We’ll now pick up where we left off end of the last chapter. The last chapter set the foundations of OpenGL 4.3. In this we’ll study more advanced features, as well as the two optional shader stages, particularly, tessellation and geometry.
We begin in Section 21.1 by trying to reconstitute the pre-shader toolbox of Chapter 3. In the process we’ll find that even though a few of the older gadgets have been discarded from 4.3, new ones have been added and, in fact, the programmable pipeline often affords a more efficient way to do what an old gadget used to.
Section 21.2 introduces shader subroutines, which offer an elegant method of switching threads of control at run-time. ...