Cleanup: Move object_dupli.cc to C++

This will hopefully allow more refactoring in the future to improve
the instancing system, especially how it relates to geometry nodes
instances.

1 files changed, 1602 insertions, 0 deletions

diff --git a/source/blender/blenkernel/intern/object_dupli.cc b/source/blender/blenkernel/intern/object_dupli.cc
new file mode 100644
index 00000000000..1830870b854
--- /dev/null
+++ b/source/blender/blenkernel/intern/object_dupli.cc
@@ -0,0 +1,1602 @@
+/*
+ * 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) 2001-2002 by NaN Holding BV.
+ * All rights reserved.
+ */
+
+/** \file
+ * \ingroup bke
+ */
+
+#include <climits>
+#include <cstddef>
+#include <cstdlib>
+
+#include "MEM_guardedalloc.h"
+
+#include "BLI_listbase.h"
+#include "BLI_string_utf8.h"
+
+#include "BLI_alloca.h"
+#include "BLI_math.h"
+#include "BLI_rand.h"
+
+#include "DNA_anim_types.h"
+#include "DNA_collection_types.h"
+#include "DNA_mesh_types.h"
+#include "DNA_meshdata_types.h"
+#include "DNA_pointcloud_types.h"
+#include "DNA_scene_types.h"
+#include "DNA_vfont_types.h"
+
+#include "BKE_collection.h"
+#include "BKE_duplilist.h"
+#include "BKE_editmesh.h"
+#include "BKE_editmesh_cache.h"
+#include "BKE_font.h"
+#include "BKE_geometry_set.h"
+#include "BKE_global.h"
+#include "BKE_idprop.h"
+#include "BKE_lattice.h"
+#include "BKE_main.h"
+#include "BKE_mesh.h"
+#include "BKE_mesh_iterators.h"
+#include "BKE_mesh_runtime.h"
+#include "BKE_object.h"
+#include "BKE_particle.h"
+#include "BKE_scene.h"
+
+#include "DEG_depsgraph.h"
+#include "DEG_depsgraph_query.h"
+
+#include "BLI_hash.h"
+#include "BLI_strict_flags.h"
+
+/* -------------------------------------------------------------------- */
+/** \name Internal Duplicate Context
+ * \{ */
+
+struct DupliContext {
+  Depsgraph *depsgraph;
+  /** XXX child objects are selected from this group if set, could be nicer. */
+  Collection *collection;
+  /** Only to check if the object is in edit-mode. */
+  Object *obedit;
+
+  Scene *scene;
+  ViewLayer *view_layer;
+  Object *object;
+  float space_mat[4][4];
+
+  int persistent_id[MAX_DUPLI_RECUR];
+  int level;
+
+  const struct DupliGenerator *gen;
+
+  /** Result containers. */
+  ListBase *duplilist; /* Legacy doubly-linked list. */
+};
+
+struct DupliGenerator {
+  short type; /* Dupli Type, see members of #OB_DUPLI. */
+  void (*make_duplis)(const DupliContext *ctx);
+};
+
+static const DupliGenerator *get_dupli_generator(const DupliContext *ctx);
+
+/**
+ * Create initial context for root object.
+ */
+static void init_context(DupliContext *r_ctx,
+                         Depsgraph *depsgraph,
+                         Scene *scene,
+                         Object *ob,
+                         const float space_mat[4][4])
+{
+  r_ctx->depsgraph = depsgraph;
+  r_ctx->scene = scene;
+  r_ctx->view_layer = DEG_get_evaluated_view_layer(depsgraph);
+  r_ctx->collection = nullptr;
+
+  r_ctx->object = ob;
+  r_ctx->obedit = OBEDIT_FROM_OBACT(ob);
+  if (space_mat) {
+    copy_m4_m4(r_ctx->space_mat, space_mat);
+  }
+  else {
+    unit_m4(r_ctx->space_mat);
+  }
+  r_ctx->level = 0;
+
+  r_ctx->gen = get_dupli_generator(r_ctx);
+
+  r_ctx->duplilist = nullptr;
+}
+
+/**
+ * Create sub-context for recursive duplis.
+ */
+static void copy_dupli_context(
+    DupliContext *r_ctx, const DupliContext *ctx, Object *ob, const float mat[4][4], int index)
+{
+  *r_ctx = *ctx;
+
+  /* XXX annoying, previously was done by passing an ID* argument,
+   * this at least is more explicit. */
+  if (ctx->gen->type == OB_DUPLICOLLECTION) {
+    r_ctx->collection = ctx->object->instance_collection;
+  }
+
+  r_ctx->object = ob;
+  if (mat) {
+    mul_m4_m4m4(r_ctx->space_mat, (float(*)[4])ctx->space_mat, mat);
+  }
+  r_ctx->persistent_id[r_ctx->level] = index;
+  ++r_ctx->level;
+
+  r_ctx->gen = get_dupli_generator(r_ctx);
+}
+
+/**
+ * Generate a dupli instance.
+ *
+ * \param mat: is transform of the object relative to current context (including #Object.obmat).
+ */
+static DupliObject *make_dupli(const DupliContext *ctx,
+                               Object *ob,
+                               const float mat[4][4],
+                               int index)
+{
+  DupliObject *dob;
+  int i;
+
+  /* Add a #DupliObject instance to the result container. */
+  if (ctx->duplilist) {
+    dob = (DupliObject *)MEM_callocN(sizeof(DupliObject), "dupli object");
+    BLI_addtail(ctx->duplilist, dob);
+  }
+  else {
+    return nullptr;
+  }
+
+  dob->ob = ob;
+  mul_m4_m4m4(dob->mat, (float(*)[4])ctx->space_mat, mat);
+  dob->type = ctx->gen->type;
+
+  /* Set persistent id, which is an array with a persistent index for each level
+   * (particle number, vertex number, ..). by comparing this we can find the same
+   * dupli-object between frames, which is needed for motion blur.
+   * The last level is ordered first in the array. */
+  dob->persistent_id[0] = index;
+  for (i = 1; i < ctx->level + 1; i++) {
+    dob->persistent_id[i] = ctx->persistent_id[ctx->level - i];
+  }
+  /* Fill rest of values with #INT_MAX which index will never have as value. */
+  for (; i < MAX_DUPLI_RECUR; i++) {
+    dob->persistent_id[i] = INT_MAX;
+  }
+
+  /* Meta-balls never draw in duplis, they are instead merged into one by the basis
+   * meta-ball outside of the group. this does mean that if that meta-ball is not in the
+   * scene, they will not show up at all, limitation that should be solved once. */
+  if (ob->type == OB_MBALL) {
+    dob->no_draw = true;
+  }
+
+  /* Random number.
+   * The logic here is designed to match Cycles. */
+  dob->random_id = BLI_hash_string(dob->ob->id.name + 2);
+
+  if (dob->persistent_id[0] != INT_MAX) {
+    for (i = 0; i < MAX_DUPLI_RECUR; i++) {
+      dob->random_id = BLI_hash_int_2d(dob->random_id, (unsigned int)dob->persistent_id[i]);
+    }
+  }
+  else {
+    dob->random_id = BLI_hash_int_2d(dob->random_id, 0);
+  }
+
+  if (ctx->object != ob) {
+    dob->random_id ^= BLI_hash_int(BLI_hash_string(ctx->object->id.name + 2));
+  }
+
+  return dob;
+}
+
+/**
+ * Recursive dupli-objects.
