#include <QApplication>#include <iostream>#include "tetrahedron.h"using namespace std;int main(int argc, char *argv[]){    QApplication app(argc, argv);    if (!QGLFormat::hasOpenGL()) {        cerr << "This system has no OpenGL support" << endl;        return 1;    }    Tetrahedron tetrahedron;    tetrahedron.setWindowTitle(QObject::tr("Tetrahedron"));    tetrahedron.resize(300, 300);    tetrahedron.show();    return app.exec();}