Pointclouds: support mesh <-> pointcloud in convert operator

Just converts verts to points and vice versa.
Materials and Attribute layers are preserved (so for example if you set
custom radii on the pointcloud, convert to mesh, then convert back to
pointcloud, this will be preserved).

Also not add a Radius layer by default (it is still added and
filled when adding a pointcloud object from the menu), a global Radius
property that will be used if there is no radius attribute can be added
later. A Radius attribute can also be added in the pointcloud data
properties (and filled via python).

This will also add a new utility function that copies materials between
datablocks: BKE_id_materials_copy

ref T75717

Differential Revision: https://developer.blender.org/D7391

4 files changed, 139 insertions, 11 deletions

diff --git a/source/blender/blenkernel/intern/material.c b/source/blender/blenkernel/intern/material.c
index 885cc1baefc..d8c0b5d6dce 100644
--- a/source/blender/blenkernel/intern/material.c
+++ b/source/blender/blenkernel/intern/material.c
@@ -535,6 +535,27 @@ static void material_data_index_clear_id(ID *id)
   }
 }
 
+void BKE_id_materials_copy(Main *bmain, ID *id_src, ID *id_dst)
+{
+  Material ***matar_src = BKE_id_material_array_p(id_src);
+  const short *materials_len_p_src = BKE_id_material_len_p(id_src);
+
+  Material ***matar_dst = BKE_id_material_array_p(id_dst);
+  short *materials_len_p_dst = BKE_id_material_len_p(id_dst);
+
+  *materials_len_p_dst = *materials_len_p_src;
+  if (*materials_len_p_src != 0) {
+    (*matar_dst) = MEM_dupallocN(*matar_src);
+
+    for (int a = 0; a < *materials_len_p_src; a++) {
+      id_us_plus((ID *)(*matar_dst)[a]);
+    }
+
+    DEG_id_tag_update(id_dst, ID_RECALC_COPY_ON_WRITE);
+    DEG_relations_tag_update(bmain);
+  }
+}
+
 void BKE_id_material_resize(Main *bmain, ID *id, short totcol, bool do_id_user)
 {
   Material ***matar = BKE_id_material_array_p(id);
diff --git a/source/blender/blenkernel/intern/mesh_convert.c b/source/blender/blenkernel/intern/mesh_convert.c
index 60a9ef2df55..557948ef3a4 100644
--- a/source/blender/blenkernel/intern/mesh_convert.c
+++ b/source/blender/blenkernel/intern/mesh_convert.c
@@ -28,6 +28,7 @@
 #include "DNA_mesh_types.h"
 #include "DNA_meta_types.h"
 #include "DNA_object_types.h"
+#include "DNA_pointcloud_types.h"
 #include "DNA_scene_types.h"
 
 #include "BLI_edgehash.h"
@@ -53,6 +54,8 @@
 #include "BKE_curve.h"
 /* -- */
 #include "BKE_object.h"
+/* -- */
+#include "BKE_pointcloud.h"
 
 #include "DEG_depsgraph.h"
 #include "DEG_depsgraph_query.h"
@@ -903,6 +906,100 @@ void BKE_mesh_to_curve(Main *bmain, Depsgraph *depsgraph, Scene *UNUSED(scene),
   }
 }
 
