QT5 - multiple OpenGL widgets in the same window

Question

I have developed a basic graphical engine monitoring application using OpenGL ES. It draws basic 2D geometry. I am interested in porting this to QT5 for the cross-platform comparability.

I want to turn each gauge into an individual widget with it's own signals and slots. QT provides a nice example of how to make an OpenGL widget. However, this method makes a new window for each widget. It there a method to make each gauge it's own widget and draw them all in the same window?

Answer 1

QOpenGLWidget is a widget so you can place it inside another widget, in the example when creating a single widget this will be the window. You can create some QMainWindow, QDialog or QWidget and place within them a QOpenGLWidget, the following is an example of how to do it, just replace this main to the main example:

#include <QApplication>
#include <QDialog>
#include <QLabel>
#include <QSurfaceFormat>
#include <QVBoxLayout>

#ifndef QT_NO_OPENGL
#include "mainwidget.h"
#endif

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);

    QSurfaceFormat format;
    format.setDepthBufferSize(24);
    QSurfaceFormat::setDefaultFormat(format);

    app.setApplicationName("cube");
    app.setApplicationVersion("0.1");
#ifndef QT_NO_OPENGL
    QDialog w;
    QHBoxLayout *lay = new QHBoxLayout(&w);
    QHBoxLayout *hlay = new QHBoxLayout;
    hlay->addWidget(new MainWidget(&w));
    hlay->addWidget(new MainWidget(&w));
    QVBoxLayout *vlay = new QVBoxLayout;
    vlay->addLayout(hlay);
    vlay->addWidget(new MainWidget(&w));
    lay->addWidget(new MainWidget(&w));
    lay->addLayout(vlay);
    w.resize(640, 480);
    w.show();
#else
    QLabel note("OpenGL Support required");
    note.show();
#endif
    return app.exec();
}

Output: