The operation does not make sense at the "fundamental" level
for these classes (algebraic, in this case), so it shouldn't exist.
It's also a semantic trap:
* it interprets a _vector_ as a _point_ instead (the vector gets
1-extended in 4D)
* after the multiplication, it gets perspective divided.
These semantics do not belong to operator*.
operator*(QVector3D/QPoint(F), QMatrix) will be tackled in a next commit;
we don't have a straightforward replacement for it.
Drive-by, document that map() interprets vectors as points.
[ChangeLog][QtGui][QMatrix4x4] operator* between a QMatrix4x4 and a
QVector3D, QPoint, or QPointF has been deprecated in favor of map()
and mapVector().
Pick-to: 6.1
Task-number: QTBUG-89708
Change-Id: Iad78d6eb68cc8cdc3ac16b1635c4d3b522c95213
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
6862ce3d77