3. Mod Developer Things

Want to integrate with CreateWorldUI? Here's what you need to know.

How to create a fully custom GameRule in the GameRule Editor UI?

Well, quite simple, just add the game rules through the GameRule class like you used to do, name your Rule name then set a default boolean or number value. And then, boom, they appeared on the page. Has their name and their default value will show on your screen.
But... There's something wrong. What if I want to add tooltip descriptions for my rules, and also, how to custom vanilla Rule name tooltip?
Well, more things need to be done. And we have two ways for it.

Simple way (Recommended)

The modpack usage is showing how to use it. That's it.

Another hard way

It can only be achieved by the hard code, and this doesn't like the simple way if you cannot handle it carefully it cannot show the localized name. so it's not welcomed to the only using simple ways.
Codes are belowed: (After 1.0.1)

package idk.unknown.which;

import cpw.mods.fml.common.Mod;
import cpw.mods.fml.common.event.FMLInitializationEvent;
import decok.dfcdvadstf.createworldui.gamerule.GuiScreenGameRuleEditor;

@Mod(modid = "idk", name = "idk", version = "idk")
public class idk {
    @Mod.EventHandler
    public void init(FMLInitializationEvent event){
        // There are two ways to register this
        // registerTooltip() can add one single tooltip
        // registerTooltips() can add a Map, which contains many rules and tooltips, to the tooltip list. 
        GuiScreenGameRuleEditor.registerTooltip("randomTickSpeed", "Controls how fast random ticks occur");
        GuiScreenGameRuleEditor.registerTooltip("myCustomRule", "This is a rule added by another mod"); // Former is ruleName, latter is tooltips. 
        Map<String,String> myCustomTooltips = new HashMap<>();
        myCustomTooltips.put("myCustomRule2","This is a rule added by another mod");
        myCustomTooltips.put("myCustomRule3","This is a rule added by another mod");
        myCustomTooltips.put("myCustomRule4","This is a rule added by another mod");
        // myCustomTooltips.put(........);
        GuiScreenGameRuleEditor.registerTooltips("myCustomToolTips");
    }
}

API Overview

Here are the API classes you can use.

GameRuleApplier

Package: decok.dfcdvadstf.createworldui.api.gamerule.GameRuleApplier

Handles applying game rules when a world loads.

Method	What it does
`setPendingGameRules(Map<String, String>)`	Queue up game rules to apply when the next world is created.
`getPendingGameRules()`	Get the currently pending rules (may be `null`).

Pending rules are applied via WorldEvent.Load and then cleared.

GameRuleMonitorNSetter

Package: decok.dfcdvadstf.createworldui.api.gamerule.GameRuleMonitorNSetter

For getting, setting, and adding game rules.

Method	What it does
`getAllGamerules(World)`	Get all game rules from a world as `Map<String, GameruleValue>`.
`setGamerule(World, String, String)`	Set a game rule on a world.

The GameruleValue inner class stores values in multiple types (String, boolean, int, double) and has getOptimalValue() to pick the best one.

DifficultyApplier

Package: decok.dfcdvadstf.createworldui.api.DifficultyApplier

Applies difficulty settings when a world is created. Works with the tab system to set difficulty on the IntegratedServer via Mixin.

GuiCyclableButton

Package: decok.dfcdvadstf.createworldui.api.GuiCyclableButton

A button that cycles through values on click. Used for game mode, difficulty, and world type. You can use it in your own tabs.

TabRegistry

Package: decok.dfcdvadstf.createworldui.api.tab.TabRegistry

The static registry for external mods to register custom tabs. See Adding a Custom Tab for details and examples.

Tab System

After 2.0.0, the world creation screen uses a tab system. Each tab implements AbstractScreenTab. And after 4.0.0, this mod finally abled to registry the tabs.

