Cleanup: Move pose brush to its own file

Reviewed By: brecht

Differential Revision: https://developer.blender.org/D6973

1 files changed, 688 insertions, 0 deletions

diff --git a/source/blender/editors/sculpt_paint/sculpt_pose.c b/source/blender/editors/sculpt_paint/sculpt_pose.c
new file mode 100644
index 00000000000..c596a8d0135
--- /dev/null
+++ b/source/blender/editors/sculpt_paint/sculpt_pose.c
@@ -0,0 +1,688 @@
+/*
+ * 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) 2020 Blender Foundation.
+ * All rights reserved.
+ */
+
+/** \file
+ * \ingroup edsculpt
+ */
+
+#include "MEM_guardedalloc.h"
+
+#include "BLI_math.h"
+#include "BLI_blenlib.h"
+#include "BLI_task.h"
+
+#include "DNA_mesh_types.h"
+#include "DNA_meshdata_types.h"
+#include "DNA_object_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_mesh.h"
+#include "BKE_multires.h"
+#include "BKE_node.h"
+#include "BKE_object.h"
+#include "BKE_paint.h"
+#include "BKE_pbvh.h"
+#include "BKE_scene.h"
+
+#include "paint_intern.h"
+#include "sculpt_intern.h"
+
+#include "bmesh.h"
+
+#include <math.h>
+#include <stdlib.h>
+
+static void pose_solve_ik_chain(SculptPoseIKChain *ik_chain,
+                                const float initial_target[3],
+                                const bool use_anchor)
+{
+  SculptPoseIKChainSegment *segments = ik_chain->segments;
+  int tot_segments = ik_chain->tot_segments;
+
+  float target[3];
+
+  /* Set the initial target. */
+  copy_v3_v3(target, initial_target);
+
+  /* Solve the positions and rotations of all segments in the chain. */
+  for (int i = 0; i < tot_segments; i++) {
+    float initial_orientation[3];
+    float current_orientation[3];
+    float current_head_position[3];
+    float current_origin_position[3];
+
+    /* Calculate the rotation to orientate the segment to the target from its initial state. */
+    sub_v3_v3v3(current_orientation, target, segments[i].orig);
+    normalize_v3(current_orientation);
+    sub_v3_v3v3(initial_orientation, segments[i].initial_head, segments[i].initial_orig);
+    normalize_v3(initial_orientation);
+    rotation_between_vecs_to_quat(segments[i].rot, initial_orientation, current_orientation);
+
+    /* Rotate the segment by calculating a new head position. */
+    madd_v3_v3v3fl(current_head_position, segments[i].orig, current_orientation, segments[i].len);
+
+    /* Move the origin of the segment towards the target. */
+    sub_v3_v3v3(current_origin_position, target, current_head_position);
+
+    /* Store the new head and origin positions to the segment. */
+    copy_v3_v3(segments[i].head, current_head_position);
+    add_v3_v3(segments[i].orig, current_origin_position);
+
+    /* Use the origin of this segment as target for the next segment in the chain. */
+    copy_v3_v3(target, segments[i].orig);
+  }
+
+  /* Move back the whole chain to preserve the anchor point. */
+  if (use_anchor) {
+    float anchor_diff[3];
+    sub_v3_v3v3(
+        anchor_diff, segments[tot_segments - 1].initial_orig, segments[tot_segments - 1].orig);
+
+    for (int i = 0; i < tot_segments; i++) {
+      add_v3_v3(segments[i].orig, anchor_diff);
+      add_v3_v3(segments[i].head, anchor_diff);
+    }
+  }
+}
+
+static void pose_solve_roll_chain(SculptPoseIKChain *ik_chain,
+                                  const Brush *brush,
+                                  const float roll)
+{
+  SculptPoseIKChainSegment *segments = ik_chain->segments;
+  int tot_segments = ik_chain->tot_segments;
+
+  for (int i = 0; i < tot_segments; i++) {
+    float initial_orientation[3];
+    float initial_rotation[4];
+    float current_rotation[4];
