#include <QApplication>
#include <QOpenGLWidget>
#include <QPainter>

class MyOpenGLWidget : public QOpenGLWidget
{
public:
    MyOpenGLWidget(QWidget* parent = nullptr) : QOpenGLWidget(parent) {}

    void paintGL() override {
        QPainter painter(this);
        painter.setPen(Qt::white);
        painter.drawText(rect(), Qt::AlignCenter, "Qt");
    }
};

int main(int argc, char** argv)
{
    QApplication app(argc, argv);
    MyOpenGLWidget w;
    w.show();
    w.grab();
    return 0;
}