toJson method
meta - object containing metadata such as materials, textures for
objects.
Convert the light to three.js JSON Object/Scene format.
Implementation
@override
Map<String,dynamic> toJson({Object3dMeta? meta}) {
  Map<String,dynamic> data = super.toJson(meta: meta);
  data["object"]["width"] = width;
  data["object"]["height"] = height;
  return data;
}