyntopo_node_layers_add(ss);
    /* make sure the data for existing faces are initialized */
    if (me->totpoly != ss->bm->totface) {
      BM_mesh_normals_update(ss->bm);
    }
  
    /* Enable dynamic topology */
    me->flag |= ME_SCULPT_DYNAMIC_TOPOLOGY;
  
    /* Enable logging for undo/redo */
    ss->bm_log = BM_log_create(ss->bm);
  
    /* Update dependency graph, so modifiers that depend on dyntopo being enabled
     * are re-evaluated and the PBVH is re-created */
    DEG_id_tag_update(&ob->id, ID_RECALC_GEOMETRY);
    BKE_scene_graph_update_tagged(depsgraph, bmain);
  }
  
  /* Free the sculpt BMesh and BMLog
   *
   * If 'unode' is given, the BMesh's data is copied out to the unode
   * before the BMesh is deleted so that it can be restored from */
  static void sculpt_dynamic_topology_disable_ex(
      Main *bmain, Depsgraph *depsgraph, Scene *scene, Object *ob, SculptUndoNode *unode)
  {
    SculptSession *ss = ob->sculpt;
    Mesh *me = ob->data;
  
    sculpt_pbvh_clear(ob);
  
    if (unode) {
      /* Free all existing custom data */
      CustomData_free(&me->vdata, me->totvert);
      CustomData_free(&me->edata, me->totedge);
      CustomData_free(&me->fdata, me->totface);
      CustomData_free(&me->ldata, me->totloop);
      CustomData_free(&me->pdata, me->totpoly);
  
      /* Copy over stored custom data */
      me->totvert = unode->bm_enter_totvert;
      me->totloop = unode->bm_enter_totloop;
      me->totpoly = unode->bm_enter_totpoly;
      me->totedge = unode->bm_enter_totedge;
      me->totface = 0;
      CustomData_copy(&unode->bm_enter_vdata,
                      &me->vdata,
                      CD_MASK_MESH.vmask,
                      CD_DUPLICATE,
                      unode->bm_enter_totvert);
      CustomData_copy(&unode->bm_enter_edata,
                      &me->edata,
                      CD_MASK_MESH.emask,
                      CD_DUPLICATE,
                      unode->bm_enter_totedge);
      CustomData_copy(&unode->bm_enter_ldata,
                      &me->ldata,
                      CD_MASK_MESH.lmask,
                      CD_DUPLICATE,
                      unode->bm_enter_totloop);
      CustomData_copy(&unode->bm_enter_pdata,
                      &me->pdata,
                      CD_MASK_MESH.pmask,
                      CD_DUPLICATE,
                      unode->bm_enter_totpoly);
  
      BKE_mesh_update_customdata_pointers(me, false);
    }
    else {
      BKE_sculptsession_bm_to_me(ob, true);
    }
  
    /* Clear data */
    me->flag &= ~ME_SCULPT_DYNAMIC_TOPOLOGY;
  
    /* typically valid but with global-undo they can be NULL, [#36234] */
    if (ss->bm) {
      BM_mesh_free(ss->bm);
      ss->bm = NULL;
    }
    if (ss->bm_log) {
      BM_log_free(ss->bm_log);
      ss->bm_log = NULL;
    }
  
    BKE_particlesystem_reset_all(ob);
    BKE_ptcache_object_reset(scene, ob, PTCACHE_RESET_OUTDATED);
  
    /* Update dependency graph, so modifiers that depend on dyntopo being enabled
     * are re-evaluated and the PBVH is re-created */
    DEG_id_tag_update(&ob->id, ID_RECALC_GEOMETRY);
    BKE_scene_graph_update_tagged(depsgraph, bmain);
  }
  
  void sculpt_dynamic_topology_disable(bContext *C, SculptUndoNode *unode)
  {
    Main *bmain = CTX_data_main(C);
    Depsgraph *depsgraph = CTX_data_ensure_evaluated_depsgraph(C);
    Scene *scene = CTX_data_scene(C);
    Object *ob = CTX_data_active_object(C);
    sculpt_dynamic_topology_disable_ex(bmain, depsgraph, scene, ob, unode);
  }
  
  static void sculpt_dynamic_topology_disable_with_undo(Main *bmain,
                                                        Depsgraph *depsgraph,
                                                        Scene *scene,
                                                        Object *ob)
  {
    SculptSession *ss = ob->sculpt;
    if (ss->bm) {
      sculpt_undo_push_begin("Dynamic topology disable");
      sculpt_undo_push_node(ob, NULL, SCULPT_UNDO_DYNTOPO_END);
      sculpt_dynamic_topology_disable_ex(bmain, depsgraph, scene, ob, NULL);
      sculpt_undo_push_end();
    }
  }
  
