C++ QSGGeometry::vertexDataAsPoint2D方法代码示例

void PEQGraph::_drawHumpOutline(QSGNode * parentNode, int n, QColor color) {
    //Solid Outline
    QSGGeometryNode * lineNode = new QSGGeometryNode();
    QSGGeometry * lineGeom = new QSGGeometry(QSGGeometry::defaultAttributes_Point2D(), (HorizontalDivisions));

    QSGFlatColorMaterial *material2 = new QSGFlatColorMaterial;

    material2->setColor(color);
    material2->setFlag(QSGMaterial::Blending);

    lineNode->setMaterial(material2);
    lineNode->setFlag(QSGNode::OwnsGeometry);
    lineNode->setFlag(QSGNode::OwnedByParent);
    lineNode->setFlag(QSGNode::OwnsMaterial);

    lineGeom->setDrawingMode(GL_LINE_STRIP);
    glLineWidth(2.0f);

    QSGGeometry::Point2D* point2 = lineGeom->vertexDataAsPoint2D();

    float left = graphToNodeX(xAxis.min);
    float width = graphToNodeX(xAxis.max) - graphToNodeX(xAxis.min);
    float stride = width / HorizontalDivisions;

    for (int i = 0; i < HorizontalDivisions; i++) {
        float x1 = left + (i)*stride;
        float y1 = graphToNodeY(computedData[i][n]);

        point2->set(x1, y1);
        point2++;
    }

    lineNode->setGeometry(lineGeom);
    parentNode->appendChildNode(lineNode);
}

void PEQGraph::_drawHumpSolid(QSGNode * parentNode, int n, QColor color) {
    //Transparent shaded part//
    QSGGeometryNode * solidNode = new QSGGeometryNode();
    QSGGeometry * solidGeom = new QSGGeometry(QSGGeometry::defaultAttributes_Point2D(), 2 * (HorizontalDivisions + 1));
    QSGFlatColorMaterial *material = new QSGFlatColorMaterial;

    material->setColor(color);
    material->setFlag(QSGMaterial::Blending);

    solidNode->setMaterial(material);
    solidNode->setFlag(QSGNode::OwnsGeometry);
    solidNode->setFlag(QSGNode::OwnedByParent);
    solidNode->setFlag(QSGNode::OwnsMaterial);

    solidGeom->setDrawingMode(GL_TRIANGLE_STRIP);

    QSGGeometry::Point2D* point = solidGeom->vertexDataAsPoint2D();

    float left = graphToNodeX(xAxis.min);
    float mid = graphToNodeY(0);
    float width = graphToNodeX(xAxis.max) - graphToNodeX(xAxis.min);
    float stride = width / HorizontalDivisions;

    for (int i = 0; i < HorizontalDivisions + 1; i++) {
        point->set(left + i*stride, mid);
        point++;
        point->set(left + i*stride, graphToNodeY(computedData[i][n]));
        point++;
    }

    solidNode->setGeometry(solidGeom);
    parentNode->appendChildNode(solidNode);
}

/*
 * The function hardcodes a fixed set of grid lines and scales
 * those to the bounding rect.
 */
void GridNode::setRect(const QRectF &rect)
{
    int vCount = int((rect.width() - 1) / GRID_SIZE);
    int hCount = int((rect.height() - 1) / GRID_SIZE);

    int lineCount = vCount + hCount;

    QSGGeometry *g = geometry();

    g->allocate(lineCount * 2);

    float x = rect.x();
    float y = rect.y();
    float w = rect.width();
    float h = rect.height();

    QSGGeometry::Point2D *v = g->vertexDataAsPoint2D();

    // Then write the vertical lines
    for (int i=0; i<vCount; ++i)  {
        float dx = (i + 1) * GRID_SIZE;
        v[i*2].set(dx, y);
        v[i*2+1].set(dx, y + h);
    }
    v += vCount * 2;
    // Then write the horizontal lines
    for (int i=0; i<hCount; ++i)  {
        float dy = (i + 1) * GRID_SIZE;
        v[i*2].set(x, dy);
        v[i*2+1].set(x + w, dy);
    }

