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

4 files changed, 28 insertions, 2 deletions

diff --git a/source/blender/windowmanager/WM_api.h b/source/blender/windowmanager/WM_api.h
index c7087b28783..2988aacc4d3 100644
--- a/source/blender/windowmanager/WM_api.h
+++ b/source/blender/windowmanager/WM_api.h
@@ -757,9 +757,11 @@ struct ID *WM_drag_get_local_ID_from_event(const struct wmEvent *event, short id
 bool WM_drag_is_ID_type(const struct wmDrag *drag, int idcode);
 
 wmDragAsset *WM_drag_create_asset_data(const struct AssetHandle *asset,
+                                       struct AssetMetaData *metadata,
                                        const char *path,
                                        int import_type);
 struct wmDragAsset *WM_drag_get_asset_data(const struct wmDrag *drag, int idcode);
+struct AssetMetaData *WM_drag_get_asset_meta_data(const struct wmDrag *drag, int idcode);
 struct ID *WM_drag_get_local_ID_or_import_from_asset(const struct wmDrag *drag, int idcode);
 
 void WM_drag_free_imported_drag_ID(struct Main *bmain,
diff --git a/source/blender/windowmanager/WM_types.h b/source/blender/windowmanager/WM_types.h
index bbfc9d53e44..2813047f0e4 100644
--- a/source/blender/windowmanager/WM_types.h
+++ b/source/blender/windowmanager/WM_types.h
@@ -989,6 +989,7 @@ typedef struct wmDragAsset {
   /* Always freed. */
   const char *path;
   int id_type;
+  struct AssetMetaData *metadata;
   int import_type; /* eFileAssetImportType */
 
   /* FIXME: This is temporary evil solution to get scene/view-layer/etc in the copy callback of the
diff --git a/source/blender/windowmanager/intern/wm_dragdrop.c b/source/blender/windowmanager/intern/wm_dragdrop.c
index bad58c32cdb..f78bd528c5e 100644
--- a/source/blender/windowmanager/intern/wm_dragdrop.c
+++ b/source/blender/windowmanager/intern/wm_dragdrop.c
@@ -40,6 +40,7 @@
 
 #include "BKE_context.h"
 #include "BKE_global.h"
+#include "BKE_idprop.h"
 #include "BKE_idtype.h"
 #include "BKE_lib_id.h"
 #include "BKE_main.h"
@@ -405,11 +406,15 @@ bool WM_drag_is_ID_type(const wmDrag *drag, int idcode)
 /**
  * \note: Does not store \a asset in any way, so it's fine to pass a temporary.
  */
-wmDragAsset *WM_drag_create_asset_data(const AssetHandle *asset, const char *path, int import_type)
+wmDragAsset *WM_drag_create_asset_data(const AssetHandle *asset,
+                                       AssetMetaData *metadata,
+                                       const char *path,
+                                       int import_type)
 {
   wmDragAsset *asset_drag = MEM_mallocN(sizeof(*asset_drag), "wmDragAsset");
 
   BLI_strncpy(asset_drag->name, ED_asset_handle_get_name(asset), sizeof(asset_drag->name));
+  asset_drag->metadata = metadata;
   asset_drag->path = path;
   asset_drag->id_type = ED_asset_handle_get_id_type(asset);
   asset_drag->import_type = import_type;
@@ -433,6 +438,21 @@ wmDragAsset *WM_drag_get_asset_data(const wmDrag *drag, int idcode)
   return (ELEM(idcode, 0, asset_drag->id_type)) ? asset_drag : NULL;
 }
 
+struct AssetMetaData *WM_drag_get_asset_meta_data(const wmDrag *drag, int idcode)
+{
+  wmDragAsset *drag_asset = WM_drag_get_asset_data(drag, idcode);
+  if (drag_asset) {
+    return drag_asset->metadata;
+  }
+
+  ID *local_id = WM_drag_get_local_ID(drag, idcode);
+  if (local_id) {
+    return local_id->asset_data;
+  }
+
+  return NULL;
+}
+
 static ID *wm_drag_asset_id_import(wmDragAsset *asset_drag)
 {
   const char *name = asset_drag->name;
@@ -566,11 +586,12 @@ void WM_drag_add_asset_list_item(
     drag_asset->asset_data.local_id = local_id;
   }
   else {
+    AssetMetaData *metadata = ED_asset_handle_get_metadata(asset);
     char asset_blend_path[FILE_MAX_LIBEXTRA];
     ED_asset_handle_get_full_library_path(C, asset_library_ref, asset, asset_blend_path);
     drag_asset->is_external = true;
     drag_asset->asset_data.external_info = WM_drag_create_asset_data(
-        asset, BLI_strdup(asset_blend_path), FILE_ASSET_IMPORT_APPEND);
+        asset, metadata, BLI_strdup(asset_blend_path), FILE_ASSET_IMPORT_APPEND);
   }
   BLI_addtail(&drag->asset_items, drag_asset);
 }
diff --git a/source/blender/windowmanager/intern/wm_files.c b/source/blender/windowmanager/intern/wm_files.c
index 2525c627785..8fcc30dfed7 100644
--- a/source/blender/windowmanager/intern/wm_files.c
+++ b/source/blender/windowmanager/intern/wm_files.c
@@ -1788,6 +1788,7 @@ static bool wm_file_write(bContext *C,
   /* Call pre-save callbacks before writing preview,
    * that way you can generate custom file thumbnail. */
   BKE_callback_exec_null(bmain, BKE_CB_EVT_SAVE_PRE);
+  ED_assets_pre_save(bmain);
 
   /* Enforce full override check/generation on file save. */
   BKE_lib_override_library_main_operations_create(bmain, true);
@@ -2105,6 +2106,7 @@ static int wm_homefile_write_exec(bContext *C, wmOperator *op)
   }
 
   BKE_callback_exec_null(bmain, BKE_CB_EVT_SAVE_PRE);
+  ED_assets_pre_save(bmain);
 
   /* check current window and close it if temp */
   if (win && WM_window_is_temp_screen(win)) {