  static void sculpt_dynamic_topology_enable_with_undo(Main *bmain,
                                                       Depsgraph *depsgraph,
                                                       Scene *scene,
                                                       Object *ob)
  {
    SculptSession *ss = ob->sculpt;
    if (ss->bm == NULL) {
      sculpt_undo_push_begin("Dynamic topology enable");
      sculpt_dynamic_topology_enable_ex(bmain, depsgraph, scene, ob);
      sculpt_undo_push_node(ob, NULL, SCULPT_UNDO_DYNTOPO_BEGIN);
      sculpt_undo_push_end();
    }
  }
  
  static int sculpt_dynamic_topology_toggle_exec(bContext *C, wmOperator *UNUSED(op))
  {
    Main *bmain = CTX_data_main(C);
    Depsgraph *depsgraph = CTX_data_ensure_evaluated_depsgraph(C);
    Scene *scene = CTX_data_scene(C);
    Object *ob = CTX_data_active_object(C);
    SculptSession *ss = ob->sculpt;
  
    WM_cursor_wait(1);
  
    if (ss->bm) {
      sculpt_dynamic_topology_disable_with_undo(bmain, depsgraph, scene, ob);
    }
    else {
      sculpt_dynamic_topology_enable_with_undo(bmain, depsgraph, scene, ob);
    }
  
    WM_cursor_wait(0);
    WM_main_add_notifier(NC_SCENE | ND_TOOLSETTINGS, NULL);
  
    return OPERATOR_FINISHED;
  }
  
  enum eDynTopoWarnFlag {
    DYNTOPO_WARN_VDATA = (1 << 0),
    DYNTOPO_WARN_EDATA = (1 << 1),
    DYNTOPO_WARN_LDATA = (1 << 2),
    DYNTOPO_WARN_MODIFIER = (1 << 3),
  };
  
  static int dyntopo_warning_popup(bContext *C, wmOperatorType *ot, enum eDynTopoWarnFlag flag)
  {
    uiPopupMenu *pup = UI_popup_menu_begin(C, IFACE_("Warning!"), ICON_ERROR);
    uiLayout *layout = UI_popup_menu_layout(pup);
  
    if (flag & (DYNTOPO_WARN_VDATA | DYNTOPO_WARN_EDATA | DYNTOPO_WARN_LDATA)) {
      const char *msg_error = TIP_("Vertex Data Detected!");
      const char *msg = TIP_("Dyntopo will not preserve vertex colors, UVs, or other customdata");
      uiItemL(layout, msg_error, ICON_INFO);
      uiItemL(layout, msg, ICON_NONE);
      uiItemS(layout);
    }
  
    if (flag & DYNTOPO_WARN_MODIFIER) {
      const char *msg_error = TIP_("Generative Modifiers Detected!");
      const char *msg = TIP_(
          "Keeping the modifiers will increase polycount when returning to object mode");
  
      uiItemL(layout, msg_error, ICON_INFO);
      uiItemL(layout, msg, ICON_NONE);
      uiItemS(layout);
    }
  
    uiItemFullO_ptr(layout, ot, IFACE_("OK"), ICON_NONE, NULL, WM_OP_EXEC_DEFAULT, 0, NULL);
  
    UI_popup_menu_end(C, pup);
  
    return OPERATOR_INTERFACE;
  }
  
  static enum eDynTopoWarnFlag sculpt_dynamic_topology_check(Scene *scene, Object *ob)
  {
    Mesh *me = ob->data;
    SculptSession *ss = ob->sculpt;
  
    enum eDynTopoWarnFlag flag = 0;
  
    BLI_assert(ss->bm == NULL);
    UNUSED_VARS_NDEBUG(ss);
  
    for (int i = 0; i < CD_NUMTYPES; i++) {
      if (!ELEM(i, CD_MVERT, CD_MEDGE, CD_MFACE, CD_MLOOP, CD_MPOLY, CD_PAINT_MASK, CD_ORIGINDEX)) {
        if (CustomData_has_layer(&me->vdata, i)) {
          flag |= DYNTOPO_WARN_VDATA;
        }
        if (CustomData_has_layer(&me->edata, i)) {
          flag |= DYNTOPO_WARN_EDATA;
        }
        if (CustomData_has_layer(&me->ldata, i)) {
          flag |= DYNTOPO_WARN_LDATA;
        }
      }
    }
  