    // Tell the scenegraph we updated the geometry..
    markDirty(QSGNode::DirtyGeometry);
}

QSGNode *PhosphorRender::updatePaintNode(QSGNode *oldNode, UpdatePaintNodeData *)
{
    if (!m_ybuffer) {
        return 0;
    }

    QSGGeometryNode *node = 0;
    QSGGeometry *geometry = 0;
    Material *material = 0;

    unsigned n_points;

    if (m_xbuffer) {
        n_points = std::min(m_xbuffer->size(), m_ybuffer->size());
    } else {
        n_points = m_ybuffer->countPointsBetween(m_xmin, m_xmax);
    }

    n_points = std::min(n_points,(unsigned) 65767);

    if (!oldNode) {
        node = new QSGGeometryNode;
        geometry = new QSGGeometry(QSGGeometry::defaultAttributes_Point2D(), n_points);
        geometry->setDrawingMode(GL_POINTS);
        node->setGeometry(geometry);
        node->setFlag(QSGNode::OwnsGeometry);
        material = new Material;
        material->setFlag(QSGMaterial::Blending);
        node->setMaterial(material);
        node->setFlag(QSGNode::OwnsMaterial);
    } else {
        node = static_cast<QSGGeometryNode *>(oldNode);
        geometry = node->geometry();
        geometry->allocate(n_points);
        geometry->setLineWidth(m_pointSize);
        material = static_cast<Material*>(node->material());
    }

    QRectF bounds = boundingRect();

    material->transformation.setToIdentity();
    material->transformation.scale(bounds.width()/(m_xmax - m_xmin), bounds.height()/(m_ymin - m_ymax));
    material->transformation.translate(-m_xmin, -m_ymax);

    material->pointSize = m_pointSize;
    material->color = m_color;

    auto verticies = geometry->vertexDataAsPoint2D();
    if (m_xbuffer) {
        for (unsigned i=0; i<n_points; i++) {
            verticies[i].set(m_xbuffer->get(i), m_ybuffer->get(i));
        }
    } else {
        m_ybuffer->toVertexData(m_xmin, m_xmax, verticies, n_points);
    }
    node->markDirty(QSGNode::DirtyGeometry | QSGNode::DirtyMaterial);

    return node;
}

void SceneGraphDeviceContext::DrawPolygon(int n, vrv::Point points[], int xoffset, int yoffset, int)
{
    // Note: No support for vertex antialiasing. Use a top-level QQuickView with multisample antialiasing.
    // TODO: Add vertex antialiasing, refer to
    // 1) Qt sources for "void QSGBasicInternalRectangleNode::updateGeometry()" in
    // qtdeclarative/src/quick/scenegraph/qsgbasicinternalrectanglenode.cpp
    // 2) https://stackoverflow.com/questions/28125425/smooth-painting-in-custom-qml-element

    // TODO: This function only works for convex polygons. At the moment verovio calls this function only with n = 4.
    // Maybe this function should be renamed to DrawConvexPolygon

    vrv::Pen currentPen = m_penStack.top();

    QSGGeometry *geometry;
    geometry = new QSGGeometry(QSGGeometry::defaultAttributes_Point2D(), n);
    geometry->setDrawingMode(QSGGeometry::DrawTriangleStrip);

    QSGFlatColorMaterial *material = new QSGFlatColorMaterial;
    material->setColor(static_cast<QRgb>(currentPen.GetColour()));

    // Reorder points so that they can be drawn with DrawTriangleStrip.
    int counter1 = 0;
    int counter2 = n - 1;
    for (int i = 0; i < n; i++) {
        if (i % 2 == 0) {
            geometry->vertexDataAsPoint2D()[i].set(
                translateX(points[counter1].x + xoffset), translateY(points[counter1].y + yoffset));
            counter1++;
        }
        else {
            geometry->vertexDataAsPoint2D()[i].set(
                translateX(points[counter2].x + xoffset), translateY(points[counter2].y + yoffset));
            counter2--;
        }
    }