+
+    sub_v3_v3v3(initial_orientation, segments[i].initial_head, segments[i].initial_orig);
+    normalize_v3(initial_orientation);
+
+    /* Calculate the current roll angle using the brush curve. */
+    float current_roll = roll * BKE_brush_curve_strength(brush, i, tot_segments);
+
+    axis_angle_normalized_to_quat(initial_rotation, initial_orientation, 0.0f);
+    axis_angle_normalized_to_quat(current_rotation, initial_orientation, current_roll);
+
+    /* Store the difference of the rotations in the segment rotation. */
+    rotation_between_quats_to_quat(segments[i].rot, current_rotation, initial_rotation);
+  }
+}
+
+static void do_pose_brush_task_cb_ex(void *__restrict userdata,
+                                     const int n,
+                                     const TaskParallelTLS *__restrict UNUSED(tls))
+{
+  SculptThreadedTaskData *data = userdata;
+  SculptSession *ss = data->ob->sculpt;
+  SculptPoseIKChain *ik_chain = ss->cache->pose_ik_chain;
+  SculptPoseIKChainSegment *segments = ik_chain->segments;
+
+  PBVHVertexIter vd;
+  float disp[3], new_co[3];
+  float final_pos[3];
+
+  SculptOrigVertData orig_data;
+  SCULPT_orig_vert_data_init(&orig_data, data->ob, data->nodes[n]);
+
+  BKE_pbvh_vertex_iter_begin(ss->pbvh, data->nodes[n], vd, PBVH_ITER_UNIQUE)
+  {
+    SCULPT_orig_vert_data_update(&orig_data, &vd);
+
+    float total_disp[3];
+    zero_v3(total_disp);
+
+    ePaintSymmetryAreas symm_area = SCULPT_get_vertex_symm_area(orig_data.co);
+
+    /* Calculate the displacement of each vertex for all the segments in the chain. */
+    for (int ik = 0; ik < ik_chain->tot_segments; ik++) {
+      copy_v3_v3(new_co, orig_data.co);
+
+      /* Get the transform matrix for the vertex symmetry area to calculate a displacement in the
+       * vertex. */
+      mul_m4_v3(segments[ik].pivot_mat_inv[(int)symm_area], new_co);
+      mul_m4_v3(segments[ik].trans_mat[(int)symm_area], new_co);
+      mul_m4_v3(segments[ik].pivot_mat[(int)symm_area], new_co);
+
+      /* Apply the segment weight of the vertex to the displacement. */
+      sub_v3_v3v3(disp, new_co, orig_data.co);
+      mul_v3_fl(disp, segments[ik].weights[vd.index]);
+
+      /* Apply the vertex mask to the displacement. */
+      float mask = vd.mask ? *vd.mask : 0.0f;
+      mul_v3_fl(disp, 1.0f - mask);
+
+      /* Accumulate the displacement. */
+      add_v3_v3(total_disp, disp);
+    }
+
+    /* Apply the accumulated displacement to the vertex. */
+    add_v3_v3v3(final_pos, orig_data.co, total_disp);
+    copy_v3_v3(vd.co, final_pos);
+
+    if (vd.mvert) {
+      vd.mvert->flag |= ME_VERT_PBVH_UPDATE;
+    }
+  }
+  BKE_pbvh_vertex_iter_end;
+}
+
+typedef struct PoseGrowFactorTLSData {
+  float pos_avg[3];
+  int pos_count;
+} PoseGrowFactorTLSData;
+
+static void pose_brush_grow_factor_task_cb_ex(void *__restrict userdata,
+                                              const int n,
+                                              const TaskParallelTLS *__restrict tls)
+{
+  SculptThreadedTaskData *data = userdata;
+  PoseGrowFactorTLSData *gftd = tls->userdata_chunk;
+  SculptSession *ss = data->ob->sculpt;
+  const char symm = data->sd->paint.symmetry_flags & PAINT_SYMM_AXIS_ALL;
+  PBVHVertexIter vd;
+  BKE_pbvh_vertex_iter_begin(ss->pbvh, data->nodes[n], vd, PBVH_ITER_UNIQUE)
+  {
+    SculptVertexNeighborIter ni;
+    float max = 0.0f;
+
+    /* Grow the factor. */
+    sculpt_vertex_neighbors_iter_begin(ss, vd.index, ni)
+    {
+      float vmask_f = data->prev_mask[ni.index];
+      max = MAX2(vmask_f, max);
+    }
+    sculpt_vertex_neighbors_iter_end(ni);