+ *
+ * \param space_mat: is the local dupli-space (excluding dupli #Object.obmat).
+ */
+static void make_recursive_duplis(const DupliContext *ctx,
+                                  Object *ob,
+                                  const float space_mat[4][4],
+                                  int index)
+{
+  /* Simple preventing of too deep nested collections with #MAX_DUPLI_RECUR. */
+  if (ctx->level < MAX_DUPLI_RECUR) {
+    DupliContext rctx;
+    copy_dupli_context(&rctx, ctx, ob, space_mat, index);
+    if (rctx.gen) {
+      rctx.gen->make_duplis(&rctx);
+    }
+  }
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Internal Child Duplicates (Used by Other Functions)
+ * \{ */
+
+using MakeChildDuplisFunc = void (*)(const DupliContext *ctx, void *userdata, Object *child);
+
+static bool is_child(const Object *ob, const Object *parent)
+{
+  const Object *ob_parent = ob->parent;
+  while (ob_parent) {
+    if (ob_parent == parent) {
+      return true;
+    }
+    ob_parent = ob_parent->parent;
+  }
+  return false;
+}
+
+/**
+ * Create duplis from every child in scene or collection.
+ */
+static void make_child_duplis(const DupliContext *ctx,
+                              void *userdata,
+                              MakeChildDuplisFunc make_child_duplis_cb)
+{
+  Object *parent = ctx->object;
+
+  if (ctx->collection) {
+    eEvaluationMode mode = DEG_get_mode(ctx->depsgraph);
+    FOREACH_COLLECTION_VISIBLE_OBJECT_RECURSIVE_BEGIN (ctx->collection, ob, mode) {
+      if ((ob != ctx->obedit) && is_child(ob, parent)) {
+        DupliContext pctx;
+        copy_dupli_context(&pctx, ctx, ctx->object, nullptr, _base_id);
+
+        /* Meta-balls have a different dupli handling. */
+        if (ob->type != OB_MBALL) {
+          ob->flag |= OB_DONE; /* Doesn't render. */
+        }
+        make_child_duplis_cb(&pctx, userdata, ob);
+      }
+    }
+    FOREACH_COLLECTION_VISIBLE_OBJECT_RECURSIVE_END;
+  }
+  else {
+    int baseid;
+    ViewLayer *view_layer = ctx->view_layer;
+    LISTBASE_FOREACH_INDEX (Base *, base, &view_layer->object_bases, baseid) {
+      Object *ob = base->object;
+      if ((ob != ctx->obedit) && is_child(ob, parent)) {
+        DupliContext pctx;
+        copy_dupli_context(&pctx, ctx, ctx->object, nullptr, baseid);
+
+        /* Meta-balls have a different dupli-handling. */
+        if (ob->type != OB_MBALL) {
+          ob->flag |= OB_DONE; /* Doesn't render. */
+        }
+
+        make_child_duplis_cb(&pctx, userdata, ob);
+      }
+    }
+  }
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Internal Data Access Utilities
+ * \{ */
+
+static Mesh *mesh_data_from_duplicator_object(Object *ob,
+                                              BMEditMesh **r_em,
+                                              const float (**r_vert_coords)[3],
+                                              const float (**r_vert_normals)[3])
+{
+  /* Gather mesh info. */
+  BMEditMesh *em = BKE_editmesh_from_object(ob);
+  Mesh *me_eval;
+
+  *r_em = nullptr;
+  *r_vert_coords = nullptr;
+  if (r_vert_normals != nullptr) {
+    *r_vert_normals = nullptr;
+  }
+
+  /* We do not need any render-specific handling anymore, depsgraph takes care of that. */
+  /* NOTE: Do direct access to the evaluated mesh: this function is used
+   * during meta balls evaluation. But even without those all the objects
+   * which are needed for correct instancing are already evaluated. */
+  if (em != nullptr) {
+    /* Note that this will only show deformation if #eModifierMode_OnCage is enabled.
+     * We could change this but it matches 2.7x behavior. */
+    me_eval = em->mesh_eval_cage;
+    if ((me_eval == nullptr) || (me_eval->runtime.wrapper_type == ME_WRAPPER_TYPE_BMESH)) {
+      EditMeshData *emd = me_eval ? me_eval->runtime.edit_data : nullptr;
+
+      /* Only assign edit-mesh in the case we can't use `me_eval`. */
+      *r_em = em;
+      me_eval = nullptr;
+
+      if ((emd != nullptr) && (emd->vertexCos != nullptr)) {
+        *r_vert_coords = emd->vertexCos;
+        if (r_vert_normals != nullptr) {
+          BKE_editmesh_cache_ensure_vert_normals(em, emd);
+          *r_vert_normals = emd->vertexNos;
+        }
+      }
+    }
+  }
+  else {
+    me_eval = BKE_object_get_evaluated_mesh(ob);
+  }
+  return me_eval;
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Dupli-Collection Implementation (#OB_DUPLICOLLECTION)
+ * \{ */
+
+static void make_duplis_collection(const DupliContext *ctx)
+{
+  Object *ob = ctx->object;
+  Collection *collection;
+  float collection_mat[4][4];
+
+  if (ob->instance_collection == nullptr) {
+    return;
+  }
+  collection = ob->instance_collection;
+
+  /* Combine collection offset and `obmat`. */
+  unit_m4(collection_mat);
+  sub_v3_v3(collection_mat[3], collection->instance_offset);
+  mul_m4_m4m4(collection_mat, ob->obmat, collection_mat);
+  /* Don't access 'ob->obmat' from now on. */
+
+  eEvaluationMode mode = DEG_get_mode(ctx->depsgraph);
+  FOREACH_COLLECTION_VISIBLE_OBJECT_RECURSIVE_BEGIN (collection, cob, mode) {
+    if (cob != ob) {
+      float mat[4][4];
+
+      /* Collection dupli-offset, should apply after everything else. */
+      mul_m4_m4m4(mat, collection_mat, cob->obmat);
+
+      make_dupli(ctx, cob, mat, _base_id);
+
+      /* Recursion. */
+      make_recursive_duplis(ctx, cob, collection_mat, _base_id);
+    }
+  }
+  FOREACH_COLLECTION_VISIBLE_OBJECT_RECURSIVE_END;
+}
+
+static const DupliGenerator gen_dupli_collection = {
+    OB_DUPLICOLLECTION,    /* type */
+    make_duplis_collection /* make_duplis */
+};
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Dupli-Vertices Implementation (#OB_DUPLIVERTS for Geometry)
+ * \{ */
+
+/** Values shared between different mesh types. */
+struct VertexDupliData_Params {
+  /**
+   * It's important we use this context instead of the `ctx` passed into #make_child_duplis
+   * since these won't match in the case of recursion.
