glewInit with Qt5 returns Missing GL version - qt

Question

I have been trying to use Qt5 to give me an OpenGL context, which I believe it does, but when I try to call glewInit() from within the initializeGL function, the error returns back "Missing GL version," which I have been led to believe indicates that there is no valid context. The solution I saw was to call glewInit() from within initializeGL... but I'm already doing that.
I am setting the clear color and clearing to dark red to verify that gl calls are working, which they appear to be.
Any suggestions?
main.c
#define QT_NO_OPENGL_ES_2
#include <QApplication>
#include "glwidget.h"
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
GLWidget w;
w.show();
return a.exec();
}
glwidget.h
#ifndef GLWIDGET_H
#define GLWIDGET_H
#include <GL/glew.h>
#define QT_NO_OPENGL_ES_2
#include <QGLWidget>
class GLWidget : public QGLWidget
{
Q_OBJECT
public:
explicit GLWidget(QGLWidget *parent = 0);
~GLWidget();
QSize minimumSizeHint() const;
QSize sizeHint() const;
protected:
void initializeGL();
void paintGL();
void resizeGL(int width, int height);
};
#endif // GLWIDGET_H
glwidget.cpp
#include "glwidget.h"
GLWidget::GLWidget(QGLWidget *parent) :
QGLWidget(parent)
{
}
GLWidget::~GLWidget() {}
QSize GLWidget::minimumSizeHint() const {
return QSize(640, 480);
}
QSize GLWidget::sizeHint() const {
return QSize(800, 600);
}
void GLWidget::initializeGL() {
GLenum err = glewInit();
if (GLEW_OK != err) {
printf("GLEW error: %s\n", glewGetErrorString(err));
} else {
printf("Glew loaded; using version %s\n", glewGetString(GLEW_VERSION));
}
glClearColor(0.2f, 0, 0, 1.0f);
}
void GLWidget::resizeGL(int w, int h) {
}
void GLWidget::paintGL() {
glClear( GL_COLOR_BUFFER_BIT );
}

Answer 1

Something tells me this is because of the QGLWidget's default QGLFormat using OpenGL version 1.0 (Looking through GLEW's change logs, it seems the earliest version they claim to fully support is 1.5) . Try instead to override the QGLWidget constructor that requires a QGLFormat and pass it an instance of QGLFormat that uses the version you are targeting.
The call to your widget should look something like:
QGLFormat format;
format.setVersion(3,3); // or whatever version you are targeting.
format.setDoubleBuffer(true);
GLWidget * widget = new GLWidget(format);