Drawables

Drawables define things which draw pixels on the screen as if rendering a real 3D objetc. Usually Drawables contain PrimitiveSets which contain polygons. These are known as osg::Geometry - this is the main interest of this note.

Drawables can also be stand alone:

  Shape Drawable - simple shapes, box, sphere etc.
  Impostor Sprite
  Particle System
  osgText

or you can derive your own class from drawable.

If the drawable is a geometry it will refer to arrays of:

  vertices
  texture coordinates (up to 8 textures on each polygon)
  normals (for lighting)
  possibly vertex indices
and

  PrimitiveSets. 

These last are among the most complex of osg classes as they can be defined in a large number of ways.