minor, replace pure getter get_vertex() by unaltering routines

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
Merge branch 'core/rotz' into next

* core/rotz:
  minor, replace pure getter get_vertex() by unaltering routines
Merge branch 'next'

* next:
  minor, replace pure getter get_vertex() by unaltering routines