Qt uploading texture thread - multithreading

Question

I am using a QGLWidget for displaying a live Image Stream. Since uploading textures is an expensive operation I would like to avoid doing this on the GUI Thread. I have read here http://blog.qt.digia.com/blog/2011/06/03/threaded-opengl-in-4-8/ that it is possible to do this in from a different thread. Could anyone provide a short example how to do so? I am uncertain how to share the GL Context and how to make sure that there is no race condition.
This is what i currently have:
.h:
class ImageDisplay : public QGLWidget
{
Q_OBJECT
public:
ImageDisplay(QWidget* parent = 0);
void paintGL();
void resizeGL(int w, int h);
private:
QRectF plane;
GLuint texID;
public slots:
void sl_update(spImageHolder_t _myImageShPtr);
};
.cpp:
ImageDisplay::ImageDisplay(QWidget *parent)
: QGLWidget(parent)
, plane(QPointF(0,1),QSizeF(1,1))
{
QImage initImg(400,300,QImage::Format_Indexed8);
resize(initImg.size());
makeCurrent();
texID = bindTexture ( initImg, GL_TEXTURE_2D, GL_LUMINANCE, QGLContext::NoBindOption );
}
void ImageDisplay::paintGL()
{
makeCurrent();
drawTexture ( plane, texID, GL_TEXTURE_2D );
}
void ImageDisplay::resizeGL(int w, int h)
{
glViewport (0, 0, w, h);
glMatrixMode (GL_PROJECTION);
glLoadIdentity();
glOrtho(0, 1,0,1,-1,1);
glMatrixMode (GL_MODELVIEW);
}
void ImageDisplay::sl_update(spImageHolder_t _myImageShPtr) //slot
{
QImage * imgPtr = _myImageShPtr->getImagePtr();
if (NULLPTR != imgPtr)
{
deleteTexture(texID);
texID = bindTexture( *imgPtr, GL_TEXTURE_2D, GL_LUMINANCE, QGLContext::NoBindOption );
}
updateGL();
}