IItemHandler Capabilities

[lyn mimistrobell]

I'm building a TileEntity which I want to have multiple ItemStackHandler for different slots.

I'm trying to add capability constants to use in getCapability:

  @CapabilityInject(IItemHandler.class)
  public static Capability<IItemHandler> CAPABILITY_SET1 = null;

  @CapabilityInject(IItemHandler.class)
  public static Capability<IItemHandler> CAPABILITY_SET2 = null;

 

On runtime, both CAPABILITY_SET1 and CAPABILITY_SET2 reference the same Capability object so I can't distinguish between them.

I tried this:

  @CapabilityInject(IItemHandler1.class)
  public static Capability<IItemHandler1> CAPABILITY_SET1 = null;

  @CapabilityInject(IItemHandler2.class)
  public static Capability<IItemHandler2> CAPABILITY_SET2 = null;

Where both IItemHandler1 and IItemHandler2 are empty interfaces with extends IItemHandler. On runtime, CAPABILITY_SET1 and CAPABILITY_SET2 remain null.

 

Do I really have to build a custom Capability with custom writeNBT, custom readNBT, custom Factory, custom implementation, etc.?

[Alexiy]

You don't need to create a capability, you need to create IItemHandler(s) and provide them depending on the EnumFacing passed in. For example, if you are making a furnace-like tile entity, you can create 3 handlers: one for inputting items from top, one for inputting fuel from horizontal sides, and one for extracting results from bottom. So like this stub:

    public class TileExample extends TileEntity {
    
    IItemHandler fuelInput;     //To implement
    IItemHandler smeltableInput;
    IItemHandler resultOutput;

    @Override
    public boolean hasCapability(Capability<?> capability, @Nullable EnumFacing facing) {
        if(capability== CapabilityItemHandler.ITEM_HANDLER_CAPABILITY && facing!=null) return true;
        return super.hasCapability(capability, facing);
    }

    @Nullable
    @Override
    public <T> T getCapability(Capability<T> capability, @Nullable EnumFacing facing) {
        if(capability==CapabilityItemHandler.ITEM_HANDLER_CAPABILITY && facing!=null)
        {
            if(facing==EnumFacing.UP) return (T) fuelInput;
            else if(facing==EnumFacing.DOWN) return (T) resultOutput;
            else return (T) smeltableInput;
        }
        return super.getCapability(capability, facing);
    }
}

 

[lyn mimistrobell]

Clever, thank!

[Draco18s]

For reference, this:

 @CapabilityInject(IItemHandler.class)
  public static Capability<IItemHandler> CAPABILITY_SET1 = null;

Is how you define a capability. It's equivalent to CapabilityItemHandler.ITEM_HANDLER_CAPABILITY

It is not the implementation thereof. For that, you need a new ItemStackHandler().

[lyn mimistrobell]

I was able to get it working with the facing option (of course, it restricts me to 6 IItemHandlers but for now I just needed 3 anyway). I feel it's a hack/workaround and not a proper solution tho...

 

I did create a custom capability for my furnace progress. The vanilla furnace uses IInventory which offers getField and setField, I feel that's missing from the standard capabilities; perhaps I'll create a generic IStorage<IProperties> capability to offer generic properties handling to any TE...

 

For now, I created a Progress capability (with minValue, maxValue, value and a method to get actual progress) that my TE sets to 0, initialBurnTime, remainingBurnTime and from which my Gui calls getProgress(34) (my progress bar is 34 pixels).

Am I correct that every custom capability needs all this?

 - Capability interface (ICapabilityProgress)

 - Capability class (CapabilityProgress implements ICapabilityProgress)

 - Serializer (CapabilityProgressProvider implements ICapabilitySerializable<NBTBase>)

 - Storage class (CapabilityProgressStorage implements IStorage<ICapabilityProgress>)

 

[lyn mimistrobell]

42 minutes ago, diesieben07 said:

Unless you want other mods to interact with this functionality of your tile entity, you do not need to make a capability for it.

I found it to be the best way without the need to expose new methods (requiring me to cast the TE to my own TE class). I didn't feel like doing this just for the IItemHandler issue but I suspect a Progress capability can will be useful more often.