Assets: Snapping with visual feedback while dragging

The drag and drop feature of objects in 3D View has been modified to include:
- Snap the object being dragged.
- Visual feedback through a box and the placement tool grid.

Maniphest Tasks: T90198

Differential Revision: https://developer.blender.org/D12912

5 files changed, 81 insertions, 2 deletions

diff --git a/source/blender/blenkernel/BKE_asset.h b/source/blender/blenkernel/BKE_asset.h
index 42eea41b7a7..722d142b56c 100644
--- a/source/blender/blenkernel/BKE_asset.h
+++ b/source/blender/blenkernel/BKE_asset.h
@@ -20,6 +20,7 @@
 
 #pragma once
 
+#include "BLI_compiler_attrs.h"
 #include "BLI_utildefines.h"
 
 #include "DNA_asset_types.h"
@@ -29,11 +30,23 @@ extern "C" {
 #endif
 
 struct AssetLibraryReference;
+struct AssetMetaData;
 struct BlendDataReader;
 struct BlendWriter;
 struct ID;
+struct IDProperty;
 struct PreviewImage;
 
+typedef void (*PreSaveFn)(void *asset_ptr, struct AssetMetaData *asset_data);
+
+typedef struct AssetTypeInfo {
+  /**
+   * For local assets (assets in the current .blend file), a callback to execute before the file is
+   * saved.
+   */
+  PreSaveFn pre_save_fn;
+} AssetTypeInfo;
+
 struct AssetMetaData *BKE_asset_metadata_create(void);
 void BKE_asset_metadata_free(struct AssetMetaData **asset_data);
 
@@ -56,6 +69,10 @@ void BKE_asset_metadata_catalog_id_set(struct AssetMetaData *asset_data,
 
 void BKE_asset_library_reference_init_default(struct AssetLibraryReference *library_ref);
 
+void BKE_asset_metadata_idprop_ensure(struct AssetMetaData *asset_data, struct IDProperty *prop);
+struct IDProperty *BKE_asset_metadata_idprop_find(const struct AssetMetaData *asset_data,
+                                                  const char *name) ATTR_WARN_UNUSED_RESULT;
+
 struct PreviewImage *BKE_asset_metadata_preview_get_from_id(const struct AssetMetaData *asset_data,
                                                             const struct ID *owner_id);
 
diff --git a/source/blender/blenkernel/BKE_idtype.h b/source/blender/blenkernel/BKE_idtype.h
index cd656d94fce..d33c24f2c75 100644
--- a/source/blender/blenkernel/BKE_idtype.h
+++ b/source/blender/blenkernel/BKE_idtype.h
@@ -228,6 +228,11 @@ typedef struct IDTypeInfo {
    * \note Currently needed for some update operation on point caches.
    */
   IDTypeLibOverrideApplyPost lib_override_apply_post;
+
+  /**
+   * Callbacks for assets, based on the type of asset.
+   */
+  struct AssetTypeInfo *asset_type_info;
 } IDTypeInfo;
 
 /* ********** Declaration of each IDTypeInfo. ********** */
diff --git a/source/blender/blenkernel/BKE_main.h b/source/blender/blenkernel/BKE_main.h
index 68b1b55f47f..9ded97e0003 100644
--- a/source/blender/blenkernel/BKE_main.h
+++ b/source/blender/blenkernel/BKE_main.h
@@ -244,9 +244,9 @@ void BKE_main_library_weak_reference_remove_item(struct GHash *library_weak_refe
 
 #define FOREACH_MAIN_LISTBASE_ID_BEGIN(_lb, _id) \
   { \
-    ID *_id_next = (_lb)->first; \
+    ID *_id_next = (ID *)(_lb)->first; \
     for ((_id) = _id_next; (_id) != NULL; (_id) = _id_next) { \
-      _id_next = (_id)->next;
+      _id_next = (ID *)(_id)->next;
 