    {
      VirtualModifierData virtualModifierData;
      ModifierData *md = modifiers_getVirtualModifierList(ob, &virtualModifierData);
  
      /* exception for shape keys because we can edit those */
      for (; md; md = md->next) {
        const ModifierTypeInfo *mti = modifierType_getInfo(md->type);
        if (!modifier_isEnabled(scene, md, eModifierMode_Realtime)) {
          continue;
        }
  
        if (mti->type == eModifierTypeType_Constructive) {
          flag |= DYNTOPO_WARN_MODIFIER;
          break;
        }
      }
    }
  
    return flag;
  }
  
  static int sculpt_dynamic_topology_toggle_invoke(bContext *C,
                                                   wmOperator *op,
                                                   const wmEvent *UNUSED(event))
  {
    Object *ob = CTX_data_active_object(C);
    SculptSession *ss = ob->sculpt;
  
    if (!ss->bm) {
      Scene *scene = CTX_data_scene(C);
      enum eDynTopoWarnFlag flag = sculpt_dynamic_topology_check(scene, ob);
  
      if (flag) {
        /* The mesh has customdata that will be lost, let the user confirm this is OK */
        return dyntopo_warning_popup(C, op->type, flag);
      }
    }
  
    return sculpt_dynamic_topology_toggle_exec(C, op);
  }
  
  static void SCULPT_OT_dynamic_topology_toggle(wmOperatorType *ot)
  {
    /* identifiers */
    ot->name = "Dynamic Topology Toggle";
    ot->idname = "SCULPT_OT_dynamic_topology_toggle";
    ot->description = "Dynamic topology alters the mesh topology while sculpting";
  
    /* api callbacks */
    ot->invoke = sculpt_dynamic_topology_toggle_invoke;
    ot->exec = sculpt_dynamic_topology_toggle_exec;
    ot->poll = sculpt_mode_poll;
  
    ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
  }
  
  /************************* SCULPT_OT_optimize *************************/
  
  static int sculpt_optimize_exec(bContext *C, wmOperator *UNUSED(op))
  {
    Object *ob = CTX_data_active_object(C);
  
    sculpt_pbvh_clear(ob);
    WM_event_add_notifier(C, NC_OBJECT | ND_DRAW, ob);
  
    return OPERATOR_FINISHED;
  }
  
  static bool sculpt_and_dynamic_topology_poll(bContext *C)
  {
    Object *ob = CTX_data_active_object(C);
  
    return sculpt_mode_poll(C) && ob->sculpt->bm;
  }
  
  /* The BVH gets less optimal more quickly with dynamic topology than
   * regular sculpting. There is no doubt more clever stuff we can do to
   * optimize it on the fly, but for now this gives the user a nicer way
   * to recalculate it than toggling modes. */
  static void SCULPT_OT_optimize(wmOperatorType *ot)
  {
    /* identifiers */
    ot->name = "Optimize";
    ot->idname = "SCULPT_OT_optimize";
    ot->description = "Recalculate the sculpt BVH to improve performance";
  
    /* api callbacks */
    ot->exec = sculpt_optimize_exec;
    ot->poll = sculpt_and_dynamic_topology_poll;
  
    ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
  }
  
  /********************* Dynamic topology symmetrize ********************/
  
  static int sculpt_symmetrize_exec(bContext *C, wmOperator *UNUSED(op))
  {
    Object *ob = CTX_data_active_object(C);
    const Sculpt *sd = CTX_data_tool_settings(C)->sculpt;
    SculptSession *ss = ob->sculpt;
  
    /* To simplify undo for symmetrize, all BMesh elements are logged
     * as deleted, then after symmetrize operation all BMesh elements
     * are logged as added (as opposed to attempting to store just the
     * parts that symmetrize modifies) */
    sculpt_undo_push_begin("Dynamic topology symmetrize");
    sculpt_undo_push_node(ob, NULL, SCULPT_UNDO_DYNTOPO_SYMMETRIZE);
    BM_log_before_all_removed(ss->bm, ss->bm_log);
  
    BM_mesh_toolflags_set(ss->bm, true);
  