+
+    /* Keep the count of the vertices that where added to the factors in this grow iteration. */
+    if (max > data->prev_mask[vd.index]) {
+      data->pose_factor[vd.index] = max;
+      if (SCULPT_check_vertex_pivot_symmetry(vd.co, data->pose_initial_co, symm)) {
+        add_v3_v3(gftd->pos_avg, vd.co);
+        gftd->pos_count++;
+      }
+    }
+  }
+
+  BKE_pbvh_vertex_iter_end;
+}
+
+static void pose_brush_grow_factor_reduce(const void *__restrict UNUSED(userdata),
+                                          void *__restrict chunk_join,
+                                          void *__restrict chunk)
+{
+  PoseGrowFactorTLSData *join = chunk_join;
+  PoseGrowFactorTLSData *gftd = chunk;
+  add_v3_v3(join->pos_avg, gftd->pos_avg);
+  join->pos_count += gftd->pos_count;
+}
+
+/* Grow the factor until its boundary is near to the offset pose origin or outside the target
+ * distance. */
+static void sculpt_pose_grow_pose_factor(Sculpt *sd,
+                                         Object *ob,
+                                         SculptSession *ss,
+                                         float pose_origin[3],
+                                         float pose_target[3],
+                                         float max_len,
+                                         float *r_pose_origin,
+                                         float *pose_factor)
+{
+  PBVHNode **nodes;
+  PBVH *pbvh = ob->sculpt->pbvh;
+  int totnode;
+
+  BKE_pbvh_search_gather(pbvh, NULL, NULL, &nodes, &totnode);
+  SculptThreadedTaskData data = {
+      .sd = sd,
+      .ob = ob,
+      .nodes = nodes,
+      .totnode = totnode,
+      .pose_factor = pose_factor,
+  };
+
+  data.pose_initial_co = pose_target;
+  PBVHParallelSettings settings;
+  PoseGrowFactorTLSData gftd;
+  gftd.pos_count = 0;
+  zero_v3(gftd.pos_avg);
+  BKE_pbvh_parallel_range_settings(&settings, (sd->flags & SCULPT_USE_OPENMP), totnode);
+  settings.func_reduce = pose_brush_grow_factor_reduce;
+  settings.userdata_chunk = &gftd;
+  settings.userdata_chunk_size = sizeof(PoseGrowFactorTLSData);
+
+  bool grow_next_iteration = true;
+  float prev_len = FLT_MAX;
+  data.prev_mask = MEM_mallocN(sculpt_vertex_count_get(ss) * sizeof(float), "prev mask");
+  while (grow_next_iteration) {
+    zero_v3(gftd.pos_avg);
+    gftd.pos_count = 0;
+    memcpy(data.prev_mask, pose_factor, sculpt_vertex_count_get(ss) * sizeof(float));
+    BKE_pbvh_parallel_range(0, totnode, &data, pose_brush_grow_factor_task_cb_ex, &settings);
+
+    if (gftd.pos_count != 0) {
+      mul_v3_fl(gftd.pos_avg, 1.0f / (float)gftd.pos_count);
+      if (pose_origin) {
+        /* Test with pose origin. Used when growing the factors to compensate the Origin Offset. */
+        /* Stop when the factor's avg_pos starts moving away from the origin instead of getting
+         * closer to it. */
+        float len = len_v3v3(gftd.pos_avg, pose_origin);
+        if (len < prev_len) {
+          prev_len = len;
+          grow_next_iteration = true;
+        }
+        else {
+          grow_next_iteration = false;
+          memcpy(pose_factor, data.prev_mask, sculpt_vertex_count_get(ss) * sizeof(float));
+        }
+      }
+      else {
+        /* Test with length. Used to calculate the origin positions of the IK chain. */
+        /* Stops when the factors have grown enough to generate a new segment origin. */
+        float len = len_v3v3(gftd.pos_avg, pose_target);
+        if (len < max_len) {
+          prev_len = len;
+          grow_next_iteration = true;
+        }
+        else {
+          grow_next_iteration = false;
