<s>
Xgl	B-Application
is	O
an	O
obsolete	O
display	O
server	O
implementation	O
supporting	O
the	O
X	B-Operating_System
Window	I-Operating_System
System	I-Operating_System
protocol	O
designed	O
to	O
take	O
advantage	O
of	O
modern	O
graphics	O
cards	O
via	O
their	O
OpenGL	B-Application
drivers	O
,	O
layered	O
on	O
top	O
of	O
OpenGL	B-Application
.	O
</s>
<s>
It	O
supports	O
hardware	B-General_Concept
acceleration	I-General_Concept
of	O
all	O
X	B-Operating_System
,	O
OpenGL	B-Application
and	O
XVideo	B-Protocol
applications	O
and	O
graphical	O
effects	O
by	O
a	O
compositing	B-Operating_System
window	I-Operating_System
manager	I-Operating_System
such	O
as	O
Compiz	B-Language
or	O
Beryl	B-Language
.	O
</s>
<s>
The	O
project	O
was	O
started	O
by	O
David	B-Language
Reveman	I-Language
of	O
Novell	O
and	O
first	O
released	O
on	O
January	O
2	O
,	O
2006	O
.	O
</s>
<s>
It	O
was	O
removed	O
from	O
the	O
X.org	O
server	O
in	O
favor	O
of	O
AIGLX	B-Application
on	O
June	O
12	O
,	O
2008	O
.	O
</s>
<s>
Development	O
of	O
Xgl	B-Application
started	O
in	O
2004	O
.	O
</s>
<s>
Until	O
its	O
release	O
in	O
2006	O
it	O
was	O
developed	O
in	O
the	O
open	O
on	O
public	O
mailing	O
lists	O
,	O
though	O
during	O
the	O
last	O
few	O
months	O
development	O
of	O
Xgl	B-Application
was	O
private	O
.	O
</s>
<s>
On	O
that	O
day	O
the	O
source	O
to	O
Xgl	B-Application
was	O
re-opened	O
to	O
the	O
public	O
,	O
and	O
included	O
in	O
freedesktop.org,	O
along	O
with	O
major	O
restructuring	O
to	O
allow	O
a	O
wider	O
range	O
of	O
supported	O
display	O
drivers	O
.	O
</s>
<s>
X	B-Protocol
server	I-Protocol
backends	O
used	O
by	O
Xgl	B-Application
include	O
Xglx	B-Application
and	O
Xegl	B-Application
.	O
</s>
<s>
In	O
February	O
2006	O
the	O
server	O
gained	O
wide	O
publicity	O
after	O
a	O
public	O
display	O
where	O
the	O
Novell	O
desktop	O
team	O
demonstrated	O
a	O
desktop	O
using	O
Xgl	B-Application
with	O
several	O
visual	O
effects	O
such	O
as	O
translucent	O
windows	O
and	O
a	O
rotating	O
3D	O
desktop	O
.	O
</s>
<s>
As	O
a	O
solution	O
David	B-Language
Reveman	I-Language
developed	O
Compiz	B-Language
,	O
the	O
first	O
proper	O
OpenGL	B-Application
compositing	B-Operating_System
window	I-Operating_System
manager	I-Operating_System
for	O
the	O
X	B-Operating_System
Window	I-Operating_System
System	I-Operating_System
.	O
</s>
<s>
Later	O
,	O
in	O
September	O
2006	O
,	O
the	O
Beryl	B-Language
compositing	B-Operating_System
window	I-Operating_System
manager	I-Operating_System
was	O
released	O
as	O
a	O
fork	O
of	O
the	O
original	O
Compiz	B-Language
.	O
</s>
<s>
Compiz	B-Language
and	O
Beryl	B-Language
have	O
merged	O
back	O
in	O
April	O
2007	O
,	O
which	O
resulted	O
in	O
the	O
development	O
of	O
Compiz	B-Language
Fusion	I-Language
.	O
</s>
<s>
OpenGL	B-Application
does	O
not	O
specify	O
how	O
to	O
initialize	O
a	O
display	O
and	O
manipulate	O
drawing	O
contexts	O
.	O
</s>
<s>
Xglx	B-Application
was	O
the	O
