Qt3d transparency texture will be covered. How to slove that?

问题

I add a plane to the 3D world and it should be in torus's center.

But if I add the plane first and the tour second, the plane will be tour covered (plane's coordinate is in tour center):

I think it is about paint order. The plane should be drawn in last order.

Changing plane and torus adding order will be correct:

Can QDepthTest help me? Or any other way?

Can show me some examples? Thanks!

code (without the sphere):

class FlippedTextureImage : public Qt3DRender::QPaintedTextureImage
{
public:
    FlippedTextureImage(Qt3DCore::QNode *parent = Q_NULLPTR):Qt3DRender::QPaintedTextureImage(parent) {}
    void paint(QPainter *painter) override {
        // qDebug() << backgroundImage.isNull();
        qDebug() << qApp->applicationDirPath() + "/gift.svg";
                QSvgRenderer renderer(QString(qApp->applicationDirPath() + "/gift.svg"));
        QImage image(3000, 3000, QImage::Format_RGBA8888);  // 512x512 RGBA
        image.fill(0x00ffffff);                           // white background
        QPainter painter2(&image);
        renderer.render(&painter2);
        painter->setCompositionMode(QPainter::CompositionMode::CompositionMode_Source);
        painter->drawImage(0, 0, image);
    }
};

Qt3DCore::QEntity *createScene()
{
    // Root entity
    Qt3DCore::QEntity *rootEntity = new Qt3DCore::QEntity;

    // Material
    Qt3DRender::QMaterial *material = new Qt3DExtras::QPhongMaterial(rootEntity);

    // Plane 
        Qt3DCore::QEntity *planeEntity = new Qt3DCore::QEntity(rootEntity);
        Qt3DExtras::QPlaneMesh *planeMesh = new Qt3DExtras::QPlaneMesh(planeEntity);
        planeMesh->setHeight(2);
        planeMesh->setWidth(2);

        planeMaterial = new Qt3DExtras::QTextureMaterial(planeEntity);
        Qt3DRender::QTexture2D *planeTexture = new Qt3DRender::QTexture2D(planeMaterial);

        FlippedTextureImage *planeTextureImage = new FlippedTextureImage(planeTexture);
        planeTextureImage->setSize(QSize(3000, 3000));
        planeTexture->addTextureImage(planeTextureImage);
        planeMaterial->setTexture(planeTexture);
        planeMaterial->setAlphaBlendingEnabled(true);
        planeTransformClass *planeTransform = new planeTransformClass(planeEntity);
        //planeTransform->setRotationX(90);
        planeTransform->setTranslation(QVector3D(2, 0, 0));

        planeEntity->addComponent(planeMesh);
        planeEntity->addComponent(planeMaterial);
        planeEntity->addComponent(planeTransform);

    // Torus
    Qt3DCore::QEntity *torusEntity = new Qt3DCore::QEntity(rootEntity);
    Qt3DExtras::QTorusMesh *torusMesh = new Qt3DExtras::QTorusMesh;
    torusMesh->setRadius(5);
    torusMesh->setMinorRadius(1);
    torusMesh->setRings(100);
    torusMesh->setSlices(20);

    Qt3DCore::QTransform *torusTransform = new Qt3DCore::QTransform;
    torusTransform->setScale3D(QVector3D(1.5, 1, 0.5));
    torusTransform->setRotation(QQuaternion::fromAxisAndAngle(QVector3D(1, 0, 0), 90.0f));

    torusEntity->addComponent(torusMesh);
    torusEntity->addComponent(torusTransform);
    torusEntity->addComponent(material);

    return rootEntity;
}

int main(int argc, char* argv[])
{
    QGuiApplication app(argc, argv);
    Qt3DExtras::Qt3DWindow view;

    Qt3DCore::QEntity *scene = createScene();

    // Camera
    camera = view.camera();
    camera->lens()->setPerspectiveProjection(45.0f, 16.0f/9.0f, 0.1f, 1000.0f);
    camera->setPosition(QVector3D(0, 0, 40.0f));
    camera->setViewCenter(QVector3D(0, 0, 0));

    // For camera controls
    Qt3DExtras::QOrbitCameraController *camController = new Qt3DExtras::QOrbitCameraController(scene);
    camController->setLinearSpeed( 50.0f );
    camController->setLookSpeed( 180.0f );
    camController->setCamera(camera);

    view.setRootEntity(scene);
    view.show();

    return app.exec();
}

This is the SVG I use:

来源：https://stackoverflow.com/questions/62957001/qt3d-transparency-texture-will-be-covered-how-to-slove-that