+   */
+  const DupliContext *ctx;
+
+  bool use_rotation;
+};
+
+struct VertexDupliData_Mesh {
+  VertexDupliData_Params params;
+
+  int totvert;
+  const MVert *mvert;
+
+  const float (*orco)[3];
+};
+
+struct VertexDupliData_EditMesh {
+  VertexDupliData_Params params;
+
+  BMEditMesh *em;
+
+  /* Can be nullptr. */
+  const float (*vert_coords)[3];
+  const float (*vert_normals)[3];
+
+  /**
+   * \note The edit-mesh may assign #DupliObject.orco in cases when a regular mesh wouldn't.
+   * For edit-meshes we only check for deformation, for regular meshes we check if #CD_ORCO exists.
+   *
+   * At the moment this isn't a meaningful difference since requesting #CD_ORCO causes the
+   * edit-mesh to be converted into a mesh.
+   */
+  bool has_orco;
+};
+
+/**
+ * \param no: The direction,
+ * currently this is copied from a `short[3]` normal without division.
+ * Can be null when \a use_rotation is false.
+ */
+static void get_duplivert_transform(const float co[3],
+                                    const float no[3],
+                                    const bool use_rotation,
+                                    const short axis,
+                                    const short upflag,
+                                    float r_mat[4][4])
+{
+  float quat[4];
+  const float size[3] = {1.0f, 1.0f, 1.0f};
+
+  if (use_rotation) {
+    /* Construct rotation matrix from normals. */
+    float no_flip[3];
+    negate_v3_v3(no_flip, no);
+    vec_to_quat(quat, no_flip, axis, upflag);
+  }
+  else {
+    unit_qt(quat);
+  }
+
+  loc_quat_size_to_mat4(r_mat, co, quat, size);
+}
+
+static DupliObject *vertex_dupli(const DupliContext *ctx,
+                                 Object *inst_ob,
+                                 const float child_imat[4][4],
+                                 int index,
+                                 const float co[3],
+                                 const float no[3],
+                                 const bool use_rotation)
+{
+  /* `obmat` is transform to vertex. */
+  float obmat[4][4];
+  get_duplivert_transform(co, no, use_rotation, inst_ob->trackflag, inst_ob->upflag, obmat);
+
+  float space_mat[4][4];
+
+  /* Make offset relative to inst_ob using relative child transform. */
+  mul_mat3_m4_v3(child_imat, obmat[3]);
+  /* Apply `obmat` _after_ the local vertex transform. */
+  mul_m4_m4m4(obmat, inst_ob->obmat, obmat);
+
+  /* Space matrix is constructed by removing `obmat` transform,
+   * this yields the world-space transform for recursive duplis. */
+  mul_m4_m4m4(space_mat, obmat, inst_ob->imat);
+
+  DupliObject *dob = make_dupli(ctx, inst_ob, obmat, index);
+
+  /* Recursion. */
+  make_recursive_duplis(ctx, inst_ob, space_mat, index);
+
+  return dob;
+}
+
+static void make_child_duplis_verts_from_mesh(const DupliContext *ctx,
+                                              void *userdata,
+                                              Object *inst_ob)
+{
+  VertexDupliData_Mesh *vdd = (VertexDupliData_Mesh *)userdata;
+  const bool use_rotation = vdd->params.use_rotation;
+
+  const MVert *mvert = vdd->mvert;
+  const int totvert = vdd->totvert;
+
+  invert_m4_m4(inst_ob->imat, inst_ob->obmat);
+  /* Relative transform from parent to child space. */
+  float child_imat[4][4];
+  mul_m4_m4m4(child_imat, inst_ob->imat, ctx->object->obmat);
+
+  const MVert *mv = mvert;
+  for (int i = 0; i < totvert; i++, mv++) {
+    const float *co = mv->co;
+    float no[3];
+    normal_short_to_float_v3(no, mv->no);
+    DupliObject *dob = vertex_dupli(vdd->params.ctx, inst_ob, child_imat, i, co, no, use_rotation);
+    if (vdd->orco) {
+      copy_v3_v3(dob->orco, vdd->orco[i]);
+    }
+  }
+}
+
+static void make_child_duplis_verts_from_editmesh(const DupliContext *ctx,
+                                                  void *userdata,
+                                                  Object *inst_ob)
+{
+  VertexDupliData_EditMesh *vdd = (VertexDupliData_EditMesh *)userdata;
+  BMEditMesh *em = vdd->em;
+  const bool use_rotation = vdd->params.use_rotation;
+
+  invert_m4_m4(inst_ob->imat, inst_ob->obmat);
+  /* Relative transform from parent to child space. */
+  float child_imat[4][4];
+  mul_m4_m4m4(child_imat, inst_ob->imat, ctx->object->obmat);
+
+  BMVert *v;
+  BMIter iter;
+  int i;
+
+  const float(*vert_coords)[3] = vdd->vert_coords;
+  const float(*vert_normals)[3] = vdd->vert_normals;
+
+  BM_ITER_MESH_INDEX (v, &iter, em->bm, BM_VERTS_OF_MESH, i) {
+    const float *co, *no;
+    if (vert_coords != nullptr) {
+      co = vert_coords[i];
+      no = vert_normals ? vert_normals[i] : nullptr;
+    }
+    else {
+      co = v->co;
+      no = v->no;
+    }
+
+    DupliObject *dob = vertex_dupli(vdd->params.ctx, inst_ob, child_imat, i, co, no, use_rotation);
+    if (vdd->has_orco) {
+      copy_v3_v3(dob->orco, v->co);
+    }
+  }
+}
+
+static void make_duplis_verts(const DupliContext *ctx)
+{
+  Object *parent = ctx->object;
+  const bool use_rotation = parent->transflag & OB_DUPLIROT;
+
+  /* Gather mesh info. */
+  BMEditMesh *em = nullptr;
+  const float(*vert_coords)[3] = nullptr;
+  const float(*vert_normals)[3] = nullptr;
+  Mesh *me_eval = mesh_data_from_duplicator_object(
+      parent, &em, &vert_coords, use_rotation ? &vert_normals : nullptr);
+  if (em == nullptr && me_eval == nullptr) {
+    return;
+  }
+
+  VertexDupliData_Params vdd_params{ctx, use_rotation};
+
+  if (em != nullptr) {
+    VertexDupliData_EditMesh vdd{};
+    vdd.params = vdd_params;
+    vdd.em = em;
+    vdd.vert_coords = vert_coords;
+    vdd.vert_normals = vert_normals;
+    vdd.has_orco = (vert_coords != nullptr);
+
+    make_child_duplis(ctx, &vdd, make_child_duplis_verts_from_editmesh);
+  }
+  else {
+    VertexDupliData_Mesh vdd{};
+    vdd.params = vdd_params;
