Shading

Abstract

In chapter 10 we introduced the routine facetfill to produce the viewport representation of a facet. Up to now this routine has consisted of a simple area-fill using a logical colour prescribed in the data construction routines. We can do much more than this! The realism of the images we produce is greatly enhanced by the use of shading. We take advantage of the colour display of the graphics device to model the different appearances of surfaces depending on the light striking them. Plates III, XIII and IX show pictures produced using the shading techniques introduced in this chapter.