+void BKE_pointcloud_from_mesh(Mesh *me, PointCloud *pointcloud)
+{
+  BLI_assert(me != NULL);
+
+  pointcloud->totpoint = me->totvert;
+  CustomData_realloc(&pointcloud->pdata, pointcloud->totpoint);
+
+  /* Copy over all attributes. */
+  const CustomData_MeshMasks mask = {
+      .vmask = CD_MASK_PROP_ALL,
+  };
+  CustomData_merge(&me->vdata, &pointcloud->pdata, mask.vmask, CD_DUPLICATE, me->totvert);
+  BKE_pointcloud_update_customdata_pointers(pointcloud);
+  CustomData_update_typemap(&pointcloud->pdata);
+
+  MVert *mvert;
+  mvert = me->mvert;
+  for (int i = 0; i < me->totvert; i++, mvert++) {
+    copy_v3_v3(pointcloud->co[i], mvert->co);
+  }
+}
+
+void BKE_mesh_to_pointcloud(Main *bmain, Depsgraph *depsgraph, Scene *UNUSED(scene), Object *ob)
+{
+  BLI_assert(ob->type == OB_MESH);
+
+  Scene *scene_eval = DEG_get_evaluated_scene(depsgraph);
+  Object *ob_eval = DEG_get_evaluated_object(depsgraph, ob);
+  Mesh *me_eval = mesh_get_eval_final(depsgraph, scene_eval, ob_eval, &CD_MASK_MESH);
+
+  PointCloud *pointcloud = BKE_pointcloud_add(bmain, ob->id.name + 2);
+
+  BKE_pointcloud_from_mesh(me_eval, pointcloud);
+
+  BKE_id_materials_copy(bmain, (ID *)ob->data, (ID *)pointcloud);
+
+  id_us_min(&((Mesh *)ob->data)->id);
+  ob->data = pointcloud;
+  ob->type = OB_POINTCLOUD;
+
+  BKE_object_free_derived_caches(ob);
+}
+
+void BKE_mesh_from_pointcloud(PointCloud *pointcloud, Mesh *me)
+{
+  BLI_assert(pointcloud != NULL);
+
+  me->totvert = pointcloud->totpoint;
+
+  /* Merge over all attributes. */
+  const CustomData_MeshMasks mask = {
+      .vmask = CD_MASK_PROP_ALL,
+  };
+  CustomData_merge(&pointcloud->pdata, &me->vdata, mask.vmask, CD_DUPLICATE, pointcloud->totpoint);
+
+  /* Convert the Position attribute to a mesh vertex. */
+  me->mvert = CustomData_add_layer(&me->vdata, CD_MVERT, CD_CALLOC, NULL, me->totvert);
+  CustomData_update_typemap(&me->vdata);
+
+  const int layer_idx = CustomData_get_named_layer_index(
+      &me->vdata, CD_PROP_FLOAT3, POINTCLOUD_ATTR_POSITION);
+  CustomDataLayer *pos_layer = &me->vdata.layers[layer_idx];
+  float(*positions)[3] = pos_layer->data;
+
+  MVert *mvert;
+  mvert = me->mvert;
+  for (int i = 0; i < me->totvert; i++, mvert++) {
+    copy_v3_v3(mvert->co, positions[i]);
+  }
+
+  /* Delete Position attribute since it is now in vertex coordinates. */
+  CustomData_free_layer(&me->vdata, CD_PROP_FLOAT3, me->totvert, layer_idx);
+}
+
+void BKE_pointcloud_to_mesh(Main *bmain, Depsgraph *depsgraph, Scene *UNUSED(scene), Object *ob)
+{
+  BLI_assert(ob->type == OB_POINTCLOUD);
+
+  Object *ob_eval = DEG_get_evaluated_object(depsgraph, ob);
+  PointCloud *pointcloud_eval = (PointCloud *)ob_eval->runtime.data_eval;
+
+  Mesh *me = BKE_mesh_add(bmain, ob->id.name + 2);
+
+  BKE_mesh_from_pointcloud(pointcloud_eval, me);
+
+  BKE_id_materials_copy(bmain, (ID *)ob->data, (ID *)me);
+
+  id_us_min(&((PointCloud *)ob->data)->id);
+  ob->data = me;
+  ob->type = OB_MESH;
+
+  BKE_object_free_derived_caches(ob);
+}
+
 /* Create a temporary object to be used for nurbs-to-mesh conversion.
  *
  * This is more complex that it should be because BKE_mesh_from_nurbs_displist() will do more than
diff --git a/source/blender/blenkernel/intern/object.c b/source/blender/blenkernel/intern/object.c
index 07a20c417fe..23faaff7734 100644
--- a/source/blender/blenkernel/intern/object.c
+++ b/source/blender/blenkernel/intern/object.c
@@ -48,6 +48,7 @@
 #include "DNA_meta_types.h"
 #include "DNA_movieclip_types.h"
 #include "DNA_object_types.h"
+#include "DNA_pointcloud_types.h"
 #include "DNA_rigidbody_types.h"
 #include "DNA_scene_types.h"
 #include "DNA_screen_types.h"
@@ -1285,7 +1286,7 @@ void *BKE_object_obdata_add_from_type(Main *bmain, int type, const char *name)
     case OB_HAIR:
       return BKE_hair_add(bmain, name);
     case OB_POINTCLOUD:
-      return BKE_pointcloud_add(bmain, name);
+      return BKE_pointcloud_add_default(bmain, name);
     case OB_VOLUME:
       return BKE_volume_add(bmain, name);
     case OB_EMPTY:
diff --git a/source/blender/blenkernel/intern/pointcloud.c b/source/blender/blenkernel/intern/pointcloud.c
index 6ec305a971c..02f318445ac 100644
--- a/source/blender/blenkernel/intern/pointcloud.c
+++ b/source/blender/blenkernel/intern/pointcloud.c
@@ -53,8 +53,8 @@
 
 static void pointcloud_random(PointCloud *pointcloud);
 
-static const char *POINTCLOUD_ATTR_POSITION = "Position";
-static const char *POINTCLOUD_ATTR_RADIUS = "Radius";
+const char *POINTCLOUD_ATTR_POSITION = "Position";
+const char *POINTCLOUD_ATTR_RADIUS = "Radius";
 
 static void pointcloud_init_data(ID *id)
 {
@@ -70,15 +70,7 @@ static void pointcloud_init_data(ID *id)
                              NULL,
                              pointcloud->totpoint,
                              POINTCLOUD_ATTR_POSITION);
-  CustomData_add_layer_named(&pointcloud->pdata,
-                             CD_PROP_FLOAT,
-                             CD_CALLOC,
-                             NULL,
-                             pointcloud->totpoint,
-                             POINTCLOUD_ATTR_RADIUS);
   BKE_pointcloud_update_customdata_pointers(pointcloud);
-
-  pointcloud_random(pointcloud);
 }
 
 static void pointcloud_copy_data(Main *UNUSED(bmain), ID *id_dst, const ID *id_src, const int flag)
@@ -221,6 +213,23 @@ void *BKE_pointcloud_add(Main *bmain, const char *name)
   return pointcloud;
 }
 
+void *BKE_pointcloud_add_default(Main *bmain, const char *name)
+{
+  PointCloud *pointcloud = BKE_libblock_alloc(bmain, ID_PT, name, 0);
+
+  pointcloud_init_data(&pointcloud->id);
+
+  CustomData_add_layer_named(&pointcloud->pdata,
+                             CD_PROP_FLOAT,
+                             CD_CALLOC,
+                             NULL,
+                             pointcloud->totpoint,
+                             POINTCLOUD_ATTR_RADIUS);
+  pointcloud_random(pointcloud);
+
+  return pointcloud;
+}
+
 PointCloud *BKE_pointcloud_copy(Main *bmain, const PointCloud *pointcloud)
 {
   PointCloud *pointcloud_copy;