[OpenGL] Drawing simple polygon crashes application

Hi there,
I`m new OpenGL programmer but I have some experience from programming with WinAPI+OpenGL or plain GLUT. Now I decided to move into Qt4 + OpenGL but I have plenty of troubles during getting first steps in this topic :) I was looking at example source code for OpenGL programs but there are too sophisicated (I don`t want to use any sliders or rotate something yet). I tried to write as simple app as it can be using source code from here:
http://doc.trolltech.com/4.4/opengl-hellogl.html
My programm compile (wrote in Qt Creator under Windows XP) without any errors but it crash and I just see Window`s error dialog with sending report about bug (i hope you know what i mean). I don`t know how to debuge OpenGL apps, so there is my whole source code:
File: window.h

Code:

---

#ifndef WINDOW_H
#define WINDOW_H
 
#include <QtGui/QWidget>
#include <QHBoxLayout>
#include "ui_window.h"
#include "glwidget.h"
 
 
class Window : public QWidget
{
    Q_OBJECT
 
public:
    Window(QWidget *parent = 0, Qt::WFlags flags = 0);
    ~Window();
 
private:
    Ui::WindowClass ui;
    GLWidget* glWidget;
};
 
#endif // WINDOW_H

---

File: window.cpp

Code:

---

#include "window.h"
 
Window::Window(QWidget *parent, Qt::WFlags flags)
    : QWidget(parent, flags)
{
    ui.setupUi(this);
    QHBoxLayout *mainLayout = new QHBoxLayout();
    mainLayout->addWidget(glWidget);
    setLayout(mainLayout);
 
    setWindowTitle(tr("Hello OpenGL"));
}
 
Window::~Window()
{
 
}

---

and most important files, I guess...
File: glwidget.h

Code:

---

#ifndef GLWIDGET_H
#define GLWIDGET_H
#include <QGLWidget>
#include <QtOpenGL>
 
class GLWidget: public QGLWidget
{
    Q_OBJECT
  public:
        GLWidget(QWidget *parent = 0);
        ~GLWidget();
 
 
  protected:
        void    initializeGL();
        void    paintGL();
        void    resizeGL(int width, int height);
};
#endif // GLWIDGET_H

---

File: glwidget.cpp

Code:

---

#include "glwidget.h"
 
GLWidget::GLWidget(QWidget* parent): QGLWidget(parent)
{
}
 
GLWidget::~GLWidget()
{
}
 
void GLWidget::initializeGL()
{
    qglClearColor(QColor(255, 0, 0, 127));
    glEnable(GL_DEPTH_TEST);
}
 
void GLWidget::resizeGL(int width, int height)
{
    int side = qMin(width, height);
    glViewport((width - side) / 2, (height - side)/2, side, side);
    glMatrixMode(GL_PROJECTION);
 
    glLoadIdentity();
    glMatrixMode(GL_MODELVIEW);
}
 
void GLWidget::paintGL()
{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glLoadIdentity();
    glBegin(GL_POLYGON);
        //glColor3f(1.0f, 0.4f, 0.5f);
        glVertex3f(-1.0f , 4.0f, 0.0f);
        glVertex3f(2.0f, -1.0f, 0.0f);
        glVertex3f(4.0f, -4.0f, -1.0f);
        //glColor3f(0.4f, 0.4f, 0.4f);
        glVertex3f(1.3f, -2.3f, -2.0f);
        glVertex3f(0.0f, 4.0f, -2.0f);
    glEnd();
}

---

Main.cpp is of course very simple:

Code:

---

#include <QtGui/QApplication>
#include "window.h"
 
int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    Window *window = new Window();
    window->show();
    return app.exec();
}

---

Thank you for attention, I`m waiting for any help :)

Hi,

I am trying to use glut.h along in a qt application under windows. My application won't build, I get 4 unresolved references: __glutInitWithExit, __glutCreateWindowWithExit, __glutCreateMenuWithExit and the only glut function I am explicitely calling in my code glutSolidCube.

Anyone know the trick to use glut.h functionality along with Qtcreator in Windows?

Stephane

stephanepoirier please don't hijack threads

It seems glWidget is an uninitialized variable.
You need the line

Code:

---

glWidget = new GlWidget;

---

somewhere in your code.