GPencil: New support for Asset Manager

Changing operator order works.

@@ -5223,6 +5224,26 @@ class VIEW3D_MT_edit_gpencil_point(Menu):
         layout.menu("VIEW3D_MT_gpencil_vertex_group")
 
 
+class VIEW3D_MT_edit_gpencil_asset(Menu):

@@ -5226,0 +5230,4 @@
+    def draw(self, _context):
+        layout = self.layout
+
+        layout.operator("gpencil.asset_create", text="Active Layer").source = 'LAYER'

@@ -2212,3 +2227,3 @@
     read_ma = BKE_object_material_get(ob, i + 1);
     /* Material names are like "MAMaterial.001" */
-    if (STREQ(name, &read_ma->id.name[2])) {
+    if ((read_ma) && (STREQ(name, &read_ma->id.name[2]))) {

@@ -0,0 +400,4 @@
+
+void GPENCIL_OT_asset_create(wmOperatorType *ot)
+{
+  static const EnumPropertyItem mode_types[] = {

@@ -0,0 +405,4 @@
+       "LAYER",
+       0,
+       "Active Layer",
+       "Copy the strokes of the active layer into a new grease pencil asset."},

@@ -0,0 +415,4 @@
+       "LAYERS_SPLIT",
+       0,
+       "All Layers Separated",
+       "Create an asset by layer."},

@@ -0,0 +421,4 @@
+       "KEYFRAME",
+       0,
+       "Active Keyframe (Active Layer)",
+       "Create asset using active keyframe for active layer"},

@@ -0,0 +741,4 @@
+  /* Asset GP data block. */
+  tgpa->gpd_asset = (bGPdata *)id;
+
+  tgpa->asset_strokes.clear();

@@ -0,0 +753,4 @@
+
+  /* check context */
+  op->customdata = tgpa = static_cast<tGPDasset *>(gpencil_session_init_asset_import(C, op));
+  op->customdata = tgpa;

@@ -0,0 +772,4 @@
+  /* Try to initialize context data needed. */
+  if (!gpencil_asset_import_init(C, op)) {
+    if (op->customdata) {
+      MEM_delete(op->customdata);

@@ -0,0 +784,4 @@
+
+  /* Load of the strokes in the target data block. */
+  if (!gpencil_asset_append_strokes(tgpa)) {
+    gpencil_asset_import_exit(C, op);

@@ -0,0 +785,4 @@
+  /* Load of the strokes in the target data block. */
+  if (!gpencil_asset_append_strokes(tgpa)) {
+    gpencil_asset_import_exit(C, op);
+    return OPERATOR_CANCELLED;

@@ -0,0 +804,4 @@
+  /* identifiers */
+  ot->name = "Grease Pencil Import Asset";
+  ot->idname = "GPENCIL_OT_asset_import";
+  ot->description = "Import Asset into existing grease pencil object";

@@ -0,0 +815,4 @@
+
+  /* Properties. */
+  WM_operator_properties_id_lookup(ot, true);
+  PropertyRNA *prop = RNA_def_enum(ot->srna, "type", rna_enum_id_type_items, 0, "Type", "");

@@ -855,4 +890,2 @@
   preview_data.pr_main = preview_main;
   /* Act on a copy. */
-  preview_data.object = (Object *)preview->id_copy;
-  preview_data.cfra = preview->scene->r.cfra;

@@ -806,6 +811,11 @@ static Scene *object_preview_scene_create(const struct ObjectPreviewData *previe
                                           Depsgraph **r_depsgraph)
 {
   Scene *scene = BKE_scene_add(preview_data->pr_main, "Object preview scene");
+  const bool is_gpencil = (preview_data->object == nullptr ||

@@ -821,0 +833,4 @@
+  }
+  else {
+    /* Grease pencil draw engine needs an object to draw the datablock. */
+    ob_gpencil_temp = BKE_object_add_for_data(preview_data->pr_main,

@@ -821,0 +844,4 @@
+    /* Copy the materials to get full color previews. */
+    const short *materials_len_p = BKE_id_material_len_p(preview_data->datablock);
+    if (materials_len_p && *materials_len_p > 0) {
+      BKE_object_materials_test(preview_data->pr_main, ob_gpencil_temp, preview_data->datablock);

@@ -862,0 +909,4 @@
+                             f_min :
+                             preview->scene->r.cfra;
+    preview_data.cfra = framenum;
+  }

@@ -1034,6 +1086,7 @@ static void action_preview_render(IconPreview *preview, IconPreviewSize *preview
 
 /** \} */
 
+/* -------------------------------------------------------------------- */

@@ -627,3 +627,3 @@
 {
   ID_Type id_type = view3d_drop_id_in_main_region_poll_get_id_type(C, drag, event);
-  if (id_type && OB_DATA_SUPPORT_ID(id_type)) {
+  if (id_type && OB_DATA_SUPPORT_ID(id_type) && (id_type != ID_GD)) {

@@ -5161,2 +5161,4 @@
         # Remove
         layout.menu("VIEW3D_MT_edit_gpencil_delete")
+        # Assets
+        layout.menu("VIEW3D_MT_edit_gpencil_asset", text="Create Asset...")

@@ -7479,1 +7489,4 @@
 
+        # Assets
+        col.separator()
+        col.operator_menu_enum("gpencil.asset_create", "source", text="Create Grease Pencil Asset")