Modifiers: Refactor Mask modifier

The functionality of the mask modifier remains unchanged.

This patch updates the mask modifier so that it uses C++.
The manual memory management has been replaced with proper containers.
The large `applyModifier` function has been splitup into multiple smaller functions.
A large speedup is achieved by using simple arrays instead of hash tables in multiple places.

In my performance test file the playback speed increased from 1.1 to 5.1 fps on my laptop.

Reviewers: campbellbarton, brecht

Differential Revision: https://developer.blender.org/D6779

1 files changed, 417 insertions, 0 deletions

diff --git a/source/blender/modifiers/intern/MOD_mask.cc b/source/blender/modifiers/intern/MOD_mask.cc
new file mode 100644
index 00000000000..fb179d2e485
--- /dev/null
+++ b/source/blender/modifiers/intern/MOD_mask.cc
@@ -0,0 +1,417 @@
+/*
+ * 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) 2005 by the Blender Foundation.
+ * All rights reserved.
+ */
+
+/** \file
+ * \ingroup modifiers
+ */
+
+#include "MEM_guardedalloc.h"
+
+#include "BLI_utildefines.h"
+
+#include "BLI_listbase.h"
+#include "BLI_ghash.h"
+
+#include "DNA_armature_types.h"
+#include "DNA_mesh_types.h"
+#include "DNA_meshdata_types.h"
+#include "DNA_modifier_types.h"
+#include "DNA_object_types.h"
+
+#include "BKE_action.h" /* BKE_pose_channel_find_name */
+#include "BKE_customdata.h"
+#include "BKE_lib_query.h"
+#include "BKE_mesh.h"
+#include "BKE_modifier.h"
+#include "BKE_deform.h"
+
+#include "DEG_depsgraph_build.h"
+#include "DEG_depsgraph_query.h"
+
+#include "MOD_modifiertypes.h"
+
+#include "BLI_array_cxx.h"
+#include "BLI_vector.h"
+#include "BLI_listbase_wrapper.h"
+
+using BLI::Array;
+using BLI::ArrayRef;
+using BLI::IndexRange;
+using BLI::IntrusiveListBaseWrapper;
+using BLI::MutableArrayRef;
+using BLI::Vector;
+
+static void requiredDataMask(Object *UNUSED(ob),
+                             ModifierData *UNUSED(md),
+                             CustomData_MeshMasks *r_cddata_masks)
+{
+  r_cddata_masks->vmask |= CD_MASK_MDEFORMVERT;
+}
+
+static void foreachObjectLink(ModifierData *md, Object *ob, ObjectWalkFunc walk, void *userData)
+{
+  MaskModifierData *mmd = (MaskModifierData *)md;
+  walk(userData, ob, &mmd->ob_arm, IDWALK_CB_NOP);
+}
+
+static void updateDepsgraph(ModifierData *md, const ModifierUpdateDepsgraphContext *ctx)
+{
+  MaskModifierData *mmd = (MaskModifierData *)md;
+  if (mmd->ob_arm) {
+    bArmature *arm = (bArmature *)mmd->ob_arm->data;
+    /* Tag relationship in depsgraph, but also on the armature. */
+    /* TODO(sergey): Is it a proper relation here? */
+    DEG_add_object_relation(ctx->node, mmd->ob_arm, DEG_OB_COMP_TRANSFORM, "Mask Modifier");
+    arm->flag |= ARM_HAS_VIZ_DEPS;
+    DEG_add_modifier_to_transform_relation(ctx->node, "Mask Modifier");
+  }
+}
+
+/* A vertex will be in the mask if a selected bone influences it more than a certain threshold. */
+static void compute_vertex_mask__armature_mode(MDeformVert *dvert,
+                                               Object *ob,
+                                               Object *armature_ob,
+                                               float threshold,
+                                               MutableArrayRef<bool> r_vertex_mask)
+{
+  /* Element i is true if there is a selected bone that uses vertex group i. */
+  Vector<bool> selected_bone_uses_group;
+
+  for (bDeformGroup *def : IntrusiveListBaseWrapper<bDeformGroup>(ob->defbase)) {
+    bPoseChannel *pchan = BKE_pose_channel_find_name(armature_ob->pose, def->name);
+    bool bone_for_group_exists = pchan && pchan->bone && (pchan->bone->flag & BONE_SELECTED);