+          if (r_pose_origin) {
+            copy_v3_v3(r_pose_origin, gftd.pos_avg);
+          }
+          memcpy(pose_factor, data.prev_mask, sculpt_vertex_count_get(ss) * sizeof(float));
+        }
+      }
+    }
+    else {
+      if (r_pose_origin) {
+        copy_v3_v3(r_pose_origin, pose_target);
+      }
+      grow_next_iteration = false;
+    }
+  }
+  MEM_freeN(data.prev_mask);
+
+  MEM_SAFE_FREE(nodes);
+}
+
+static bool sculpt_pose_brush_is_vertex_inside_brush_radius(const float vertex[3],
+                                                            const float br_co[3],
+                                                            float radius,
+                                                            char symm)
+{
+  for (char i = 0; i <= symm; ++i) {
+    if (SCULPT_is_symmetry_iteration_valid(i, symm)) {
+      float location[3];
+      flip_v3_v3(location, br_co, (char)i);
+      if (len_v3v3(location, vertex) < radius) {
+        return true;
+      }
+    }
+  }
+  return false;
+}
+
+typedef struct PoseFloodFillData {
+  float pose_initial_co[3];
+  float radius;
+  int symm;
+
+  float *pose_factor;
+  float pose_origin[3];
+  int tot_co;
+} PoseFloodFillData;
+
+static bool pose_floodfill_cb(
+    SculptSession *ss, int UNUSED(from_v), int to_v, bool is_duplicate, void *userdata)
+{
+  PoseFloodFillData *data = userdata;
+
+  if (data->pose_factor) {
+    data->pose_factor[to_v] = 1.0f;
+  }
+
+  const float *co = sculpt_vertex_co_get(ss, to_v);
+  if (sculpt_pose_brush_is_vertex_inside_brush_radius(
+          co, data->pose_initial_co, data->radius, data->symm)) {
+    return true;
+  }
+  else if (SCULPT_check_vertex_pivot_symmetry(co, data->pose_initial_co, data->symm)) {
+    if (!is_duplicate) {
+      add_v3_v3(data->pose_origin, co);
+      data->tot_co++;
+    }
+  }
+
+  return false;
+}
+
+/* Public functions. */
+
+/* Calculate the pose origin and (Optionaly the pose factor) that is used when using the pose brush
+ *
+ * r_pose_origin must be a valid pointer. the r_pose_factor is optional. When set to NULL it won't
+ * be calculated. */
+void SCULPT_pose_calc_pose_data(Sculpt *sd,
+                                Object *ob,
+                                SculptSession *ss,
+                                float initial_location[3],
+                                float radius,
+                                float pose_offset,
+                                float *r_pose_origin,
+                                float *r_pose_factor)
+{
+  sculpt_vertex_random_access_init(ss);
+
+  /* Calculate the pose rotation point based on the boundaries of the brush factor. */
+  SculptFloodFill flood;
+  SCULPT_floodfill_init(ss, &flood);
+  SCULPT_floodfill_add_active(sd, ob, ss, &flood, (r_pose_factor) ? radius : 0.0f);
+
+  PoseFloodFillData fdata = {
+      .radius = radius,
+      .symm = sd->paint.symmetry_flags & PAINT_SYMM_AXIS_ALL,
+      .pose_factor = r_pose_factor,
+      .tot_co = 0,
+  };
+  zero_v3(fdata.pose_origin);
+  copy_v3_v3(fdata.pose_initial_co, initial_location);
+  SCULPT_floodfill_execute(ss, &flood, pose_floodfill_cb, &fdata);
+  SCULPT_floodfill_free(&flood);
+
+  if (fdata.tot_co > 0) {
+    mul_v3_fl(fdata.pose_origin, 1.0f / (float)fdata.tot_co);
+  }
+
+  /* Offset the pose origin. */
+  float pose_d[3];
+  sub_v3_v3v3(pose_d, fdata.pose_origin, fdata.pose_initial_co);
+  normalize_v3(pose_d);
+  madd_v3_v3fl(fdata.pose_origin, pose_d, radius * pose_offset);
+  copy_v3_v3(r_pose_origin, fdata.pose_origin);
+
+  /* Do the initial grow of the factors to get the first segment of the chain with Origin Offset.
