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tutorial:items [2019/05/20 15:36]
draylar attempt at making language more tutorial-like part 1
tutorial:items [2019/08/13 14:48] (current)
i509vcb Add section showing how to set maximum stack size on custom item
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 ==== Introduction ==== ==== Introduction ====
  
-One of the first things you'll want to do with Fabric is adding a new item. +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.
- +
-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. +
-  ​+
 ==== Registering an Item ==== ==== Registering an Item ====
  
 First, create an instance of Item. We'll store it at the top of our initializer class. The constructor takes in an Item.Settings object, which is used to set item properties such as the inventory category, durability, and stack count. ​ First, create an instance of Item. We'll store it at the top of our initializer class. The constructor takes in an Item.Settings object, which is used to set item properties such as the inventory category, durability, and stack count. ​
- +<code java [enable_line_numbers="​true"​]>​ 
-  public class ExampleMod implements ModInitializer +public class ExampleMod implements ModInitializer 
-  +
-      // an instance of our new item +    // an instance of our new item 
-      public static final Item FABRIC_ITEM = new Item(new Item.Settings().itemGroup(ItemGroup.MISC));​ +    public static final Item FABRIC_ITEM = new Item(new Item.Settings().group(ItemGroup.MISC));​ 
-      [...] +    [...] 
-  +
- +</​code>​ 
- +You'll use the vanilla registry system for registering new content. The basic syntax is ''​Registry#​register(Registry TypeIdentifier, Content)''​. Registry types are stored as static ​fields in the ''​Registry'' ​object, 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. 
-To register ​an `Item`you can call register on the static Registry object. This takes in a registry type, Identifier, and an instance of what you'​re ​registering. This can be called anywhere as long as it occurs during initialization. +<code java [enable_line_numbers="​true"​]>​ 
- +public class ExampleMod implements ModInitializer 
-  public class ExampleMod implements ModInitializer +
-  +    // an instance of our new item 
-      // an instance of our new item +    public static final Item FABRIC_ITEM = new Item(new Item.Settings().group(ItemGroup.MISC));​
-      public static final Item FABRIC_ITEM = new Item(new Item.Settings().itemGroup(ItemGroup.MISC));​+
       ​       ​
-      ​@Override +    ​@Override 
-      public void onInitialize() +    public void onInitialize() 
-      +    
-          Registry.register(Registry.ITEM,​ new Identifier("​wikitut", "​fabric_item"​),​ FABRIC_ITEM);​ +        Registry.register(Registry.ITEM,​ new Identifier("​tutorial", "​fabric_item"​),​ FABRIC_ITEM);​ 
-      +    }  
-  +
- +</​code>​
 Your new item has now been added to Minecraft. Run the `runClient` gradle task to see it in action. Your new item has now been added to Minecraft. Run the `runClient` gradle task to see it in action.
  
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 ==== Adding Item textures ==== ==== Adding Item textures ====
  
-You'​re ​probably annoyed with the black & purple missing texture, so we'll fix that now+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 directoryThe direct path of each is:
  
-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/​fabric_item.json 
 +    Item texture: ​.../​resources/​assets/​tutorial/​textures/​item/​fabric_item.png
  
-    Item model.../resources/assets/​wikitut/​models/​item/​fabric_item.json +Our example texture can be found [[https://i.imgur.com/CqLSMEQ.png|here]].
-    Item texture: .../resources/​assets/​wikitut/​textures/​item/​fabric_item.png+
  
-Note that wikitut is your modid. Our example ​texture ​can be found [[https://​i.imgur.com/​CqLSMEQ.png|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:
  
-If you registered your item properly in the first step, your game will also complain about a missing texture file in a fashion similar to this: +    ​[Server-Worker-1/​WARN]:​ Unable to load model: 'tutorial:​fabric_item#​inventory'​ referenced from: tutorial:​fabric_item#​inventory:​ java.io.FileNotFoundException: ​tutorial:​models/​item/​fabric_item.json
- +
-    ​[Server-Worker-1/​WARN]:​ Unable to load model: 'wikitut:​fabric_item#​inventory'​ referenced from: wikitut:​fabric_item#​inventory:​ java.io.FileNotFoundException: ​wikitut:​models/​item/​fabric_item.json+
 It conveniently tells you exactly where it expects your asset[s] to be found-- when in doubt, check the log. It conveniently tells you exactly where it expects your asset[s] to be found-- when in doubt, check the log.
  
