Summary
In this chapter, we have explored the importance of normals, not only for determining the front and backfaces of a polygon but also for controlling lighting. We started by examining how a proper normal could be drawn and calculated it for each triangle face before using backface culling to investigate how both or a single side of a polygon could be drawn. Following this, we added to our project the ability to load normals calculated in a modeling package out of an OBJ file and into OpenGL. We illustrated just how important it is, in rendering, to ensure you specify the correct values instead of making certain assumptions if the output doesn’t look quite right.
As we progress through the book, we will encounter more and more uses of normals, including their use in calculating collisions, as well as creating special texturing and lighting effects. However, I am sure you are beginning to gain an appreciation of their importance.
By now, you should be comfortable with...