+   */
+  if (pose_offset != 0.0f && r_pose_factor) {
+    sculpt_pose_grow_pose_factor(
+        sd, ob, ss, fdata.pose_origin, fdata.pose_origin, 0, NULL, r_pose_factor);
+  }
+}
+
+static void pose_brush_init_task_cb_ex(void *__restrict userdata,
+                                       const int n,
+                                       const TaskParallelTLS *__restrict UNUSED(tls))
+{
+  SculptThreadedTaskData *data = userdata;
+  SculptSession *ss = data->ob->sculpt;
+  PBVHVertexIter vd;
+  BKE_pbvh_vertex_iter_begin(ss->pbvh, data->nodes[n], vd, PBVH_ITER_UNIQUE)
+  {
+    SculptVertexNeighborIter ni;
+    float avg = 0.0f;
+    int total = 0;
+    sculpt_vertex_neighbors_iter_begin(ss, vd.index, ni)
+    {
+      avg += data->pose_factor[ni.index];
+      total++;
+    }
+    sculpt_vertex_neighbors_iter_end(ni);
+
+    if (total > 0) {
+      data->pose_factor[vd.index] = avg / total;
+    }
+  }
+  BKE_pbvh_vertex_iter_end;
+}
+
+SculptPoseIKChain *SCULPT_pose_ik_chain_init(Sculpt *sd,
+                                             Object *ob,
+                                             SculptSession *ss,
+                                             Brush *br,
+                                             const float initial_location[3],
+                                             const float radius)
+{
+
+  const float chain_segment_len = radius * (1.0f + br->pose_offset);
+  float next_chain_segment_target[3];
+
+  int totvert = sculpt_vertex_count_get(ss);
+  int nearest_vertex_index = SCULPT_nearest_vertex_get(sd, ob, initial_location, FLT_MAX, true);
+
+  /* Init the buffers used to keep track of the changes in the pose factors as more segments are
+   * added to the IK chain. */
+
+  /* This stores the whole pose factors values as they grow through the mesh. */
+  float *pose_factor_grow = MEM_callocN(totvert * sizeof(float), "Pose Factor Grow");
+
+  /* This stores the previous status of the factors when growing a new iteration. */
+  float *pose_factor_grow_prev = MEM_callocN(totvert * sizeof(float),
+                                             "Pose Factor Grow Prev Iteration");
+
+  pose_factor_grow[nearest_vertex_index] = 1.0f;
+
+  /* Init the IK chain with empty weights. */
+  SculptPoseIKChain *ik_chain = MEM_callocN(sizeof(SculptPoseIKChain), "Pose IK Chain");
+  ik_chain->tot_segments = br->pose_ik_segments;
+  ik_chain->segments = MEM_callocN(ik_chain->tot_segments * sizeof(SculptPoseIKChainSegment),
+                                   "Pose IK Chain Segments");
+  for (int i = 0; i < br->pose_ik_segments; i++) {
+    ik_chain->segments[i].weights = MEM_callocN(totvert * sizeof(float), "Pose IK weights");
+  }
+
+  /* Calculate the first segment in the chain using the brush radius and the pose origin offset. */
+  copy_v3_v3(next_chain_segment_target, initial_location);
+  SCULPT_pose_calc_pose_data(sd,
+                             ob,
+                             ss,
+                             next_chain_segment_target,
+                             radius,
+                             br->pose_offset,
+                             ik_chain->segments[0].orig,
+                             pose_factor_grow);
+
+  copy_v3_v3(next_chain_segment_target, ik_chain->segments[0].orig);
+
+  /* Init the weights of this segment and store the status of the pose factors to start calculating
