OpenSceneGraph 3.0

Implementing your own drawables

There are two very important virtual methods in the osg::Drawable pure class:

• The computeBound() constant method computes the bounding box around the geometry, which will be used in the view frustum culling process to decide whether to cull the geometry or not
• The drawImplementation() constant method actually draws the geometry with OSG and OpenGL calls

To customize a user-defined drawable class, you have to re-implement these two methods and add your own drawing code at the appropriate place.

The computeBound() constant method returns an osg::BoundingBox value as the geometry's bounding box. The simplest way to create a bounding box is to set its minimum and maximum extents, both of which are three-element vectors. ...