This revision of the guide documents the following features of OpenGL Performer 2.5:
Image-Based rendering to replace a complex object with pre-rendered images of the object as seen from different angles
Real-Time shadows to project an object's true shadow upon any and all other objects in the scene
Light shafts with cone attenuation and spot illumination of objects in the scene
Cull programs to optimize and combine multi-pass rendering effects by selection of the OpenGL Performer draw bin based on user-defined attributes