audio samplers

Let us assume you have created an audio-reactive PopcornFX effect which exports one audio attribute sampler called sound. Your objective is to have this effect react to your game’s audio bus called Music. Let’s walk through the steps to make it work inside Godot.

First, as usual, add a PKEmitter3D to your scene. In the inspector, set its Effect property to your audio-reactive effect. You should see that in the inspector panel, sound has been added to the list of attribute samplers.

Now, open Godot’s Audio panel. It is assumed you know how to set up your audio on the Godot side, and that you have already created an audio bus called Music aswell as an AudioStreamPlayer that feeds into it. If not, you may want to consult the Godot documentation on audio buses.

On your Music bus, add a PKCapture audio effect. It will take care of passing the audio from Godot to the PopcornFX runtime.

Finally, in your sound attribute sampler, set Bus Name dropdown to the name of your Godot bus (here, Music), and set Effect Index dropdown to the 0-based index of your PKCapture in the bus. For example, if you added a filter effect before the PKCapture, Effect Index`should be `1.

Now, if you play the music from your AudioStreamPlayer inside the Godot editor or in your game, the effect will react to it !

The other properties available in the audio attribute sampler are explained further down this page.

PopcornFX has a notion of audio channels. Just like Godot buses, they allow routing audio from one or multiple sources to one or multiple destinations. They are mostly working under the runtime’s hat, therefore the only thing you need to know about them is that they are uniquely defined by their name.

An audio attribute sampler targets one channel. Multiple samplers can target the same channel. In the editor, you can "sample" a sampler to access the data of its targeted channel.

In Godot, you are able to send data from Godot into the channel of an audio sampler targets. You can also change the targeted channel by changing its name (no need to "create" it beforehand), or make this sampler’s targeted channel local, meaning only this sampler can send or use data from this channel (the name then becomes irrelevant).

In order to pass audio from Godot to the PopcornFX runtime, you need to use a custom Godot audio effect called PKCapture.

There are a few key things to keep in mind about PKFXCapture:
* Contrary to Godot’s audio capture, you can safely use the same one as the source of multiple audio attribute samplers.
* Moving a PKCapture used by attribute samplers to a different index or bus may cause strange issues. If you move one, it is advised that you update the Bus name and Effect index of your attribute samplers immediately, even if they still seem to be working as intended.

The plugin allows you to modify the following properties of your audio sampler: