Bump Mapping
A texture-mapping alternative which can make an objects surface [see page 24, appear] bumpy.
We store a gray-scale texture ([see page 26, intensity-map]) to indicate where the bumps should appear on the surface. We calculate the vertex normal for the bumps and the actual object and then combine them. This changes the intensity of light on the object producing a bumpy affect.
Note: This approach [see page 28, doesn't alter] the surface, all it does is change the normals causing the visual affect of bumps. This means the silhouette of the object remains unchanged.
This approach often [see page 26, uses] a TBN-space at each relevant surface point.