shadowfacts.net/site/tutorials/forge-modding-112/ore-dictionary.md

metadata.title = "Ore Dictionary"
metadata.date = "2016-08-08 11:28:00 -0400"
metadata.series = "forge-modding-112"
metadata.seriesName = "Forge Mods for 1.12"

Forge's Ore Dictionary system provides an API that modders can use to mark items/blocks as equivalent to one another. This was originally created because multiple mods were all adding their own versions of the same ores and ingots (copper, tin, etc.). The way this system works is each ItemStack as a list of String ore names associated with it.

Let's create a ItemOre class that extends ItemBase and has a initOreDict method for handling Ore Dictionary registration. This will give us a nice fully implemented class for ore-dictionaried items.

package net.shadowfacts.tutorial.item;

import net.minecraftforge.oredict.OreDictionary;

public class ItemOre extends ItemBase {

	private String oreName;

	public ItemOre(String name, String oreName) {
		super(name);
	
		this.oreName = oreName;
	}
	
	public void initOreDict() {
		OreDictionary.registerOre(oreName, this);
	}

}

This class simply takes a second String parameter in its constructor that is the ore-dictionary name and then uses that in the initOreDict method.

We'll also update our BlockOre class to provide a similar initOreDict method.

package net.shadowfacts.tutorial.block;

import net.minecraft.block.material.Material;
import net.minecraft.creativetab.CreativeTabs;
import net.minecraftforge.oredict.OreDictionary;

public class BlockOre extends BlockBase {

	private String oreName;

	public BlockOre(String name, String oreName) {
		super(Material.ROCK, name);
	
		this.oreName = oreName;
	
		setHardness(3f);
		setResistance(5f);
	}
	
	public void initOreDict() {
		OreDictionary.registerOre(oreName, this);
	}
	
	@Override
	public BlockOre setCreativeTab(CreativeTabs tab) {
		super.setCreativeTab(tab);
		return this;
	}

}

Now that we've got all our base classes setup, we're going to modify some of our items and blocks to given the ore dictionary names!

The only block that will have an ore dictionary name is the Copper Ore block. Following with the conventions for ore dictionary names (if you look in the OreDictionary class, you can get a general idea for what these conventions are), our Copper Ore block will have an ore dictionary name of oreCopper.

We'll simply change our registration call for the Copper Ore block to have a second parameter that is also "oreCopper", telling the BlockOre class to use oreCopper as the ore dictionary name for that block.

// ...
public class ModBlocks {
	// ...
	public static BlockOre oreCopper = new BlockOre("ore_copper", "oreCopper");
	// ...
}

We'll now change both our Copper Ingot and Corn items to have ore dictionary names ingotCopper and cropCorn respectively. All this requires is changing the ItemBase instantiations to ItemOre instantiations and passing in the desired ore dictionary name as the second constructor parameter.

// ...
public class ModItems {
	// ...
	public static ItemOre ingotCopper = new ItemOre("ingot_copper", "ingotCopper");
	public static ItemOre corn = new ItemOre("corn", "cropCorn");
	// ...
}

Lastly, we'll update our ModRecipes class to call the various initOreDict methods.

// ...
public class ModRecipes {

	public static void init() {
		// Ore Dict
		ModBlocks.oreCopper.initOreDict();
		ModItems.ingotCopper.initOreDict();
		ModItems.corn.initOreDict();
	
		// ...
	}

}

Recipes

Now that we've got ore dictionary names for some of our items and blocks, let's add recipes that utilize them. Forge provides two new recipe types specifically for use with Ore Dictionary inputs: forge:ore_shaped and forge:ore_shapeless.

We'll create a new file in the recipes subfolder of our assets folder called bucket.json. In the root object, there will be a couple properties similar to the other shaped recipe we added. This time, the recipe type will be forge:ore_shaped, the pattern will be the bucket pattern, the result item will be minecraft:bucket, and the input ingredient will be a bit different so that it uses the ore dictionary.

Instead of only specifying an item parameter for the ingredient, we'll specify the type as forge:ore_dict, so the Ore Dictionary ingredient is used, and we'll specify the ore as ingotCopper, so that any copper ingot is accepted.

{
	"type": "forge:ore_shaped",
	"pattern": [
		"I I",
		" I "
	],
	"key": {
		"I": {
			"type": "forge:ore_dict",
			"ore": "ingotCopper"
		}
	},
	"result": {
		"item": "minecraft:bucket"
	}
}