+   * new segment origins. */
+  for (int j = 0; j < totvert; j++) {
+    ik_chain->segments[0].weights[j] = pose_factor_grow[j];
+    pose_factor_grow_prev[j] = pose_factor_grow[j];
+  }
+
+  /* Calculate the next segments in the chain growing the pose factors. */
+  for (int i = 1; i < ik_chain->tot_segments; i++) {
+
+    /* Grow the factors to get the new segment origin. */
+    sculpt_pose_grow_pose_factor(sd,
+                                 ob,
+                                 ss,
+                                 NULL,
+                                 next_chain_segment_target,
+                                 chain_segment_len,
+                                 ik_chain->segments[i].orig,
+                                 pose_factor_grow);
+    copy_v3_v3(next_chain_segment_target, ik_chain->segments[i].orig);
+
+    /* Create the weights for this segment from the difference between the previous grow factor
+     * iteration an the current iteration. */
+    for (int j = 0; j < totvert; j++) {
+      ik_chain->segments[i].weights[j] = pose_factor_grow[j] - pose_factor_grow_prev[j];
+      /* Store the current grow factor status for the next interation. */
+      pose_factor_grow_prev[j] = pose_factor_grow[j];
+    }
+  }
+
+  /* Init the origin/head pairs of all the segments from the calculated origins. */
+  float origin[3];
+  float head[3];
+  for (int i = 0; i < ik_chain->tot_segments; i++) {
+    if (i == 0) {
+      copy_v3_v3(head, initial_location);
+      copy_v3_v3(origin, ik_chain->segments[i].orig);
+    }
+    else {
+      copy_v3_v3(head, ik_chain->segments[i - 1].orig);
+      copy_v3_v3(origin, ik_chain->segments[i].orig);
+    }
+    copy_v3_v3(ik_chain->segments[i].orig, origin);
+    copy_v3_v3(ik_chain->segments[i].initial_orig, origin);
+    copy_v3_v3(ik_chain->segments[i].initial_head, head);
+    ik_chain->segments[i].len = len_v3v3(head, origin);
+  }
+
+  MEM_freeN(pose_factor_grow);
+  MEM_freeN(pose_factor_grow_prev);
+
+  return ik_chain;
+}
+
+void SCULPT_pose_brush_init(Sculpt *sd, Object *ob, SculptSession *ss, Brush *br)
+{
+  PBVHNode **nodes;
+  PBVH *pbvh = ob->sculpt->pbvh;
+  int totnode;
+
+  BKE_pbvh_search_gather(pbvh, NULL, NULL, &nodes, &totnode);
+
+  SculptThreadedTaskData data = {
+      .sd = sd,
+      .ob = ob,
+      .brush = br,
+      .nodes = nodes,
+  };
+
+  /* Init the IK chain that is going to be used to deform the vertices. */
+  ss->cache->pose_ik_chain = SCULPT_pose_ik_chain_init(
+      sd, ob, ss, br, ss->cache->true_location, ss->cache->radius);
+
+  /* Smooth the weights of each segment for cleaner deformation. */
+  for (int ik = 0; ik < ss->cache->pose_ik_chain->tot_segments; ik++) {
+    data.pose_factor = ss->cache->pose_ik_chain->segments[ik].weights;
+    for (int i = 0; i < br->pose_smooth_iterations; i++) {
+      PBVHParallelSettings settings;
+      BKE_pbvh_parallel_range_settings(&settings, (sd->flags & SCULPT_USE_OPENMP), totnode);
+      BKE_pbvh_parallel_range(0, totnode, &data, pose_brush_init_task_cb_ex, &settings);
+    }
+  }
+
+  MEM_SAFE_FREE(nodes);
+}
+
+/* Main Brush Function. */
+void SCULPT_do_pose_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 ik_target[3];
+  const ePaintSymmetryFlags symm = sd->paint.symmetry_flags & PAINT_SYMM_AXIS_ALL;
+
