Single-shot ray cast: won't disable itself after the shot

m3g1dd

I have this ray caster setup:

m_rayCaster = new Qt3DRender::QRayCaster(m_scene->rootEntity());
m_rayCaster->setRunMode(Qt3DRender::QAbstractRayCaster::SingleShot);
m_scene->rootEntity()->addComponent(m_rayCaster);

I'm doing consecutive ray cast tests. I handle hit results with this slot:

QObject::connect(m_rayCaster, &Qt3DRender::QRayCaster::hitsChanged, this, &RayCastHandler::handleRayCasterHits);

void RayCastHandler::handleRayCasterHits(const Qt3DRender::QAbstractRayCaster::Hits hits)
{
    analyzeHits( ... , hits);
    return;
}

To decide when to do the next ray cast test, I'm using this slot. The logic is that whenever the ray-caster disables itself, it is ready to do the next test, according to this documentation.

QObject::connect(m_rayCaster, &Qt3DCore::QNode::enabledChanged, this, &RayCastHandler::handleRayCasterEnabledChange);

void RayCastHandler::handleRayCasterEnabledChange(const bool enabled)
{
    // When the component disables itself, it is ready for the next ray-cast test
    if (!enabled) {
        bool required = isNextTestRequired( ... );
        if (required)
            triggerTest( ... );
        else
            // Send final ray-cast results by a signal, if next test is NOT needed
            emit rayCastResultsChanged( ... );
    }
    return;
}

I have a strange observation: the following code does NOT work. I mean, at some point ray-caster remains enabled forever and it won't disable itself after a test (cast):

void RayCastHandler::triggerTest( ... )
{
    ...
    // No delay
    rayCaster->trigger(origin, direction, length);

    ...
}

However, by adding a delay of a few milliseconds, the code works, at least most of the time. Sometimes I have to increase the time-delay to make it work:

void RayCastHandler::triggerTest( ... )
{
    ...
    // 1 millisecond delay time
    QTimer::singleShot(1, [rayCaster, origin, direction, length](){rayCaster->trigger(origin, direction, length);});

    ...
}

Does anybody know the cause of this observation? How can I do consecutive ray-casts reliably?