GeneratorInstance

Description

A ProcessorInstance that generates audio data.

A GeneratorInstance can be defined through implementing the GeneratorInstance<T0> and IRealtime interfaces, which defines the control and real-time thread behaviour respectively.

To use a generator in a scene, for example with an AudioSource, it must have an associated IAudioGenerator that will instantiate it. In the Unity Audio system they are used with an AudioSource by setting the AudioSource._generator property to the associated IAudioGenerator.

It is also possible to create your own generators through code using a ControlContext. Interacting with an instantiated generator depends on the ownership of the GeneratorInstance: If the generator has been created from an AudioSource, you would interact with it through the instance obtained from AudioSource._generatorInstance.

using Unity.Burst;
using Unity.IntegerTime;
using UnityEngine;
using UnityEngine.Audio;
using static UnityEngine.Audio.ProcessorInstance;

[BurstCompile(CompileSynchronously = true)]
public struct SineProcessor : GeneratorInstance.IRealtime
{
    private const float k_Tau = Mathf.PI * 2;
    private float m_Frequency;
    private float m_Phase;

    public static GeneratorInstance Allocate(ControlContext context, float frequency)
    {
        return context.AllocateGenerator(new SineProcessor(frequency), new Control());
    }

    public bool isFinite => false;
    public bool isRealtime => true;
    public DiscreteTime? length => null;

    private GeneratorInstance.Setup m_Setup;

    SineProcessor(float initialFrequency)
    {
        m_Frequency = initialFrequency;
        m_Phase = 0.0f;
        m_Setup = new GeneratorInstance.Setup();
    }

    public void Update(UpdatedDataContext context, Pipe pipe)
    {
        foreach (var data in pipe.GetAvailableData(context))
        {
            if (data.TryGetData(out FrequencyData freq))
            {
                m_Frequency = freq.Value;
            }
        }
    }

    public GeneratorInstance.Result Process(in RealtimeContext ctx, Pipe pipe, ChannelBuffer buffer, GeneratorInstance.Arguments args)
    {
        for (var frame = 0; frame < buffer.frameCount; frame++)
        {
            for (var channel = 0; channel < buffer.channelCount; channel++)
                buffer[channel, frame] = Mathf.Sin(m_Phase * k_Tau);

            m_Phase += m_Frequency / m_Setup.sampleRate;

            if (m_Phase > 1.0f) m_Phase -= 1.0f;
        }

        return buffer.frameCount;
    }

    struct Control : GeneratorInstance.IControl<SineProcessor>
    {
        public void Configure(ControlContext context, ref SineProcessor generator, in AudioFormat format, out GeneratorInstance.Setup setup, ref GeneratorInstance.Properties p)
        {
            generator.m_Setup = new GeneratorInstance.Setup(speakerMode: AudioSpeakerMode.Mono, sampleRate: format.sampleRate);
            setup = generator.m_Setup;
        }

        public void Dispose(ControlContext context, ref SineProcessor processor) { }

        public void Update(ControlContext context, Pipe pipe) { }

        public ProcessorInstance.Response OnMessage(ControlContext context, Pipe pipe, Message message)
        {
            return ProcessorInstance.Response.Unhandled;
        }
    }

    public struct FrequencyData
    {
        public readonly float Value;
        public FrequencyData(float value)
        {
            Value = value;
        }
    }
}

Public Methods

Operators