    QSGGeometryNode *node = new QSGGeometryNode;
    node->setGeometry(geometry);
    node->setFlag(QSGNode::OwnsGeometry);
    node->setMaterial(material);
    node->setFlag(QSGNode::OwnsMaterial);

    AddGeometryNode(node);
}

QSGNode * QQuickLineItem::updatePaintNode(QSGNode *prev_node,
                                          UpdatePaintNodeData *upd_data)
{
    Q_UNUSED(upd_data);

    QSGGeometryNode * node = static_cast<QSGGeometryNode*>(prev_node);
    QSGGeometry * geometry = NULL;
    QSGFlatColorMaterial * material = NULL;

    if(!node) {
        // http://qt-project.org/doc/qt-5/qsggeometrynode.html
        node = new QSGGeometryNode;
        geometry = new QSGGeometry(QSGGeometry::defaultAttributes_Point2D(),4);
        geometry->setDrawingMode(GL_TRIANGLE_STRIP);
        node->setGeometry(geometry);
        node->setFlag(QSGNode::OwnsGeometry);

        material = new QSGFlatColorMaterial;
        material->setColor(m_color);
        node->setMaterial(material);
        node->setFlag(QSGNode::OwnsMaterial);
    }
    else {
        geometry = node->geometry();
        geometry->allocate(4); // we have to call allocate to invalidate
                               // the older vertex buffer
        material = static_cast<QSGFlatColorMaterial*>(node->material());
    }

    // geometry
    std::vector<QPointF> list_vx;
    if(!calcTriStrip(list_vx)) {
        list_vx.clear();
        list_vx.push_back(QPointF(0,0));
        list_vx.push_back(QPointF(0,0));
        list_vx.push_back(QPointF(0,0));
        list_vx.push_back(QPointF(0,0));
    }

    QSGGeometry::Point2D * vertices =
            geometry->vertexDataAsPoint2D();

    for(size_t i=0; i < list_vx.size(); i++) {
        vertices[i].set(list_vx[i].x(),
                        list_vx[i].y());
    }

    node->markDirty(QSGNode::DirtyGeometry);

    // material
    material->setColor(m_color);
    node->markDirty(QSGNode::DirtyMaterial);

    return node;
}

void SceneGraphDeviceContext::DrawComplexBezierPath(vrv::Point bezier1[4], vrv::Point bezier2[4])
{
    // Note: No support for vertex antialiasing. Use a top-level QQuickView with multisample antialiasing.
    // TODO: Add vertex antialiasing, refer to
    // 1) Qt sources for "void QSGBasicInternalRectangleNode::updateGeometry()" in
    // qtdeclarative/src/quick/scenegraph/qsgbasicinternalrectanglenode.cpp
    // 2) https://stackoverflow.com/questions/28125425/smooth-painting-in-custom-qml-element

    vrv::Pen currentPen = m_penStack.top();

    int segmentCount = 16;

    QSGGeometryNode *node = new QSGGeometryNode;
    QSGGeometry *geometry = new QSGGeometry(QSGGeometry::defaultAttributes_Point2D(), 2 * segmentCount);
    geometry->setDrawingMode(QSGGeometry::DrawTriangleStrip);
    node->setGeometry(geometry);
    node->setFlag(QSGNode::OwnsGeometry);

