various tutorials on cl-opengl and related topics

Unless otherwise specified, I'm generally assuming gl2.1 for most of these. Some options or functions might not exist in earlier versions, or might only be available as extensions.

• getting started
• textures
• textures part 2
• textures part 3
• textures part 4
• 2d sprites
• 2d sprites part 2
• 2d sprites part 3