[1.15] Loot Table Function/Condition Issues [SOLVED]

[Tikaji]

I'm trying to add a loot table function/condition so that I can change the item that is dropped by a block based on a condition. I've tried adding both a function and a condition and I have had no success. What am I missing here?
 

This is the function that I tried.

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package com.novamachina.ens.common.loot.function;

import com.google.gson.JsonDeserializationContext;
import com.google.gson.JsonObject;
import com.novamachina.ens.common.item.tools.hammer.HammerBaseItem;
import com.novamachina.ens.common.registry.MasterRegistry;
import com.novamachina.ens.common.utility.LogUtil;
import net.minecraft.block.BlockState;
import net.minecraft.item.ItemStack;
import net.minecraft.util.ResourceLocation;
import net.minecraft.world.storage.loot.LootContext;
import net.minecraft.world.storage.loot.LootFunction;
import net.minecraft.world.storage.loot.LootParameters;
import net.minecraft.world.storage.loot.conditions.ILootCondition;

public class UseHammerFunction extends LootFunction {

    private UseHammerFunction(ILootCondition[] conditionsIn) {
        super(conditionsIn);
        LogUtil.info("Register Hammer Function");
    }

    @Override
    protected ItemStack doApply(ItemStack stack, LootContext context) {
        LogUtil.info("Ran Hammer Function");
        BlockState state = context.get(LootParameters.BLOCK_STATE);
        ItemStack itemstack = context.get(LootParameters.TOOL);

        if(itemstack != null && state != null)
        {
            if(itemstack.getItem() instanceof HammerBaseItem)
            {
                LogUtil.info("Used Hammer");
                return new ItemStack(MasterRegistry.HAMMER_REGISTRY.getResult(state.getBlock()));
            }
        }

        return stack;
    }

    public static class Serializer extends LootFunction.Serializer<UseHammerFunction> {

        public Serializer() {
            super(new ResourceLocation("ens:use_hammer_fun"), UseHammerFunction.class);
            LogUtil.info("UseHammerFunction.Serializer called");
        }

        @Override
        public UseHammerFunction deserialize(JsonObject object,
            JsonDeserializationContext deserializationContext, ILootCondition[] conditionsIn) {
            LogUtil.info("UseHammerFunction deserialize");
            return new UseHammerFunction(conditionsIn);
        }
    }
}

 

This is the loot table that I create for the function.

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{
  "type": "minecraft:block",
  "pools": [
    {
      "rolls": 1,
      "entries": [
        {
          "type": "minecraft:item",
          "conditions": [
            {
              "condition": "minecraft:survives_explosion"
            }
          ],
          "functions": [
            {
              "function": "ens:use_hammer_fun"
            }
          ],
          "name": "minecraft:cobblestone"
        }
      ]
    }
  ]
}

 

This is the condition that I tried.

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package com.novamachina.ens.common.loot.condition;

import com.google.common.collect.ImmutableSet;
import com.google.gson.JsonDeserializationContext;
import com.google.gson.JsonObject;
import com.google.gson.JsonSerializationContext;
import com.novamachina.ens.common.item.tools.hammer.HammerBaseItem;
import com.novamachina.ens.common.utility.LogUtil;
import java.util.Set;
import net.minecraft.item.ItemStack;
import net.minecraft.util.ResourceLocation;
import net.minecraft.world.storage.loot.LootContext;
import net.minecraft.world.storage.loot.LootParameter;
import net.minecraft.world.storage.loot.LootParameters;
import net.minecraft.world.storage.loot.conditions.ILootCondition;

public class UseHammerCondition implements ILootCondition {

    public UseHammerCondition() {
    }

    public Set<LootParameter<?>> getRequiredParameters() {
        return ImmutableSet.of(LootParameters.TOOL);
    }

    public boolean test(LootContext p_test_1_) {
        LogUtil.info("Check Used Hammer");
        ItemStack itemstack = p_test_1_.get(LootParameters.TOOL);
        return itemstack != null && itemstack.getItem() instanceof HammerBaseItem;
    }

    public static ILootCondition.IBuilder builder() {
        return UseHammerCondition::new;
    }

    public static class Serializer extends ILootCondition.AbstractSerializer<UseHammerCondition> {
        public Serializer() {
            super(new ResourceLocation("ens:use_hammer_cond"), UseHammerCondition.class);
        }

        public void serialize(JsonObject json, UseHammerCondition value, JsonSerializationContext context) {

        }

        public UseHammerCondition deserialize(JsonObject json, JsonDeserializationContext context) {
            return new UseHammerCondition();
        }
    }

}

 

This is the loot table I create for the condition.

