The functioning of a standard graphics system is typically described by an abstraction called the graphics pipeline. The term “pipeline” is used because the transformation from mathematical model to pixels on the screen involves multiple steps, and in a typical architecture, these are performed in sequence; the results of one stage are pushed on to the next stage so that the first stage can begin processing the next polygon immediately
Texture Mapping and Approximation
One standard component of the black box is the texture map. With texture mapping, we take a polygon (or a collection of polygons) and assign a color to each point via a lookup in a texture image; the technique is a little like applying a stencil to a surface or gluing a decal onto an object. You can think of the texture image, which can be a piece of artwork scanned into the system, a photo taken with a digital camera, or an image created in a paint program, for instance, as a rubber sheet with a picture on it. The texture coordinates describe how this sheet is stretched and deformed to cover some part of the object.