Subobject Replication - Inventory System - Invalid items when originator is destroyed

Development Programming & Scripting
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1

I’m having trouble with replicated subobjects for an inventory system, and these results are very concerning. Hopefully someone can shed some light here:

  • Two actors (A and B) with “ItemContainer” actor components
  • ItemContainers are just replicated TArray of pointers to replicated UObjects.
  • Adding / removing items to these arrays renames (to change the outer) and appropriately assigns subobject list replication.
  • Renames are also sent to the client (to change the outer on the client)
  • Moving an item from A → B works fine, the subobject is networked.
  • After some delay I destroy actor A.
  • Checking slightly later in B, the array still contains a pointer to the object, but the pointer to the subobject is now invalid. It becomes invalid instantly after A was destroyed by the server.

So I guess that means only the original networked pointer is meaningful on the client? Am I doing something wrong here? This seems to make working with replicated subobjects completely useless if we’re expecting them to act independently of their original replicating owner. Seems like a pretty obvious way to implement an inventory system would be to use subobject replication in this way.

2

im not sure if thats normal behaviour, i think it is but one way around this would be to have an itemmanager where every item in the game is created and stored and then your actors just reference their item on that manager

3

that wouldn’t work, and I think I’ve figured out why:

It appears that RemoveReplicatedSubObject actually invalidates networked object, so if you’re passing around UObjects for use, you should use TearOffReplicatedSubObjectOnRemotePeers instead. Even if you keep valid networked pointers to objects, they will become invalid upon calling RemoveReplicatedSubObject!