    /* Symmetrize and re-triangulate */
    BMO_op_callf(ss->bm,
                 (BMO_FLAG_DEFAULTS & ~BMO_FLAG_RESPECT_HIDE),
                 "symmetrize input=%avef direction=%i  dist=%f",
                 sd->symmetrize_direction,
                 0.00001f);
    sculpt_dynamic_topology_triangulate(ss->bm);
  
    /* bisect operator flags edges (keep tags clean for edge queue) */
    BM_mesh_elem_hflag_disable_all(ss->bm, BM_EDGE, BM_ELEM_TAG, false);
  
    BM_mesh_toolflags_set(ss->bm, false);
  
    /* Finish undo */
    BM_log_all_added(ss->bm, ss->bm_log);
    sculpt_undo_push_end();
  
    /* Redraw */
    sculpt_pbvh_clear(ob);
    WM_event_add_notifier(C, NC_OBJECT | ND_DRAW, ob);
  
    return OPERATOR_FINISHED;
  }
  
  static void SCULPT_OT_symmetrize(wmOperatorType *ot)
  {
    /* identifiers */
    ot->name = "Symmetrize";
    ot->idname = "SCULPT_OT_symmetrize";
    ot->description = "Symmetrize the topology modifications";
  
    /* api callbacks */
    ot->exec = sculpt_symmetrize_exec;
    ot->poll = sculpt_and_dynamic_topology_poll;
  }
  
  /**** Toggle operator for turning sculpt mode on or off ****/
  
  static void sculpt_init_session(Depsgraph *depsgraph, Scene *scene, Object *ob)
  {
    /* Create persistent sculpt mode data */
    BKE_sculpt_toolsettings_data_ensure(scene);
  
    ob->sculpt = MEM_callocN(sizeof(SculptSession), "sculpt session");
    ob->sculpt->mode_type = OB_MODE_SCULPT;
    BKE_sculpt_update_object_for_edit(depsgraph, ob, false, false);
  }
  
  static int ed_object_sculptmode_flush_recalc_flag(Scene *scene,
                                                    Object *ob,
                                                    MultiresModifierData *mmd)
  {
    int flush_recalc = 0;
    /* multires in sculpt mode could have different from object mode subdivision level */
    flush_recalc |= mmd && mmd->sculptlvl != mmd->lvl;
    /* if object has got active modifiers, it's dm could be different in sculpt mode  */
    flush_recalc |= sculpt_has_active_modifiers(scene, ob);
    return flush_recalc;
  }
  
  void ED_object_sculptmode_enter_ex(Main *bmain,
                                     Depsgraph *depsgraph,
                                     Scene *scene,
                                     Object *ob,
                                     const bool force_dyntopo,
                                     ReportList *reports)
  {
    const int mode_flag = OB_MODE_SCULPT;
    Mesh *me = BKE_mesh_from_object(ob);
  
    /* Enter sculptmode */
    ob->mode |= mode_flag;
  
    MultiresModifierData *mmd = BKE_sculpt_multires_active(scene, ob);
  
    const int flush_recalc = ed_object_sculptmode_flush_recalc_flag(scene, ob, mmd);
  
    if (flush_recalc) {
      DEG_id_tag_update(&ob->id, ID_RECALC_GEOMETRY);
    }
  
    /* Create sculpt mode session data */
    if (ob->sculpt) {
      BKE_sculptsession_free(ob);
    }
  
    /* Make sure derived final from original object does not reference possibly
     * freed memory.
     */
    BKE_object_free_derived_caches(ob);
  
    sculpt_init_session(depsgraph, scene, ob);
  
    /* Mask layer is required */
    if (mmd) {
      /* XXX, we could attempt to support adding mask data mid-sculpt mode (with multi-res)
       * but this ends up being quite tricky (and slow) */
      BKE_sculpt_mask_layers_ensure(ob, mmd);
    }
  
    if (!(fabsf(ob->scale[0] - ob->scale[1]) < 1e-4f &&
          fabsf(ob->scale[1] - ob->scale[2]) < 1e-4f)) {
      BKE_report(
          reports, RPT_WARNING, "Object has non-uniform scale, sculpting may be unpredictable");
    }
    else if (is_negative_m4(ob->obmat)) {
      BKE_report(reports, RPT_WARNING, "Object has negative scale, sculpting may be unpredictable");
    }
  
    Paint *paint = BKE_paint_get_active_from_paintmode(scene, PAINT_MODE_SCULPT);
    BKE_paint_init(bmain, scene, PAINT_MODE_SCULPT, PAINT_CURSOR_SCULPT);
  
    paint_cursor_start_explicit(paint, bmain->wm.first, sculpt_poll_view3d);
  