+    vdd.totvert = me_eval->totvert;
+    vdd.mvert = me_eval->mvert;
+    vdd.orco = (const float(*)[3])CustomData_get_layer(&me_eval->vdata, CD_ORCO);
+
+    make_child_duplis(ctx, &vdd, make_child_duplis_verts_from_mesh);
+  }
+}
+
+static const DupliGenerator gen_dupli_verts = {
+    OB_DUPLIVERTS,    /* type */
+    make_duplis_verts /* make_duplis */
+};
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Dupli-Vertices Implementation (#OB_DUPLIVERTS for 3D Text)
+ * \{ */
+
+static Object *find_family_object(
+    Main *bmain, const char *family, size_t family_len, unsigned int ch, GHash *family_gh)
+{
+  void *ch_key = POINTER_FROM_UINT(ch);
+
+  Object **ob_pt;
+  if ((ob_pt = (Object **)BLI_ghash_lookup_p(family_gh, ch_key))) {
+    return *ob_pt;
+  }
+
+  char ch_utf8[7];
+  size_t ch_utf8_len;
+
+  ch_utf8_len = BLI_str_utf8_from_unicode(ch, ch_utf8);
+  ch_utf8[ch_utf8_len] = '\0';
+  ch_utf8_len += 1; /* Compare with null terminator. */
+
+  LISTBASE_FOREACH (Object *, ob, &bmain->objects) {
+    if (STREQLEN(ob->id.name + 2 + family_len, ch_utf8, ch_utf8_len)) {
+      if (STREQLEN(ob->id.name + 2, family, family_len)) {
+        /* Inserted value can be nullptr, just to save searches in future. */
+        BLI_ghash_insert(family_gh, ch_key, ob);
+        return ob;
+      }
+    }
+  }
+
+  return nullptr;
+}
+
+static void make_duplis_font(const DupliContext *ctx)
+{
+  Object *par = ctx->object;
+  GHash *family_gh;
+  Object *ob;
+  Curve *cu;
+  struct CharTrans *ct, *chartransdata = nullptr;
+  float vec[3], obmat[4][4], pmat[4][4], fsize, xof, yof;
+  int text_len, a;
+  size_t family_len;
+  const char32_t *text = nullptr;
+  bool text_free = false;
+
+  /* Font dupli-verts not supported inside collections. */
+  if (ctx->collection) {
+    return;
+  }
+
+  copy_m4_m4(pmat, par->obmat);
+
+  /* In `par` the family name is stored, use this to find the other objects. */
+
+  BKE_vfont_to_curve_ex(
+      par, (Curve *)par->data, FO_DUPLI, nullptr, &text, &text_len, &text_free, &chartransdata);
+
+  if (text == nullptr || chartransdata == nullptr) {
+    return;
+  }
+
+  cu = (Curve *)par->data;
+  fsize = cu->fsize;
+  xof = cu->xof;
+  yof = cu->yof;
+
+  ct = chartransdata;
+
+  /* Cache result. */
+  family_len = strlen(cu->family);
+  family_gh = BLI_ghash_int_new_ex(__func__, 256);
+
+  /* Safety check even if it might fail badly when called for original object. */
+  const bool is_eval_curve = DEG_is_evaluated_id(&cu->id);
+
+  /* Advance matching BLI_str_utf8_as_utf32. */
+  for (a = 0; a < text_len; a++, ct++) {
+
+    /* XXX That G.main is *really* ugly, but not sure what to do here.
+     * Definitively don't think it would be safe to put back `Main *bmain` pointer
+     * in #DupliContext as done in 2.7x? */
+    ob = find_family_object(G.main, cu->family, family_len, (unsigned int)text[a], family_gh);
+
+    if (is_eval_curve) {
+      /* Workaround for the above hack. */
+      ob = DEG_get_evaluated_object(ctx->depsgraph, ob);
+    }
+
+    if (ob) {
+      vec[0] = fsize * (ct->xof - xof);
+      vec[1] = fsize * (ct->yof - yof);
+      vec[2] = 0.0;
+
+      mul_m4_v3(pmat, vec);
+
+      copy_m4_m4(obmat, par->obmat);
+
+      if (UNLIKELY(ct->rot != 0.0f)) {
+        float rmat[4][4];
+
+        zero_v3(obmat[3]);
+        axis_angle_to_mat4_single(rmat, 'Z', -ct->rot);
+        mul_m4_m4m4(obmat, obmat, rmat);
+      }
+
+      copy_v3_v3(obmat[3], vec);
+
+      make_dupli(ctx, ob, obmat, a);
+    }
+  }
+
+  if (text_free) {
+    MEM_freeN((void *)text);
+  }
+
+  BLI_ghash_free(family_gh, nullptr, nullptr);
+
+  MEM_freeN(chartransdata);
+}
+
+static const DupliGenerator gen_dupli_verts_font = {
+    OB_DUPLIVERTS,   /* type */
+    make_duplis_font /* make_duplis */
+};
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Dupli-Vertices Implementation (#OB_DUPLIVERTS for #PointCloud)
+ * \{ */
+
+static void make_child_duplis_pointcloud(const DupliContext *ctx,
+                                         void *UNUSED(userdata),
+                                         Object *child)
+{
+  const Object *parent = ctx->object;
+  const PointCloud *pointcloud = (PointCloud *)parent->data;
+  const float(*co)[3] = pointcloud->co;
+  const float *radius = pointcloud->radius;
+  const float(*rotation)[4] = nullptr; /* TODO: add optional rotation attribute. */
+  const float(*orco)[3] = nullptr;     /* TODO: add optional texture coordinate attribute. */
+
+  /* Relative transform from parent to child space. */
+  float child_imat[4][4];
+  mul_m4_m4m4(child_imat, child->imat, parent->obmat);
+
+  for (int i = 0; i < pointcloud->totpoint; i++) {
+    /* Transform matrix from point position, radius and rotation. */
+    float quat[4] = {1.0f, 0.0f, 0.0f, 0.0f};
+    float size[3] = {1.0f, 1.0f, 1.0f};
+    if (radius) {
+      copy_v3_fl(size, radius[i]);
+    }
+    if (rotation) {
+      copy_v4_v4(quat, rotation[i]);
+    }
+
+    float space_mat[4][4];
+    loc_quat_size_to_mat4(space_mat, co[i], quat, size);
+
+    /* Make offset relative to child object using relative child transform,
+     * and apply object matrix after local vertex transform. */
+    mul_mat3_m4_v3(child_imat, space_mat[3]);
+
+    /* Create dupli object. */
+    float obmat[4][4];
+    mul_m4_m4m4(obmat, child->obmat, space_mat);
+    DupliObject *dob = make_dupli(ctx, child, obmat, i);
+    if (orco) {
+      copy_v3_v3(dob->orco, orco[i]);
+    }
+
+    /* Recursion. */
+    make_recursive_duplis(ctx, child, space_mat, i);
+  }
+}
+
+static void make_duplis_pointcloud(const DupliContext *ctx)
+{
+  make_child_duplis(ctx, nullptr, make_child_duplis_pointcloud);
+}
+
+static const DupliGenerator gen_dupli_verts_pointcloud = {
+    OB_DUPLIVERTS,         /* type */
+    make_duplis_pointcloud /* make_duplis */
+};
