mutter-performance-source/doc/compositor-control.txt

The compositor is the box of tricks inside the window manager which performs
special effects on the windows on your screen. Metacity's compositor is
under development. Your help is requested in finding and fixing bugs. This
document tells you how to configure Metacity so that you can use compositing.

To turn the compositor on initially, you need to pass --enable-compositor to
the configure script. This will introduce a dependence on libcm, which you
can get from <URL:http://ftp.gnome.org/pub/GNOME/sources/libcm/>.

When Metacity is compiled, you will need to turn the compositor on in gconf
for it to have any effect. You will find the boolean switch at

   /apps/metacity/general/compositing_manager

When that's done, you can set some environment variables before you launch
Metacity to influence how the compositor works. These will eventually become
configuration options or gconf options when they grow up. Define them to any
value to turn them on; leave them undefined to turn them off. Currently the
options you can set are:

   LIBCM_DIRECT

      If this is set, the compositor will bypass the X server and do all its
      work directly with the hardware. I know of no reason you would want to
      do so, but perhaps you do.

   LIBCM_TFP

      If this is set ("tfp mode"), the compositor will feel free to use the
      texture_from_pixmap extension; if this is not set ("non-tfp mode"), the
      compositor will use a workaround. Many drivers require non-tfp mode in
      order to work, and will paint all windows clear blue or clear white
      without it. Thanks to Travis Watkins for suggesting this switch; he
      cautions that some games or video players may require tfp mode.

   METACITY_BLING

      This turns on several pretty but non-essential animations (dialogues
      fracturing and exploding, minimisations doing a shrinkydink effect,
      and so on). If it is not set, the standard non-GL animations are
      retained. This affects only window event animations; it doesn't change
      menus zooming, dialogues being semi-transparent, and so on. Try it
      and see whether you like it.

If you have any problems, ask on mutter-devel-list@gnome.org, or
#gnome-hackers on gimpnet, or come and find me (tthurman at gnome) and ask.