The OpenGL Utility Library (GLU) provides many of the modeling features, such as quadric surfaces and NURBS curves and surfaces. With OpenGL, you must build up your desired model from a small set of geometric primitives - points, lines, and polygons.Ī sophisticated library that provides these features could certainly be built on top of OpenGL. Such commands might allow you to specify relatively complicated shapes such as automobiles, parts of the body, airplanes, or molecules. Similarly, OpenGL doesn't provide high-level commands for describing models of three-dimensional objects. To achieve these qualities, no commands for performing windowing tasks or obtaining user input are included in OpenGL instead, you must work through whatever windowing system controls the particular hardware you're using. OpenGL is designed as a streamlined, hardware-independent interface to be implemented on many different hardware platforms.
This interface consists of about 150 distinct commands that you use to specify the objects and operations needed to produce interactive three-dimensional applications. OpenGL is a software interface to graphics hardware.
"Animation" explains in general terms how to create pictures on the screen that move."OpenGL-Related Libraries" describes sets of OpenGL-related routines, including an auxiliary library specifically written for this book to simplify programming examples."OpenGL Rendering Pipeline" shows a typical sequence of operations for processing geometric and image data."OpenGL as a State Machine" describes the use of state variables in OpenGL and the commands for querying, enabling, and disabling states."OpenGL Command Syntax" explains some of the conventions and notations used by OpenGL commands.This section also defines a few basic computer-graphics terms. "A Smidgen of OpenGL Code" presents a small OpenGL program and briefly discusses it."What Is OpenGL?" explains what OpenGL is, what it does and doesn't do, and how it works.Understand in general terms how to animate graphics in an OpenGL program.Identify the sequence of operations of the OpenGL rendering pipeline.Understand the basic structure of an OpenGL program.Identify different levels of rendering complexity.Appreciate in general terms what OpenGL does.
After reading this chapter, you'll be able to do the following:
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