+    selected_bone_uses_group.append(bone_for_group_exists);
+  }
+
+  ArrayRef<bool> use_vertex_group = selected_bone_uses_group;
+
+  for (int i : r_vertex_mask.index_range()) {
+    ArrayRef<MDeformWeight> weights(dvert[i].dw, dvert[i].totweight);
+    r_vertex_mask[i] = false;
+
+    /* check the groups that vertex is assigned to, and see if it was any use */
+    for (const MDeformWeight &dw : weights) {
+      if (use_vertex_group.get(dw.def_nr, false)) {
+        if (dw.weight > threshold) {
+          r_vertex_mask[i] = true;
+          break;
+        }
+      }
+    }
+  }
+}
+
+/* A vertex will be in the mask if the vertex group influences it more than a certain threshold. */
+static void compute_vertex_mask__vertex_group_mode(MDeformVert *dvert,
+                                                   int defgrp_index,
+                                                   float threshold,
+                                                   MutableArrayRef<bool> r_vertex_mask)
+{
+  for (int i : r_vertex_mask.index_range()) {
+    const bool found = defvert_find_weight(&dvert[i], defgrp_index) > threshold;
+    r_vertex_mask[i] = found;
+  }
+}
+
+static void invert_boolean_array(MutableArrayRef<bool> array)
+{
+  for (bool &value : array) {
+    value = !value;
+  }
+}
+
+static void compute_masked_vertices(ArrayRef<bool> vertex_mask,
+                                    MutableArrayRef<int> r_vertex_map,
+                                    uint *r_num_masked_vertices)
+{
+  BLI_assert(vertex_mask.size() == r_vertex_map.size());
+
+  uint num_masked_vertices = 0;
+  for (uint i_src : r_vertex_map.index_range()) {
+    if (vertex_mask[i_src]) {
+      r_vertex_map[i_src] = num_masked_vertices;
+      num_masked_vertices++;
+    }
+    else {
+      r_vertex_map[i_src] = -1;
+    }
+  }
+
+  *r_num_masked_vertices = num_masked_vertices;
+}
+
+static void computed_masked_edges(const Mesh *mesh,
+                                  ArrayRef<bool> vertex_mask,
+                                  MutableArrayRef<int> r_edge_map,
+                                  uint *r_num_masked_edges)
+{
+  BLI_assert(mesh->totedge == r_edge_map.size());
+
+  uint num_masked_edges = 0;
+  for (int i : IndexRange(mesh->totedge)) {
+    const MEdge &edge = mesh->medge[i];
+
+    /* only add if both verts will be in new mesh */
+    if (vertex_mask[edge.v1] && vertex_mask[edge.v2]) {
+      r_edge_map[i] = num_masked_edges;
+      num_masked_edges++;
+    }
+    else {
+      r_edge_map[i] = -1;
+    }
+  }
+
+  *r_num_masked_edges = num_masked_edges;
+}
+
+static void computed_masked_polygons(const Mesh *mesh,
+                                     ArrayRef<bool> vertex_mask,
+                                     Vector<int> &r_masked_poly_indices,
+                                     Vector<int> &r_loop_starts,
+                                     uint *r_num_masked_polys,
+                                     uint *r_num_masked_loops)
+{
+  BLI_assert(mesh->totvert == vertex_mask.size());
+
+  r_masked_poly_indices.reserve(mesh->totpoly);
+  r_loop_starts.reserve(mesh->totloop);
+
+  uint num_masked_loops = 0;
+  for (int i : IndexRange(mesh->totpoly)) {
+    const MPoly &poly_src = mesh->mpoly[i];
+
+    bool all_verts_in_mask = true;
+    ArrayRef<MLoop> loops_src(&mesh->mloop[poly_src.loopstart], poly_src.totloop);
+    for (const MLoop &loop : loops_src) {
+      if (!vertex_mask[loop.v]) {
+        all_verts_in_mask = false;
+        break;
+      }
+    }
+
+    if (all_verts_in_mask) {
+      r_masked_poly_indices.append_unchecked(i);
