The view gets disappeared at some point

[create]

Hi all I have a problem with my view.In my application I have written a mouse move events.And with mouse move events the rotation is done.When I mouse move the view with left and right sometimes I can’t see a full view.It gradually gets disappeares .Something is happening which I am not able to understand.And anybody give a clue for my problem.This is how it looks like now.

This is how my code looks like.

OpenGLView::OpenGLView(QWidget* parent)
  : QGLWidget(QGLFormat(QGL::SampleBuffers), parent)
{
  xRot = 0;
  yRot = 0;
  zRot = 0;

}

OpenGLView::~OpenGLView()
{
}

QSize OpenGLView::minimumSizeHint() const
{
  return QSize(510, 50);
}

QSize OpenGLView::sizeHint() const
{
  return QSize(1920, 1080);
}

static void qNormalizeAngle(int& angle)
{
  while (angle < 0)
    angle += 360 * 16;
  while (angle > 360)
    angle -= 360 * 16;
}

void OpenGLView::setXRotation(int angle)
{
  qNormalizeAngle(angle);
  if (angle != xRot) {
    xRot = angle;
    emit xRotationChanged(angle);
    updateGL();
  }
}

void OpenGLView::setYRotation(int angle)
{
  qNormalizeAngle(angle);
  if (angle != yRot) {
    yRot = angle;
    emit yRotationChanged(angle);
    updateGL();
  }
}

void OpenGLView::setZRotation(int angle)
{
  qNormalizeAngle(angle);
  if (angle != zRot) {
    zRot = angle;
    emit zRotationChanged(angle);
    updateGL();
  }
}

void OpenGLView::initializeGL()
{
  qglClearColor(Qt::black);

  glEnable(GL_DEPTH_TEST);
  glEnable(GL_CULL_FACE);
  glShadeModel(GL_SMOOTH);


  static GLfloat lightPosition[4] = { 0, 0, 500, 2.0 };
  glLightfv(GL_LIGHT0, GL_POSITION, lightPosition);
}

void OpenGLView::paintGL()
{
  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  glLoadIdentity();
  glTranslatef(10.0, -60.0, -10.0);
  glRotatef(xRot / 10.0, 1.0, 0.0, 0.0);
  glRotatef(yRot / 10.0, 0.0, 1.0, 0.0);
  glRotatef(zRot / 10.0, 0.0, 0.0, 1.0);



  glEnable(GL_CULL_FACE);
  glCullFace(GL_FRONT_AND_BACK);
  glDisable(GL_CULL_FACE);
  //draw();
  draw1();
}

void OpenGLView::resizeGL(int width, int height)
{
  int side = qMin(width, height);
  glViewport(0.0f, 0.0f, width, height);
  //glViewport((width - side) / 2, (height - side) / 2, side, side);

  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();

#ifdef QT_OPENGL_ES_1

  glOrthof(-200, 200, -200, 200, 1.0, 100000.0);
#else

  glOrtho(-200, 200, -200, 200, 1.0, 100000.0);

  gluLookAt(
    2, 2, 2,
    0, 3.8, 0,
    0, 1, 0

    /*0,0, 2,
    0, 2.8, 0,
    0, 1, 0*/
  );

#endif
  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();
}


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


}

void OpenGLView::mouseMoveEvent(QMouseEvent* event)
{
  int dx = event->x() - lastPos.x();
  int dy = event->y() - lastPos.y();

  if (event->buttons() & Qt::LeftButton) {
    setXRotation(xRot + 8 * dy);
    setYRotation(yRot + 8 * dx);
  }
  else if (event->buttons() & Qt::RightButton) {
    setXRotation(xRot + 8 * dy);
    setZRotation(zRot + 8 * dx);
  }

  lastPos = event->pos();

  event->accept();
}

void OpenGLView::wheelEvent(QWheelEvent* event)
{
  if (event->delta() > 0) {
    zoomIn();
  }
  else {
    zoomOut();
  }
}

void OpenGLView::zoomIn()
{
  m_zoom *= 1.1;
  updateProjection();
}

void OpenGLView::zoomOut()
{
  m_zoom /= 1.1;
  updateProjection();
}

void OpenGLView::updateProjection()
{
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();

  glOrtho(-200 / m_zoom, 200 / m_zoom,
    -200 / m_zoom, 200 / m_zoom,
    1.0, 100000.0);

  glMatrixMode(GL_MODELVIEW);
  updateGL();
}

can Anybody please help me with this issue.Thank you in advance.