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Instances Geometry Component Implementation
+ * \{ */
+
+static void make_duplis_instances_component(const DupliContext *ctx)
+{
+  float(*instance_offset_matrices)[4][4];
+  InstancedData *instanced_data;
+  const int *almost_unique_ids;
+  const int amount = BKE_geometry_set_instances(ctx->object->runtime.geometry_set_eval,
+                                                &instance_offset_matrices,
+                                                &almost_unique_ids,
+                                                &instanced_data);
+
+  for (int i = 0; i < amount; i++) {
+    InstancedData *data = &instanced_data[i];
+
+    const int id = almost_unique_ids[i];
+
+    if (data->type == INSTANCE_DATA_TYPE_OBJECT) {
+      Object *object = data->data.object;
+      if (object != nullptr) {
+        float matrix[4][4];
+        mul_m4_m4m4(matrix, ctx->object->obmat, instance_offset_matrices[i]);
+        make_dupli(ctx, object, matrix, id);
+
+        float space_matrix[4][4];
+        mul_m4_m4m4(space_matrix, instance_offset_matrices[i], object->imat);
+        mul_m4_m4_pre(space_matrix, ctx->object->obmat);
+        make_recursive_duplis(ctx, object, space_matrix, id);
+      }
+    }
+    else if (data->type == INSTANCE_DATA_TYPE_COLLECTION) {
+      Collection *collection = data->data.collection;
+      if (collection != nullptr) {
+        float collection_matrix[4][4];
+        unit_m4(collection_matrix);
+        sub_v3_v3(collection_matrix[3], collection->instance_offset);
+        mul_m4_m4_pre(collection_matrix, instance_offset_matrices[i]);
+        mul_m4_m4_pre(collection_matrix, ctx->object->obmat);
+
+        eEvaluationMode mode = DEG_get_mode(ctx->depsgraph);
+        FOREACH_COLLECTION_VISIBLE_OBJECT_RECURSIVE_BEGIN (collection, object, mode) {
+          if (object == ctx->object) {
+            continue;
+          }
+
+          float instance_matrix[4][4];
+          mul_m4_m4m4(instance_matrix, collection_matrix, object->obmat);
+
+          make_dupli(ctx, object, instance_matrix, id);
+          make_recursive_duplis(ctx, object, collection_matrix, id);
+        }
+        FOREACH_COLLECTION_VISIBLE_OBJECT_RECURSIVE_END;
+      }
+    }
+  }
+}
+
+static const DupliGenerator gen_dupli_instances_component = {
+    0,
+    make_duplis_instances_component,
+};
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Dupli-Faces Implementation (#OB_DUPLIFACES)
+ * \{ */
+
+/** Values shared between different mesh types. */
+struct FaceDupliData_Params {
+  /**
+   * It's important we use this context instead of the `ctx` passed into #make_child_duplis
+   * since these won't match in the case of recursion.
+   */
+  const DupliContext *ctx;
+
+  bool use_scale;
+};
+
+struct FaceDupliData_Mesh {
+  FaceDupliData_Params params;
+
+  int totface;
+  const MPoly *mpoly;
+  const MLoop *mloop;
+  const MVert *mvert;
+  const float (*orco)[3];
+  const MLoopUV *mloopuv;
+};
+
+struct FaceDupliData_EditMesh {
+  FaceDupliData_Params params;
+
+  BMEditMesh *em;
+
+  bool has_orco, has_uvs;
+  int cd_loop_uv_offset;
+  /* Can be nullptr. */
+  const float (*vert_coords)[3];
+};
+
+static void get_dupliface_transform_from_coords(const float coords[][3],
+                                                const int coords_len,
+                                                const bool use_scale,
+                                                const float scale_fac,
+                                                float r_mat[4][4])
+{
+  float loc[3], quat[4], scale, size[3];
+
+  /* Location. */
+  {
+    const float w = 1.0f / (float)coords_len;
+    zero_v3(loc);
+    for (int i = 0; i < coords_len; i++) {
+      madd_v3_v3fl(loc, coords[i], w);
+    }
+  }
+  /* Rotation. */
+  {
+    float f_no[3];
+    cross_poly_v3(f_no, coords, (uint)coords_len);
+    normalize_v3(f_no);
+    tri_to_quat_ex(quat, coords[0], coords[1], coords[2], f_no);
+  }
+  /* Scale. */
+  if (use_scale) {
+    const float area = area_poly_v3(coords, (uint)coords_len);
+    scale = sqrtf(area) * scale_fac;
+  }
+  else {
+    scale = 1.0f;
+  }
+  size[0] = size[1] = size[2] = scale;
+
+  loc_quat_size_to_mat4(r_mat, loc, quat, size);
+}
+
+static DupliObject *face_dupli(const DupliContext *ctx,
+                               Object *inst_ob,
+                               const float child_imat[4][4],
+                               const int index,
+                               const bool use_scale,
+                               const float scale_fac,
+                               const float (*coords)[3],
+                               const int coords_len)
+{
+  float obmat[4][4];
+  float space_mat[4][4];
+
+  /* `obmat` is transform to face. */
+  get_dupliface_transform_from_coords(coords, coords_len, use_scale, scale_fac, obmat);
+
+  /* Make offset relative to inst_ob using relative child transform. */
+  mul_mat3_m4_v3(child_imat, obmat[3]);
+
+  /* XXX ugly hack to ensure same behavior as in master.
+   * This should not be needed, #Object.parentinv is not consistent outside of parenting. */
+  {
+    float imat[3][3];
+    copy_m3_m4(imat, inst_ob->parentinv);
+    mul_m4_m3m4(obmat, imat, obmat);
+  }
+
+  /* Apply `obmat` _after_ the local face transform. */
+  mul_m4_m4m4(obmat, inst_ob->obmat, obmat);
+
+  /* Space matrix is constructed by removing `obmat` transform,
+   * this yields the world-space transform for recursive duplis. */
+  mul_m4_m4m4(space_mat, obmat, inst_ob->imat);
+
+  DupliObject *dob = make_dupli(ctx, inst_ob, obmat, index);
+
+  /* Recursion. */
+  make_recursive_duplis(ctx, inst_ob, space_mat, index);
+
+  return dob;
+}
+
+/** Wrap #face_dupli, needed since we can't #alloca in a loop. */
+static DupliObject *face_dupli_from_mesh(const DupliContext *ctx,