    QSGFlatColorMaterial *material = new QSGFlatColorMaterial;
    material->setColor(static_cast<QRgb>(currentPen.GetColour()));
    node->setMaterial(material);
    node->setFlag(QSGNode::OwnsMaterial);

    auto calculateCubicBezierPoint = [](vrv::Point p[4], float t) -> std::tuple<float, float> {
        auto invt = 1 - t;
        auto x = invt * invt * invt * p[0].x + 3 * invt * invt * t * p[1].x + 3 * invt * t * t * p[2].x
            + t * t * t * p[3].x;
        auto y = invt * invt * invt * p[0].y + 3 * invt * invt * t * p[1].y + 3 * invt * t * t * p[2].y
            + t * t * t * p[3].y;
        return std::make_tuple(x, y);
    };

    // This loop calculates the bezier points for the inner and the outer line and add them as vertices. The list of
    // vertices is built so that points from the inner and outer line are alternating. This allows to draw a filled area
    // with DrawTriangleStrip.
    QSGGeometry::Point2D *vertices = geometry->vertexDataAsPoint2D();
    for (int i = 0; i < segmentCount; ++i) {
        float bezierPointX = 0;
        float bezierPointY = 0;
        float currentSegment = i / static_cast<float>(segmentCount - 1);

        // Calculate bezier point on bezier1
        std::tie(bezierPointX, bezierPointY) = calculateCubicBezierPoint(bezier1, currentSegment);
        vertices[i * 2].set(translateX(bezierPointX), translateY(bezierPointY));

        // Calculate bezier point on bezier2
        std::tie(bezierPointX, bezierPointY) = calculateCubicBezierPoint(bezier2, currentSegment);
        vertices[i * 2 + 1].set(translateX(bezierPointX), translateY(bezierPointY));
    }

    node->markDirty(QSGNode::DirtyGeometry);
    AddGeometryNode(node);
}

QSGNode* drawRect(const QRect& rect, QSGNode* oldNode)
{
    QSGGeometryNode* node;
    if (oldNode == nullptr)
    {
        node = new QSGGeometryNode;

        QSGGeometry* geometry = new QSGGeometry(QSGGeometry::defaultAttributes_Point2D(), 8);
        geometry->setDrawingMode(GL_LINES);
        geometry->setLineWidth(1);

        QSGFlatColorMaterial* material = new QSGFlatColorMaterial;
        material->setColor(QGuiApplication::palette().color(QPalette::Normal, QPalette::WindowText));

        node->setGeometry(geometry);
        node->setFlag(QSGNode::OwnsGeometry);
        node->setMaterial(material);
        node->setFlag(QSGNode::OwnsMaterial);
    }
    else
    {
        node = static_cast<QSGGeometryNode*>(oldNode);
    }

    QSGGeometry* geometry = node->geometry();

    // FIXME: check if these really have to be updated
    geometry->vertexDataAsPoint2D()[0].set(rect.topLeft().x(), rect.topLeft().y());
    geometry->vertexDataAsPoint2D()[1].set(rect.topRight().x(), rect.topRight().y());
    geometry->vertexDataAsPoint2D()[2].set(rect.topRight().x(), rect.topRight().y());
    geometry->vertexDataAsPoint2D()[3].set(rect.bottomRight().x(), rect.bottomRight().y());
    geometry->vertexDataAsPoint2D()[4].set(rect.bottomRight().x(), rect.bottomRight().y());
    geometry->vertexDataAsPoint2D()[5].set(rect.bottomLeft().x(), rect.bottomLeft().y());
    geometry->vertexDataAsPoint2D()[6].set(rect.bottomLeft().x(), rect.bottomLeft().y());
    geometry->vertexDataAsPoint2D()[7].set(rect.topLeft().x(), rect.topLeft().y());

    node->markDirty(QSGNode::DirtyGeometry);

    return node;
}

//! [4]
QSGNode *BezierCurve::updatePaintNode(QSGNode *oldNode, UpdatePaintNodeData *)
{
    QSGGeometryNode *node = 0;
    QSGGeometry *geometry = 0;