    /* Check dynamic-topology flag; re-enter dynamic-topology mode when changing modes,
     * As long as no data was added that is not supported. */
    if (me->flag & ME_SCULPT_DYNAMIC_TOPOLOGY) {
      const char *message_unsupported = NULL;
      if (me->totloop != me->totpoly * 3) {
        message_unsupported = TIP_("non-triangle face");
      }
      else if (mmd != NULL) {
        message_unsupported = TIP_("multi-res modifier");
      }
      else {
        enum eDynTopoWarnFlag flag = sculpt_dynamic_topology_check(scene, ob);
        if (flag == 0) {
          /* pass */
        }
        else if (flag & DYNTOPO_WARN_VDATA) {
          message_unsupported = TIP_("vertex data");
        }
        else if (flag & DYNTOPO_WARN_EDATA) {
          message_unsupported = TIP_("edge data");
        }
        else if (flag & DYNTOPO_WARN_LDATA) {
          message_unsupported = TIP_("face data");
        }
        else if (flag & DYNTOPO_WARN_MODIFIER) {
          message_unsupported = TIP_("constructive modifier");
        }
        else {
          BLI_assert(0);
        }
      }
  
      if ((message_unsupported == NULL) || force_dyntopo) {
        /* Needed because we may be entering this mode before the undo system loads. */
        wmWindowManager *wm = bmain->wm.first;
        bool has_undo = wm->undo_stack != NULL;
        /* undo push is needed to prevent memory leak */
        if (has_undo) {
          sculpt_undo_push_begin("Dynamic topology enable");
        }
        sculpt_dynamic_topology_enable_ex(bmain, depsgraph, scene, ob);
        if (has_undo) {
          sculpt_undo_push_node(ob, NULL, SCULPT_UNDO_DYNTOPO_BEGIN);
          sculpt_undo_push_end();
        }
      }
      else {
        BKE_reportf(
            reports, RPT_WARNING, "Dynamic Topology found: %s, disabled", message_unsupported);
        me->flag &= ~ME_SCULPT_DYNAMIC_TOPOLOGY;
      }
    }
  
    /* Flush object mode. */
    DEG_id_tag_update(&ob->id, ID_RECALC_COPY_ON_WRITE);
  }
  
  void ED_object_sculptmode_enter(struct bContext *C, Depsgraph *depsgraph, ReportList *reports)
  {
    Main *bmain = CTX_data_main(C);
    Scene *scene = CTX_data_scene(C);
    ViewLayer *view_layer = CTX_data_view_layer(C);
    Object *ob = OBACT(view_layer);
    ED_object_sculptmode_enter_ex(bmain, depsgraph, scene, ob, false, reports);
  }
  
  void ED_object_sculptmode_exit_ex(Main *bmain, Depsgraph *depsgraph, Scene *scene, Object *ob)
  {
    const int mode_flag = OB_MODE_SCULPT;
    Mesh *me = BKE_mesh_from_object(ob);
  
    MultiresModifierData *mmd = BKE_sculpt_multires_active(scene, ob);
    if (mmd) {
      multires_force_update(ob);
    }
  
    /* Not needed for now. */
  #if 0
    const int flush_recalc = ed_object_sculptmode_flush_recalc_flag(scene, ob, mmd);
  #endif
  
    /* Always for now, so leaving sculpt mode always ensures scene is in
     * a consistent state.
     */
    if (true || /* flush_recalc || */ (ob->sculpt && ob->sculpt->bm)) {
      DEG_id_tag_update(&ob->id, ID_RECALC_GEOMETRY);
    }
  
    if (me->flag & ME_SCULPT_DYNAMIC_TOPOLOGY) {
      /* Dynamic topology must be disabled before exiting sculpt
       * mode to ensure the undo stack stays in a consistent
       * state */
      sculpt_dynamic_topology_disable_with_undo(bmain, depsgraph, scene, ob);
  
      /* store so we know to re-enable when entering sculpt mode */
      me->flag |= ME_SCULPT_DYNAMIC_TOPOLOGY;
    }
  
    /* Leave sculptmode */
    ob->mode &= ~mode_flag;
  
    BKE_sculptsession_free(ob);
  
    paint_cursor_delete_textures();
  
    /* Never leave derived meshes behind. */
    BKE_object_free_derived_caches(ob);
  
