
opengl.org
http://opengl.org/sdk/docs/
OpenGL SDK
OpenGL 4.1 Reference Card OpenGL 4.0 Reference Card OpenGL 3.2 Reference Card The OpenGL Registry, hosted outside of the SDK, contains the formal Specifications for OpenGL and the OpenGL Shading Language, as well as for companion APIs like GLX and GLU. Specifications are the authoritative documents about how OpenGL is intended to work.