+      r_loop_starts.append_unchecked(num_masked_loops);
+      num_masked_loops += poly_src.totloop;
+    }
+  }
+
+  *r_num_masked_polys = r_masked_poly_indices.size();
+  *r_num_masked_loops = num_masked_loops;
+}
+
+static void copy_masked_vertices_to_new_mesh(const Mesh &src_mesh,
+                                             Mesh &dst_mesh,
+                                             ArrayRef<int> vertex_map)
+{
+  BLI_assert(src_mesh.totvert == vertex_map.size());
+  for (const int i_src : vertex_map.index_range()) {
+    const int i_dst = vertex_map[i_src];
+    if (i_dst == -1) {
+      continue;
+    }
+
+    const MVert &v_src = src_mesh.mvert[i_src];
+    MVert &v_dst = dst_mesh.mvert[i_dst];
+
+    v_dst = v_src;
+    CustomData_copy_data(&src_mesh.vdata, &dst_mesh.vdata, i_src, i_dst, 1);
+  }
+}
+
+static void copy_masked_edges_to_new_mesh(const Mesh &src_mesh,
+                                          Mesh &dst_mesh,
+                                          ArrayRef<int> vertex_map,
+                                          ArrayRef<int> edge_map)
+{
+  BLI_assert(src_mesh.totvert == vertex_map.size());
+  BLI_assert(src_mesh.totedge == edge_map.size());
+  for (const int i_src : IndexRange(src_mesh.totedge)) {
+    const int i_dst = edge_map[i_src];
+    if (i_dst == -1) {
+      continue;
+    }
+
+    const MEdge &e_src = src_mesh.medge[i_src];
+    MEdge &e_dst = dst_mesh.medge[i_dst];
+
+    CustomData_copy_data(&src_mesh.edata, &dst_mesh.edata, i_src, i_dst, 1);
+    e_dst = e_src;
+    e_dst.v1 = vertex_map[e_src.v1];
+    e_dst.v2 = vertex_map[e_src.v2];
+  }
+}
+
+static void copy_masked_polys_to_new_mesh(const Mesh &src_mesh,
+                                          Mesh &dst_mesh,
+                                          ArrayRef<int> vertex_map,
+                                          ArrayRef<int> edge_map,
+                                          ArrayRef<int> masked_poly_indices,
+                                          ArrayRef<int> new_loop_starts)
+{
+  for (const int i_dst : masked_poly_indices.index_range()) {
+    const int i_src = masked_poly_indices[i_dst];
+
+    const MPoly &mp_src = src_mesh.mpoly[i_src];
+    MPoly &mp_dst = dst_mesh.mpoly[i_dst];
+    const int i_ml_src = mp_src.loopstart;
+    const int i_ml_dst = new_loop_starts[i_dst];
+
+    CustomData_copy_data(&src_mesh.pdata, &dst_mesh.pdata, i_src, i_dst, 1);
+    CustomData_copy_data(&src_mesh.ldata, &dst_mesh.ldata, i_ml_src, i_ml_dst, mp_src.totloop);
+
+    const MLoop *ml_src = src_mesh.mloop + i_ml_src;
+    MLoop *ml_dst = dst_mesh.mloop + i_ml_dst;
+
+    mp_dst = mp_src;
+    mp_dst.loopstart = i_ml_dst;
+    for (int i : IndexRange(mp_src.totloop)) {
+      ml_dst[i].v = vertex_map[ml_src[i].v];
+      ml_dst[i].e = edge_map[ml_src[i].e];
+    }
+  }
+}
+
+/* Components of the algorithm:
+ * 1. Figure out which vertices should be present in the output mesh.
+ * 2. Find edges and polygons only using those vertices.
+ * 3. Create a new mesh that only uses the found vertices, edges and polygons.
+ */
+static Mesh *applyModifier(ModifierData *md, const ModifierEvalContext *ctx, Mesh *mesh)
+{
+  MaskModifierData *mmd = (MaskModifierData *)md;
+  Object *ob = ctx->object;
+  const bool invert_mask = mmd->flag & MOD_MASK_INV;
+
+  /* Return empty or input mesh when there are no vertex groups. */
+  MDeformVert *dvert = (MDeformVert *)CustomData_get_layer(&mesh->vdata, CD_MDEFORMVERT);
+  if (dvert == NULL) {
+    return invert_mask ? mesh : BKE_mesh_new_nomain_from_template(mesh, 0, 0, 0, 0, 0);
+  }
+
+  /* Quick test to see if we can return early. */
