QOpenGLWidget show black screen

Question

I tried the QOpenGLWidget example described here: https://stackoverflow.com/a/31524956/4564882

but I get only a black widget. The code is exactly the same. this the code

Answer 1

I had a black screen on desktop. I solved the problem by adding this line of code:

QCoreApplication::setAttribute(Qt::AA_UseDesktopOpenGL);

For example, put it here:

#include "widget.h"

#include 

int main(int argc, char *argv[])
{
    QCoreApplication::setAttribute(Qt::AA_UseDesktopOpenGL);
    QApplication a(argc, argv);
    Widget w;
    w.show();
    return a.exec();
}