How to register new LootFunction - 1.16.5

[Tut]

Hi, I'm trying to register a new LootFunction to use in my loot table data generator. I was loosely basing it off of Astral Sorcery's loot table data generators, since I'm trying to achieve a similar effect.

Here's my loot table provider: 

package org.tutmods.shungite.data;

import com.google.common.collect.ImmutableList;
import com.mojang.datafixers.util.Pair;
import net.minecraft.block.Block;
import net.minecraft.block.Blocks;
import net.minecraft.data.DataGenerator;
import net.minecraft.data.LootTableProvider;
import net.minecraft.data.loot.BlockLootTables;
import net.minecraft.enchantment.Enchantments;
import net.minecraft.item.Item;
import net.minecraft.item.Items;
import net.minecraft.loot.ItemLootEntry;
import net.minecraft.loot.LootParameterSet;
import net.minecraft.loot.LootParameterSets;
import net.minecraft.loot.LootPool;
import net.minecraft.loot.LootTable;
import net.minecraft.loot.LootTableManager;
import net.minecraft.loot.RandomValueRange;
import net.minecraft.loot.ValidationTracker;
import net.minecraft.loot.functions.ApplyBonus;
import net.minecraft.loot.functions.ExplosionDecay;
import net.minecraft.util.ResourceLocation;
import net.minecraftforge.fml.RegistryObject;
import org.tutmods.shungite.loot.ShungiteCrystalPropertiesLoot;
import org.tutmods.shungite.setup.ModBlocks;
import org.tutmods.shungite.setup.ModItems;
import org.tutmods.shungite.setup.Registration;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.function.BiConsumer;
import java.util.function.Consumer;
import java.util.function.Supplier;
import java.util.stream.Collectors;

public class ModLootTableProvider extends LootTableProvider {
    public ModLootTableProvider(DataGenerator generator) {
        super(generator);
    }

    @Override
    protected List<Pair<Supplier<Consumer<BiConsumer<ResourceLocation, LootTable.Builder>>>, LootParameterSet>> getTables() {
        return ImmutableList.of(Pair.of(ModBlockLootTables::new, LootParameterSets.BLOCK));
    }

    @Override
    protected void validate(Map<ResourceLocation, LootTable> map, ValidationTracker validationtracker) {
        map.forEach( (one, two) -> LootTableManager.validate(validationtracker, one, two));
    }

   public static class ModBlockLootTables extends BlockLootTables {
       @Override
       protected void addTables() {
           this.add(ModBlocks.SHUNGITE_CRYSTAL_ORE.get(), (block) ->
                   LootTable.lootTable()
                            .withPool(LootPool.lootPool()
                                              .setRolls(RandomValueRange.between(2F, 5F))
                                              .add(ItemLootEntry.lootTableItem(ModItems.SHUNGITE.get())
                                                                .apply(ExplosionDecay.explosionDecay())
                                                                .apply(ShungiteCrystalPropertiesLoot.builder()))
                           ));
       }

       @Override
       protected Iterable<Block> getKnownBlocks() {
           return Registration.BLOCK_DEFERRED_REGISTER.getEntries()
                   .stream().map(RegistryObject::get).collect(Collectors.toList());
       }
   }
}

And the loot function I want to add: 

package org.tutmods.shungite.loot;

import com.google.gson.JsonDeserializationContext;
import com.google.gson.JsonObject;
import net.minecraft.item.ItemStack;
import net.minecraft.loot.LootContext;
import net.minecraft.loot.LootFunction;
import net.minecraft.loot.LootFunctionType;
import net.minecraft.loot.conditions.ILootCondition;
import org.tutmods.shungite.items.crystal.ShungiteCrystal;
import org.tutmods.shungite.items.crystal.properties.ShungiteCrystalProperties;
import org.tutmods.shungite.util.crystal.CrystalUtils;

public class ShungiteCrystalPropertiesLoot extends LootFunction {
    protected ShungiteCrystalPropertiesLoot(ILootCondition[] conditions) {
        super(conditions);
    }

    @Override
    protected ItemStack run(ItemStack stack, LootContext lootContext) {
        if (stack.getItem() instanceof ShungiteCrystal) {
            final ShungiteCrystalProperties properties = CrystalPropertyGenerator.getRandomNewCrystalProperties();
            CrystalUtils.putProperties(stack, properties);
        }

        return stack;
    }

    public static LootFunction.Builder<?> builder() {
        return simpleBuilder(ShungiteCrystalPropertiesLoot::new);
    }

    @Override
    public LootFunctionType getType() {
        return Functions.ShungiteCrystalsLoot;
    }

    public static class Functions {
        public static LootFunctionType ShungiteCrystalsLoot;
    }

    public static class Serializer extends LootFunction.Serializer<ShungiteCrystalPropertiesLoot> {
        @Override
        public ShungiteCrystalPropertiesLoot deserialize(JsonObject jsonObject, JsonDeserializationContext jsonDeserializationContext, ILootCondition[] iLootConditions) {
            return new ShungiteCrystalPropertiesLoot(iLootConditions);
        }
    }
}

 

I see Astral doing similar things here:

https://github.com/HellFirePvP/AstralSorcery/blob/1.16-indev/src/main/java/hellfirepvp/astralsorcery/common/loot/RandomCrystalProperty.java

https://github.com/HellFirePvP/AstralSorcery/blob/e8434f1a09356632babefee1925626dc3deefb2a/src/main/java/hellfirepvp/astralsorcery/datagen/data/loot/BlockLootTableProvider.java#L77

However, my trouble comes when running the data generator. I can't register the serializer as Astral does here https://github.com/HellFirePvP/AstralSorcery/blob/e8434f1a09356632babefee1925626dc3deefb2a/src/main/java/hellfirepvp/astralsorcery/common/registry/RegistryLoot.java#L49, since LootFunctionManager.register is private. Is there a new way of doing this?

 

I tried just calling Registry.register as LootFunctionManager.register does itself, and I was able to generate JSON with that, however my game hung as soon as I broke the block; so I assume I'm doing something wrong. I saw there's a new DeferredRegister for LootModifiers, but I'm not sure if that fulfills the same role as a LootFunction?

 

So I guess I have two questions:

How do I register my serializer for my LootFunction correctly?

What's the difference between a LootFunction and a LootModifier?

 

[Tut]

I see now Astral is able to do that since they use an access transformer for that function.

https://github.com/HellFirePvP/AstralSorcery/blob/e8434f1a09356632babefee1925626dc3deefb2a/src/main/resources/META-INF/accesstransformer.cfg#L12

 

Is that the only way to do this?

[Tut]

Slight update - I had a bug in my code that caused minecraft to hang. Pretty sure directly registering it with Registry.register would have worked; but my question of how to do it the "right" way still stands. Right now the access transformer works as intended.

Edited May 15, 2021 by Tut