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Integrating the Switchboard SDK Into a Unity Project

Switchboard SDK is implemented in C++. To be able to use it from Unity, which is written in C#, you have to use Native Plugins. It allows for calling into C++ code from C#, through a C interface.

  1. Write your Switchboard audio engine in C++.
  2. Create a C interface for it.
  3. Compile it as a library. Add the library to the Assets/Plugins directory of your Unity project.
  4. Add a C# script that imports the library and calls the C interface.
  5. Integrate the C# script into your Unity app.

This way the audio processing is completely detached from the Unity audio system, making it possible to create a low-latency, real-time audio pipeline for your purposes.

Write the Audio Engine in C++ with a C Interface​

Download the Switchboard SDK for your required platform. Create a new C++ project and implement your audio engine using the Switchboard SDK. Here is an example of how to initialize the SDK and create a simple audio graph with Switchboard SDK in C++ with a C interface on macOS:

#include "AudioEngine.hpp"
#include "AudioGraph.hpp"
#include "AudioGraphFactory.hpp"

const std::string json = R"(
{
    "title": "Audio Engine",
    "nodes": [
        {
            "id": "gain",
            "type": "Gain"
        }
    ],
    "connections": [
        {
            "sourceNode": "inputNode",
            "destinationNode": "gain"
        },
        {
            "sourceNode": "gain",
            "destinationNode": "outputNode"
        }
    ]
})";

extern "C" {

static AudioGraph* audioGraph { AudioGraphFactory::parseJSON(json) }
static AudioEngine audioEngine { AudioIO::Core };

void initializeSwitchboardSDK() {
    SwitchboardSDK::initialize("Your app ID", "Your app secret");
}

void start() {
    audioEngine.start(&audioGraph);
}

void stop() {
    audioEngine.stop();
}

}

Compile the C++ Code as a Dynamic Library​

Compile your C++ code into a static or dynamic library (e.g., .dll for Windows, .dylib for macOS, .so for Linux). Make sure to export the C interface functions.

Use the Native Plugin in Unity​

  1. Place the compiled dynamic library and the C interface header in the Assets/Plugins directory of your Unity project.
  2. Create a C# script to call the native functions. Here is an example with SwitchboardAudioEngine as the library name:
using System.Runtime.InteropServices;
using UnityEngine;

public class SwitchboardAudioEnginePlugin : MonoBehaviour
{
    [DllImport("SwitchboardAudioEngine")]
    private static extern void initializeSwitchboardSDK();
    [DllImport("SwitchboardAudioEngine")]
    private static extern void start();
    [DllImport("SwitchboardAudioEngine")]
    private static extern void stop();

    void Initialize()
    {
        initializeSwitchboardSDK();
    }

    void Start()
    {
        start();
    }

    void Stop()
    {
        stop();
    }

    // ...other Unity code...
}
  1. Attach the C# script to a GameObject in your Unity scene.

By following these steps, you can integrate the Switchboard SDK into your Unity project using a C++ audio engine and a Native Plugin.