Enabling dynamic lighting that syncs with music beats

Looking for some guidance on how to integrate Reactional Music to enable dynamic lighting that syncs with music beats in a game. Any tutorial or example you can provide would be greatly appreciated! Thank you!

Hi @carrotwho and welcome to the forum! I will be looking to add more tutorials like this in the near future, but in the meantime I hope this answer will be helpful.

With Reactional there are several ways to achieve this. Below is a script I made for a demo scene recently. In that scene I was using the high definition render pipeline, but the same principle can be applied to any light with some modification.

Code Example

using UnityEngine;
using UnityEngine.Rendering.HighDefinition;

public class LightIntensityBeat : MonoBehaviour
    public HDAdditionalLightData light; 
    public AnimationCurve animationCurve;
    public float maxIntensity = 30000f;
    public float beatFrequency = 2f;    
    public bool useLux = false;
    public float offset = 0f;
    void Start()
      light = GetComponent<HDAdditionalLightData>();   

    void Update()
        if(light == null)

        var value = animationCurve.Evaluate(((ReactionalEngine.Instance.CurrentBeat + offset) % beatFrequency)/beatFrequency);

            light.SetIntensity(value * maxIntensity, LightUnit.Lux); 
            light.SetIntensity(value * maxIntensity, LightUnit.Lumen); 

Note that I am using ReactionalEngine.Instance.CurrentBeat however the “proper” approach is Reactional.Playback.MusicSystem.GetCurrentBeat() but the second simply returns the first so I tend to use them interchangeably.

Inspector settings

With this setup you will, of course need to reference the light source itself.
Then I have set up an animation curve going from 1 to 0.
The animation curve is then evaluated by the beat clock using the CurrentBeat.
The MaxIntensity variable is basically multiplying the 1 to 0 range into something that makes sense for the light.
BeatFrequency is how often it should happen; in this case every 2 beats.
The UseLux boolean is specific to this use case, as some of my lights in the scene uses Lux and some uses Lumen for it’s intensity.
The offset is a beat offset in case you want to delay the light ever so slightly, or have it trigger slightly early; If used I normally put something like 0.1 or so at most.


This script will yield something like this!

I hope that helps!