Method pan

src/internal/src/HRTFPanner.cpp:638–841

}

void HRTFPanner::pan(ContextRenderLock & r,
                double desiredAzimuth, double elevation,
                const AudioBus & inputBus, AudioBus & outputBus,
                int busOffset,
                int framesToProcess) 
{
    int numInputChannels = inputBus.numberOfChannels();

    bool isInputGood = numInputChannels >= Channels::Mono && numInputChannels <= Channels::Stereo;
    ASSERT(isInputGood);

    bool isOutputGood = outputBus.numberOfChannels() == Channels::Stereo && framesToProcess <= outputBus.length();
    ASSERT(isOutputGood);

    if (!isInputGood || !isOutputGood)
    {
        outputBus.zero();
        return;
    }

    // This code only runs as long as the context is alive and after database has been loaded.
    HRTFDatabase * database = HRTFDatabaseLoader::defaultHRTFDatabase();
    ASSERT(database);

    if (!database)
    {
        outputBus.zero();
        return;
    }

    // IRCAM HRTF azimuths values from the loaded database is reversed from the panner's notion of azimuth.
    double azimuth = -desiredAzimuth;

    bool isAzimuthGood = azimuth >= -180.0 && azimuth <= 180.0;
    ASSERT(isAzimuthGood);
    if (!isAzimuthGood)
    {
        outputBus.zero();
        return;
    }

    // Normally, we'll just be dealing with mono sources.
    // If we have a stereo input, implement stereo panning with left source processed by left HRTF, and right source by right HRTF.
    const AudioChannel * inputChannelL = inputBus.channelByType(Channel::Left);
    const AudioChannel * inputChannelR = numInputChannels > Channels::Mono ? inputBus.channelByType(Channel::Right) : 0;

    // Get source and destination pointers.
    const float * sourceL = inputChannelL->data();
    const float * sourceR = numInputChannels > Channels::Mono ? inputChannelR->data() : sourceL;

    float * destinationL = outputBus.channelByType(Channel::Left)->mutableData();
    float * destinationR = outputBus.channelByType(Channel::Right)->mutableData();

    double azimuthBlend;
    int desiredAzimuthIndex = calculateDesiredAzimuthIndexAndBlend(azimuth, azimuthBlend);

    // Initially snap azimuth and elevation values to first values encountered.
    if (m_azimuthIndex1 == UninitializedAzimuth)