first	O
backend	O
implemented	O
for	O
this	O
architecture	O
.	O
</s>
<s>
It	O
requires	O
an	O
already	O
existing	O
X	B-Protocol
server	I-Protocol
to	O
run	O
on	O
top	O
of	O
and	O
uses	O
GLX	B-Device
to	O
create	O
an	O
OpenGL	B-Application
window	O
which	O
Xgl	B-Application
then	O
uses	O
,	O
similar	O
to	O
Xnest	O
.	O
</s>
<s>
This	O
mode	O
is	O
only	O
intended	O
to	O
be	O
used	O
for	O
development	O
in	O
the	O
future	O
,	O
as	O
it	O
is	O
redundant	O
to	O
require	O
an	O
X	B-Protocol
server	I-Protocol
to	O
run	O
Xgl	B-Application
on	O
top	O
of	O
.	O
</s>
<s>
At	O
XDevConf	O
2006	O
(	O
the	O
2006	O
X	B-Operating_System
development	O
conference	O
)	O
,	O
NVIDIA	O
made	O
a	O
presentation	O
arguing	O
that	O
this	O
is	O
the	O
wrong	O
direction	O
to	O
take	O
because	O
the	O
layered	O
server	O
abstracts	O
features	O
of	O
the	O
cards	O
away	O
.	O
</s>
<s>
However	O
,	O
delegating	O
initialization	O
to	O
an	O
existing	O
X	B-Protocol
server	I-Protocol
allows	O
the	O
developers	O
to	O
immediately	O
focus	O
on	O
server	O
functionality	O
rather	O
than	O
dedicating	O
substantial	O
time	O
to	O
specifics	O
of	O
interfacing	O
with	O
numerous	O
video	O
hardware	O
.	O
</s>
<s>
At	O
the	O
moment	O
,	O
Xglx	B-Application
does	O
not	O
officially	O
support	O
multiple	O
monitors	O
,	O
although	O
it	O
has	O
been	O
achieved	O
on	O
Ubuntu	B-Operating_System
Dapper	O
/	O
ATI	O
/	O
NVIDIA	O
(	O
twinview	O
)	O
.	O
</s>
<s>
Xegl	B-Application
was	O
a	O
long-term	O
goal	O
of	O
X	B-Protocol
server	I-Protocol
development	O
.	O
</s>
<s>
It	O
shares	O
much	O
of	O
the	O
drawing	O
code	O
with	O
the	O
Xglx	B-Application
server	O
,	O
but	O
the	O
initialization	O
of	O
the	O
OpenGL	B-Application
drawable	O
and	O
context	O
management	O
is	O
handled	O
by	O
the	O
EGL	O
API	O
developed	O
by	O
Khronos	O
(	O
EGL	O
is	O
a	O
window	O
system-independent	O
equivalent	O
to	O
the	O
GLX	B-Device
and	O
WGL	O
APIs	O
,	O
which	O
respectively	O
enable	O
OpenGL	B-Application
support	O
in	O
X	B-Operating_System
and	O
Microsoft	O
Windows	O
)	O
.	O
</s>
<s>
The	O
current	O
implementation	O
uses	O
Mesa-solo	B-Application
to	O
provide	O
OpenGL	B-Application
rendering	O
directly	O
to	O
the	O
Linux	B-Language
framebuffer	I-Language
or	O
DRI	B-Application
to	O
the	O
graphics	O
hardware	O
.	O
</s>
<s>
Xegl	B-Application
can	O
only	O
be	O
run	O
using	O
Radeon	B-Device
R200	I-Device
graphics	O
hardware	O
and	O
development	O
is	O
currently	O
stalled	O
.	O
</s>
<s>
It	O
is	O
likely	O
that	O
it	O
will	O
remain	O
so	O
until	O
the	O
Xglx	B-Application
server	O
has	O
proven	O
itself	O
and	O
the	O
closed	O
source	O
drivers	O
add	O
support	O
for	O
the	O
EGL	O
API	O
,	O
when	O
it	O
should	O
be	O
a	O
transparent	O
replacement	O
for	O
the	O
nested	O
Xglx	B-Application
server	O
.	O
</s>
<s>
Structuring	O
all	O
rendering	O
on	O
top	O
of	O
OpenGL	B-Application
could	O
potentially	O
simplify	O
video	O
driver	O
development	O
.	O
</s>
<s>
It	O