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{
  "type": "minecraft:block",
  "pools": [
    {
      "rolls": 1,
      "entries": [
        {
          "type": "minecraft:item",
          "conditions": [
            {
              "condition": "minecraft:survives_explosion"
            },
            {
              "condition": "minecraft:inverted",
              "term": {
                "condition": "ens:use_hammer_cond"
              }
            }
          ],
          "name": "minecraft:cobblestone"
        }
      ]
    },
    {
      "rolls": 1,
      "entries": [
        {
          "type": "minecraft:item",
          "conditions": [
            {
              "condition": "minecraft:survives_explosion"
            },
            {
              "condition": "ens:use_hammer_cond"
            }
          ],
          "name": "minecraft:gravel"
        }
      ]
    }
  ]
}

 

I register both of them here.

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public static void init(final FMLCommonSetupEvent event) {
        addRegistries();
        LootFunctionManager.registerFunction(new UseHammerFunction.Serializer());
        LootConditionManager.registerCondition(new UseHammerCondition.Serializer());
    }

 

 

Any help would be much appreciated.

 

EDIT: I'm overriding the cobblestone loot table and the loot table file is placed in data/minecraft/loot_tables/blocks

Edited April 15, 2020 by Tikaji
Some more info on issue.

[Ugdhar]

I was messing with loot recently using global loot modifiers, and it worked pretty sweet. Looks very similar in setup to what you're doing here, just different way of registering I guess. Here's the link: https://github.com/MinecraftForge/MinecraftForge/blob/1.15.x/src/test/java/net/minecraftforge/debug/gameplay/loot/GlobalLootModifiersTest.java

 

And here's a link to the thread I had started while trying to figure it out, hope it helps!

https://www.minecraftforge.net/forum/topic/83671-1152-manipulate-actual-block-drops-not-what-can-drop/

 

[Draco18s]

And a docs page (currently up for PR)

https://github.com/Draco18s/Documentation/blob/1.15.x/docs/items/globallootmodifiers.md

[Tikaji]

Ok, so I got the Loot Modifier to work, but now I have the issue that gravel and sand will drop two of the same item. However, cobblestone drops one item using the same functionality. Why would that be?

[Draco18s]

  On 4/17/2020 at 2:56 AM, Tikaji said:

Ok, so I got the Loot Modifier to work, but now I have the issue that gravel and sand will drop two of the same item. However, cobblestone drops one item using the same functionality. Why would that be?

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Show your code.

[Tikaji]

Here's the modifier:

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package com.novamachina.ens.common.loot.modifier;

import com.google.gson.JsonObject;
import com.novamachina.ens.common.item.tools.hammer.HammerBaseItem;
import com.novamachina.ens.common.registry.MasterRegistry;
import com.novamachina.ens.common.utility.LogUtil;
import java.util.ArrayList;
import java.util.List;
import javax.annotation.Nonnull;
import net.minecraft.block.Block;
import net.minecraft.block.BlockState;
import net.minecraft.item.ItemStack;
import net.minecraft.util.ResourceLocation;
import net.minecraft.world.storage.loot.LootContext;
import net.minecraft.world.storage.loot.LootParameters;
import net.minecraft.world.storage.loot.conditions.ILootCondition;
import net.minecraftforge.common.loot.GlobalLootModifierSerializer;
import net.minecraftforge.common.loot.LootModifier;

public class UseHammerModifier extends LootModifier {

    public UseHammerModifier(ILootCondition[] conditionsIn) {
        super(conditionsIn);
    }

    @Nonnull
    @Override
    public List<ItemStack> doApply(List<ItemStack> generatedLoot, LootContext context) {
        ItemStack  tool       = context.get(LootParameters.TOOL);
        BlockState blockState = context.get(LootParameters.BLOCK_STATE);
        if (tool != null && blockState != null) {
            if (tool.getItem() instanceof HammerBaseItem) {
                List<ItemStack> newLoot     = new ArrayList<>();
                Block           returnBlock = MasterRegistry.HAMMER_REGISTRY
                    .getResult(blockState.getBlock());
                newLoot.add(new ItemStack(returnBlock));
                return newLoot;
            }
        }
        return generatedLoot;
    }

    public static class Serializer extends GlobalLootModifierSerializer<UseHammerModifier> {


