If you are writing a graphical application on Linux and want it to take advantage of GPU hardware that every computer has these days, your only option is to use OpenGL, because that is the only API exposed by the drivers. Unfortunately, using OpenGL is not without its problems.

The most acute problem is inability to run your applications remotely. X and Unix in general have a long history of allowing remote use, a very useful capability in many circumstances, but while there is an X extension (GLX) allowing OpenGL remoting, it is restricted to the ancient version 1.2 API that does not support essential capabilities such as vertex buffer objects. Furthermore, GLX is at this time being deprecated in favor of EGL, and will be replaced by it in some near future. Even worse, the entire X11 protocol is in danger of disappearing and being replaced by Wayland, which is not designed for remote use.

Another problem is the libraritis infection you get by having to link to the OpenGL shared library. No static library is available for this, so no statically linked executables can be created. The OpenGL library is huge and contains a lot of low-level tie-ins to the kernel driver guts, resulting in bloat and instability. Crashing your application may cause a kernel panic, just like in good old Windows 3.1, which likewise made the mistake of putting driver guts into user application process space. The driver initialization sequence can also be slow (~.3s), and must be done every time you start your application.

Finally, one must mention the problem of debugging an OpenGL application. If you happen to hit a breakpoint at some location unexpected by the driver developers, sometimes you would not be able to switch to the debugger because you've just trapped something critical in the driver and stopped all X rendering. Often, this situation requires a hard power cycle. After a while you give up trying the debugger at all.

Now, wouldn't it be nice if there was a network protocol letting us write applications that use OpenGL remotely, without linking to the entire graphics driver? Well, GLERI is it.