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tutorial:items

Adding an Item

Introduction

Adding a basic item is one of the first steps in modding. You're going to need to create an Item object, register it, and give it a texture. To add additional behavior to the item you will need a custom Item class. In this tutorial and all future ones, the “tutorial” namespace is used as a placeholder. If you have a separate modid, feel free to use it instead.

Registering an Item

First, create an instance of Item and store it as a static final field. The constructor takes in an Item.Settings (or a FabricItemSettings unless versions since 1.20.5) instance, which is used to set item properties such as the durability, and stack count.

  1. public class ExampleMod implements ModInitializer {
  2.  
  3. // an instance of our new item
  4. // for versions below 1.20.4
  5. public static final Item CUSTOM_ITEM = new Item(new FabricItemSettings());
  6. // for versions since 1.20.5
  7. public static final Item CUSTOM_ITEM = new Item(new Item.Settings());
  8. [...]
  9. }

You'll use the vanilla registry system for registering new content. The basic syntax is Registry#register(Registry Type, Identifier, Content). Registry types are stored as static fields in the Registries or Registry class, and the identifier is what labels your content. Content is an instance of whatever you're adding. This can be called anywhere as long as it occurs during initialization.

For versions since 1.21, an Identifier is created through Identifier.of(“namespace”, “path”). For versions below 1.21, it is created through new Identifier(“namespace”, “path”) or new Identifier(“namespace:path”). It will fail if the namespace or path contains illegal characters.

  1. public class ExampleMod implements ModInitializer {
  2.  
  3. // an instance of our new item
  4. public static final Item CUSTOM_ITEM = new Item(new Item.Settings());
  5.  
  6. @Override
  7. public void onInitialize() {
  8. // For versions below 1.21, please replace ''Identifier.of'' with ''new Identifier''
  9. Registry.register(Registries.ITEM, Identifier.of("tutorial", "custom_item"), CUSTOM_ITEM);
  10. }
  11. }
Your new item has now been added to Minecraft. Run the run config Minecraft Client or runClient Gradle task to see it in action, execute the command /give @s tutorial:custom_item in game.

For simplicity, you can simplify your code as following:

  1. public class ExampleMod implements ModInitializer {
  2.  
  3. // an instance of our new item
  4. public static final Item CUSTOM_ITEM =
  5. // For versions below 1.21, use ''new Identifier("tutorial", "custom_item")''.
  6. Registry.register(Registries.ITEM, Identifier.of("tutorial", "custom_item"),
  7. new Item(new Item.Settings()));
  8.  
  9. @Override
  10. public void onInitialize() {
  11. }
  12. }

Adding Item textures

Registering a texture for an item requires an item model json file and a texture image. You're going to need to add these to your resource directory. The direct path of each is:

  Item model: .../resources/assets/tutorial/models/item/custom_item.json
  Item texture: .../resources/assets/tutorial/textures/item/custom_item.png

Our example texture can be found here.

If you registered your item properly in the first step, your game will complain about a missing texture file in a fashion similar to this:

  [Server-Worker-1/WARN]: Unable to load model: 'tutorial:custom_item#inventory' referenced from: tutorial:custom_item#inventory: java.io.FileNotFoundException: tutorial:models/item/custom_item.json

It conveniently tells you exactly where it expects your asset[s] to be found– when in doubt, check the log.

A basic item model template is:

{
  "parent": "item/generated",
  "textures": {
    "layer0": "tutorial:item/custom_item"
  }
}

The parent of your item changes how it's rendered in the hand and comes in useful for things like block items in the inventory. “item/handheld” is used for tools that are held from the bottom left of the texture. textures/layer0 is the location of your image file.

Final textured result:

Creating an Item class

To add additional behavior to the item you will need to create an Item class. The default constructor requires an Item.Settings object.

  1. public class CustomItem extends Item {
  2.  
  3. public CustomItem(Settings settings) {
  4. super(settings);
  5. }
  6. }

A practical use-case for a custom item class would be making the item play a sound when you use it:

  1. public class CustomItem extends Item {
  2.  
  3. public CustomItem(Settings settings) {
  4. super(settings);
  5. }
  6.  
  7. @Override
  8. public TypedActionResult<ItemStack> use(World world, PlayerEntity user, Hand hand) {
  9. user.playSound(SoundEvents.BLOCK_WOOL_BREAK, 1.0F, 1.0F);
  10. return TypedActionResult.success(user.getStackInHand(hand));
  11. }
  12. }

Replace the old Item object with an instance of your new item class:

  1. public class ExampleMod implements ModInitializer {
  2.  
  3. // an instance of our new item
  4. public static final CustomItem CUSTOM_ITEM = new CustomItem(new Item.Settings());
  5. [...]
  6. }
If you did everything correctly, using the item should now play a sound.

What if I want to change the stack size of my item?

For this you would use maxCount(int size) inside Item.Settings to specify the max stack size. Note that if your item is damageable you cannot specify a maximum stack size or the game will throw a RuntimeException.

  1. public class ExampleMod implements ModInitializer {
  2.  
  3. // An instance of our new item, where the maximum stack size is 16
  4. public static final CustomItem CUSTOM_ITEM = new CustomItem(new Item.Settings().maxCount(16));
  5. [...]
  6. }

Make your item become fuel, or compostable

If you want to make it a fuel so that it can be used in a furnace, you can use FuelRegistry, for example:

public class ExampleMod implements ModInitializer {
    [...]
 
    @Override
    public void onInitialize() {
        [...]
        FuelRegistry.INSTANCE.add(CUSTOM_ITEM, 300)
    }
}

Similarly, you can use a CompostingChanceRegistry to make it compostable in a composter.

Next Steps

tutorial/items.txt · Last modified: 2024/06/17 12:49 by solidblock