    if (!oldNode) {
        node = new QSGGeometryNode;
//! [4] //! [5]
        geometry = new QSGGeometry(QSGGeometry::defaultAttributes_Point2D(), m_segmentCount);
        geometry->setLineWidth(2);
        geometry->setDrawingMode(GL_LINE_STRIP);
        node->setGeometry(geometry);
        node->setFlag(QSGNode::OwnsGeometry);
//! [5] //! [6]
        QSGFlatColorMaterial *material = new QSGFlatColorMaterial;
        material->setColor(QColor(255, 0, 0));
        node->setMaterial(material);
        node->setFlag(QSGNode::OwnsMaterial);
//! [6] //! [7]
    } else {
        node = static_cast<QSGGeometryNode *>(oldNode);
        geometry = node->geometry();
        geometry->allocate(m_segmentCount);
    }
//! [7]

//! [8]
    QRectF bounds = boundingRect();
    QSGGeometry::Point2D *vertices = geometry->vertexDataAsPoint2D();
    for (int i = 0; i < m_segmentCount; ++i) {
        qreal t = i / qreal(m_segmentCount - 1);
        qreal invt = 1 - t;

        QPointF pos = invt * invt * invt * m_p1
                    + 3 * invt * invt * t * m_p2
                    + 3 * invt * t * t * m_p3
                    + t * t * t * m_p4;

        float x = bounds.x() + pos.x() * bounds.width();
        float y = bounds.y() + pos.y() * bounds.height();

        vertices[i].set(x, y);
    }
    node->markDirty(QSGNode::DirtyGeometry);
//! [8]


//! [9]
    return node;
}

void DynamicController::drawGateCompressor(QSGNode * rootNode) {

    if (knobs.count() == 0) {
        return;
    }
    //Update knobs
    if (!this->simple()) {
        QObject * gateKnob = knobs[0];
        QObject * compThreshKnob = knobs[1];
        QObject * compRatioKnob = knobs[2];

        gateKnob->setProperty("x", graphToNodeX(_tempModel["gatex"]));
        gateKnob->setProperty("y", graphToNodeY(_tempModel["gatey"]));

        compThreshKnob->setProperty("x", graphToNodeX(_tempModel["compx"]));
        compThreshKnob->setProperty("y", graphToNodeY(_tempModel["compy"]));

        compRatioKnob->setProperty("x", graphToNodeX(xAxis.max));
        compRatioKnob->setProperty("y", graphToNodeY(_tempModel["compy"]) * (1 - _tempModel["ratio"]));
    }

    QSGGeometryNode * lineNode = new QSGGeometryNode();
    QSGGeometry * lineGeom = new QSGGeometry(QSGGeometry::defaultAttributes_Point2D(), (4));

    QSGFlatColorMaterial *material = new QSGFlatColorMaterial;

    material->setColor(this->curveColor());
    material->setFlag(QSGMaterial::Blending);

    lineNode->setMaterial(material);
    lineNode->setFlag(QSGNode::OwnsGeometry);
    lineNode->setFlag(QSGNode::OwnedByParent);
    lineNode->setFlag(QSGNode::OwnsMaterial);

    lineGeom->setDrawingMode(GL_LINE_STRIP);
    glLineWidth(2.0f);

    QSGGeometry::Point2D* points = lineGeom->vertexDataAsPoint2D();

    QRectF bounds = boundingRect();

    points->set(graphToNodeX(_tempModel["gatex"]), bounds.bottom()); points++;
    points->set(graphToNodeX(_tempModel["gatex"]), graphToNodeY(_tempModel["gatey"])); points++;
    points->set(graphToNodeX(_tempModel["compx"]), graphToNodeY(_tempModel["compy"])); points++;
    points->set(graphToNodeX(xAxis.max), graphToNodeY(_tempModel["compy"]) * (1 - _tempModel["ratio"])); points++;

    lineNode->setGeometry(lineGeom);
    rootNode->appendChildNode(lineNode);
}

void DynamicController::drawCompressor(QSGNode * rootNode) {
    //Update knobs
    if (!this->simple()) {
        QObject * threshKnob = knobs[0];
        QObject * ratKnob = knobs[1];

        threshKnob->setProperty("x", graphToNodeX(_tempModel["compx"]));
        threshKnob->setProperty("y", graphToNodeY(_tempModel["compy"]));

        ratKnob->setProperty("x", graphToNodeX(yAxis.max));
        ratKnob->setProperty("y", graphToNodeY(_tempModel["compy"]) * (1 - _tempModel["ratio"]));
    }

