Just Dire Fuels

A NeoForge 1.21.1 addon for Just Dire Things that replaces JDT's hardcoded, config-locked fuel values with data-driven fuels for both the Fluid Generator T1 and the Solid Generator T1. Datapacks can add new fuels, override existing values, and the changes are reflected in JEI.

Requirements

• Minecraft 1.21.1
• NeoForge 21.1.209+
• Just Dire Things 1.5.7+
• JEI (optional, for the in-game fuel browser)

What it changes

Fluid Generator T1

In stock JDT, the fluid generator only accepts fluids that implement the internal RefinedFuel interface, and energy output per millibucket is locked to three server-config values (fuel_tier2_fe_per_mb, fuel_tier3_fe_per_mb, fuel_tier4_fe_per_mb). New mods or packs cannot register fuels.

Just Dire Fuels adds the justdirefuels:fluid_fuels data map on the minecraft:fluid registry. Any fluid present in the map is now a valid generator fuel at the rate the map specifies.

// data/<your-pack>/data_maps/fluid/fluid_fuels.json
{
  "values": {
    "minecraft:lava": { "fe_per_mb": 100 },
    "yourmod:plasma":  { "fe_per_mb": 7500 }
  }
}

The addon ships defaults mirroring JDT's current config values so out-of-the-box behavior is unchanged. Datapacks can override any of them.

Solid Generator T1

JDT's solid generator already reads burn time from NeoForge's furnace_fuels data map, so adding new burnable items has always been datapack-driven. What was not datapack-driven was the FE generated per burn tick and the per-fuel burn-speed multiplier (these were hardcoded in Coal_T1/Coal_T2/etc. with a single global config knob for FE/tick).

Just Dire Fuels adds the justdirefuels:item_fuels data map on the minecraft:item registry with two optional fields:

// data/<your-pack>/data_maps/item/item_fuels.json
{
  "values": {
    "minecraft:diamond":         { "fe_per_tick": 500, "burn_speed_multiplier": 8 },
    "justdirethings:coal_t2":    { "burn_speed_multiplier": 6 }
  }
}

Field	Default behavior if omitted
fe_per_tick	Falls back to JDT's generator_t1_fe_per_fuel_tick server config (15).
burn_speed_multiplier	Falls back to JDT's hardcoded value (1 for items not specially handled by JDT).

Solid fuels still need a burn_time in NeoForge's furnace_fuels data map — that's separate, and the addon does not touch it.

JEI

A new "Fluid Generator Fuels" category lists every fluid currently in the data map with its FE/mB rate. The Fluid Generator T1 block is the recipe catalyst, so right-clicking it in JEI takes you straight to the fuel list.

Installation

Drop the mod into your mods/ folder alongside the JDT jar. That's it.

Sample datapack

A working demo datapack lives at examples/justdirefuels_demo/. It does three things at once:

1. Makes vanilla lava a fluid fuel at 100 FE/mB.
2. Overrides JDT's T2 refined fuel from 450 to 999 FE/mB.
3. Makes vanilla diamond a (rather overpowered) solid fuel.

Copy the folder into <world>/datapacks/, /reload, and check JEI.

How it works under the hood

The addon uses five mixins against JDT. None of them remove or break existing JDT behavior; they layer a data-map check in front of it.

Mixin target	What it does
GeneratorFluidT1BE	Configures the current Fluid Generator T1 tank to accept data-map fuels while preserving JDT RefinedFuel, and returns data-map fe_per_mb when present.
BaseMachineBE.loadAdditional	Reapplies the Fluid Generator T1 validator after NeoForge replaces the serialized tank attachment during chunk/world loading. Other JDT machines are ignored.
GeneratorFluidItemHandler.isItemValid	Accepts buckets/containers of any fluid present in the data map.
RefinedFuelSlot.mayPlace	Allows data-map fuel containers to be placed in the generator GUI slot.
GeneratorT1BE (capture + getter + NBT)	Snapshots data-map fe_per_tick and burn_speed_multiplier at burn start, persists them across world reloads, and serves them from the getters during the burn.

License

MIT. See LICENSE.md.

Changelog

See metadata/changelogs/.