Link/Append: support instancing object data

This patch supports instantiating object data on append/link,
reported as a bug T58304.

This is an option, available when linking/appending,
similar to the existing "Instance Collections" option.

Reviewed by @sybren

Ref D8792

4 files changed, 74 insertions, 3 deletions

diff --git a/source/blender/blenloader/intern/readfile.c b/source/blender/blenloader/intern/readfile.c
index 35534963433..c809a87b188 100644
--- a/source/blender/blenloader/intern/readfile.c
+++ b/source/blender/blenloader/intern/readfile.c
@@ -10328,6 +10328,60 @@ static void add_loose_objects_to_scene(Main *mainvar,
   }
 }
 
+static void add_loose_object_data_to_scene(Main *mainvar,
+                                           Main *bmain,
+                                           Scene *scene,
+                                           ViewLayer *view_layer,
+                                           const View3D *v3d,
+                                           const short flag)
+{
+  if ((flag & FILE_OBDATA_INSTANCE) == 0) {
+    return;
+  }
+
+  Collection *active_collection = scene->master_collection;
+  if (flag & FILE_ACTIVE_COLLECTION) {
+    LayerCollection *lc = BKE_layer_collection_get_active(view_layer);
+    active_collection = lc->collection;
+  }
+
+  /* Loop over all ID types, instancing object-data for ID types that have support for it. */
+  ListBase *lbarray[MAX_LIBARRAY];
+  int i = set_listbasepointers(mainvar, lbarray);
+  while (i--) {
+    const short idcode = BKE_idtype_idcode_from_index(i);
+    if (!OB_DATA_SUPPORT_ID(idcode)) {
+      continue;
+    }
+
+    LISTBASE_FOREACH (ID *, id, lbarray[i]) {
+      if (id->tag & LIB_TAG_DOIT) {
+        const int type = BKE_object_obdata_to_type(id);
+        BLI_assert(type != -1);
+        Object *ob = BKE_object_add_only_object(bmain, type, id->name + 2);
+        ob->data = id;
+        id_us_plus(id);
+        BKE_object_materials_test(bmain, ob, ob->data);
+
+        BKE_collection_object_add(bmain, active_collection, ob);
+        Base *base = BKE_view_layer_base_find(view_layer, ob);
+
+        if (v3d != NULL) {
+          base->local_view_bits |= v3d->local_view_uuid;
+        }
+
+        if (flag & FILE_AUTOSELECT) {
+          base->flag |= BASE_SELECTED;
+        }
+
+        BKE_scene_object_base_flag_sync_from_base(base);
+
+        copy_v3_v3(ob->loc, scene->cursor.location);
+      }
+    }
+  }
+}
+
 static void add_collections_to_scene(Main *mainvar,
                                      Main *bmain,
                                      Scene *scene,
@@ -10554,6 +10608,11 @@ static bool library_link_idcode_needs_tag_check(const short idcode, const int fl
     if (ELEM(idcode, ID_OB, ID_GR)) {
       return true;
     }
+    if (flag & FILE_OBDATA_INSTANCE) {
+      if (OB_DATA_SUPPORT_ID(idcode)) {
+        return true;
+      }
+    }
   }
   return false;
 }
@@ -10761,6 +10820,7 @@ static void library_link_end(Main *mainl,
     if (scene != NULL) {
       add_collections_to_scene(mainvar, bmain, scene, view_layer, v3d, curlib, flag);
       add_loose_objects_to_scene(mainvar, bmain, scene, view_layer, v3d, curlib, flag);
+      add_loose_object_data_to_scene(mainvar, bmain, scene, view_layer, v3d, flag);
     }
 
     /* Clear objects and collections instantiating tag. */
diff --git a/source/blender/blenloader/intern/versioning_280.c b/source/blender/blenloader/intern/versioning_280.c
index 2434d9e9f74..e07ee7ee2b9 100644
--- a/source/blender/blenloader/intern/versioning_280.c
+++ b/source/blender/blenloader/intern/versioning_280.c
@@ -3422,7 +3422,7 @@ void blo_do_versions_280(FileData *fd, Library *UNUSED(lib), Main *bmain)
               SpaceFile *sfile = (SpaceFile *)sl;
               if (sfile->params) {
                 sfile->params->flag &= ~(FILE_PARAMS_FLAG_UNUSED_1 | FILE_PARAMS_FLAG_UNUSED_6 |
-                                         FILE_PARAMS_FLAG_UNUSED_9);
+                                         FILE_OBDATA_INSTANCE);
               }
               break;
             }
diff --git a/source/blender/makesdna/DNA_space_types.h b/source/blender/makesdna/DNA_space_types.h
index ad1635ba0c0..7778a3aa234 100644
--- a/source/blender/makesdna/DNA_space_types.h
+++ b/source/blender/makesdna/DNA_space_types.h
@@ -813,7 +813,7 @@ typedef enum eFileSel_Params_Flag {
   FILE_PARAMS_FLAG_UNUSED_6 = (1 << 6), /* cleared */
   FILE_DIRSEL_ONLY = (1 << 7),
   FILE_FILTER = (1 << 8),
-  FILE_PARAMS_FLAG_UNUSED_9 = (1 << 9), /* cleared */
+  FILE_OBDATA_INSTANCE = (1 << 9),
   FILE_GROUP_INSTANCE = (1 << 10),
   FILE_SORT_INVERT = (1 << 11),
   FILE_HIDE_TOOL_PROPS = (1 << 12),
diff --git a/source/blender/windowmanager/intern/wm_files_link.c b/source/blender/windowmanager/intern/wm_files_link.c
index 8c14055696c..6c7205b25d4 100644
--- a/source/blender/windowmanager/intern/wm_files_link.c
+++ b/source/blender/windowmanager/intern/wm_files_link.c
@@ -137,6 +137,9 @@ static short wm_link_append_flag(wmOperator *op)
   if (RNA_boolean_get(op->ptr, "instance_collections")) {
     flag |= FILE_GROUP_INSTANCE;
   }
+  if (RNA_boolean_get(op->ptr, "instance_object_data")) {
+    flag |= FILE_OBDATA_INSTANCE;
+  }
 
   return flag;
 }
@@ -395,7 +398,7 @@ static int wm_link_append_exec(bContext *C, wmOperator *op)
                 RPT_WARNING,
                 "Scene '%s' is linked, instantiation of objects & groups is disabled",
                 scene->id.name + 2);
-    flag &= ~FILE_GROUP_INSTANCE;
+    flag &= ~(FILE_GROUP_INSTANCE | FILE_OBDATA_INSTANCE);
     scene = NULL;
   }
 
@@ -566,6 +569,14 @@ static void wm_link_append_properties_common(wmOperatorType *ot, bool is_link)
       "Instance Collections",
       "Create instances for collections, rather than adding them directly to the scene");
   RNA_def_property_flag(prop, PROP_SKIP_SAVE);
+
+  prop = RNA_def_boolean(
+      ot->srna,
+      "instance_object_data",
+      true,
+      "Instance Object Data",
+      "Create instances for object data which are not referenced by any objects");
+  RNA_def_property_flag(prop, PROP_SKIP_SAVE);
 }
 
 void WM_OT_link(wmOperatorType *ot)