+  if (!(ELEM(mmd->mode, MOD_MASK_MODE_ARM, MOD_MASK_MODE_VGROUP)) || (mesh->totvert == 0) ||
+      BLI_listbase_is_empty(&ob->defbase)) {
+    return mesh;
+  }
+
+  Array<bool> vertex_mask;
+  if (mmd->mode == MOD_MASK_MODE_ARM) {
+    Object *armature_ob = mmd->ob_arm;
+
+    /* Return input mesh if there is no armature with bones. */
+    if (ELEM(NULL, armature_ob, armature_ob->pose, ob->defbase.first)) {
+      return mesh;
+    }
+
+    vertex_mask = Array<bool>(mesh->totvert);
+    compute_vertex_mask__armature_mode(dvert, ob, armature_ob, mmd->threshold, vertex_mask);
+  }
+  else {
+    int defgrp_index = defgroup_name_index(ob, mmd->vgroup);
+
+    /* Return input mesh if the vertex group does not exist. */
+    if (defgrp_index == -1) {
+      return mesh;
+    }
+
+    vertex_mask = Array<bool>(mesh->totvert);
+    compute_vertex_mask__vertex_group_mode(dvert, defgrp_index, mmd->threshold, vertex_mask);
+  }
+
+  if (invert_mask) {
+    invert_boolean_array(vertex_mask);
+  }
+
+  Array<int> vertex_map(mesh->totvert);
+  uint num_masked_vertices;
+  compute_masked_vertices(vertex_mask, vertex_map, &num_masked_vertices);
+
+  Array<int> edge_map(mesh->totedge);
+  uint num_masked_edges;
+  computed_masked_edges(mesh, vertex_mask, edge_map, &num_masked_edges);
+
+  Vector<int> masked_poly_indices;
+  Vector<int> new_loop_starts;
+  uint num_masked_polys;
+  uint num_masked_loops;
+  computed_masked_polygons(mesh,
+                           vertex_mask,
+                           masked_poly_indices,
+                           new_loop_starts,
+                           &num_masked_polys,
+                           &num_masked_loops);
+
+  Mesh *result = BKE_mesh_new_nomain_from_template(
+      mesh, num_masked_vertices, num_masked_edges, 0, num_masked_loops, num_masked_polys);
+
+  copy_masked_vertices_to_new_mesh(*mesh, *result, vertex_map);
+  copy_masked_edges_to_new_mesh(*mesh, *result, vertex_map, edge_map);
+  copy_masked_polys_to_new_mesh(
+      *mesh, *result, vertex_map, edge_map, masked_poly_indices, new_loop_starts);
+
+  /* Tag to recalculate normals later. */
+  result->runtime.cd_dirty_vert |= CD_MASK_NORMAL;
+
+  return result;
+}
+
+static bool isDisabled(const struct Scene *UNUSED(scene),
+                       ModifierData *md,
+                       bool UNUSED(useRenderParams))
+{
+  MaskModifierData *mmd = (MaskModifierData *)md;
+
+  /* The object type check is only needed here in case we have a placeholder
+   * object assigned (because the library containing the armature is missing).
+   *
+   * In other cases it should be impossible to have a type mismatch.
+   */
+  return mmd->ob_arm && mmd->ob_arm->type != OB_ARMATURE;
+}
+
+ModifierTypeInfo modifierType_Mask = {
+    /* name */ "Mask",
+    /* structName */ "MaskModifierData",
+    /* structSize */ sizeof(MaskModifierData),
+    /* type */ eModifierTypeType_Nonconstructive,
+    /* flags */
+    (ModifierTypeFlag)(eModifierTypeFlag_AcceptsMesh | eModifierTypeFlag_SupportsMapping |
+                       eModifierTypeFlag_SupportsEditmode),
+
+    /* copyData */ modifier_copyData_generic,
+
+    /* deformVerts */ NULL,
+    /* deformMatrices */ NULL,
+    /* deformVertsEM */ NULL,
+    /* deformMatricesEM */ NULL,
+    /* applyModifier */ applyModifier,
+
+    /* initData */ NULL,
+    /* requiredDataMask */ requiredDataMask,
+    /* freeData */ NULL,
+    /* isDisabled */ isDisabled,
+    /* updateDepsgraph */ updateDepsgraph,
+    /* dependsOnTime */ NULL,
+    /* dependsOnNormals */ NULL,
+    /* foreachObjectLink */ foreachObjectLink,
+    /* foreachIDLink */ NULL,
+    /* foreachTexLink */ NULL,
+    /* freeRuntimeData */ NULL,
+};