Chapter 5 — UI Creation

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Overview

RMAPI can create two types of in-world UI elements:

• Text — floating TextMeshPro labels in 3D space
• Buttons — interactive buttons that players can press (using RUMBLE's interaction system)

Both are cloned from existing game objects, so they look and behave like native RUMBLE UI.

using RumbleModdingAPI.RMAPI;
using UnityEngine;

Important: These objects are only available after the Gym scene has loaded at least once (that's when RMAPI clones the templates). Use them inside onMapInitialized or later.

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Creating Text

Basic Text (empty, configure it yourself)

GameObject textObj = Create.NewText();

Returns a new active TextMeshPro GameObject. You configure it manually:

using Il2CppTMPro;

GameObject textObj = Create.NewText();
TextMeshPro tmp = textObj.GetComponent<TextMeshPro>();
tmp.text = "Hello World";
tmp.fontSize = 2.0f;
tmp.color = Color.white;
textObj.transform.position = new Vector3(0, 2, 0);
textObj.transform.rotation = Quaternion.identity;

Text with Parameters (all-in-one)

Parameters in order:

#	Parameter	Type	What it sets
1	text	string	The displayed text
2	textSize	float	Font size
3	textColor	Color	Text color
4	textPosition	Vector3	World position
5	textRotation	Quaternion	World rotation

GameObject textObj = Create.NewText("Score: 0", 1.5f, Color.green, new Vector3(0, 2.5f, 3), Quaternion.Euler(0, 180, 0));

Updating Text Later

Keep a reference and modify it whenever you need:

private TextMeshPro scoreText;

void Setup()
{
    GameObject obj = Create.NewText("0", 2f, Color.white, Vector3.up * 2, Quaternion.identity);
    scoreText = obj.GetComponent<TextMeshPro>();
}

void UpdateScore(int score)
{
    scoreText.text = $"Score: {score}";
    scoreText.color = score > 10 ? Color.green : Color.red;
}

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Creating Buttons

Buttons use RUMBLE's InteractionButton component — players interact with them the same way they interact with in-game buttons (by pressing/touching them in VR).

NewButton has four versions — pick the one that matches what you need:

Version	What you get
NewButton()	Button at default position, no action
NewButton(position, rotation)	Button at a specific spot, no action
NewButton(action)	Button at default position, runs your code when pressed
NewButton(position, rotation, action)	Button at a specific spot, runs your code when pressed

Note: You always need () after Create.NewButton — writing Create.NewButton alone without parentheses doesn't create anything and will cause a compile error. Even Create.NewButton() with empty parentheses is valid — it creates a button with defaults.

Basic Button (no position, no action)

GameObject buttonObj = Create.NewButton();

Button at a Position

#	Parameter	Type	What it sets
1	buttonPosition	Vector3	World position
2	buttonRotation	Quaternion	World rotation

GameObject buttonObj = Create.NewButton(new Vector3(1, 1.5f, 2), Quaternion.Euler(0, 90, 0));

Button with an Action

#	Parameter	Type	What it sets
1	action	Action	Method to call when pressed

Pass a method or lambda that runs when the button is pressed:

GameObject buttonObj = Create.NewButton(() => Melon<MyMod>.Logger.Msg("Button was pressed!"));

What's () =>? This is a lambda — a short inline function. () => means "a function that takes no parameters", and what follows is the code it runs. There are two ways to pass an action, and both work:

Inline lambda — write the code directly: Create.NewButton(() => Melon<MyMod>.Logger.Msg("pressed!"))

Method reference — define a method and pass its name (without (), because you're handing the method itself to be called later, not calling it now): Create.NewButton(OnPressed) where you have void OnPressed() { ... } elsewhere.

Button with Position and Action

#	Parameter	Type	What it sets
1	buttonPosition	Vector3	World position
2	buttonRotation	Quaternion	World rotation
3	action	Action	Method to call when pressed

GameObject buttonObj = Create.NewButton(new Vector3(1, 1.5f, 2), Quaternion.identity, () => Melon<MyMod>.Logger.Msg("Button was pressed!"));

Adding an Action to an Existing Button

If you used NewButton() without an action, you can add one later:

using Il2CppRUMBLE.Interactions.InteractionBase;

GameObject buttonObj = Create.NewButton();
InteractionButton interactBtn = buttonObj.transform.GetChild(0)
    .gameObject.GetComponent<InteractionButton>();
interactBtn.onPressed.AddListener((Action)(() =>
{
    Log("Pressed!");
}));

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Cleaning Up

GameObjects that aren't in DontDestroyOnLoad are automatically destroyed on scene change (including between matches). So in most cases you don't need to clean up — your text and buttons disappear on their own when the player leaves the scene.

If you need to remove something mid-scene (e.g., hiding a label after a timer expires), you can either destroy it or deactivate it:

// Destroy — permanently removes it (cleaner if you won't need it again)
GameObject.Destroy(textObj);

// Deactivate — hides it but keeps it around (useful if you want to show it again later)
textObj.SetActive(false);
// ... later:
textObj.SetActive(true);

If you want an object to survive scene changes, call DontDestroyOnLoad on it:

GameObject.DontDestroyOnLoad(textObj);

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Full Example: In-World Scoreboard

using MelonLoader;
using RumbleModdingAPI.RMAPI;
using Il2CppTMPro;
using Il2CppRUMBLE.Players;
using UnityEngine;

namespace Scoreboard
{
    public class Scoreboard : MelonMod
    {
        private TextMeshPro display;
        private int myScore = 0;
        private int theirScore = 0;

        public override void OnLateInitializeMelon()
        {
            Actions.onMatchStarted += OnMatch;
            Actions.onRoundEnded += OnRoundEnd;
        }

        private void OnMatch()
        {
            myScore = 0;
            theirScore = 0;

            // Create a scoreboard floating in front of the player
            Player local = Calls.Players.GetLocalPlayer();
            Transform t = local.Controller.transform;
            Vector3 pos = t.position + t.forward * 2 + Vector3.up * 1.5f;
            Quaternion rot = Quaternion.LookRotation(pos - t.position);

            GameObject displayObj = Create.NewText("0 - 0", 3f, Color.white, pos, rot);
            display = displayObj.GetComponent<TextMeshPro>();
        }

        private void OnRoundEnd()
        {
            // Simple: whoever has more HP wins the round
            var players = Calls.Players.GetAllPlayers();
            if (players.Count < 2) return;

            Player local = Calls.Players.GetLocalPlayer();
            if (local.Data.HealthPoints > 0)
                myScore++;
            else
                theirScore++;

            if (display != null)
                display.text = $"{myScore} - {theirScore}";
        }
    }
}

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