GL: 3-D Graphics

The sgl libraries provide access to the rendering functions of OpenGL 1.5 and GLU 1.3 libraries. The sgl libraries to not address system-level concerns, such as the attachment of GL rendering contexts to displays. Instead, the libraries should work with any PLT Scheme extension that provides GL with access to the system (such as a binding for glx). Notably, the scheme/gui/base library provides support for rendering contexts via the canvas% class and its with-gl-context method.