I'm looking for the best way to add an item to existing chest loot tables without completely overwriting them, through an existing method (preferable) or from an event handler if necessary.

Thanks in advance.

Edited June 27, 20223 yr by CrackedScreen
Marking thread as solved

You need to use a GlobalLootModifier

Wrote the following code and passed the serializer through a deferred register:

public class ModLoot extends LootModifier {

    protected ModLoot(LootItemCondition[] conditionsIn) {
        super(conditionsIn);
    }

    @NotNull
    @Override
    protected List<ItemStack> doApply(List<ItemStack> generatedLoot, LootContext context) {
        generatedLoot.add(new ItemStack(Items.NETHERITE_SCRAP));
        return generatedLoot;
    }

    public static class ModLootSerializer extends GlobalLootModifierSerializer<ModLoot> {

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

        @Override
        public JsonObject write(ModLoot instance) {
                return new JsonObject();
        }
    }
}

Assuming any of this even works in the first place, what would a reliable way to test if the netherite scrap appears in loot chests? Currently using a seed which contains a broken nether portal next to spawn, but the contents are the same across recreating the world.

you can use the /loot command: https://minecraft.fandom.com/wiki/Commands/loot

 

Are there any recommended built in functions for modifying an item's loot chance/itemstack size inside of doApply() or is this something I should handle with a random number generator?

42 minutes ago, CrackedScreen said:

random number generator?

handle it in the way you want, there is no recommended way

if you want you can add the final values to your json files of your LootModifier,
then it would be possible to change the values simply by the user or other Mods via a data pack

{
  "type": "loot_test:mod_loot",
  "conditions": [
    {
      "condition": "forge:loot_table_id",
      "loot_table_id": "minecraft:chests/ruined_portal"
    }
  ],
  "min": 1,
  "max": 3,
  "chance": 0.5
}

Do loot table files currently support multiple conditions (such as adding modded loot in ruined_portal and nether_bridge loot) or will a new file need to be created and serialized for this?

I cannot swap the type to minecraft:alternatives since the type field is used by the loot table serializer. If you have an example of an OR condition I could use for the json in my previous post that would work best. I'm specifically looking to change the condition so that loot will be added to multiple loot chest types instead of only "ruined_portal".

Edited June 27, 20223 yr by CrackedScreen

{
  "type": "loot_test:mod_loot",
  "conditions": [
      {
        "condition": "minecraft:alternative",
          "terms": [
          {
            "condition": "forge:loot_table_id",
            "loot_table_id": "minecraft:chests/ruined_portal"
          },
          {
            "condition": "forge:loot_table_id",
            "loot_table_id": "minecraft:chests/nether_bridge"
          }
        ]
      }
  ],
  "min": 1,
  "max": 3,
  "chance": 0.5
}

This works. Marking the thread as solved.