+  /* The pose brush applies all enabled symmetry axis in a single iteration, so the rest can be
+   * ignored. */
+  if (ss->cache->mirror_symmetry_pass != 0) {
+    return;
+  }
+
+  SculptPoseIKChain *ik_chain = ss->cache->pose_ik_chain;
+
+  /* Solve the positions and rotations of the IK chain. */
+  if (ss->cache->invert) {
+    /* Roll Mode. */
+    /* Calculate the maximum roll. 0.02 radians per pixel works fine. */
+    float roll = (ss->cache->initial_mouse[0] - ss->cache->mouse[0]) * ss->cache->bstrength *
+                 0.02f;
+    BKE_curvemapping_initialize(brush->curve);
+    pose_solve_roll_chain(ik_chain, brush, roll);
+  }
+  else {
+    /* IK follow target mode. */
+    /* Calculate the IK target. */
+
+    copy_v3_v3(grab_delta, ss->cache->grab_delta);
+    copy_v3_v3(ik_target, ss->cache->true_location);
+    add_v3_v3(ik_target, ss->cache->grab_delta);
+
+    /* Solve the IK positions. */
+    pose_solve_ik_chain(ik_chain, ik_target, brush->flag2 & BRUSH_POSE_IK_ANCHORED);
+  }
+
+  /* Flip the segment chain in all symmetry axis and calculate the transform matrices for each
+   * possible combination. */
+  /* This can be optimized by skipping the calculation of matrices where the symmetry is not
+   * enabled. */
+  for (int symm_it = 0; symm_it < PAINT_SYMM_AREAS; symm_it++) {
+    for (int i = 0; i < brush->pose_ik_segments; i++) {
+      float symm_rot[4];
+      float symm_orig[3];
+      float symm_initial_orig[3];
+
+      ePaintSymmetryAreas symm_area = symm_it;
+
+      copy_qt_qt(symm_rot, ik_chain->segments[i].rot);
+      copy_v3_v3(symm_orig, ik_chain->segments[i].orig);
+      copy_v3_v3(symm_initial_orig, ik_chain->segments[i].initial_orig);
+
+      /* Flip the origins and rotation quats of each segment. */
+      SCULPT_flip_quat_by_symm_area(symm_rot, symm, symm_area, ss->cache->orig_grab_location);
+      SCULPT_flip_v3_by_symm_area(symm_orig, symm, symm_area, ss->cache->orig_grab_location);
+      SCULPT_flip_v3_by_symm_area(
+          symm_initial_orig, symm, symm_area, ss->cache->orig_grab_location);
+
+      /* Create the transform matrix and store it in the segment. */
+      unit_m4(ik_chain->segments[i].pivot_mat[symm_it]);
+      quat_to_mat4(ik_chain->segments[i].trans_mat[symm_it], symm_rot);
+
+      translate_m4(ik_chain->segments[i].trans_mat[symm_it],
+                   symm_orig[0] - symm_initial_orig[0],
+                   symm_orig[1] - symm_initial_orig[1],
+                   symm_orig[2] - symm_initial_orig[2]);
+      translate_m4(
+          ik_chain->segments[i].pivot_mat[symm_it], symm_orig[0], symm_orig[1], symm_orig[2]);
+      invert_m4_m4(ik_chain->segments[i].pivot_mat_inv[symm_it],
+                   ik_chain->segments[i].pivot_mat[symm_it]);
+    }
+  }
+
+  SculptThreadedTaskData data = {
+      .sd = sd,
+      .ob = ob,
+      .brush = brush,
+      .nodes = nodes,
+      .grab_delta = grab_delta,
+  };
+
+  PBVHParallelSettings settings;
+  BKE_pbvh_parallel_range_settings(&settings, (sd->flags & SCULPT_USE_OPENMP), totnode);
+  BKE_pbvh_parallel_range(0, totnode, &data, do_pose_brush_task_cb_ex, &settings);
+}
+
+void SCULPT_pose_ik_chain_free(SculptPoseIKChain *ik_chain)
+{
+  for (int i = 0; i < ik_chain->tot_segments; i++) {
+    MEM_SAFE_FREE(ik_chain->segments[i].weights);
+  }
+  MEM_SAFE_FREE(ik_chain->segments);
+  MEM_SAFE_FREE(ik_chain);
+}