Fix hash map check to prevent fetching duplicate meshes (#59)

* Fix hash map check to prevent fetching duplicate meshes 

1. Fix check for existing mesh file key so as to avoid fetching duplicate meshes
2. Added check to avoid publishing empty array messages, which is can result from how we need to check for new scene objects using the Zenoh pubsub "/tf" topic 

Signed-off-by: John TGZ <[email protected]>

* fix check on wrong field

---------

Signed-off-by: John TGZ <[email protected]>

Author: JohnTGZ

flowstate_ros_bridge/src/bridges/world_bridge.cpp

@@ -191,7 +191,7 @@ absl::Status WorldBridge::Data::SendObjectVisualizationMessages(
               "gltf/%s_%s.glb",
               geometry.geometry_storage_refs().geometry_ref().substr(9),
               geometry.geometry_storage_refs().renderable_ref().substr(9));
-          if (renderables_.contains(gltf_path)) {
+          if (renderables_.contains(std::string("/") + gltf_path)) {
             continue;
           }
 
@@ -265,7 +265,10 @@ absl::Status WorldBridge::Data::SendObjectVisualizationMessages(
   }
   LOG(INFO) << "Total gltf size: " << total_gltf_size << " bytes";
 
-  workcell_markers_pub_->publish(array_msg);
+  if (!array_msg.markers.empty()){
+    workcell_markers_pub_->publish(array_msg);
+  }
+
   return absl::OkStatus();
 }