    /* Flush object mode. */
    DEG_id_tag_update(&ob->id, ID_RECALC_COPY_ON_WRITE);
  }
  
  void ED_object_sculptmode_exit(bContext *C, Depsgraph *depsgraph)
  {
    Main *bmain = CTX_data_main(C);
    Scene *scene = CTX_data_scene(C);
    ViewLayer *view_layer = CTX_data_view_layer(C);
    Object *ob = OBACT(view_layer);
    ED_object_sculptmode_exit_ex(bmain, depsgraph, scene, ob);
  }
  
  static int sculpt_mode_toggle_exec(bContext *C, wmOperator *op)
  {
    struct wmMsgBus *mbus = CTX_wm_message_bus(C);
    Main *bmain = CTX_data_main(C);
    Depsgraph *depsgraph = CTX_data_depsgraph_on_load(C);
    Scene *scene = CTX_data_scene(C);
    ToolSettings *ts = scene->toolsettings;
    ViewLayer *view_layer = CTX_data_view_layer(C);
    Object *ob = OBACT(view_layer);
    const int mode_flag = OB_MODE_SCULPT;
    const bool is_mode_set = (ob->mode & mode_flag) != 0;
  
    if (!is_mode_set) {
      if (!ED_object_mode_compat_set(C, ob, mode_flag, op->reports)) {
        return OPERATOR_CANCELLED;
      }
    }
  
    if (is_mode_set) {
      ED_object_sculptmode_exit_ex(bmain, depsgraph, scene, ob);
    }
    else {
      ED_object_sculptmode_enter_ex(bmain, depsgraph, scene, ob, false, op->reports);
      BKE_paint_toolslots_brush_validate(bmain, &ts->sculpt->paint);
    }
  
    WM_event_add_notifier(C, NC_SCENE | ND_MODE, scene);
  
    WM_msg_publish_rna_prop(mbus, &ob->id, ob, Object, mode);
  
    WM_toolsystem_update_from_context_view3d(C);
  
    return OPERATOR_FINISHED;
  }
  
  static void SCULPT_OT_sculptmode_toggle(wmOperatorType *ot)
  {
    /* identifiers */
    ot->name = "Sculpt Mode";
    ot->idname = "SCULPT_OT_sculptmode_toggle";
    ot->description = "Toggle sculpt mode in 3D view";
  
    /* api callbacks */
    ot->exec = sculpt_mode_toggle_exec;
    ot->poll = ED_operator_object_active_editable_mesh;
  
    ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
  }
  
  static bool sculpt_and_constant_or_manual_detail_poll(bContext *C)
  {
    Object *ob = CTX_data_active_object(C);
    Sculpt *sd = CTX_data_tool_settings(C)->sculpt;
  
    return sculpt_mode_poll(C) && ob->sculpt->bm &&
           (sd->flags & (SCULPT_DYNTOPO_DETAIL_CONSTANT | SCULPT_DYNTOPO_DETAIL_MANUAL));
  }
  
  static int sculpt_detail_flood_fill_exec(bContext *C, wmOperator *UNUSED(op))
  {
    Sculpt *sd = CTX_data_tool_settings(C)->sculpt;
    Object *ob = CTX_data_active_object(C);
    SculptSession *ss = ob->sculpt;
    float size;
    float bb_min[3], bb_max[3], center[3], dim[3];
    int i, totnodes;
    PBVHNode **nodes;
  
    BKE_pbvh_search_gather(ss->pbvh, NULL, NULL, &nodes, &totnodes);
  
    if (!totnodes) {
      return OPERATOR_CANCELLED;
    }
  
    for (i = 0; i < totnodes; i++) {
      BKE_pbvh_node_mark_topology_update(nodes[i]);
    }
    /* get the bounding box, it's center and size */
    BKE_pbvh_bounding_box(ob->sculpt->pbvh, bb_min, bb_max);
    add_v3_v3v3(center, bb_min, bb_max);
    mul_v3_fl(center, 0.5f);
    sub_v3_v3v3(dim, bb_max, bb_min);
    size = max_fff(dim[0], dim[1], dim[2]);
  
    /* update topology size */
    float object_space_constant_detail = 1.0f / (sd->constant_detail * mat4_to_scale(ob->obmat));
    BKE_pbvh_bmesh_detail_size_set(ss->pbvh, object_space_constant_detail);
  
    sculpt_undo_push_begin("Dynamic topology flood fill");
    sculpt_undo_push_node(ob, NULL, SCULPT_UNDO_COORDS);
  
    while (BKE_pbvh_bmesh_update_topology(
        ss->pbvh, PBVH_Collapse | PBVH_Subdivide, center, NULL, size, false, false)) {
      for (i = 0; i < totnodes; i++) {
        BKE_pbvh_node_mark_topology_update(nodes[i]);
      }
    }
  