Built-in Tabs

Class	Tab ID	What it does
`GameTab`	100	World name, game mode, difficulty, cheats
`WorldTab`	101	Seed, world type, structures, bonus chest
`MoreTab`	102	GameRule Editor, experiments, data packs

TabManager

Package: decok.dfcdvadstf.createworldui.api.tab.TabManager

TabManager handles tab switching, state persistence (survives window resizes), and gives you accessors for the shared state:

Method	What it does
`getWorldName()` / `setWorldName(String)`	Get or set the world name.
`getGameMode()` / `setGameMode(String)`	Get or set the game mode.
`getDifficulty()` / `setDifficulty(EnumDifficulty)`	Get or set the difficulty.
`getHardcore()` / `setHardcore(boolean)`	Get or set hardcore mode.
`getAllowCheats()` / `setAllowCheats(boolean)`	Get or set allow cheats.
`getSeed()` / `setSeed(String)`	Get or set the world seed.
`getWorldTypeIndex()` / `setWorldTypeIndex(int)`	Get or set the world type.
`getGenerateStructures()` / `setGenerateStructures(boolean)`	Get or set generate structures.
`getBonusChest()` / `setBonusChest(boolean)`	Get or set bonus chest.

TabState

Package: decok.dfcdvadstf.createworldui.api.tab.TabState

Stores tab state (active tab, all tab fields) that persists across GUI reinitialization — like when you resize the window.

Adding a Custom Tab

You can register custom tabs into the world creation screen using the TabRegistry API.

TabRegistry

Package: decok.dfcdvadstf.createworldui.api.tab.TabRegistry

It's a static registry — you register your tabs during mod init, and when the world creation screen opens, TabManager freezes the registry and creates all the tabs.

Key Methods

Method	What it does
`registerTab(Supplier<Tab>, int, String, int)`	Register a tab with factory, ID, name key, and priority.
`registerTab(Supplier<Tab>, int, String)`	Same thing, but priority defaults to `tabId`.
`getEntries()`	Get all entries sorted by priority (unmodifiable).
`isFrozen()`	Check if the registry is frozen (GUI already initialized).
`freeze()`	Freeze the registry. Called internally by `TabManager`.

Parameters

Parameter	Type	What it means
`factory`	`Supplier<Tab>`	A factory that creates your `Tab` instance. Called once when `TabManager` is constructed.
`tabId`	`int`	Unique tab ID. Built-in tabs use 100–102, so start from 103.
`nameKey`	`String`	Localization key for the tab name (like `"mymod.tab.custom"`).
`priority`	`int`	Sort order — lower comes first. Defaults to `tabId` if not specified. Built-in tabs use 0, 1, 2.

Entries are sorted by priority ascending, then tabId ascending as a tiebreaker.

Registration Example

import cpw.mods.fml.common.Mod;
import cpw.mods.fml.common.event.FMLPreInitializationEvent;
import decok.dfcdvadstf.createworldui.api.tab.AbstractScreenTab;
import decok.dfcdvadstf.createworldui.api.tab.Tab;
import decok.dfcdvadstf.createworldui.api.tab.TabManager;
import decok.dfcdvadstf.createworldui.api.tab.TabRegistry;
import net.minecraft.client.gui.GuiButton;

@Mod(modid = "mymod", name = "My Mod", version = "1.0")
public class MyMod {

    @Mod.EventHandler
    public void preInit(FMLPreInitializationEvent event) {
        TabRegistry.registerTab(
            MyCustomTab::new,        // Supplier<Tab> factory
            103,                     // Unique tab ID (start from 103)
            "mymod.tab.custom",      // Localization key
            5                        // Sort priority (lower = earlier)
        );
    }
}

// Your custom tab
public class MyCustomTab extends AbstractScreenTab {

    public MyCustomTab() {
        super(103, "mymod.tab.custom"); // Must match what you registered
    }

    @Override
    public void initGui(TabManager tabManager, int width, int height) {
        super.initGui(tabManager, width, height);
        // Add your buttons and fields here
        setVisible(false);
    }

    @Override
    public void drawScreen(int mouseX, int mouseY, float partialTicks) {
        if (!visible) return;
        // Draw your tab content here
    }

