[1.16.5] Get effect amplifier in Loot Modifier

[MLGDuckboi]

I am trying to make a loot modifier which has varying effects based off the level of a certain status effect a player has. My modifier JSON currently checks if the player has the status effect.

{
  "conditions": [
    {
      "condition": "minecraft:entity_properties",
      "entity": "this",
      "predicate": {
        "effects": {
          "calebsmod:golden_touch": {}
        }
      }
    }
  ],
  "chance_per_level": 20,
  "drop": {
    "min": 1,
    "max": 3,
    "item": "minecraft:gold"
  }
}

Basically, "chance_per_level" dictates the chance of a block dropping somewhere between one and three gold (as defined in "drop") per level of my effect, calebsmod:golden_touch. For example, level 1 is 20% chance for gold, level 2 is 40% chance, and so on. What I'm stuck on is in my LootModifier class in the doApply method, how to get the level of the effect on the given entity. The only solution I can think of is making a loot modifier JSON for each level of the effect, but I was hoping there might be a better way. Thanks in advance!

[MLGDuckboi]

Thanks, that helps a ton

[MLGDuckboi]

Update: Sorry, I cant seem to figure out where LootParameters comes into my class.

public class LootModification extends LootModifier {
    private final int minDrop;
    private final int maxDrop;
    private final Item replacementItem;
    private final int chancePerLvl;
    public LootModification(ILootCondition[] conditionsIn, int minDrop, int maxDrop, Item itemDrop, int chancePerLvl) {
        super(conditionsIn);
        this.minDrop = minDrop;
        this.maxDrop = maxDrop;
        this.replacementItem = itemDrop;
        this.chancePerLvl = chancePerLvl;
    }

    @Nonnull
    @Override
    public List<ItemStack> doApply(List<ItemStack> generatedLoot, LootContext context) {
        return generatedLoot;
    }

    public static class Serializer extends GlobalLootModifierSerializer<LootModification> {

        @Override
        public LootModification read(ResourceLocation name, JsonObject object, ILootCondition[] conditionsIn) {
            int chance = JSONUtils.getAsInt(object, "chance_per_level");
            int max = JSONUtils.getAsInt(object, "drop.max");
            int min = JSONUtils.getAsInt(object, "drop.min");
            Item drop = ForgeRegistries.ITEMS.getValue(new ResourceLocation((JSONUtils.getAsString(object, "drop.item"))));
            return new LootModification(conditionsIn, min, max, drop, chance);
        }

        @Override
        public JsonObject write(LootModification instance) {
            JsonObject json = makeConditions(instance.conditions);
            json.addProperty("chance_per_level", instance.chancePerLvl);
            json.addProperty("drop.min", instance.minDrop);
            json.addProperty("drop.max", instance.maxDrop);
            json.addProperty("drop.item", ForgeRegistries.ITEMS.getKey(instance.replacementItem).toString());
            return json;
        }
    }
}

Could you point me in the right direction?

[MLGDuckboi]

Another issue:
My loot modifier won't load, the log just says it can't parse it, as well as a NullPointerException error. Do I have to specify that my class should be used to parse it somewhere?

All related files below:

data/forge/loot_modifiers/global_loot_modifiers.json

{
  "replace": false,
  "entries": [
    "calebsmod:golden_touch"
  ]
}

data/calebsmod/loot_modifiers/golden_touch.json

{
  "conditions": [
    {
      "condition": "minecraft:entity_properties",
      "entity": "this",
      "predicate": {
        "effects": {
          "calebsmod:golden_touch": {}
        }
      }
    }
  ],
  "chance_per_level": 0.2,
  "drop": {
    "min": 1,
    "max": 3,
    "item": "minecraft:gold"
  }
}

LootModification

public class LootModification extends LootModifier {
    private final int minDrop;
    private final int maxDrop;
    private final Item replacementItem;
    private final float chancePerLvl;
    public LootModification(ILootCondition[] conditionsIn, int minDrop, int maxDrop, Item itemDrop, float chancePerLvl) {
        super(conditionsIn);
        this.minDrop = minDrop;
        this.maxDrop = maxDrop;
        this.replacementItem = itemDrop;
        this.chancePerLvl = chancePerLvl;
    }

    @Nonnull
    @Override
    public List<ItemStack> doApply(List<ItemStack> generatedLoot, LootContext context) {
        LivingEntity entity = (LivingEntity)context.getParamOrNull(LootParameters.THIS_ENTITY);
        Random random = new Random();
        if (entity.getEffect(ModEffects.GOLDEN_TOUCH.get()).getAmplifier() * chancePerLvl > random.nextFloat()) {
            generatedLoot.removeAll(generatedLoot);
            generatedLoot.add(new ItemStack(replacementItem, minDrop + random.nextInt(maxDrop - minDrop)));
        }
        return generatedLoot;
    }

    public static class Serializer extends GlobalLootModifierSerializer<LootModification> {

        @Override
        public LootModification read(ResourceLocation name, JsonObject object, ILootCondition[] conditionsIn) {
            float chance = JSONUtils.getAsFloat(object, "chance_per_level");
            int max = JSONUtils.getAsInt(object, "drop.max");
            int min = JSONUtils.getAsInt(object, "drop.min");
            Item drop = ForgeRegistries.ITEMS.getValue(new ResourceLocation((JSONUtils.getAsString(object, "drop.item"))));
            return new LootModification(conditionsIn, min, max, drop, chance);
        }

        @Override
        public JsonObject write(LootModification instance) {
            JsonObject json = makeConditions(instance.conditions);
            json.addProperty("chance_per_level", instance.chancePerLvl);
            json.addProperty("drop.min", instance.minDrop);
            json.addProperty("drop.max", instance.maxDrop);
            json.addProperty("drop.item", ForgeRegistries.ITEMS.getKey(instance.replacementItem).toString());
            return json;
        }
    }
}

 

Edited July 12, 2021 by MLGDuckboi

[Draco18s]

Closer to how custom recipe types are registered, but yes: Things need to be registered.

the forge/loot_modifiers/global_loot_modifiers.json file is there for specifying processing order (obviously if you don't include it or don't reference a registered serializer, it won't be run at all, even if it's registered). It doesn't do the registration. It's purpose is to allow data pack folks to resolve conflicts.

[Draco18s]

5 hours ago, diesieben07 said:

Unless you mean recipe serializers, in which case it's still the same way as blocks or items. So really, this is just wrong.

No I meant custom recipe types.

Custom recipe types register their serializers.
Blocks register themselves.

So while you're not wrong, it's missing the point. The way that that most people think about it is "recipes" because "recipes are data assets" and that "custom recipe types" need to have a serializer registered rather than registering the recipe itself whereas items and blocks are just registered "normally."

There's a degree of indirection that is the same between "Recipes" and "Loot Modifiers" that isn't present for "Blocks" and "Items."

 

(Unless there's a BlockSerializer implements ForgeRegistryEntry around that I'm unaware of...)

[Draco18s]

1 hour ago, diesieben07 said:

You register LootModifierSerializer the same way you do a block.

Yes.

But you don't register LootModifiers.