+                                         Object *inst_ob,
+                                         const float child_imat[4][4],
+                                         const int index,
+                                         const bool use_scale,
+                                         const float scale_fac,
+
+                                         /* Mesh variables. */
+                                         const MPoly *mpoly,
+                                         const MLoop *mloopstart,
+                                         const MVert *mvert)
+{
+  const int coords_len = mpoly->totloop;
+  float(*coords)[3] = BLI_array_alloca(coords, (size_t)coords_len);
+
+  const MLoop *ml = mloopstart;
+  for (int i = 0; i < coords_len; i++, ml++) {
+    copy_v3_v3(coords[i], mvert[ml->v].co);
+  }
+
+  return face_dupli(ctx, inst_ob, child_imat, index, use_scale, scale_fac, coords, coords_len);
+}
+
+/** Wrap #face_dupli, needed since we can't #alloca in a loop. */
+static DupliObject *face_dupli_from_editmesh(const DupliContext *ctx,
+                                             Object *inst_ob,
+                                             const float child_imat[4][4],
+                                             const int index,
+                                             const bool use_scale,
+                                             const float scale_fac,
+
+                                             /* Mesh variables. */
+                                             BMFace *f,
+                                             const float (*vert_coords)[3])
+{
+  const int coords_len = f->len;
+  float(*coords)[3] = BLI_array_alloca(coords, (size_t)coords_len);
+
+  BMLoop *l_first, *l_iter;
+  int i = 0;
+  l_iter = l_first = BM_FACE_FIRST_LOOP(f);
+  if (vert_coords != nullptr) {
+    do {
+      copy_v3_v3(coords[i++], vert_coords[BM_elem_index_get(l_iter->v)]);
+    } while ((l_iter = l_iter->next) != l_first);
+  }
+  else {
+    do {
+      copy_v3_v3(coords[i++], l_iter->v->co);
+    } while ((l_iter = l_iter->next) != l_first);
+  }
+
+  return face_dupli(ctx, inst_ob, child_imat, index, use_scale, scale_fac, coords, coords_len);
+}
+
+static void make_child_duplis_faces_from_mesh(const DupliContext *ctx,
+                                              void *userdata,
+                                              Object *inst_ob)
+{
+  FaceDupliData_Mesh *fdd = (FaceDupliData_Mesh *)userdata;
+  const MPoly *mpoly = fdd->mpoly, *mp;
+  const MLoop *mloop = fdd->mloop;
+  const MVert *mvert = fdd->mvert;
+  const float(*orco)[3] = fdd->orco;
+  const MLoopUV *mloopuv = fdd->mloopuv;
+  const int totface = fdd->totface;
+  const bool use_scale = fdd->params.use_scale;
+  int a;
+
+  float child_imat[4][4];
+
+  invert_m4_m4(inst_ob->imat, inst_ob->obmat);
+  /* Relative transform from parent to child space. */
+  mul_m4_m4m4(child_imat, inst_ob->imat, ctx->object->obmat);
+  const float scale_fac = ctx->object->instance_faces_scale;
+
+  for (a = 0, mp = mpoly; a < totface; a++, mp++) {
+    const MLoop *loopstart = mloop + mp->loopstart;
+    DupliObject *dob = face_dupli_from_mesh(
+        fdd->params.ctx, inst_ob, child_imat, a, use_scale, scale_fac, mp, loopstart, mvert);
+
+    const float w = 1.0f / (float)mp->totloop;
+    if (orco) {
+      for (int j = 0; j < mp->totloop; j++) {
+        madd_v3_v3fl(dob->orco, orco[loopstart[j].v], w);
+      }
+    }
+    if (mloopuv) {
+      for (int j = 0; j < mp->totloop; j++) {
+        madd_v2_v2fl(dob->uv, mloopuv[mp->loopstart + j].uv, w);
+      }
+    }
+  }
+}
+
+static void make_child_duplis_faces_from_editmesh(const DupliContext *ctx,
+                                                  void *userdata,
+                                                  Object *inst_ob)
+{
+  FaceDupliData_EditMesh *fdd = (FaceDupliData_EditMesh *)userdata;
+  BMEditMesh *em = fdd->em;
+  float child_imat[4][4];
+  int a;
+  BMFace *f;
+  BMIter iter;
+  const bool use_scale = fdd->params.use_scale;
+
+  const float(*vert_coords)[3] = fdd->vert_coords;
+
+  BLI_assert((vert_coords == nullptr) || (em->bm->elem_index_dirty & BM_VERT) == 0);
+
+  invert_m4_m4(inst_ob->imat, inst_ob->obmat);
+  /* Relative transform from parent to child space. */
+  mul_m4_m4m4(child_imat, inst_ob->imat, ctx->object->obmat);
+  const float scale_fac = ctx->object->instance_faces_scale;
+
+  BM_ITER_MESH_INDEX (f, &iter, em->bm, BM_FACES_OF_MESH, a) {
+    DupliObject *dob = face_dupli_from_editmesh(
+        fdd->params.ctx, inst_ob, child_imat, a, use_scale, scale_fac, f, vert_coords);
+
+    if (fdd->has_orco) {
+      const float w = 1.0f / (float)f->len;
+      BMLoop *l_first, *l_iter;
+      l_iter = l_first = BM_FACE_FIRST_LOOP(f);
+      do {
+        madd_v3_v3fl(dob->orco, l_iter->v->co, w);
+      } while ((l_iter = l_iter->next) != l_first);
+    }
+    if (fdd->has_uvs) {
+      BM_face_uv_calc_center_median(f, fdd->cd_loop_uv_offset, dob->uv);
+    }
+  }
+}
+
+static void make_duplis_faces(const DupliContext *ctx)
+{
+  Object *parent = ctx->object;
+
+  /* Gather mesh info. */
+  BMEditMesh *em = nullptr;
+  const float(*vert_coords)[3] = nullptr;
+  Mesh *me_eval = mesh_data_from_duplicator_object(parent, &em, &vert_coords, nullptr);
+  if (em == nullptr && me_eval == nullptr) {
+    return;
+  }
+
+  FaceDupliData_Params fdd_params = {ctx, (parent->transflag & OB_DUPLIFACES_SCALE) != 0};
+
+  if (em != nullptr) {
+    const int uv_idx = CustomData_get_render_layer(&em->bm->ldata, CD_MLOOPUV);
+    FaceDupliData_EditMesh fdd{};
+    fdd.params = fdd_params;
+    fdd.em = em;
+    fdd.vert_coords = vert_coords;
+    fdd.has_orco = (vert_coords != nullptr);
+    fdd.has_uvs = (uv_idx != -1);
+    fdd.cd_loop_uv_offset = (uv_idx != -1) ?
