Class AudioNodeOutput

include/LabSound/core/AudioNodeOutput.h:22–119

AudioNodeOutput represents a single output for an AudioNode. It may be connected to one or more AudioNodeInputs.

// AudioNodeOutput represents a single output for an AudioNode.
// It may be connected to one or more AudioNodeInputs.
class AudioNodeOutput
{
public:
    // It's OK to pass 0 for numberOfChannels in which case setNumberOfChannels() must be called later on.
    AudioNodeOutput(AudioNode * audioNode, int numberOfChannels, int processingSizeInFrames = AudioNode::ProcessingSizeInFrames);
    AudioNodeOutput(AudioNode * audioNode, char const*const name, int numberOfChannels, int processingSizeInFrames = AudioNode::ProcessingSizeInFrames);
    virtual ~AudioNodeOutput();

    // Can be called from any thread.
    AudioNode * sourceNode() const { return m_sourceNode; }

    // Causes our AudioNode to process if it hasn't already for this render quantum.
    // It returns the bus containing the processed audio for this output, returning inPlaceBus if in-place processing was possible.
    // Called from context's audio thread.
    AudioBus * pull(ContextRenderLock &, AudioBus * inPlaceBus, int bufferSize);

    // bus() will contain the rendered audio after pull() is called for each rendering time quantum.
    AudioBus * bus(ContextRenderLock &) const;

    // renderingFanOutCount() is the number of AudioNodeInputs that we're connected to during rendering.
    // Unlike fanOutCount() it will not change during the course of a render quantum.
    int renderingFanOutCount() const;

    // renderingParamFanOutCount() is the number of AudioParams that we're connected to during rendering.
    // Unlike paramFanOutCount() it will not change during the course of a render quantum.
    int renderingParamFanOutCount() const;

    void setNumberOfChannels(ContextRenderLock &, int);
    int numberOfChannels() const { return m_numberOfChannels; }
    bool isChannelCountKnown() const { return numberOfChannels() > 0; }

    bool isConnected() { return fanOutCount() > 0 || paramFanOutCount() > 0; }

    // updateRenderingState() is called in the audio thread at the start or end of the render quantum to handle any recent changes to the graph state.
    void updateRenderingState(ContextRenderLock &);

    const std::string& name() const { return m_name; }

    // Must be called within the context's graph lock.
    static void disconnectAll(ContextGraphLock &, std::shared_ptr<AudioNodeOutput>);
    static void disconnectAllInputs(ContextGraphLock &, std::shared_ptr<AudioNodeOutput>);
    static void disconnectAllParams(ContextGraphLock &, std::shared_ptr<AudioNodeOutput>);

private:
    AudioNode * m_sourceNode;

    friend class AudioNodeInput;
    friend class AudioParam;

    // These are called from AudioNodeInput.
    // They must be called with the context's graph lock.
    void addInput(ContextGraphLock & g, std::shared_ptr<AudioNodeInput>);
    void removeInput(ContextGraphLock & g, std::shared_ptr<AudioNodeInput>);
    void addParam(ContextGraphLock & g, std::shared_ptr<AudioParam>);
    void removeParam(ContextGraphLock & g, std::shared_ptr<AudioParam>);

    // fanOutCount() is the number of AudioNodeInputs that we're connected to.
    // This method should not be called in audio thread rendering code, instead renderingFanOutCount() should be used.