ABSTRACT
In fi xed-function OpenGL, the geometry processing in the graphics pipeline is responsible for taking the model-space geometry you defi ne, along with whatever color, lighting, materials, shading, and texture information you specify, and creating a set of vertices in clip space that have color, depth, normal, and texture associated with each. The vertex shader takes over the role of the vertex processor in Figure 6.1. The task of a vertex shader is to replace much of the fi xed-function vertex processing, and possibly to change the vertex coordinates as well.
