Putting an opengl widget in to a mainwindow

[bod]

Hello,
I'm trying make a connection between an opengl window and a tree object.
For example there will be a cube, a circle, and a piramid in the openglwidget on the left.
And in the tree there will be nodes: cube, circle and piramid.
When user selects the cube, cube will be higlighted in the graphic.
But I can not even succeed to place the required items on mainwindow.
Could you help me please.
Here is my Header:

#ifndef QTGL_H
#define QTGL_H

#include <QtGui/QMainWindow>
#include <QtOpenGL>
#include "ui_qtgl.h"

class QtGL : public QMainWindow
{
Q_OBJECT

public:
QtGL(QWidget *parent = 0, Qt::WFlags flags = 0);
~QtGL();
QGLWidget *glwidget;


protected:
void initializeGL();
void resizeGL(int width, int height);
void paintGL();
void mousePressEvent(QMouseEvent *event);
void mouseMoveEvent(QMouseEvent *event);
void mouseDoubleClickEvent(QMouseEvent *event);

private:
void draw();
int faceAtPosition(const QPoint &pos);

GLfloat rotationX;
GLfloat rotationY;
GLfloat rotationZ;
QColor faceColors[4];
QPoint lastPos;

Ui::QtGLClass ui;
};

#endif // QTGL_H


and here is my cpp:


#include "qtgl.h"
#include <QtOpenGL>

QtGL::QtGL(QWidget *parent, Qt::WFlags flags)
: QMainWindow(parent, flags)
{
ui.setupUi(this);
glwidget = new QGLWidget(parent);

}

QtGL::~QtGL()
{

}

void QtGL::initializeGL()
{
glwidget->qglClearColor(Qt::black);
glShadeModel(GL_FLAT);
glEnable(GL_DEPTH_TEST);
glEnable(GL_CULL_FACE);
}

void QtGL::resizeGL(int width, int height)
{
glViewport(0, 0, width, height);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
GLfloat x = GLfloat(width) / height;
glFrustum(-x, +x, -1.0, +1.0, 4.0, 15.0);
glMatrixMode(GL_MODELVIEW);
}

void QtGL::paintGL()
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
draw();
}

void QtGL::draw()
{
static const GLfloat P1[3] = { 0.0, -1.0, +2.0 };
static const GLfloat P2[3] = { +1.73205081, -1.0, -1.0 };
static const GLfloat P3[3] = { -1.73205081, -1.0, -1.0 };
static const GLfloat P4[3] = { 0.0, +2.0, 0.0 };

static const GLfloat * const coords[4][3] = {
{ P1, P2, P3 }, { P1, P3, P4 }, { P1, P4, P2 }, { P2, P4, P3 }
};

glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glTranslatef(0.0, 0.0, -10.0);
glRotatef(rotationX, 1.0, 0.0, 0.0);
glRotatef(rotationY, 0.0, 1.0, 0.0);
glRotatef(rotationZ, 0.0, 0.0, 1.0);

for (int i = 0; i < 4; ++i) {
glLoadName(i);
glBegin(GL_TRIANGLES);
glwidget->qglColor(faceColors[i]);
for (int j = 0; j < 3; ++j) {
glVertex3f(coords[i][j][0], coords[i][j][1],
coords[i][j][2]);
}
glEnd();
}
}

void QtGL::mousePressEvent(QMouseEvent *event)
{
lastPos = event->pos();
}

void QtGL::mouseMoveEvent(QMouseEvent *event)
{
GLfloat dx = GLfloat(event->x() - lastPos.x()) / width();
GLfloat dy = GLfloat(event->y() - lastPos.y()) / height();
if (event->buttons() & Qt::LeftButton) {
rotationX += 180 * dy;
rotationY += 180 * dx;
glwidget->updateGL();
} else if (event->buttons() & Qt::RightButton) {
rotationX += 180 * dy;
rotationZ += 180 * dx;
glwidget->updateGL();
}
lastPos = event->pos();
}

void QtGL::mouseDoubleClickEvent(QMouseEvent *event)
{
int face = faceAtPosition(event->pos());
if (face != -1) {
QColor color = QColorDialog::getColor(faceColors[face], this);
if (color.isValid()) {
faceColors[face] = color;
glwidget->updateGL();
}
}
}

int QtGL::faceAtPosition(const QPoint &pos)
{
const int MaxSize = 512;
GLuint buffer[MaxSize];
GLint viewport[4];

glwidget->makeCurrent();

glGetIntegerv(GL_VIEWPORT, viewport);
glSelectBuffer(MaxSize, buffer);
glRenderMode(GL_SELECT);

glInitNames();
glPushName(0);

glMatrixMode(GL_PROJECTION);
glPushMatrix();
glLoadIdentity();
gluPickMatrix(GLdouble(pos.x()), GLdouble(viewport[3] - pos.y()),
5.0, 5.0, viewport);
GLfloat x = GLfloat(width()) / height();
glFrustum(-x, x, -1.0, 1.0, 4.0, 15.0);
draw();
glMatrixMode(GL_PROJECTION);
glPopMatrix();

if (!glRenderMode(GL_RENDER))
return -1;
return buffer[3];
}

[jpn]

You are supposed to subclass QGLWidget, and reimplement all those xxxGL() methods in that class, not in a QMainWindow subclass.

[bod]

So, u mean i need to write 2 ".h", and 2 ".cpp" file??

[jpn]

So, u mean i need to write 2 ".h", and 2 ".cpp" file??
If you have two classes in the end, that would be a good practice.