    MEM_freeN(nodes);
    sculpt_undo_push_end();
  
    /* force rebuild of pbvh for better BB placement */
    sculpt_pbvh_clear(ob);
    /* Redraw */
    WM_event_add_notifier(C, NC_OBJECT | ND_DRAW, ob);
  
    return OPERATOR_FINISHED;
  }
  
  static void SCULPT_OT_detail_flood_fill(wmOperatorType *ot)
  {
    /* identifiers */
    ot->name = "Detail Flood Fill";
    ot->idname = "SCULPT_OT_detail_flood_fill";
    ot->description = "Flood fill the mesh with the selected detail setting";
  
    /* api callbacks */
    ot->exec = sculpt_detail_flood_fill_exec;
    ot->poll = sculpt_and_constant_or_manual_detail_poll;
  
    ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
  }
  
  static void sample_detail(bContext *C, int mx, int my)
  {
    /* Find 3D view to pick from. */
    bScreen *screen = CTX_wm_screen(C);
    ScrArea *sa = BKE_screen_find_area_xy(screen, SPACE_VIEW3D, mx, my);
    ARegion *ar = (sa) ? BKE_area_find_region_xy(sa, RGN_TYPE_WINDOW, mx, my) : NULL;
    if (ar == NULL) {
      return;
    }
  
    /* Set context to 3D view. */
    ScrArea *prev_sa = CTX_wm_area(C);
    ARegion *prev_ar = CTX_wm_region(C);
    CTX_wm_area_set(C, sa);
    CTX_wm_region_set(C, ar);
  
    ViewContext vc;
    ED_view3d_viewcontext_init(C, &vc);
  
    /* Pick sample detail. */
    Sculpt *sd = CTX_data_tool_settings(C)->sculpt;
    Object *ob = vc.obact;
    Brush *brush = BKE_paint_brush(&sd->paint);
  
    sculpt_stroke_modifiers_check(C, ob, brush);
  
    float mouse[2] = {mx - ar->winrct.xmin, my - ar->winrct.ymin};
    float ray_start[3], ray_end[3], ray_normal[3];
    float depth = sculpt_raycast_init(&vc, mouse, ray_start, ray_end, ray_normal, false);
  
    SculptDetailRaycastData srd;
    srd.hit = 0;
    srd.ray_start = ray_start;
    srd.depth = depth;
    srd.edge_length = 0.0f;
    isect_ray_tri_watertight_v3_precalc(&srd.isect_precalc, ray_normal);
  
    BKE_pbvh_raycast(ob->sculpt->pbvh, sculpt_raycast_detail_cb, &srd, ray_start, ray_normal, false);
  
    if (srd.hit && srd.edge_length > 0.0f) {
      /* Convert edge length to world space detail resolution. */
      sd->constant_detail = 1 / (srd.edge_length * mat4_to_scale(ob->obmat));
    }
  
    /* Restore context. */
    CTX_wm_area_set(C, prev_sa);
    CTX_wm_region_set(C, prev_ar);
  }
  
  static int sculpt_sample_detail_size_exec(bContext *C, wmOperator *op)
  {
    int ss_co[2];
    RNA_int_get_array(op->ptr, "location", ss_co);
    sample_detail(C, ss_co[0], ss_co[1]);
    return OPERATOR_FINISHED;
  }
  
  static int sculpt_sample_detail_size_invoke(bContext *C, wmOperator *op, const wmEvent *UNUSED(e))
  {
    ED_workspace_status_text(C, TIP_("Click on the mesh to set the detail"));
    WM_cursor_modal_set(CTX_wm_window(C), BC_EYEDROPPER_CURSOR);
    WM_event_add_modal_handler(C, op);
    return OPERATOR_RUNNING_MODAL;
  }
  
  static int sculpt_sample_detail_size_modal(bContext *C, wmOperator *op, const wmEvent *event)
  {
    switch (event->type) {
      case LEFTMOUSE:
        if (event->val == KM_PRESS) {
          int ss_co[2] = {event->x, event->y};
  
          sample_detail(C, ss_co[0], ss_co[1]);
  