    QSGGeometryNode * lineNode = new QSGGeometryNode();
    QSGGeometry * lineGeom = new QSGGeometry(QSGGeometry::defaultAttributes_Point2D(), (3));

    QSGFlatColorMaterial *material = new QSGFlatColorMaterial;

    material->setColor(this->curveColor());
    material->setFlag(QSGMaterial::Blending);

    lineNode->setMaterial(material);
    lineNode->setFlag(QSGNode::OwnsGeometry);
    lineNode->setFlag(QSGNode::OwnedByParent);
    lineNode->setFlag(QSGNode::OwnsMaterial);

    lineGeom->setDrawingMode(GL_LINE_STRIP);
    glLineWidth(2.0f);

    QSGGeometry::Point2D* points = lineGeom->vertexDataAsPoint2D();

    QRectF bounds = boundingRect();

    points->set(bounds.left(), bounds.bottom()); points++;

    for (int i = 0; i < 2; i++) {
        QQuickItem * q = qobject_cast<QQuickItem*>(knobs[i]);
        points->set(q->x(), q->y());
        points++;
    }

    lineNode->setGeometry(lineGeom);
    rootNode->appendChildNode(lineNode);
}

void SceneGraphDeviceContext::DrawLine(int x1, int y1, int x2, int y2)
{
    vrv::Pen currentPen = m_penStack.top();

    QSGGeometry *geometry = new QSGGeometry(QSGGeometry::defaultAttributes_Point2D(), 2);
    geometry->setDrawingMode(GL_LINES);
    geometry->setLineWidth(translate(currentPen.GetWidth()));
    geometry->vertexDataAsPoint2D()[0].set(translateX(x1), translateY(y1));
    geometry->vertexDataAsPoint2D()[1].set(translateX(x2), translateY(y2));

    QSGFlatColorMaterial *material = new QSGFlatColorMaterial;
    material->setColor(static_cast<QRgb>(currentPen.GetColour()));

    QSGGeometryNode *node = new QSGGeometryNode;
    node->setGeometry(geometry);
    node->setFlag(QSGNode::OwnsGeometry);
    node->setMaterial(material);
    node->setFlag(QSGNode::OwnsMaterial);

    AddGeometryNode(node);
}

void VideoNode::updateGeometry(const PaintAreas & areas)
{
    QSGGeometry *g = geometry();

    if (m_materialType == MaterialTypeVideo) {
        if (!m_validGeometry)
            g = new QSGGeometry(QSGGeometry::defaultAttributes_TexturedPoint2D(), 4);

        QSGGeometry::TexturedPoint2D *v = g->vertexDataAsTexturedPoint2D();

        // Set geometry first
        setGeom(v + 0, areas.videoArea.topLeft());
        setGeom(v + 1, areas.videoArea.bottomLeft());
        setGeom(v + 2, areas.videoArea.topRight());
        setGeom(v + 3, areas.videoArea.bottomRight());

        // and then texture coordinates
        setTex(v + 0, areas.sourceRect.topLeft());
        setTex(v + 1, areas.sourceRect.bottomLeft());
        setTex(v + 2, areas.sourceRect.topRight());
        setTex(v + 3, areas.sourceRect.bottomRight());
    } else {
        if (!m_validGeometry)
            g = new QSGGeometry(QSGGeometry::defaultAttributes_Point2D(), 4);

