Date: 26 Oct 93 00:00:01 EST

  GL calls can only be made from a process that has a GL context.  In
  multi-process Performer applications only the draw process has GL
  context, so you must make your GL calls in a function called in the
  draw process.

  The pipe initialization callback, draw function callback, and node
  draw callbacks are all executed in the draw process.

  In an application that only will ever run single-process, GL calls
  can be made from anywhere in the program, but this is considered a
  dangerous practice.

  To set up a pipe initialization callback, see the pfInitPipe()
  manpage.  To set up a draw function callback, see the
  pfChanDrawFunc() manpage.  To set up a node draw callback, see the
  pfNodeTravFuncs() manpage.