message: Ignore meshes that have no vertex indices
diff: @@ -727,7 +727,7 @@ struct build_scene_visitor : sg::node_visitor
  void apply(sg::indexed_triangle_mesh& itm)
  {
  - if (itm.flags() == 0 && itm.vertices->size() > 0)
  + if (itm.flags() == 0 && itm.vertex_indices.size() > 0)
  {
  assert(itm.vertex_indices.size() % 3 == 0);
  