-As for the actual contents of your item json file, a basic template is as follows+A basic item model template is: 
- +<code JavaScript>​ 
-  +
-    "​parent":​ "​item/​generated",​ +  "​parent":​ "​item/​generated",​ 
-    "​textures":​ { +  "​textures":​ { 
-      "​layer0":​ "my_mod:​item/​fabric_item"​ +    "​layer0":​ "tutorial:​item/​fabric_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. textures/​layer0 is the location of your image file.+</​code>​ 
 +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.
  
-If you set everything up correctly, you should be met with a textured ​item:+Final textured ​result:
  
 {{:​tutorial:​item_texture.png?​400|}} {{:​tutorial:​item_texture.png?​400|}}
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 ==== Creating an Item class ==== ==== Creating an Item class ====
  
-To add additonal ​behavior to the item you will need an Item class. ​We'll name our Item class '​FabricItem'​. Create a constructor ​taking ​an Item.Settings object; your class should now look like this:+To add additional ​behavior to the item you will need to create ​an Item class. ​The default ​constructor ​requires ​an Item.Settings object
 +<code java [enable_line_numbers="​true"​]>​ 
 +public ​class FabricItem extends Item 
 +
 +    public FabricItem(Settings settings) 
 +    { 
 +        super(settings);​ 
 +    } 
 +
 +</​code>​
  
-  public ​class FabricItem extends Item +A practical use-case for a custom item class would be making the item play a sound when you click with it: 
-  { +<code java [enable_line_numbers="​true"​]>​ 
-      public FabricItem(Settings settings) +public class FabricItem extends Item 
-      { +
-          super(settings);​ +    public FabricItem(Settings settings) 
-      } +    
-  } +        super(settings);​ 
- +    }
-We'll make it play a sound on use by overriding Item's use method. +
- +
-  public class FabricItem extends Item +
-  +
-      public FabricItem(Settings settings) +
-      +
-          super(settings);​ +
-      }+
       ​       ​
-      ​@Override +    ​@Override 
-      public TypedActionResult<​ItemStack>​ use(World world, PlayerEntity playerEntity,​ Hand hand) +    public TypedActionResult<​ItemStack>​ use(World world, PlayerEntity playerEntity,​ Hand hand) 
-      +    
-          playerEntity.playSound(SoundEvents.BLOCK_WOOL_BREAK,​ 1.0F, 1.0F); +        playerEntity.playSound(SoundEvents.BLOCK_WOOL_BREAK,​ 1.0F, 1.0F); 
-          return new TypedActionResult<>​(ActionResult.SUCCESS,​ playerEntity.getStackInHand(hand));​ +        return new TypedActionResult<>​(ActionResult.SUCCESS,​ playerEntity.getStackInHand(hand));​ 
-      +    
-  }+} 
 +</​code>​
  
-Finally, in our mod initializer,​ we'll replace our Item instance ​with a FabricItem ​instance.+Replace the old Item object ​with an instance ​of your new item class: 
 +<code java [enable_line_numbers="​true"​]>​ 
 +public class ExampleMod implements ModInitializer 
 +
 +    // an instance of our new item 
 +    public static final FabricItem FABRIC_ITEM = new FabricItem(new Item.Settings().group(ItemGroup.MISC));​ 
 +    [...] 
 +
 +</​code>​ 
 +If you did everything correctly, using the item should now play a sound.
  
-  public class ExampleMod implements ModInitializer +==== What if I want to change the stack size of my item? ====
-  { +
-      // an instance ​of our new item +
-      public static final FabricItem FABRIC_ITEM ​new FabricItem(new Item.Settings().itemGroup(ItemGroup.MISC));​ +
-      [...] +
-  }+
  
-If you did everything correctly, using the item should now play sound.+For this you would use ''​maxCount(int size)''​ inside ItemSettings to specify ​the max stack size. Note that if your item is damageable you cannot specify ​maximum stack size or the game will throw a RuntimeException. 
 +<code java [enable_line_numbers="​true"​]>​ 
 +public class ExampleMod implements ModInitializer 
 +
 +    // an instance of our new item, where the maximum stack size is 16 
 +    public static final FabricItem FABRIC_ITEM = new FabricItem(new Item.Settings().group(ItemGroup.MISC).maxCount(16));​ 
 +    [...] 
 +
 +</​code>​ 
 +==== Next Steps ==== 
 +[[tutorial:​itemgroup|Add your item to your own ItemGroup]].
tutorial/items.1558366601.txt.gz · Last modified: 2019/05/20 15:36 by draylar