Introduction to Computer Graphics - David J. Eck

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The term “computer graphics” refers to anything involved in the creation or manipulation of images on computer, including animated images. It is a very broad field, and one in which changes and advances seem to come at a dizzying pace. It can be difficult for a beginner to know where to start. However, there is a core of fundamental ideas that are part of the foundation of most applications of computer graphics. This book attempts to cover those foundational ideas, or at least as many of them as will fit into a one-semester college-level course.

While it is not possible to cover the entire field in a first course—or even a large part of it—this should be a good place to start.

T he main focus of this book is three-dimensional (3D) graphics, where most of the work goes into producing a 3D model of a scene. But ultimately, in almost all cases, the end result of a computer graphics project is a two-dimensional image. And of course, the direct production and manipulation of 2D images is an important topic in its own right. Furthermore, a lot of ideas carry over from two dimensions to three. So, it makes sense to start with graphics in 2D. An image that is presented on the computer screen is made up of pixels. The screen consists of a rectangular grid of pixels, arranged in rows and columns.

The pixels are small enough that they are not easy to see individually. In fact, for many very high resolution displays, they become essentially invisible. At a given time, each pixel can show only one color. Most screens these days use 24-bit color, where a color can be specified by three 8-bit numbers, giving the levels of red, green, and blue in the color. Any color that can be shown on the screen is made up of some combination of these three “primary” colors. Other formats are possible, such as grayscale, where each pixel is some shade of gray and the pixel color is given by one number that specifies the level of gray on a black-to-white scale. Typically, 256 shades of gray are used. Early computer screens used indexed color , where only a small set of colors, usually 16 or 256, could be displayed. For an indexed color display, there is a numbered list of possible colors, and the color of a pixel is specified by an integer giving the position of the color in the list.