Chapter 7
Display Lists

Chapter Objectives

After reading this chapter, you'll be able to do the following:

• Understand how display lists can be used along with commands in immediate mode to organize your data and improve performance
• Maximize performance by knowing how and when to use display lists

A display list is a group of OpenGL commands that have been stored for later execution. When a display list is invoked, the commands in it are executed in the order in which they were issued. Most OpenGL commands can be either stored in a display list or issued in immediate mode, which causes them to be executed immediately. You can freely mix immediate-mode programming and display lists within a single program. The programming examples you've seen so far have used immediate mode. This chapter discusses what display lists are and how best to use them. It has the following major sections:

• "Why Use Display Lists?" explains when to use display lists.
• "An Example of Using a Display List" gives a brief example, showing the basic commands for using display lists.
• "Display-List Design Philosophy" explains why certain design choices were made (such as making display lists uneditable) and what performance optimizations you might expect to see when using display lists.
• "Creating and Executing a Display List" discusses in detail the commands for creating, executing, and deleting display lists.
• "Executing Multiple Display Lists" shows how to execute several display lists in succession, using a small character set as an example.
• "Managing State Variables with Display Lists" illustrates how to use display lists to save and restore OpenGL commands that set state variables.