        @Override
        public UseHammerModifier read(ResourceLocation location, JsonObject object,
            ILootCondition[] ailootcondition) {
            return new UseHammerModifier(ailootcondition);
        }
    }
}

 

Here is the loot modifier json:

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{
  "type": "ens:use_hammer",
  "conditions": [
    {
      "condition": "minecraft:alternative",
      "terms": [
        {
          "condition": "minecraft:block_state_property",
          "block": "minecraft:cobblestone"
        },
        {
          "condition": "minecraft:block_state_property",
          "block": "minecraft:gravel"
        },
        {
          "condition": "minecraft:block_state_property",
          "block": "minecraft:sand"
        }
      ]
    }
  ]
}

 

And here is the item. I assumed that I have to use the onBlockDestroyed in order to cause block drops for a custom tool. I was getting no drops with it otherwise.

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package com.novamachina.ens.common.item.tools.hammer;

import com.google.common.collect.Sets;
import com.novamachina.ens.common.setup.ModSetup;
import com.novamachina.ens.common.setup.Registration;
import java.util.Set;
import net.minecraft.block.Block;
import net.minecraft.block.BlockState;
import net.minecraft.block.Blocks;
import net.minecraft.entity.LivingEntity;
import net.minecraft.item.IItemTier;
import net.minecraft.item.Item;
import net.minecraft.item.ItemStack;
import net.minecraft.item.ToolItem;
import net.minecraft.util.math.BlockPos;
import net.minecraft.world.World;

public class HammerBaseItem extends ToolItem {

    private static final Set<Block> effectiveBlocksOn = Sets
        .newHashSet(Blocks.STONE, Blocks.DIORITE, Blocks.ANDESITE, Blocks.GRANITE,
            Blocks.NETHERRACK, Blocks.END_STONE, Blocks.COBBLESTONE,
            Registration.BLOCK_CRUSHED_DIORITE.get(), Registration.BLOCK_CRUSHED_ANDESITE.get(),
            Registration.BLOCK_CRUSHED_GRANITE.get(), Registration.BLOCK_CRUSHED_NETHERRACK.get(),
            Registration.BLOCK_CRUSHED_END_STONE.get(), Blocks.GRAVEL, Blocks.SAND,
            Registration.BLOCK_DUST.get());

    public HammerBaseItem(IItemTier tier, int maxDamage) {
        super(0.5F, 0.5F, tier, effectiveBlocksOn,
            new Item.Properties().defaultMaxDamage(maxDamage).group(ModSetup.ITEM_GROUP));
    }

    @Override
    public boolean onBlockDestroyed(ItemStack stack, World worldIn, BlockState state, BlockPos pos,
        LivingEntity entityLiving) {
        super.onBlockDestroyed(stack, worldIn, state, pos, entityLiving);
        Block.spawnDrops(state, worldIn, pos, null, entityLiving, stack);
        return false;
    }
}

 

Let me know if there is anything else. I'll step through the code and it calls the spawnDrops method twice.

Edited April 17, 2020 by Tikaji

[Animefan8888]

  On 4/17/2020 at 3:32 AM, Tikaji said:

And here is the item. I assumed that I have to use the onBlockDestroyed in order to cause block drops for a custom tool. I was getting no drops with it otherwise.

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You are not supposed to do that from what I can tell I haven't messed around with Global Loot Modifiers yet, but seeing as how LootModifier::doApply returns a List<ItemStack> I assume that are the drops.

 

  On 4/17/2020 at 3:32 AM, Tikaji said:

ItemStack tool = context.get(LootParameters.TOOL);

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ItemStacks can never be null. Use itemStack::isEmpty

 

  On 4/17/2020 at 3:32 AM, Tikaji said:

blockState != null

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I'm also unsure about this. I don't know if a BlockState will ever be null. I'd assume the default null-like value is the BlockState for AIR.

 

  On 4/17/2020 at 3:32 AM, Tikaji said:

Let me know if there is anything else. I'll step through the code and it calls the spawnDrops method twice.

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Have you stepped through your LootModifier::doApply code is it called twice? Is it called at all aside from your Block.spawnDrops call?

