In the last chapter, we saw our first example of using a texture to store non-color data. In this chapter we’re going to expand on that idea, except rather than store information about our mesh surface’s shininess, we’re going to store information about bumpiness. We’ll do this with a special texture that stores normal vectors instead of colors. Until now, all our normal vectors have come directly from the geometry of our mesh. However, vertex normals can only provide information about the overall shape of a mesh face. If we want to render smaller details, like bumps or scratches, we need another source of normal data. This is much easier to explain visually, so Figure 10-1 has a close-up shot of the center of our shield mesh with vertex normal drawn as white lines.