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Computer graphics

Computer graphics (CG) is the field of visual computing, where one utilizes computers both to generate visual images synthetically and to integrate or alter visual and spatial information sampled from the real world.

The first major advance in computer graphics was the development of the Sketchpad in 1962 by Ivan Sutherland.

This field can be divided into several areas: real-time 3D rendering (often used in video games), video capture and video creation rendering, special effects editing (often used for movies and television), image editing, and modeling (often used for engineering and medical purposes). Development in computer graphics was first fueled by academic interests and government sponsorship. However, as real-world applications of computer graphics (CG) in broadcast television and movies proved a viable alternative to more traditional special effects and animation techniques, commercial parties have increasingly funded advances in the field.

It is often thought that the first feature film to use computer graphics was 2001: A Space Odyssey, which attempted to show how computers would be much more graphical in the future. However, all the "computer graphic" effects in that film were hand-drawn animation, and the special effects sequences were produced entirely with conventional optical and model effects.

Perhaps the first use of computer graphics specifically to illustrate computer graphics was in Futureworld (1976), which included an animation of a human face and hand - produced by Ed Catmull and Fred Parke at the University of Utah.


Computer Graphics, 2D

The first advance in computer graphics was in the use of CRTs. See 2D computer graphics. There are two approaches to 2D graphics: vector and raster graphics. In short, vector images are stored as colored lines and figures or other shapes. Rasterized images, on the other hand, are stored as points of color or regions of one color that blend into another color. While both of these explanations simplify greatly on the complicated encoding algorithms used to generate modern graphics files, they highlight the fundamental difference between some formats.

Computer Graphics, 3D

With the birth of the workstation computers (like LISP machines, paintbox computers and Silicon Graphics workstations) came the 3D computer graphics, based on vector or "wire-frame" representations of virtual objects.

Some major advances in 3D computer graphics since then have been:

  • Flat shading: A technique that shades each polygon of an object based on the polygon's "normal" and the position and intensity of a light source.
  • Gouraud shading: Invented by Henri Gouraud in 1971, a fast and resource-conscious technique used to simulate smoothly shaded surfaces by interpolating vertex colors across a polygon's surface.
  • Texture mapping: A technique for simulating surface detail by mapping images (textures) onto polygons.
  • Phong shading: Invented by Bui Tuong Phong , a smooth shading technique that approximates curved-surface lighting by interpolating the vertex normals of a polygon across the surface; the lighting model includes glossy reflection with a controlable level of gloss.
  • Bump mapping: Invented by Jim Blinn , a normal-perturbation technique used to simulate bumpy or wrinkled surfaces.
  • Ray Tracing: A method based on the physical principles of geometric optics that can simulate multiple reflections and transparency.
  • Radiosity: a technique for global illumination that uses radiative transfer theory to simulate indirect (reflected) illumination.

Related topics

Several important topics in 2D and 3D graphics include:

Toolkits and APIs

For an application relying heavily on computer graphics, the following could be useful:

See also

External link

Last updated: 12-22-2004 06:02:35