“OpenGL is the premier environment for developing portable, interactive 2D and 3D graphics applications. Since its introduction in 1992, OpenGL has become the industry’s most widely used and supported 2D and 3D graphics application programming interface (API), bringing thousands of applications to a wide variety of computer platforms. OpenGL fosters innovation and speeds application development by incorporating a broad set of rendering, texture mapping, special effects, and other powerful visualization functions. Developers can leverage the power of OpenGL across all popular desktop and workstation platforms, ensuring wide application deployment.” – OpenGL.org
The 2 most commonly used graphics APIs are OpenGL and Microsoft’s DirectX.
A great advantage of OpenGL is that it is platform independent, allowing your applications to be developed for Windows, Linux, Mac OS and other operating systems.
Porting a graphics program requires only that you install the appropriate OpenGL libraries on the new machine. The application itself requires no change: it calls the same functions in this library with the same parameters, and the same graphical results are produced.
OpenGL is often called an « application programming interface »(API). The interface is a collection of routines that the programmer can call, along with a model of how the routines work together to produce graphics. The programmer sees only the interface, and is therefore shielded from having to cope with the specific hardware work in a somewhat restricted fashion.
Many modern graphics systems are windows-based and manage the display of multiple overlapping windows. Using OpenGL the user can move the windows around the screen using the mouse and can resize them.
Another property of most windows-based programs is that they are event driven. This means that the program responds to various events, such as mouse click, the press of a keyboard key, or the resizing of the screen window.
The three main OpenGL libraries of interst are:
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Basic GL : The fundamental OpenGL library. It provides functions that are a permanent part of OpenGL. Each OpenGL function starts with the characters «GL ».
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GLUT: the GL Utility Toolkit, is in connection with opening windows, developing and managing menus, and managing events.
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GLU: the GL Utility Library, which provides high-level routines to handle certain matrix operations, the drawing of quadratic surfaces such as spheres and cylinders. GLU also assists in the decomposition of nonconvex and nonsimple polygons into simple shapes such as triangles.
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GLUI: the User Interface Library, as long as GLUT is available, GLUI will operate properly.The GLUI provides programmers with the ability to add sophisticated controls and menus to their OpenGL applications.
