Item pools

In an addon mod

Ship the files on this page in your jar under src/main/resources/data/<your namespace>/, or generate them from Java sources: see Recipes and data.

An item pool is a weighted list of items that HBM draws loot from. These are 1.7’s ItemPool tables. They are not vanilla loot tables: HBM’s own code and structures draw from them by name. (HBM’s additions to vanilla chests, such as dungeon and mineshaft chests, are a separate system and are not pools.)

Where pools are used

Pools	Used by
POOL_SUPPLIES, POOL_WEAPONS, POOL_AMMO	Supply drops from the C-130
POOL_SNACKS, POOL_SODA	Vending machines
POOL_SAT_MINER, POOL_SAT_LUNAR	Mining satellite cargo (the asteroid and lunar miners)
POOL_METEORITE_TREASURE	Meteorite treasure blocks
POOL_RED_PEDESTAL, POOL_BLACK_PART, POOL_BLACK_SLAB	The red room keyhole pedestals
POOL_VAULT_*, POOL_BLUEPRINTS	Safes and dungeon chests in HBM’s world generation
POOL_FILING_CABINET, POOL_OFFICE_TRASH, POOL_MACHINE_PARTS, POOL_NUKE_*, POOL_SILO, POOL_VERTIBIRD, POOL_SPACESHIP, POOL_ANTENNA, POOL_SOLID_FUEL, POOL_EXPENSIVE, POOL_GENERIC	Containers in HBM’s structures (bunker, silo, offices, desert atom sites and others)
POOL_PILE_*	Loose loot piles placed in structures
POOL_LAUNCH_KEY, POOL_REPAIR_MATERIALS, POOL_RTG, POOL_OIL_RIG, POOL_METEOR_SAFE	Loot blocks inside HBM’s NBT structures, which name their pool

HBM ships 50 pools. Their files, with every row, are in the NTM - Continuum jar under data/hbm/item_pool/.

File format

data/<ns>/item_pool/<pool>.json

The pool’s name is the file name in upper case: pool_sat_miner.json is POOL_SAT_MINER. The namespace does not matter for the name, so a file in your own namespace adds to HBM’s pool of the same name.

data/hbm/item_pool/pool_expensive.json (three rows)

{
  "entries": [
    { "item": "hbm:canister_full", "min": 1, "max": 2, "weight": 2, "fluid": "DIESEL" },
    { "item": "hbm:gas_mask_m65", "min": 1, "max": 1, "weight": 5, "components": { "minecraft:damage": 60 } },
    { "item": "hbm:canister_full", "min": 1, "max": 2, "weight": 3, "fluid": "BIOFUEL" }
  ]
}

Field	Type	Meaning
replace	boolean, optional	true drops every row that came before this file (see merging). Default false.
entries	list	The rows.

Each row:

Field	Type	Meaning
item	item id, optional	The item. Without it, the row is an empty draw: it keeps its weight but gives nothing.
min, max	integers, required	The count is rolled between them, both included.
weight	integer, required	The row’s chance relative to the pool’s total weight.
fluid	string, optional	Fills a fluid container item (hbm:canister_full, hbm:cell and the portable fluid tanks) with this fluid. It is HBM’s upper-case fluid name (DIESEL, BIOFUEL), not the hbm:diesel id.
components	object, optional	Item components, as in a vanilla item stack. On 1.20.1, which has no components, a row whose components do not decode falls back to the bare item.

A row naming an item that does not exist is skipped. A row naming a fluid the item cannot hold is skipped with a warning.

Merging

Every pack’s copy of a pool file is read. Rows are merged in this order:

1. Files in the hbm namespace first, then every other namespace in id order.
2. For one file id, every pack’s copy, lowest priority first.

A file with "replace": true removes every row merged before it, then adds its own. A file name no pool uses creates a new pool, which only matters if something draws from it by name.

To add gas masks (one or two per draw) to the supply drop pool:

data/mypack/item_pool/pool_supplies.json

{
  "entries": [
    { "item": "hbm:gas_mask_m65", "min": 1, "max": 2, "weight": 5 }
  ]
}

To replace a pool, use "replace": true in your own namespace’s file. Because other namespaces merge after hbm, it drops HBM’s rows:

data/mypack/item_pool/pool_soda.json

{
  "replace": true,
  "entries": [
    { "item": "minecraft:honey_bottle", "min": 1, "max": 1, "weight": 1 }
  ]
}

Pools reload with /reload and are sent to clients (JEI’s satellite page shows the miner pools).