undergo the same final steps (rasterization and per-fragment operations) before the final pixel data is written into the framebuffer. 
Per-Vertex 

Vertex                           Operations and 

Data                             Primi                      Per- 
Ass                        Fragment 
Operations 

Pixel 

Data 
--------------------------- 

Figure 1-2    Order of Operations 

Now you'll see more detail about the key stages in the OpenGL rendering pipeline. 

Display Lists 

All data, whether it describes geometry or pixels, can be saved in a display list for current or later use. (The alternative to retaining data in a display list is processing the data irnmediately-also known as immediate mode.) W en a display list is executed, the retained data is sent from the display list just as if it were sent by the application in immediate mode. (See Chapter 7, 
'Display Lists,' for more information about display lists.) 
Evaluators 
All geometric primitives are eventually described by vertices. Parametric curves and surfaces may be initially described by control points and polynomial functions called basis functions. Evaluators provide a method to derive the vertices used to represent the surface from the control points. The method is a polynomial mapping, which can produce surface normal, texture coordinates, colors, and spatial coordinate values from the control points. (See Chapter 12, 'Evaluators and NURBS," to learn more about evaluators.)