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>
Previously, box style selection is rendered using customized
SoBoxSelectionRenderAction, which does not support selection context,
i.e. it does not work with Link.
This patch implements context aware bound box rendering inside
SoFCSelectionRoot, SoFCSelection and SoFCPathAnnotation (for always on
top rendering). The box rendering in SoBoxSelectionRenderAction is
disabled on construction. Box style selection can be enabled for
individual object through property SelectionStyle (moved from
ViewProviderGeometryObject to ViewProviderDocumentObject), or globally
through Parameter BaseApp/Preferences/View/ShowSelectionBoundingBox.
In addition, the parameter BaseApp/Preferences/View/UseNewSelection is
used to override selection model reported from
ViewProvider::useNewSelectionModel(). The reason being that, the same
parameter is already used to toggle selection model inside
SoFCSelection. This avoids inconsistency of selection model choice
between view provider and the SoFCSelection node inside. Note that if
the parameter 'UseNewSelection' is set to false, those view providers
that choose old selection model will not work with Link.
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.
