Chapter 1
Introduction to OpenGL

Chapter Objectives

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

• Appreciate in general terms what OpenGL does
• Identify different levels of rendering complexity
• Understand the basic structure of an OpenGL program
• Recognize OpenGL command syntax
• Identify the sequence of operations of the OpenGL rendering pipeline
• Understand in general terms how to animate graphics in an OpenGL program

This chapter introduces OpenGL. It has the following major sections:

• "What Is OpenGL?" explains what OpenGL is, what it does and doesn't do, and how it works.
• "A Smidgen of OpenGL Code" presents a small OpenGL program and briefly discusses it. This section also defines a few basic computer-graphics terms.
• "OpenGL Command Syntax" explains some of the conventions and notations used by OpenGL commands.
• "OpenGL as a State Machine" describes the use of state variables in OpenGL and the commands for querying, enabling, and disabling states.
• "OpenGL Rendering Pipeline" shows a typical sequence of operations for processing geometric and image data.
• "OpenGL-Related Libraries" describes sets of OpenGL-related routines, including an auxiliary library specifically written for this book to simplify programming examples.
• "Animation" explains in general terms how to create pictures on the screen that move.