 #define FOREACH_MAIN_LISTBASE_ID_END \
   } \
diff --git a/source/blender/blenkernel/intern/asset.cc b/source/blender/blenkernel/intern/asset.cc
index dfe568729db..7bea089b9bf 100644
--- a/source/blender/blenkernel/intern/asset.cc
+++ b/source/blender/blenkernel/intern/asset.cc
@@ -141,6 +141,25 @@ void BKE_asset_metadata_catalog_id_set(struct AssetMetaData *asset_data,
   trimmed_id.copy(asset_data->catalog_simple_name, max_simple_name_length);
 }
 
+void BKE_asset_metadata_idprop_ensure(AssetMetaData *asset_data, IDProperty *prop)
+{
+  if (!asset_data->properties) {
+    IDPropertyTemplate val = {0};
+    asset_data->properties = IDP_New(IDP_GROUP, &val, "AssetMetaData.properties");
+  }
+  /* Important: The property may already exist. For now just allow always allow a newly allocated
+   * property, and replace the existing one as a way of updating. */
+  IDP_ReplaceInGroup(asset_data->properties, prop);
+}
+
+IDProperty *BKE_asset_metadata_idprop_find(const AssetMetaData *asset_data, const char *name)
+{
+  if (!asset_data->properties) {
+    return nullptr;
+  }
+  return IDP_GetPropertyFromGroup(asset_data->properties, name);
+}
+
 /* Queries -------------------------------------------- */
 
 PreviewImage *BKE_asset_metadata_preview_get_from_id(const AssetMetaData *UNUSED(asset_data),
@@ -173,6 +192,7 @@ void BKE_asset_metadata_write(BlendWriter *writer, AssetMetaData *asset_data)
 void BKE_asset_metadata_read(BlendDataReader *reader, AssetMetaData *asset_data)
 {
   /* asset_data itself has been read already. */
+  asset_data->local_type_info = nullptr;
 
   if (asset_data->properties) {
     BLO_read_data_address(reader, &asset_data->properties);
diff --git a/source/blender/blenkernel/intern/object.c b/source/blender/blenkernel/intern/object.c
index e85c6b4c7c5..45dfb9af074 100644
--- a/source/blender/blenkernel/intern/object.c
+++ b/source/blender/blenkernel/intern/object.c
@@ -82,6 +82,7 @@
 #include "BKE_anim_visualization.h"
 #include "BKE_animsys.h"
 #include "BKE_armature.h"
+#include "BKE_asset.h"
 #include "BKE_camera.h"
 #include "BKE_collection.h"
 #include "BKE_constraint.h"
@@ -1190,6 +1191,40 @@ static void object_lib_override_apply_post(ID *id_dst, ID *id_src)
   BLI_freelistN(&pidlist_src);
 }
 
+static IDProperty *object_asset_dimensions_property(Object *ob)
+{
+  float dimensions[3];
+  BKE_object_dimensions_get(ob, dimensions);
+  if (is_zero_v3(dimensions)) {
+    return NULL;
+  }
+
+  IDPropertyTemplate idprop = {0};
+  idprop.array.len = ARRAY_SIZE(dimensions);
+  idprop.array.type = IDP_FLOAT;
+
+  IDProperty *property = IDP_New(IDP_ARRAY, &idprop, "dimensions");
+  memcpy(IDP_Array(property), dimensions, sizeof(dimensions));
+
+  return property;
+}
+
+static void object_asset_pre_save(void *asset_ptr, struct AssetMetaData *asset_data)
+{
+  Object *ob = asset_ptr;
+  BLI_assert(GS(ob->id.name) == ID_OB);
+
+  /* Update dimensions hint for the asset. */
+  IDProperty *dimensions_prop = object_asset_dimensions_property(ob);
+  if (dimensions_prop) {
+    BKE_asset_metadata_idprop_ensure(asset_data, dimensions_prop);
+  }
+}
+
+AssetTypeInfo AssetType_OB = {
+    .pre_save_fn = object_asset_pre_save,
+};
+
 IDTypeInfo IDType_ID_OB = {
     .id_code = ID_OB,
     .id_filter = FILTER_ID_OB,
@@ -1216,6 +1251,8 @@ IDTypeInfo IDType_ID_OB = {
     .blend_read_undo_preserve = NULL,
 
     .lib_override_apply_post = object_lib_override_apply_post,
+
+    .asset_type_info = &AssetType_OB,
 };
 
 void BKE_object_workob_clear(Object *workob)