        QSGGeometry::Point2D *v = g->vertexDataAsPoint2D();

        setGeom(v + 0, areas.videoArea.topLeft());
        setGeom(v + 1, areas.videoArea.bottomLeft());
        setGeom(v + 2, areas.videoArea.topRight());
        setGeom(v + 3, areas.videoArea.bottomRight());
    }

    if (!m_validGeometry) {
        setGeometry(g);
        m_validGeometry = true;
    }

    markDirty(DirtyGeometry);
}

QSGNode *QPScrollingCurve::updatePaintNode(QSGNode *oldNode, QQuickItem::UpdatePaintNodeData *)
{
    QSGGeometryNode *node = 0;
    QSGGeometry *geometry = 0;
    QSGFlatColorMaterial *material = 0;

    if (!oldNode) {
        node = new QSGGeometryNode;
        geometry = new QSGGeometry(QSGGeometry::defaultAttributes_Point2D(), m_data.size());
        geometry->setLineWidth(2);
        geometry->setDrawingMode(GL_LINE_STRIP);
        node->setGeometry(geometry);
        node->setFlag(QSGNode::OwnsGeometry);
        material = new QSGFlatColorMaterial;
        material->setColor(m_color);
        node->setMaterial(material);
        node->setFlag(QSGNode::OwnsMaterial);
        node->markDirty(QSGNode::DirtyMaterial);
    } else {
        node = static_cast<QSGGeometryNode *>(oldNode);
        geometry = node->geometry();
        geometry->allocate(m_data.size());
        material = static_cast<QSGFlatColorMaterial*>(node->material());
        if (material->color() != m_color) {
            material->setColor(m_color);
            node->markDirty(QSGNode::DirtyMaterial);
        }
    }

    QSGGeometry::Point2D *vertices = geometry->vertexDataAsPoint2D();

    for (uint i = 0; i < m_data.size(); ++i) {
        QPointF p(i, m_data[i]);
        vertices[i].set(p.x(), p.y());
    }

    node->markDirty(QSGNode::DirtyGeometry);

    return node;
}

void SceneGraphDeviceContext::DrawCircle(int x, int y, int radius)
{
    // Note: No support for vertex antialiasing. Use a top-level QQuickView with multisample antialiasing.
    // TODO: Add vertex antialiasing, refer to
    // 1) Qt sources for "void QSGBasicInternalRectangleNode::updateGeometry()" in
    // qtdeclarative/src/quick/scenegraph/qsgbasicinternalrectanglenode.cpp
    // 2) https://stackoverflow.com/questions/28125425/smooth-painting-in-custom-qml-element

    vrv::Pen currentPen = m_penStack.top();

    int segmentCount = 16;

    QSGGeometryNode *node = new QSGGeometryNode();
    QSGGeometry *geometry = new QSGGeometry(QSGGeometry::defaultAttributes_Point2D(), segmentCount);
    geometry->setDrawingMode(QSGGeometry::DrawTriangleFan);
    node->setGeometry(geometry);
    node->setFlag(QSGNode::OwnsGeometry);

    QSGFlatColorMaterial *material = new QSGFlatColorMaterial;
    material->setColor(static_cast<QRgb>(currentPen.GetColour()));
    node->setMaterial(material);
    node->setFlag(QSGNode::OwnsMaterial);

    // This draws individual triangles from the first point (center) to every outer point by using DrawTriangleFan.
    QSGGeometry::Point2D *vertices = geometry->vertexDataAsPoint2D();
    int numPoints = geometry->vertexCount();
    vertices[0].x = translateX(x);
    vertices[0].y = translateY(y);
    for (int i = 1; i < numPoints; ++i) {
        double theta = i * 2 * M_PI / (numPoints - 2);
        vertices[i].x = translateX(x + radius * static_cast<float>(std::cos(theta)));
        vertices[i].y = translateY(y - radius * static_cast<float>(std::sin(theta)));
    }

    node->markDirty(QSGNode::DirtyGeometry);
    AddGeometryNode(node);
}