Time for action - creating banners facing you
The prerequisite for implementing billboards in OSG is to create one or more quad geometries first. These quads are then managed by the
osg::BillBoard class. This forces all child drawables to automatically rotate around a specified axis, or face the viewer. These can be done by presetting a unified normal value and rotating each billboard according to the normal and current rotation axis or viewing vector.
We will create two banks of OSG banners, arranged in a V, to demonstrate the use of billboards in OSG. No matter where the viewer is and how he manipulates the scene camera, the front faces of banners are facing the viewer all the time. This feature can then be used to represent textured trees and ...