Method calculateFinalValues

src/core/AudioParam.cpp:99–163

}

void AudioParam::calculateFinalValues(ContextRenderLock & r, float * values, int numberOfValues, bool sampleAccurate)
{
    bool isSafe = r.context() && values && numberOfValues;
    if (!isSafe)
        return;

    // The calculated result will be the "intrinsic" value summed with all audio-rate connections.

    if (sampleAccurate)
    {
        // Calculate sample-accurate (a-rate) intrinsic values.
        calculateTimelineValues(r, values, numberOfValues);
    }
    else
    {
        // Calculate control-rate (k-rate) intrinsic value.
        bool hasValue;
        float timelineValue = m_timeline.valueForContextTime(r, static_cast<float>(m_value), hasValue);

        if (hasValue)
            m_value = timelineValue;

        values[0] = static_cast<float>(m_value);
    }

    // if there are rendering connections, be sure they are ready
    updateRenderingState(r);

    int connectionCount = numberOfRenderingConnections(r);
    if (!connectionCount)
        return;

    // Now sum all of the audio-rate connections together (unity-gain summing junction).
    // Note that parameter connections would normally be mono, so mix down to mono if necessary.

    // LabSound: For some reason a bus was temporarily created here and the results discarded.
    // Bug still exists in WebKit top of tree.
    if (m_internalSummingBus && m_internalSummingBus->length() < numberOfValues)
        m_internalSummingBus.reset();

    if (!m_internalSummingBus)
        m_internalSummingBus.reset(new AudioBus(1, numberOfValues));

    // point the summing bus at the values array
    m_internalSummingBus->setChannelMemory(0, values, numberOfValues);

    for (int i = 0; i < connectionCount; ++i)
    {
        auto output = renderingOutput(r, i);

        ASSERT(output);

        // Render audio from this output.
        AudioBus * connectionBus = output->pull(r, nullptr, AudioNode::ProcessingSizeInFrames);

        // Sum, with unity-gain.
        /// @TODO it was surprising in practice that the inputs are summed, as opposed to simply overriding.
        /// Summing might be useful, but pure override should be an option as well.