A SoNode* is not necessarily a SoFCSelectionRoot*, and when this
assumption breaks the code causes UB (the comment related to one of the
chunks explicitly says that it is safe, but unfortunately it is not).
Instead of storing `SoFCSelectionRoot*` and blindly cast a generic
`SoNode*` to that, we can do the opposite. In this way it is obviously
necessary to use a dynamic cast when trying to reach for
`SoFCSelectionRoot` specific features, but in this way the abstraction
should be sound.
Co-authored-by: Chris Hennes <chennes@pioneerlibrarysystem.org>
The patch implements context-aware selection and rendering in 3D view.
Please check [here](https://git.io/fjiY5) for more details, including
the following 'Render Caching' section.
The patch also includes modification of View3DInventorViewer to support
always-on-top selection rendering using the secondary selection context
and the new coin node SoFCPathAnnotation.
Another small change in SoQtQuarterAdaptor for more responsive frame
rate display. The original implementation reports skewed frame rate
in the presence of long idle period.
