AudioMixer Exposed Parameters - Unity Official Tutorials

In Unity it's possible to directly control

parameters of an audio mixer

like levels and effects settings

via script at runtime.

To set a single mixer parameter via script

we'll use the SetFloat function.

SetFloat has two parameters,

a string for the name of the exposed

parameter we're going to be setting

and a float for the value to set it to.

SetFloat is called from an audio mixer.

In order for a parameter to be controlled

using SetFloat it has to be exposed to script control.

First make sure that the parameter is visible in the inspector.

Then in the inspector right click on the parameter name.

Here we'll expose volume for the master group of master mixer.

Right click and choose Expose To Script.

When this is done you'll see a little arrow appear beside the name.

You'll also notice that it's been added

to our list of exposed parameters

for the master mixer audio mixer asset.

If we click on the list of exposed parameters

we'll see two parameters that have already been exposed,

Music Vol and SFX Vol which correspond to the volumes of

the music group and the sound effects group

of master mixer.

And we have a third called My Exposed Param.

My exposed param is our new parameter

and we can see that it's the master volume.

If we double click on it we can set it's name.

The name that we choose is the

string that we'll parse to SetFloat

when setting the value via script.

Here's one example of how we can use SetFloat,

in this case to control the music volume

and sound effects volume balance in our game.

Here we have the Nightmares project which is available

as a free download from the assets store.

And we've added a simple pause menu with some

audio options to it. Let's check it out.

When we hit escape our pause menu comes up

and here we can adjust the music volume,

and the sound effects volume.

Notice how the new values are reflected in the mixer.

Now that we've seen how to expose parameters to script control

let's look at setting their values via script.

On our game object audio mixer control

we have a script called Mix Levels.

In our mix levels script we have

the namespace declaration using

UnityEngine.Audio

And what this allows us to do is to access

classes like audio mixer, which are members

of UnityEngine.Audio.

We also have a public variable

of the audio mixer type called masterMixer.

We have two public functions, SetSfxLvl,

which takes a parameter of the type float called SfxLvl.

And then in that function we're going to called the SetFloat function

from master mixer and we're going to parse in our string

SfxVol saying that's the parameter we want to address

and we're going to parse in our floating

point value SfxLvl, which is what the value is going to be set to.

In our public function SetMusicLvl

we're going to do the same thing, we're going to parse in

our float musicLvl and we're going to use that to call

SetFloat for masterMixer and parse in the string

musicVol saying we want to address the musicVol exposed parameter

and set the value

using our float music Lvl.

In the Unity editor we've dragged

our master mixer audio mixer

to our master mixer variable slot.

In order to set the floating point values in mix levels

we're using the UI system.

Here in our menu canvas we've got two sliders,

here's our effects slider.

In the slider script of our effects slider

we're choosing our audio mixer control

from our list of objects in the scene

with the audio mixer control game object selected

we're going to address our mix level script

and set SFX level within that

to parse the value of the slider to SetFloat.

For our music slider we've gone through the same

process but in this case setting it to

the float of SetMusicLvl.

When working with exposed parameters it's important to note

that exposing a parameter and setting it's value

using SetFloat removes it from control

of the audio mixer snapshot system.

The audio mixer snapshot system allows us to recall the

entire state of the mixer by toggling between

one snapshot and another.

It's possible to return a parameter to snapshot control

using the ClearFloat function.

ClearFloat is called from an audio mixer

and takes a parameter of the type string,

which specifies the parameter that we want to release

from snapshot control on that mixer.

For more information about snapshots and

controlling them via script

please see the information linked below.