+                                CustomData_get_n_offset(&em->bm->ldata, CD_MLOOPUV, uv_idx) :
+                                -1;
+    make_child_duplis(ctx, &fdd, make_child_duplis_faces_from_editmesh);
+  }
+  else {
+    const int uv_idx = CustomData_get_render_layer(&me_eval->ldata, CD_MLOOPUV);
+    FaceDupliData_Mesh fdd{};
+    fdd.params = fdd_params;
+    fdd.totface = me_eval->totpoly;
+    fdd.mpoly = me_eval->mpoly;
+    fdd.mloop = me_eval->mloop;
+    fdd.mvert = me_eval->mvert;
+    fdd.mloopuv = (uv_idx != -1) ? (const MLoopUV *)CustomData_get_layer_n(
+                                       &me_eval->ldata, CD_MLOOPUV, uv_idx) :
+                                   nullptr;
+    fdd.orco = (const float(*)[3])CustomData_get_layer(&me_eval->vdata, CD_ORCO);
+
+    make_child_duplis(ctx, &fdd, make_child_duplis_faces_from_mesh);
+  }
+}
+
+static const DupliGenerator gen_dupli_faces = {
+    OB_DUPLIFACES,    /* type */
+    make_duplis_faces /* make_duplis */
+};
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Dupli-Particles Implementation (#OB_DUPLIPARTS)
+ * \{ */
+
+static void make_duplis_particle_system(const DupliContext *ctx, ParticleSystem *psys)
+{
+  Scene *scene = ctx->scene;
+  Object *par = ctx->object;
+  eEvaluationMode mode = DEG_get_mode(ctx->depsgraph);
+  bool for_render = mode == DAG_EVAL_RENDER;
+
+  Object *ob = nullptr, **oblist = nullptr;
+  DupliObject *dob;
+  ParticleSettings *part;
+  ParticleData *pa;
+  ChildParticle *cpa = nullptr;
+  ParticleKey state;
+  ParticleCacheKey *cache;
+  float ctime, scale = 1.0f;
+  float tmat[4][4], mat[4][4], pamat[4][4], size = 0.0;
+  int a, b, hair = 0;
+  int totpart, totchild;
+
+  int no_draw_flag = PARS_UNEXIST;
+
+  if (psys == nullptr) {
+    return;
+  }
+
+  part = psys->part;
+
+  if (part == nullptr) {
+    return;
+  }
+
+  if (!psys_check_enabled(par, psys, for_render)) {
+    return;
+  }
+
+  if (!for_render) {
+    no_draw_flag |= PARS_NO_DISP;
+  }
+
+  /* NOTE: in old animation system, used parent object's time-offset. */
+  ctime = DEG_get_ctime(ctx->depsgraph);
+
+  totpart = psys->totpart;
+  totchild = psys->totchild;
+
+  if ((for_render || part->draw_as == PART_DRAW_REND) &&
+      ELEM(part->ren_as, PART_DRAW_OB, PART_DRAW_GR)) {
+    ParticleSimulationData sim = {nullptr};
+    sim.depsgraph = ctx->depsgraph;
+    sim.scene = scene;
+    sim.ob = par;
+    sim.psys = psys;
+    sim.psmd = psys_get_modifier(par, psys);
+    /* Make sure emitter `imat` is in global coordinates instead of render view coordinates. */
+    invert_m4_m4(par->imat, par->obmat);
+
+    /* First check for loops (particle system object used as dupli-object). */
+    if (part->ren_as == PART_DRAW_OB) {
+      if (ELEM(part->instance_object, nullptr, par)) {
+        return;
+      }
+    }
+    else { /* #PART_DRAW_GR. */
+      if (part->instance_collection == nullptr) {
+        return;
+      }
+
+      const ListBase dup_collection_objects = BKE_collection_object_cache_get(
+          part->instance_collection);
+      if (BLI_listbase_is_empty(&dup_collection_objects)) {
+        return;
+      }
+
+      if (BLI_findptr(&dup_collection_objects, par, offsetof(Base, object))) {
+        return;
+      }
+    }
+
+    /* If we have a hair particle system, use the path cache. */
+    if (part->type == PART_HAIR) {
+      if (psys->flag & PSYS_HAIR_DONE) {
+        hair = (totchild == 0 || psys->childcache) && psys->pathcache;
+      }
+      if (!hair) {
+        return;
+      }
+
+      /* We use cache, update `totchild` according to cached data. */
+      totchild = psys->totchildcache;
+      totpart = psys->totcached;
+    }
+
+    RNG *rng = BLI_rng_new_srandom(31415926u + (unsigned int)psys->seed);
+
+    psys->lattice_deform_data = psys_create_lattice_deform_data(&sim);
+
+    /* Gather list of objects or single object. */
+    int totcollection = 0;
+
+    const bool use_whole_collection = part->draw & PART_DRAW_WHOLE_GR;
+    const bool use_collection_count = part->draw & PART_DRAW_COUNT_GR && !use_whole_collection;
+    if (part->ren_as == PART_DRAW_GR) {
+      if (use_collection_count) {
+        psys_find_group_weights(part);
+        LISTBASE_FOREACH (ParticleDupliWeight *, dw, &part->instance_weights) {
+          FOREACH_COLLECTION_VISIBLE_OBJECT_RECURSIVE_BEGIN (
+              part->instance_collection, object, mode) {
+            if (dw->ob == object) {
+              totcollection += dw->count;
+              break;
+            }
+          }
+          FOREACH_COLLECTION_VISIBLE_OBJECT_RECURSIVE_END;
+        }
+      }
+      else {
+        FOREACH_COLLECTION_VISIBLE_OBJECT_RECURSIVE_BEGIN (
+            part->instance_collection, object, mode) {
+          (void)object;
+          totcollection++;
+        }
+        FOREACH_COLLECTION_VISIBLE_OBJECT_RECURSIVE_END;
+      }
+
+      oblist = (Object **)MEM_callocN((size_t)totcollection * sizeof(Object *),
+                                      "dupcollection object list");
+
+      if (use_collection_count) {
+        a = 0;
+        LISTBASE_FOREACH (ParticleDupliWeight *, dw, &part->instance_weights) {
+          FOREACH_COLLECTION_VISIBLE_OBJECT_RECURSIVE_BEGIN (
+              part->instance_collection, object, mode) {
+            if (dw->ob == object) {
+              for (b = 0; b < dw->count; b++, a++) {
+                oblist[a] = dw->ob;
+              }
+              break;
+            }
+          }
+          FOREACH_COLLECTION_VISIBLE_OBJECT_RECURSIVE_END;
+        }
+      }
+      else {
+        a = 0;
+        FOREACH_COLLECTION_VISIBLE_OBJECT_RECURSIVE_BEGIN (
+            part->instance_collection, object, mode) {
+          oblist[a] = object;
+          a++;
+        }
+        FOREACH_COLLECTION_VISIBLE_OBJECT_RECURSIVE_END;
+      }
+    }
+    else {
+      ob = part->instance_object;
+    }
+
+    if (totchild == 0 || part->draw & PART_DRAW_PARENT) {
+      a = 0;
+    }
+    else {
+      a = totpart;
+    }
+
+    for (pa = psys->particles; a < totpart + totchild; a++, pa++) {
+      if (a < totpart) {
+        /* Handle parent particle. */
+        if (pa->flag & no_draw_flag) {
+          continue;
+        }
+
+#if 0 /* UNUSED */
+        pa_num = pa->num;
+#endif
+        size = pa->size;
+      }
+      else {
+        /* Handle child particle. */
+        cpa = &psys->child[a - totpart];
+
+#if 0 /* UNUSED */
+        pa_num = a;
+#endif
+        size = psys_get_child_size(psys, cpa, ctime, nullptr);
+      }
+
+      /* Some hair paths might be non-existent so they can't be used for duplication. */
+      if (hair && psys->pathcache &&
+          ((a < totpart && psys->pathcache[a]->segments < 0) ||
+           (a >= totpart && psys->childcache[a - totpart]->segments < 0))) {
+        continue;
