Shaders were first added into OpenGL in version 2.0, introducing programmability into the formerly fixed-function OpenGL pipeline. Shaders give us the power to implement custom rendering algorithms and provide us with a greater degree of flexibility in the implementation of those techniques. With shaders, we can run custom code directly on the GPU, providing us with the opportunity to leverage the high degree of parallelism available with modern GPUs.
Shaders are implemented using the OpenGL Shading Language (GLSL). GLSL is syntactically similar to C, which should make it easier for experienced OpenGL programmers to learn. Due to the nature of this text, I won't present a thorough introduction to GLSL here. Instead, if you're new to GLSL, reading through these recipes should help you to learn the language through example. If you are already comfortable with...
