Web, Graphics & Perl/Tk Programming

Chapter 27. OpenGL

Alligator Descartes

With the plethora of emerging Doom clones and dancing web logos, we tend to take three-dimensional graphics for granted. This is due in part to the surging capabilities of computers to render scenes quickly. In recent years, Silicon Graphics Incorporated (SGI) has pioneered not only hardware tuned especially for 3D graphics, but software as well, notably OpenGL, an elegant and stable graphics API. OpenGL has proven a success, with implementations for all major platforms and the resulting portability advantages for applications. Add to the mix the plummeting costs of cheap 3D graphics cards and free OpenGL-like implementations, and you have a force to be reckoned with.

Enter Perl, stage left. Portable. Compilable. Powerful. Couple it with OpenGL and you have a match made in heaven for rapid 3D development.

Back to Basics

Before we delve into the soupy, steaming innards of 3D graphics and OpenGL, we ought to explain some of the concepts needed for 3D graphics programming.

The three-dimensional space we’re used to can be navigated in any of three directions: up/down, left/right, and forward/backward. The premise of Euclidean 3D space is exactly the same, although it requires more precision than “up and left a bit,” or “a few yards backward.” Imagine being blindfolded in a large field with a tree near the middle and have a friend direct you to that tree. Difficult? Try it and see! Even the simple matter of “forward” becomes a relative concept with different ...