+      }
+
+      if (part->ren_as == PART_DRAW_GR) {
+        /* Prevent divide by zero below T28336. */
+        if (totcollection == 0) {
+          continue;
+        }
+
+        /* For collections, pick the object based on settings. */
+        if (part->draw & PART_DRAW_RAND_GR && !use_whole_collection) {
+          b = BLI_rng_get_int(rng) % totcollection;
+        }
+        else {
+          b = a % totcollection;
+        }
+
+        ob = oblist[b];
+      }
+
+      if (hair) {
+        /* Hair we handle separate and compute transform based on hair keys. */
+        if (a < totpart) {
+          cache = psys->pathcache[a];
+          psys_get_dupli_path_transform(&sim, pa, nullptr, cache, pamat, &scale);
+        }
+        else {
+          cache = psys->childcache[a - totpart];
+          psys_get_dupli_path_transform(&sim, nullptr, cpa, cache, pamat, &scale);
+        }
+
+        copy_v3_v3(pamat[3], cache->co);
+        pamat[3][3] = 1.0f;
+      }
+      else {
+        /* First key. */
+        state.time = ctime;
+        if (psys_get_particle_state(&sim, a, &state, 0) == 0) {
+          continue;
+        }
+
+        float tquat[4];
+        normalize_qt_qt(tquat, state.rot);
+        quat_to_mat4(pamat, tquat);
+        copy_v3_v3(pamat[3], state.co);
+        pamat[3][3] = 1.0f;
+      }
+
+      if (part->ren_as == PART_DRAW_GR && psys->part->draw & PART_DRAW_WHOLE_GR) {
+        b = 0;
+        FOREACH_COLLECTION_VISIBLE_OBJECT_RECURSIVE_BEGIN (
+            part->instance_collection, object, mode) {
+          copy_m4_m4(tmat, oblist[b]->obmat);
+
+          /* Apply collection instance offset. */
+          sub_v3_v3(tmat[3], part->instance_collection->instance_offset);
+
+          /* Apply particle scale. */
+          mul_mat3_m4_fl(tmat, size * scale);
+          mul_v3_fl(tmat[3], size * scale);
+
+          /* Individual particle transform. */
+          mul_m4_m4m4(mat, pamat, tmat);
+
+          dob = make_dupli(ctx, object, mat, a);
+          dob->particle_system = psys;
+
+          psys_get_dupli_texture(psys, part, sim.psmd, pa, cpa, dob->uv, dob->orco);
+
+          b++;
+        }
+        FOREACH_COLLECTION_VISIBLE_OBJECT_RECURSIVE_END;
+      }
+      else {
+        float obmat[4][4];
+        copy_m4_m4(obmat, ob->obmat);
+
+        float vec[3];
+        copy_v3_v3(vec, obmat[3]);
+        zero_v3(obmat[3]);
+
+        /* Particle rotation uses x-axis as the aligned axis,
+         * so pre-rotate the object accordingly. */
+        if ((part->draw & PART_DRAW_ROTATE_OB) == 0) {
+          float xvec[3], q[4], size_mat[4][4], original_size[3];
+
+          mat4_to_size(original_size, obmat);
+          size_to_mat4(size_mat, original_size);
+
+          xvec[0] = -1.0f;
+          xvec[1] = xvec[2] = 0;
+          vec_to_quat(q, xvec, ob->trackflag, ob->upflag);
+          quat_to_mat4(obmat, q);
+          obmat[3][3] = 1.0f;
+
+          /* Add scaling if requested. */
+          if ((part->draw & PART_DRAW_NO_SCALE_OB) == 0) {
+            mul_m4_m4m4(obmat, obmat, size_mat);
+          }
+        }
+        else if (part->draw & PART_DRAW_NO_SCALE_OB) {
+          /* Remove scaling. */
+          float size_mat[4][4], original_size[3];
+
+          mat4_to_size(original_size, obmat);
+          size_to_mat4(size_mat, original_size);
+          invert_m4(size_mat);
+
+          mul_m4_m4m4(obmat, obmat, size_mat);
+        }
+
+        mul_m4_m4m4(tmat, pamat, obmat);
+        mul_mat3_m4_fl(tmat, size * scale);
+
+        copy_m4_m4(mat, tmat);
+
+        if (part->draw & PART_DRAW_GLOBAL_OB) {
+          add_v3_v3v3(mat[3], mat[3], vec);
+        }
+
+        dob = make_dupli(ctx, ob, mat, a);
+        dob->particle_system = psys;
+        psys_get_dupli_texture(psys, part, sim.psmd, pa, cpa, dob->uv, dob->orco);
+      }
+    }
+
+    BLI_rng_free(rng);
+  }
+
+  /* Clean up. */
+  if (oblist) {
+    MEM_freeN(oblist);
+  }
+
+  if (psys->lattice_deform_data) {
+    BKE_lattice_deform_data_destroy(psys->lattice_deform_data);
+    psys->lattice_deform_data = nullptr;
+  }
+}
+
+static void make_duplis_particles(const DupliContext *ctx)
+{
+  /* Particle system take up one level in id, the particles another. */
+  int psysid;
+  LISTBASE_FOREACH_INDEX (ParticleSystem *, psys, &ctx->object->particlesystem, psysid) {
+    /* Particles create one more level for persistent `psys` index. */
+    DupliContext pctx;
+    copy_dupli_context(&pctx, ctx, ctx->object, nullptr, psysid);
+    make_duplis_particle_system(&pctx, psys);
+  }
+}
+
+static const DupliGenerator gen_dupli_particles = {
+    OB_DUPLIPARTS,        /* type */
+    make_duplis_particles /* make_duplis */
+};
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Dupli-Generator Selector For The Given Context
+ * \{ */
+
+static const DupliGenerator *get_dupli_generator(const DupliContext *ctx)
+{
+  int transflag = ctx->object->transflag;
+  int restrictflag = ctx->object->restrictflag;
+
+  if ((transflag & OB_DUPLI) == 0 && ctx->object->runtime.geometry_set_eval == nullptr) {
+    return nullptr;
+  }
+
+  /* Should the dupli's be generated for this object? - Respect restrict flags. */
+  if (DEG_get_mode(ctx->depsgraph) == DAG_EVAL_RENDER ? (restrictflag & OB_RESTRICT_RENDER) :
+                                                        (restrictflag & OB_RESTRICT_VIEWPORT)) {
+    return nullptr;
+  }
+
+  if (ctx->object->runtime.geometry_set_eval != nullptr) {
+    if (BKE_geometry_set_has_instances(ctx->object->runtime.geometry_set_eval)) {
+      return &gen_dupli_instances_component;
+    }
+  }
+
+  if (transflag & OB_DUPLIPARTS) {
+    return &gen_dupli_particles;
+  }
+  if (transflag & OB_DUPLIVERTS) {
+    if (ctx->object->type == OB_MESH) {
+      return &gen_dupli_verts;
+    }
+    if (ctx->object->type == OB_FONT) {
+      return &gen_dupli_verts_font;
+    }
+    if (ctx->object->type == OB_POINTCLOUD) {
+      return &gen_dupli_verts_pointcloud;
+    }
+  }
+  else if (transflag & OB_DUPLIFACES) {
+    if (ctx->object->type == OB_MESH) {
+      return &gen_dupli_faces;
+    }
+  }
+  else if (transflag & OB_DUPLICOLLECTION) {
+    return &gen_dupli_collection;
+  }
+
+  return nullptr;
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Dupli-Container Implementation
+ * \{ */
+
+/**
+ * \return a #ListBase of #DupliObject.
+ */
+ListBase *object_duplilist(Depsgraph *depsgraph, Scene *sce, Object *ob)
+{
+  ListBase *duplilist = (ListBase *)MEM_callocN(sizeof(ListBase), "duplilist");
+  DupliContext ctx;
+  init_context(&ctx, depsgraph, sce, ob, nullptr);
+  if (ctx.gen) {
+    ctx.duplilist = duplilist;
+    ctx.gen->make_duplis(&ctx);
+  }
+
+  return duplilist;
+}
+
+void free_object_duplilist(ListBase *lb)
+{
+  BLI_freelistN(lb);
+  MEM_freeN(lb);
+}
+
+/** \} */