Containers and Layout
Last modified: 05 December 2024Containers can represent a region, an equipment slot, or an actual container.
Containers are defined by a Container Definition (
NinjaInventoryContainerDataAsset) and represented by a Container Instance (NinjaInventoryContainer).Containers must have their definition data asset added to the Asset Manager.
Layouts are defined by
NinjaInventoryLayoutDataAssetand determine all containers initially available to an Inventory Manager, including the default container.Layouts can be provided to an Inventory Manager via the default property value or via the
InventoryManagerProviderInterface.
Containers and Layouts define the structure used by the inventory to store its items.
Inventory Containers
There are many names and usages that can exemplify a container: a Region for items, a Slot that can hold equipment pieces, actual Containers representing items inside the inventory, and probably others.
Containers are defined by the Data Asset NinjaInventoryContainerDataAsset. You can assign Gameplay Tags to establish traits that will fine-tune the container's purpose, determine the specific Container Class instantiated when the container is added to an Inventory, available slots, etc.
The NinjaInventoryContainerDataAsset is a Primary Data Asset and, as such, it must be registered with the Asset Manager. This can be done in the Engine Settings or directly added to the DefaultGame.ini file.
All properties available to containers are defined in the following table:
Property | Description |
|---|---|
Display Name | The name for the container. Supports localization from String Tables. |
Gameplay Tags | Gameplay Tags defining additional traits for this container. |
Container Class | Class used to create Container Instances in an Inventory Manager. |
Priority | Priority applied when matched against other Containers. The lower the value, the higher the priority. |
Slots | Maximum number of item slots available to this container. |
Slots Attribute | Overrides the Slots property using a Gameplay Attribute instead. |
Item Compatibility Query | Query applied to all items before adding them, to ensure they are compatible. |
note
The Attribute Set provided by the Inventory System,
NinjaInventoryAttributeSet, contains an attribute for Backpack Slots.This attribute is available for convenience, but if you don't need it, you can safely ignore it.
Once a container is assigned to an Inventory through its Data Asset, it is represented by the NinjaInventoryContainer class, or a subclass defined in the data asset.
Default Containers
Default containers are important as they assist the Inventory Manager in selecting containers for new items when needed. They are usually identified by the Inventory.Container.Default Gameplay Tag, present in their Gameplay Tags property.
The Inventory Layout must then define a Gameplay Tag Query to identify such items, allowing flexibility for more complex setups.
Primary and Secondary Containers
Items stored in the inventory might consume more than one container. A classic example is an item equipped in both main and off-hands, each hand being represented by its own container.
An item can only ever have one primary container, but it can have multiple secondary ones. The relationship between primary and secondary containers is defined in the Container Definition.
Container and Position Assignment
Items added to the inventory can define their preferred container and position. However, these requests might not be viable, thus requiring a new container and position. This is also the case for items added to the inventory without deliberately defining these values.
For those situations, the Inventory Manager will attempt to determine the most appropriate container and position for the new item. This is based on the Item Compatibility for each container, ordered by their Priority.
If an automatic assignment is not possible, other aspects of the item might be triggered, such as the Drop Fragment, which, if present, will drop the item as a Pickup Actor.
Inventory Layouts
An Inventory Layout provides the initial containers available to the inventory and defines the default one.
Inventory Layouts are created from NinjaInventoryLayoutDataAsset. They contain a Gameplay Tag Query used to identify the default container, usually tagged with Inventory.Container.Default, and all containers added to an Inventory Manager by default.
note
You should always have a valid query that identifies at least one default container. If you have more than one default container, the best pick would be the one with the highest priority.
You can assign a Layout to an Inventory Manager in a few different ways, as described in the following table:
Assignment | Description |
|---|---|
Property | Directly to an Inventory Manager via its |
Interface, Owner | Via the |
Interface, Avatar | Via the |
tip
The strategies above are ordered from lowest to highest priority, meaning that every time a new avatar is initialized in an Inventory Manager, it can set its Inventory Layout over all other options.