The GLSL supports functions that are syntactically similar to C functions. However, the calling conventions are somewhat different. In the following example, we'll revisit the Phong shader using functions to help provide abstractions for the major steps.
Using functions in shaders
Getting ready
As with previous recipes, provide the vertex position at attribute location 0 and the vertex normal at attribute location 1. Uniform variables for all of the Phong coefficients should be set from the OpenGL side, as well as the light position and the standard matrices.