          RNA_int_set_array(op->ptr, "location", ss_co);
          WM_cursor_modal_restore(CTX_wm_window(C));
          ED_workspace_status_text(C, NULL);
          WM_main_add_notifier(NC_SCENE | ND_TOOLSETTINGS, NULL);
  
          return OPERATOR_FINISHED;
        }
        break;
  
      case RIGHTMOUSE: {
        WM_cursor_modal_restore(CTX_wm_window(C));
        ED_workspace_status_text(C, NULL);
  
        return OPERATOR_CANCELLED;
      }
    }
  
    return OPERATOR_RUNNING_MODAL;
  }
  
  static void SCULPT_OT_sample_detail_size(wmOperatorType *ot)
  {
    /* identifiers */
    ot->name = "Sample Detail Size";
    ot->idname = "SCULPT_OT_sample_detail_size";
    ot->description = "Sample the mesh detail on clicked point";
  
    /* api callbacks */
    ot->invoke = sculpt_sample_detail_size_invoke;
    ot->exec = sculpt_sample_detail_size_exec;
    ot->modal = sculpt_sample_detail_size_modal;
    ot->poll = sculpt_and_constant_or_manual_detail_poll;
  
    ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
  
    RNA_def_int_array(ot->srna,
                      "location",
                      2,
                      NULL,
                      0,
                      SHRT_MAX,
                      "Location",
                      "Screen Coordinates of sampling",
                      0,
                      SHRT_MAX);
  }
  
  /* Dynamic-topology detail size
   *
   * This should be improved further, perhaps by showing a triangle
   * grid rather than brush alpha */
  static void set_brush_rc_props(PointerRNA *ptr, const char *prop)
  {
    char *path = BLI_sprintfN("tool_settings.sculpt.brush.%s", prop);
    RNA_string_set(ptr, "data_path_primary", path);
    MEM_freeN(path);
  }
  
  static int sculpt_set_detail_size_exec(bContext *C, wmOperator *UNUSED(op))
  {
    Sculpt *sd = CTX_data_tool_settings(C)->sculpt;
  
    PointerRNA props_ptr;
    wmOperatorType *ot = WM_operatortype_find("WM_OT_radial_control", true);
  
    WM_operator_properties_create_ptr(&props_ptr, ot);
  
    if (sd->flags & (SCULPT_DYNTOPO_DETAIL_CONSTANT | SCULPT_DYNTOPO_DETAIL_MANUAL)) {
      set_brush_rc_props(&props_ptr, "constant_detail_resolution");
      RNA_string_set(
          &props_ptr, "data_path_primary", "tool_settings.sculpt.constant_detail_resolution");
    }
    else if (sd->flags & SCULPT_DYNTOPO_DETAIL_BRUSH) {
      set_brush_rc_props(&props_ptr, "constant_detail_resolution");
      RNA_string_set(&props_ptr, "data_path_primary", "tool_settings.sculpt.detail_percent");
    }
    else {
      set_brush_rc_props(&props_ptr, "detail_size");
      RNA_string_set(&props_ptr, "data_path_primary", "tool_settings.sculpt.detail_size");
    }
  
    WM_operator_name_call_ptr(C, ot, WM_OP_INVOKE_DEFAULT, &props_ptr);
  
    WM_operator_properties_free(&props_ptr);
  
    return OPERATOR_FINISHED;
  }
  
  static void SCULPT_OT_set_detail_size(wmOperatorType *ot)
  {
    /* identifiers */
    ot->name = "Set Detail Size";
    ot->idname = "SCULPT_OT_set_detail_size";
    ot->description =
        "Set the mesh detail (either relative or constant one, depending on current dyntopo mode)";
  
    /* api callbacks */
    ot->exec = sculpt_set_detail_size_exec;
    ot->poll = sculpt_and_dynamic_topology_poll;
  
    ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
  }
  
  void ED_operatortypes_sculpt(void)
  {
    WM_operatortype_append(SCULPT_OT_brush_stroke);
    WM_operatortype_append(SCULPT_OT_sculptmode_toggle);
    WM_operatortype_append(SCULPT_OT_set_persistent_base);
    WM_operatortype_append(SCULPT_OT_dynamic_topology_toggle);
    WM_operatortype_append(SCULPT_OT_optimize);
    WM_operatortype_append(SCULPT_OT_symmetrize);
    WM_operatortype_append(SCULPT_OT_detail_flood_fill);
    WM_operatortype_append(SCULPT_OT_sample_detail_size);
    WM_operatortype_append(SCULPT_OT_set_detail_size);
  }
  