As you have seen from Chapter 1, “Introduction to OpenGL ES 2.0,” Chapter 2, “Hello, Triangle: An OpenGL ES 2.0 Example,” and Chapter 4, “Shaders and Programs,” shaders are a fundamental concept that is at the heart of the OpenGL ES 2.0 API. Every OpenGL ES 2.0 program requires both a vertex and fragment shader to render a meaningful picture. Given the centrality of the concept of shaders to the API, we want to make sure you are grounded in the fundamentals of writing shaders before diving into more details of the graphics API.
Our goal in this chapter is to make sure you understand the following concepts in the shading language:
Variables and variable types
Vector and matrix construction and selection