coordinate space. For example, for a map shape that is planar, we take the (x,y,z)
value from the object and throw away (project) one of the components, which
leaves us with its two-dimensional (planar) coordinates. We normalize the
coordinates by the maximum extents of the object to attain coordinate values
between 0 and 1. This value is then used as the (s,t) value into the texture map.
Figure 6.30 shows such a mapping. Let us see how to specify texture maps in our
openGL environment. First, we need to specify a texture. The OpenGL command
to specify a two-dimensional image as a texture isexture