module Node_visitor:Visitor for type safe operations onsig
..end
Osg.Node
s.
Based on GOF's Visitor pattern.
The Osg.Node_visitor
is useful for developing type safe operations to nodes
in the scene graph (as per Visitor pattern), and adds to this
support for optional scene graph traversal to allow
operations to be applied to whole scenes at once. The Visitor
pattern uses a technique of double dispatch as a mechanism to
call the appropriate apply
method of the Osg.Node_visitor
. To
use this feature one must use the Osg.Node.accept
which
is extended in each Osg.Node
subclass, rather than the Osg.Node_visitor
apply directly. So use Node.accept root my_visitor
instead of
Node_visitor.apply apply root
. The later method will bypass the double
dispatch and the appropriate Node_visitor.apply
method will
not be called.
type
t