Texture mapping provides an important link between geometry and images by effectively applying an image to geometry. OpenGL makes this coupling explicit by providing the same formats for specifying texture images as for images destined for the framebuffer.
Besides being useful for adding realism to a scene (Figure 3a), texture mapping can be used to achieve a number of other useful effects[4]. Figures 3b and 3c show two examples in which the texture coordinates that index a texture image are generated from vertex coordinates. OpenGL's orthogonality makes achieving such effects with texture mapping simply a matter of enabling the appropriate modes and loading the appropriate texture image, without affecting the underlying specification of the scene.
