Method process

src/core/SampledAudioNode.cpp:440–539

    void SampledAudioNode::process(ContextRenderLock& r, int framesToProcess)
    {
        if (_internals->bus_setting_updated) {
            _internals->bus_setting_updated = false;
            setBus(r, m_sourceBus->valueBus());
        }
        _internals->greatest_cursor = -1;

        AudioBus* dstBus = output(0)->bus(r);
        size_t dstChannelCount = dstBus->numberOfChannels();
        std::shared_ptr<AudioBus> srcBus = m_sourceBus->valueBus();

        // move requested starts to the internal schedule if there's a source bus.
        // if there's no source bus, the schedule requests are discarded.
        {
            Scheduled s;
            while (_internals->incoming.try_dequeue(s))
            {
                if (s.loopCount == -3)
                {
                    m_retainedSourceBus = s.sourceBus;
                    m_sourceBus->setBus(s.sourceBus.get());
                    srcBus = s.sourceBus;
                    this->_internals->bus_setting_updated = false; // setting bus causes this -3 state to occur so clear it immediately
                }
                else if (s.loopCount == -2)
                {
                    _internals->scheduled.clear();
                }
                else if (srcBus)
                {
                    _internals->scheduled.push_back(s);
                }
            }
        }

        // zero out the buffer for summing, or for silence
        for (int i = 0; i < dstChannelCount; ++i)
            output(0)->bus(r)->zero();

        // silence the outputs if there's nothing to play.
        int schedule_count = static_cast<int>(_internals->scheduled.size());
        if (!schedule_count || !srcBus)
            return;

        // if there's something to play, conform the output channel count.
        int srcChannelCount = srcBus->numberOfChannels();
        if (dstChannelCount != srcChannelCount)
        {
            output(0)->setNumberOfChannels(r, srcChannelCount);
            dstChannelCount = srcChannelCount;
            dstBus = output(0)->bus(r);
        }

        // compute the frame timing in samples and seconds
        uint64_t quantumStartFrame = r.context()->currentSampleFrame();
        uint64_t quantumEndFrame = quantumStartFrame + AudioNode::ProcessingSizeInFrames;
        double quantumDuration = static_cast<double>(AudioNode::ProcessingSizeInFrames) / r.context()->sampleRate();