    @Override
    public void actionPerformed(GuiButton button) {
        // Handle button clicks here
    }

    @Override
    public void mouseClicked(int mouseX, int mouseY, int mouseButton) {
        // Handle mouse clicks here
    }

    @Override
    public void keyTyped(char typedChar, int keyCode) {
        // Handle key input here
    }
}

And don't forget the localization in your lang file:

mymod.tab.custom=My Tab

Things to Keep in Mind

Register early — like FMLPreInitializationEvent. Once TabManager is constructed the registry freezes, and registering after that throws an IllegalStateException.
Tab IDs must be unique — duplicate IDs throw an IllegalArgumentException.
AbstractScreenTab constructor must match — the tabId and nameKey you pass there need to be the same ones you gave TabRegistry.registerTab().
initGui() gets called by TabManager — on init and on resize. Always call super.initGui() and set setVisible(false) at the end.
Use tabManager accessors (like getWorldName(), setGameMode()) to read/write the shared world creation state.

GameRule Editor Integration

Adding Tooltips for Custom Rules

Two ways to do it:

Localization files (Recommended) — just add entries like this:

gamerule.yourRuleName.tooltip.description=Your description here
gamerule.yourRuleName.name=Display Name

Code — Use GuiScreenGameRuleEditor.registerTooltip() or registerTooltips() during FMLInitializationEvent. The hard way section above shows how.

Localizing GameRule Display Names (After 3.1.0)

Same idea as tooltips:

gamerule.yourRuleName.name=Your Display Name

If no name localization is provided, the raw rule name is shown instead.

In-Game `/gameruleEditor` Command

Class: decok.dfcdvadstf.createworldui.command.CommandGameRuleEditor

Opens the GameRule Editor in-game. You need either:

igGameruleEdit config option enabled, or
ModernDifficultyLocker installed.

Requires permission level 2 (same as /gamerule).

Mixin Classes

Here's what gets mixed into what:

Mixin Class	Target	What it does
`MixinModernCreateWorld`	`GuiCreateWorld`	Replaces the world creation screen with the tabbed UI.
`MixinGuiSelectWorld`	`GuiSelectWorld`	Enhances the world selection screen.
`MixinIntegratedServer`	`IntegratedServer`	Applies difficulty and game rules when the world loads.
`MixinMinecraft`	`Minecraft`	Client-side hooks.

Dependency Setup

To use CreateWorldUI as a dependency, add this to your build.gradle:

dependencies {
    implementation 'com.github.song682:CreateWorldUI:Tag'
}

Replace Tag with the version you want from the repository.
Also, the -deobf suffix jars are also available.

Navigation Menu

3. Mod Developer Things

How to create a fully custom GameRule in the GameRule Editor UI?

Simple way (Recommended)

Another hard way

API Overview

GameRuleApplier

GameRuleMonitorNSetter

DifficultyApplier

GuiCyclableButton

TabRegistry

Tab System

Built-in Tabs

TabManager

TabState

Adding a Custom Tab

TabRegistry

Key Methods

Parameters

Registration Example

Things to Keep in Mind

GameRule Editor Integration

Adding Tooltips for Custom Rules

Localizing GameRule Display Names (After 3.1.0)

In-Game `/gameruleEditor` Command

Mixin Classes

Dependency Setup

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3. Mod Developer Things

How to create a fully custom GameRule in the GameRule Editor UI?

Simple way (Recommended)

Another hard way

API Overview

GameRuleApplier

GameRuleMonitorNSetter

DifficultyApplier

GuiCyclableButton

TabRegistry

Tab System

Built-in Tabs

TabManager

TabState

Adding a Custom Tab

TabRegistry

Key Methods

Parameters

Registration Example

Things to Keep in Mind

GameRule Editor Integration

Adding Tooltips for Custom Rules

Localizing GameRule Display Names (After 3.1.0)

In-Game /gameruleEditor Command

Mixin Classes

Dependency Setup

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Clone this wiki locally

In-Game `/gameruleEditor` Command