unity-atoms/docs/introduction/unirx.md

id	title	hide_title	sidebar_label
unirx	Usage with UniRX	true	Usage with UniRX

Usage with UniRX

Variables and Events exposes methods that returns IObservables. Atom Variables exposes ObserveChange and ObserveChangeWithHistory, while Atom Events exposes Observe. This makes it possible to use Unity Atoms seamlessly together with UniRx.

Simple example

The HealthBar.cs script from the Basic tutorial could be rewritten like this using UniRx:

using UnityEngine;
using UnityEngine.UI;
using UniRx;

public class HealthBarUniRx : MonoBehaviour
{
    [SerializeField]
    private IntConstant _maxHealth = null;
    [SerializeField]
    private IntVariable _health = null;

    void Awake()
    {
        _health.ObserveChange().Subscribe(health =>
        {
            GetComponent<Image>().fillAmount = 1.0f * health / _maxHealth.Value;
        });
    }
}

Advanced example

Here is another example of a PlayerMove.cs script that is a little bit more advanced. Horizontal and vertical input is only getting a value from the Input class as long as the UI state is in the state of _uiStatePlaying.

NOTE: This example is also using Marvelous for its Fuse method.

using System;
using UnityEngine;
using Marvelous;
using UniRx;

public class PlayerMoveUniRx : MonoBehaviour
{
    [SerializeField]
    private StringVariable _uiState;
    [SerializeField]
    private StringConstant _uiStatePlaying;

    private void Awake()
    {
        float _horizontal = 0f, _vertical = 0f;
        string HORIZONTAL = "Horizontal", VERTICAL = "Vertical";

        Observable.EveryUpdate().Fuse<long, string>(
            _uiState.ObserveChange(),
            initialValue2: _uiState.Value
        ).Subscribe(t =>
        {
            var (_, state) = t;
            _horizontal = state == _uiStatePlaying.Value ? Input.GetAxis(HORIZONTAL) : 0f;
            _vertical = state == _uiStatePlaying.Value ? Input.GetAxis(VERTICAL) : 0f;
        });

        Observable.EveryFixedUpdate().Subscribe(t =>
        {
            GetComponent<Rigidbody2D>().velocity = new Vector2(_horizontal, _vertical) * 5f;
        });
    }
}

Using Unity Atoms together with UniRx and Marvelous (for its Fuse) makes your scripts really data driven.