It's a big ball of wax with more details than I'll ever memorize, but I know for a fact that for the last 20 years or more X11 GLX has had "indirect contexts" w

It's a big ball of wax with more details than I'll ever memorize, but I know for a fact that for the last 20 years or more X11 GLX has had "indirect contexts" where the application feeds the OpenGL requests over the display socket and the server renders them (possibly) hardware-accelerated. "direct rendering" is where the X11 client negotiates with the X server to make a direct connection from the application to /dev/whatever to talk directly to the kernel driver of the graphics card to do rendering that bypasses the X server. The whole thing with Wayland is just a new generation of coders saying "hey all this pile of new apis on top of old apis on top of older apis spanning back 40 years designed for hardware that no longer exists is insane. We need to start over." They aren't wrong, but they also haven't reached feature parity with the old stuff yet, because doing hardware accelerated 3D graphics over a pipe to a remote host was a pretty amazing feat of technology. Edit: to be a little more specific, Silicon Graphics company's whole business was accelerated graphics, and they were in business since 1982, and invented most of X11, or at least its extensions.