Inventory Manager

UMP_InventoryManager router logic

While the Component stores items, the UMP_InventoryManager routes the actions. It is an Actor Component that should exclusively live on your PlayerController.

The Central RPC Hub

Unreal Engine's networking requires Client-to-Server RPCs to be called on an Actor that the client physically owns (like the PlayerController). Because UMP_InventoryComponents can exist on unowned objects (like a random Chest in the woods), clients cannot call AddItem directly on the chest's component.

Instead, the workflow is:

  1. The UI tells the Manager to move an item into a Chest.
  2. The Manager executes a Server RPC (Server_TransferItem).
  3. The Server Manager looks up the Chest's component, validates permissions, and safely moves the item.
  4. If the action fails (e.g., Chest is full), the Manager fires a Client_OnActionNotify with a player-facing error (like "Inventory Full" or "Access Denied").

Multi-Inventory Operations

The Manager handles complex transactions that bridge two different components natively:

  • SwapItemsBetweenInventories: Safely swaps an item in the player's backpack with an item in a chest, handling reverting if either side rejects the transaction.
  • TransferItemBySlot / TransferItemByID: Moves a specific quantity of an item from one component to another without duplicating or losing data.

Proximity Loot Tracking (Nearby Loot)

A standout feature of the Manager is the Nearby Loot API.

  • When a player walks near a dropped item in the world, the item registers itself with the Manager's NearbyLoot array.
  • The Manager broadcasts OnNearbyLootChanged.
  • The UI listens to this and dynamically updates the "Loot Area" panel.
  • Because the Manager uses direct AActor* GroundActor references instead of fragile array indices, players can spam-click to pick up 50 items simultaneously in O(1) time without index-shifting desyncs!
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