[Tikaji]

Ok, so I got rid of the onBlockDestroyed method, which caused doApply to only get called once, and I'm getting block drops from sand and gravel, only one item which is the expected result, but now I'm not getting anything from cobblestone. The modifier isn't being fired. My guess is something is wrong with the JSON file because that's what determines when the modifier gets fired, correct?

[Animefan8888]

  On 4/17/2020 at 3:32 AM, Tikaji said:

MasterRegistry.HAMMER_REGISTRY .getResult(blockState.getBlock());

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What does this look like? Do you add cobblestone to it?

  On 4/17/2020 at 5:23 AM, Tikaji said:

My guess is something is wrong with the JSON file because that's what determines when the modifier gets fired, correct?

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That would be my only idea as well, but I can't see what's wrong with it. Try setting a breakpoint in the area before global loot modifiers are called to see why your loot modifier condition is not true.

[Tikaji]

  On 4/17/2020 at 5:38 AM, Animefan8888 said:

  On 4/17/2020 at 3:32 AM, Tikaji said:

MasterRegistry.HAMMER_REGISTRY .getResult(blockState.getBlock());

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What does this look like? Do you add cobblestone to it?

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I do add cobblestone to the registry. Its simply a map that takes a block as input and determines the output.

I also updated the JSON to see if any other blocks would work. The only two that work and trigger the modifier are sand and gravel. I also stripped it down to just cobblestone and it doesn't work.
Updated JSON:

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{
  "type": "ens:use_hammer",
  "conditions": [
    {
      "condition": "minecraft:alternative",
      "terms": [
        {
          "condition": "minecraft:block_state_property",
          "block": "minecraft:cobblestone"
        },
        {
          "condition": "minecraft:block_state_property",
          "block": "minecraft:gravel"
        },
        {
          "condition": "minecraft:block_state_property",
          "block": "minecraft:sand"
        },
        {
          "condition": "minecraft:block_state_property",
          "block": "minecraft:andesite"
        },
        {
          "condition": "minecraft:block_state_property",
          "block": "minecraft:diorite"
        },
        {
          "condition": "minecraft:block_state_property",
          "block": "minecraft:granite"
        },
        {
          "condition": "minecraft:block_state_property",
          "block": "minecraft:netherrack"
        },
        {
          "condition": "minecraft:block_state_property",
          "block": "minecraft:end_stone"
        }
      ]
    }
  ]
}

 

  On 4/17/2020 at 5:38 AM, Animefan8888 said:

Try setting a breakpoint in the area before global loot modifiers are called to see why your loot modifier condition is not true.

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As far as I can tell Blocks.getDrops (which does the correct calls to use the loot table modifiers) isn't called when my custom tool is used on anything except sand and gravel.

Edited April 17, 2020 by Tikaji

[Animefan8888]

  On 4/17/2020 at 6:01 AM, Tikaji said:

As far as I can tell Blocks.getDrops (which does the correct calls to use the loot table modifiers) isn't called when my custom tool is used on anything except sand and gravel.

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You either need to used the PlayerEvent.HarvestCheck event to say the player can harvest those blocks with your Hammer Item(s) or make your Hammer a Pickaxe by adding a ToolType via the Item.Properties::addToolType method.

 

I believe the first option is the most suitable.

[Tikaji]

I would assume that I need to add an event handler for this, but I'm not entirely sure exactly what I need within the handler. Got a good place to point me to for this?

[Animefan8888]

  On 4/17/2020 at 6:32 AM, Tikaji said:

Got a good place to point me to for this?

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Not sure how much you know about Events but here is the documentation. You need to subscribe to the PlayerEvent.HarvestCheck event. And call HarvestCheck::setCanHarvest(true). Use the methods within the event to determine if the player is holding your Hammer and if they are say they can harvest the block.

[Tikaji]

And that fixed all my problems! Thanks!

[Draco18s]

  On 4/17/2020 at 3:32 AM, Tikaji said:

if (tool.getItem() instanceof HammerBaseItem)

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This should also be specified by your loot json file:

https://github.com/MinecraftForge/MinecraftForge/blob/1.15.x/src/test/resources/data/global_loot_test/loot_modifiers/wheat_harvest.json#L5-L8

 

  On 4/17/2020 at 5:07 AM, Animefan8888 said:

but seeing as how LootModifier::doApply returns a List<ItemStack> I assume that are the drops.

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This is correct.