OpenGL 4 Shading Language Cookbook - Third Edition

There's more...

Diffuse shading is a technique that models only a very limited range of surfaces. It is best used for surfaces that have a matte appearance. Additionally, with the technique used previously, the dark areas may look a bit too dark. In fact, those areas that are not directly illuminated are completely black. In real scenes, there is typically some light that has been reflected about the room that brightens these surfaces. In the following recipes, we'll look at ways to model more surface types, as well as providing some light for those dark parts of the surface.