Software Engineering and Computer Games

9.3. Polygons

Particularly in three dimensions, we very often want to represent our critters by colored polygons, perhaps by just one polygon, perhaps by a few, or perhaps by a whole mesh of them. Computer graphics systems draw polygons in an entirely different way from how they draw bitmaps. A bitmap is based on discrete pixel-by-pixel information, while a polygon is based on coordinates in continuous space. In drawing a polygon, we convert its space coordinates into pixel coordinates, use fill algorithms to color it in, and use line-drawing algorithms to draw its edges.

Windows has a built-in CDC::Polygon(POINT * vertices, int vertexcount) method which makes it easy to rapidly draw polygons on the screen. Our cPolygon class is designed to ...