Introduction

In Chapter 1, Getting Started with GLSL, we covered the basics of compiling, linking, and exporting shader programs. In this chapter, we'll cover techniques for communication between shader programs and the host OpenGL program. To be more specific, we'll focus primarily on input. The input to shader programs is generally accomplished via attributes and uniform variables. In this chapter, we'll see several examples of the use of these types of variables. We'll also cover a recipe for mixing and matching shader program stages, and a recipe for creating a C++ shader program object.

We won't cover shader output in this chapter. Obviously, shader programs send their output to the default framebuffer, but there are several other techniques for receiving shader output. For example, the use of custom framebuffer objects allow us to store shader output to a texture or other buffer. A technique called transform feedback allows for the storage of vertex shader output into arbitrary buffers...