OpenGL – Build high performance graphics

Using functions in shaders

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 ADS shader using functions to help provide abstractions for the major steps.

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 ADS coefficients should be set from the OpenGL side, as well as the light position and the standard matrices.

How to do it...

To implement ADS shading using functions, use the following code:

1. Use the following vertex shader:

   layout (location = 0) in vec3 VertexPosition; layout (location = 1) in vec3 VertexNormal; ...