8.2. Bump Mapping and DOT3 Lighting

If you’d like to render an object with fine surface detail but you don’t want to use an incredibly dense mesh of triangles, there’s a technique called bump mapping that fits the bill. It’s also called normal mapping, since it works by varying the surface normals to affect the lighting. You can use this technique to create more than mere bumps; grooves or other patterns can be etched into (or raised from) a surface. Remember, a good graphics programmer thinks like a politician and uses lies to her advantage! Normal mapping doesn’t actually affect the geometry at all. This is apparent when you look along the silhouette of a normal-mapped object; it appears flat. See Figure 8-2.