QGLViewer::saveSnapshot() produces tiled images if oversampling is larger than 1.0

[jarvis170142-bit]

I use libQGLViewer 3.0.0, Qt6.10 and MinGW compiler (Windows 11).

I added a simple call to saveSnapshot(false, true) to the simpleviewer example :

`void Viewer::keyPressEvent(QKeyEvent* e)
{

if (e->key() == Qt::Key_Space)
{
    this->setSnapshotFormat(QString("PNG"));
    this->setSnapshotQuality(100);
    this->saveSnapshot(false, true);
}

}`

... and when an oversampling factor greater than 1.0 is selected, the resulting image appears tiled, as if the calls to glFrustum() in the private method saveImageSnapshot(..) had no effect.

Also : compilation of examples needs ocurrences of -lQGLViewer2 to be replaced by -lQGLViewer3 in examples.pri since QGLViewer produces libQGLViewer3.dll