How to render a part of area by QQuickRenderControl::render

class FutureRenderControl : public QQuickRenderControl
{
public:
    void render(const QRect &geometry) {
        Q_D(QQuickRenderControl);
        if (!d->window)
            return;
    
        QQuickWindowPrivate *cd = QQuickWindowPrivate::get(d->window);
        if (d->rhi) {
            if (!d->rhi->isRecordingFrame()) {
                qWarning("QQuickRenderControl can only render when beginFrame() has been called");
                return;
            }
            if (!d->cb) {
                qWarning("QQuickRenderControl cannot be used with QRhi when no QRhiCommandBuffer is provided");
                return;
            }
            cd->setCustomCommandBuffer(d->cb);
        }
    
        // should add renderSceneGraph(const QRect &geometry) for QQuickWindow
        cd->renderSceneGraph(geometry);
    }
};

void renderWindow(FutureRenderControl *rc, const QRect &geo) {
    QOpenGLContext *glOfThread = ...;
    glOfThread->makeCurrent(...);
    // This texture can is a Linux GBM buffer of a drm output device, so we can map the QQuickWindow to multi screen at the same time by multi thread.
    QOpenGLTexture *texture = ...;
    aBlockOfTexture->bind();
    rc->render(geo);
}

void demo() {
    auto rc = new FutureRenderControl();
    auto window = new QQuickWindow(rc);
    window->resize(20, 20);
    // render for part top-left
    QtConcurrent::run(renderWindow, rc, QRect(0, 0, 10, 10));
    // render for part top-right
    QtConcurrent::run(renderWindow, rc, QRect(10, 0, 10, 10));
    // render for part bottom-left
    QtConcurrent::run(renderWindow, rc, QRect(0, 10, 10, 10));
    // render for part bottom-right
    QtConcurrent::run(renderWindow, rc, QRect(10, 10, 10, 10));
}