Method getAzimuthElevation

src/core/PannerNode.cpp:334–412

}

void PannerNode::getAzimuthElevation(ContextRenderLock & r, double * outAzimuth, double * outElevation)
{
    // FIXME: we should cache azimuth and elevation (if possible), so we only re-calculate if a change has been made.

    double azimuth = 0.0;

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

    // Calculate the source-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 sourceListener = {
        positionX()->value(),
        positionY()->value(),
        positionZ()->value()};

    sourceListener = normalize(sourceListener - listenerPosition);

    if (is_zero(sourceListener))
    {
        // degenerate case if source and listener are at the same point
        *outAzimuth = 0.0;
        *outElevation = 0.0;
        return;
    }

    // Align axes
    /// @fixme these values should be per sample, not per quantum
    FloatPoint3D listenerFront = normalize(FloatPoint3D{
        listener->forwardX()->value(),
        listener->forwardY()->value(),
        listener->forwardZ()->value()});

    /// @fixme these values should be per sample, not per quantum
    FloatPoint3D listenerUp = {
        listener->upX()->value(),
        listener->upY()->value(),
        listener->upZ()->value()};

    FloatPoint3D listenerRight = normalize(cross(listenerFront, listenerUp));
    FloatPoint3D up = cross(listenerRight, listenerFront);

    float upProjection = dot(sourceListener, up);

    FloatPoint3D projectedSource = normalize(sourceListener - upProjection * up);

    azimuth = 180.0 * acos(dot(projectedSource, listenerRight)) / static_cast<double>(LAB_PI);
    fixNANs(azimuth);  // avoid illegal values

    // Source in front or behind the listener
    double frontBack = dot(projectedSource, listenerFront);
    if (frontBack < 0.0)
        azimuth = 360.0 - azimuth;