Fluids API

General Mechanics registers a large set of industrial fluids through CoreFluids. Each fluid is represented by a FluidDefinition record that bundles all NeoForge fluid objects together, and the underlying visual and chemical properties are held by a BaseFluid instance.

FluidDefinition

FluidDefinition is a record that aggregates all parts of a fluid registration.

public record FluidDefinition(
    String englishName,
    Supplier<FluidType> type,
    Supplier<FlowingFluid> source,
    Supplier<FlowingFluid> flowing,
    BlockDefinition<LiquidBlock> block,
    ItemDefinition<BucketItem> bucket
)

englishName

String

Human-readable fluid name used for item/block registration.

type

Supplier<FluidType>

Lazy supplier for the FluidType (holds visual and chemical properties).

source

Supplier<FlowingFluid>

The still/source fluid variant.

flowing

Supplier<FlowingFluid>

The flowing fluid variant.

block

BlockDefinition<LiquidBlock>

The placed liquid block.

bucket

ItemDefinition<BucketItem>

The bucket item for this fluid.

Getting a FluidStack

// Default amount: 1000 mB
FluidStack stack = CoreFluids.CRUDE_OIL.getStack();

// Custom amount
FluidStack stack500 = CoreFluids.CRUDE_OIL.getStack(500);

BaseFluid

BaseFluid extends NeoForge’s FluidType and implements IClientFluidExtensions. It holds all visual and chemical properties for a registered fluid.

public class BaseFluid extends FluidType implements IClientFluidExtensions

Constructor

public BaseFluid(
    FluidType.Properties properties,
    ResourceLocation stillTexture,
    ResourceLocation flowingTexture,
    ResourceLocation overlayTexture,
    int tintColor,
    Vector3f fogColor,
    boolean isAcidic,
    boolean isBasic,
    long temp
)

Properties

Getter	Type	Description
`getTintColor()`	`int`	ARGB tint applied to the fluid texture
`getFogColor()`	`Vector3f`	RGB fog color when submerged
`isAcidic()`	`boolean`	Whether the fluid is acidic
`isBasic()`	`boolean`	Whether the fluid is basic/alkaline
`getTemp()`	`long`	Temperature in Kelvin
`getStillTexture()`	`ResourceLocation`	Texture for the still surface
`getFlowingTexture()`	`ResourceLocation`	Texture for flowing surfaces
`getOverlayTexture()`	`ResourceLocation`	Overlay texture when inside the fluid

isAcidic, isBasic, and temp have corresponding setters.

CoreFluids registry methods

registerFluid() — short form

public static FluidDefinition registerFluid(
    String englishName,
    int tintColor,
    Vector3f fogColor,
    String chemicalFormula
)

Registers a room-temperature, neutral fluid. isAcidic and isBasic default to false; temp defaults to 298L K.

englishName

String

required

Display name used to derive registry IDs and bucket/block names.

tintColor

int

required

ARGB integer tint color (e.g. 0xFFFF9933).

fogColor

Vector3f

required

RGB fog color shown when the player is submerged.

chemicalFormula

String

required

Chemical formula string registered with CoreFormulas (e.g. "H₂SO₄"). Pass null or blank to skip formula registration.

registerFluid() — full form

public static FluidDefinition registerFluid(
    String englishName,
    int tintColor,
    Vector3f fogColor,
    String chemicalFormula,
    boolean isAcidic,
    boolean isBasic,
    long temp
)

Registers a fluid with explicit acidity and temperature values.

isAcidic

boolean

Mark the fluid as an acid.

isBasic

boolean

Mark the fluid as a base/alkali.

temp

long

Temperature in Kelvin.

getFluids()

public static List<FluidDefinition> getFluids()

Returns an unmodifiable list of every FluidDefinition registered through CoreFluids.

getBaseFluid()

public static BaseFluid getBaseFluid(FluidDefinition definition)

Casts the FluidType inside the given definition to BaseFluid. Returns null if the type is not a BaseFluid instance.

Formula integration

When a non-blank chemicalFormula is provided to registerFluid(), the mod automatically registers a Formula record for both the bucket item and the liquid block. The Formula record links an ItemLike to a formula string and can render a colored, italicized component:

public record Formula(ItemLike itemLike, String formula)

// Render with default styling (yellow, not italic)
Component component = formula.getFormulaComponent();

// Render with explicit options
Component component = formula.getFormulaComponent(boolean colored, boolean italic);

Code example: registering a custom fluid

import general.mechanics.registries.CoreFluids;
import general.mechanics.api.fluid.FluidDefinition;
import org.joml.Vector3f;

public class MyFluids {

    // Room-temperature, neutral fluid
    public static final FluidDefinition LIQUID_RESIN = CoreFluids.registerFluid(
        "Liquid Resin",
        0xFFAA6633,             // amber tint
        new Vector3f(0.7f, 0.4f, 0.2f), // brown fog
        "C₁₀H₈O₄"              // formula
    );

    // Hot acidic fluid with explicit properties
    public static final FluidDefinition HOT_ACID = CoreFluids.registerFluid(
        "Hot Acid",
        0xFFFFFF44,
        new Vector3f(0.9f, 0.9f, 0.2f),
        "HF",
        true,   // isAcidic
        false,  // isBasic
        500L    // 500 K
    );
}

Call registerFluid at mod initialization time, before FMLCommonSetupEvent fires. All registrations must happen during the DeferredRegister phase.

Integration

API Reference

Contributing

FluidDefinition

Getting a FluidStack

BaseFluid

Constructor

Properties

CoreFluids registry methods

registerFluid() — short form

registerFluid() — full form

getFluids()

getBaseFluid()

Formula integration

Code example: registering a custom fluid

Build docs developers (and LLMs) love

Integration

API Reference

Contributing

​FluidDefinition

​Getting a FluidStack

​BaseFluid

​Constructor

​Properties

​CoreFluids registry methods

​registerFluid() — short form

​registerFluid() — full form

​getFluids()

​getBaseFluid()

​Formula integration

​Code example: registering a custom fluid

Build docs developers (and LLMs) love

FluidDefinition

Getting a FluidStack

BaseFluid

Constructor

Properties

CoreFluids registry methods

registerFluid() — short form

registerFluid() — full form

getFluids()

getBaseFluid()

Formula integration

Code example: registering a custom fluid