Method dopplerRate

src/core/PannerNode.cpp:414–485

}

float PannerNode::dopplerRate(ContextRenderLock & r)
{
    double dopplerShift = 1.0;

    auto listener = r.context()->listener();

    // FIXME: optimize for case when neither source nor listener has changed...
    /// @fixme these values should be per sample, not per quantum
    double dopplerFactor = listener->dopplerFactor()->value();

    if (dopplerFactor > 0.0)
    {
        /// @fixme should be a setting
        double speedOfSound = listener->speedOfSound()->value();

        /// @fixme these values should be per sample, not per quantum
        const FloatPoint3D sourceVelocity = {
            velocityX()->value(),
            velocityY()->value(),
            velocityZ()->value()};
        /// @fixme these values should be per sample, not per quantum
        const FloatPoint3D listenerVelocity = {
            listener->velocityX()->value(),
            listener->velocityY()->value(),
            listener->velocityZ()->value()};

        // Don't bother if both source and listener have no velocity
        bool sourceHasVelocity = !is_zero(sourceVelocity);
        bool listenerHasVelocity = !is_zero(listenerVelocity);

        if (sourceHasVelocity || listenerHasVelocity)
        {
            // Calculate the source to listener vector
            /// @fixme these values should be per sample, not per quantum
            FloatPoint3D listenerPosition = {
                listener->positionX()->value(),
                listener->positionY()->value(),
                listener->positionZ()->value()};

            /// @fixme these values should be per sample, not per quantum
            FloatPoint3D sourceToListener = {
                positionX()->value(),
                positionY()->value(),
                positionZ()->value()};

            sourceToListener = sourceToListener - listenerPosition;

            double sourceListenerMagnitude = magnitude(sourceToListener);

            double listenerProjection = dot(sourceToListener, listenerVelocity) / sourceListenerMagnitude;
            double sourceProjection = dot(sourceToListener, sourceVelocity) / sourceListenerMagnitude;

            listenerProjection = -listenerProjection;
            sourceProjection = -sourceProjection;

            double scaledSpeedOfSound = speedOfSound / dopplerFactor;
            listenerProjection = min(listenerProjection, scaledSpeedOfSound);
            sourceProjection = min(sourceProjection, scaledSpeedOfSound);