removes	O
the	O
artificial	O
separation	O
of	O
2D	O
and	O
3D	O
acceleration	B-General_Concept
.	O
</s>
<s>
It	O
also	O
removes	O
all	O
driver-dependent	O
code	O
from	O
the	O
X	B-Protocol
server	I-Protocol
itself	O
,	O
and	O
allows	O
for	O
accelerated	O
Composite	O
and	O
Render	B-Device
operations	O
independent	O
of	O
the	O
graphics	O
driver	O
.	O
</s>
<s>
Hardware	B-General_Concept
acceleration	I-General_Concept
of	O
2D	O
drawing	O
operations	O
has	O
been	O
a	O
common	O
feature	O
of	O
many	O
window	O
systems	O
(	O
including	O
X11	B-Operating_System
)	O
for	O
many	O
years	O
.	O
</s>
<s>
The	O
novelty	O
of	O
Xgl	B-Application
and	O
similar	O
systems	O
is	O
the	O
use	O
of	O
APIs	O
specifically	O
developed	O
for	O
3D	O
rendering	O
for	O
accelerating	O
2D	O
desktop	O
operations	O
.	O
</s>
<s>
Prior	O
to	O
the	O
adoption	O
of	O
anti-aliased	O
drawing	O
by	O
X11	B-Operating_System
,	O
the	O
use	O
of	O
3D	O
rendering	O
APIs	O
for	O
2D	O
desktop	O
rendering	O
was	O
undesirable	O
because	O
such	O
APIs	O
did	O
not	O
make	O
the	O
pixel	O
accurate	O
rendering	O
guarantees	O
that	O
are	O
part	O
of	O
the	O
original	O
X11	B-Operating_System
protocol	O
definition	O
.	O
</s>
<s>
Hardware-accelerated	B-General_Concept
OpenGL	B-Application
window	O
and	O
desktop	O
rendering	O
,	O
limited	O
to	O
using	O
OpenGL	B-Application
for	O
texture	O
composition	O
,	O
has	O
been	O
in	O
use	O
in	O
Mac	O
OS	O
X	B-Operating_System
,	O
in	O
a	O
technology	O
called	O
Quartz	O
Extreme	O
,	O
since	O
Mac	B-Operating_System
OS	I-Operating_System
X	I-Operating_System
v10.2	I-Operating_System
.	O
</s>
<s>
Quartz	B-Operating_System
2D	I-Operating_System
Extreme	I-Operating_System
is	O
an	O
enhancement	O
of	O
this	O
feature	O
and	O
more	O
directly	O
comparable	O
to	O
Xgl	B-Application
.	O
</s>
<s>
Like	O
Xgl	B-Application
,	O
Quartz	B-Operating_System
2D	I-Operating_System
Extreme	I-Operating_System
brings	O
OpenGL	B-Application
acceleration	B-General_Concept
to	O
all	O
2D	O
drawing	O
operations	O
(	O
not	O
just	O
desktop	O
compositing	O
)	O
and	O
ships	O
with	O
Mac	B-Application
OS	I-Application
X	I-Application
v10.4	I-Application
,	O
but	O
is	O
disabled	O
by	O
default	O
pending	O
a	O
formal	O
declaration	O
of	O
production-readiness	O
.	O
</s>
<s>
Core	O
Animation	O
is	O
the	O
extension	O
of	O
this	O
effort	O
for	O
Leopard	B-Application
(	O
Mac	B-Application
OS	I-Application
X	I-Application
v10.5	I-Application
)	O
.	O
</s>
<s>
Several	O
desktop	O
interfaces	O
based	O
on	O
3D	O
APIs	O
have	O
been	O
developed	O
,	O
more	O
recently	O
OpenCroquet	B-Protocol
and	O
Sun	O
Microsystems	O
 '	O
Project	B-Language
Looking	I-Language
Glass	I-Language
;	O
these	O
take	O
advantage	O
of	O
3D	O
acceleration	B-General_Concept
for	O
software	O
built	O
within	O
their	O
own	O
framework	O
,	O
but	O
do	O
not	O
appear	O
to	O
accelerate	O
existing	O
2D	O
desktop	O
applications	O
rendered	O
within	O
their	O
environment	O
(	O
often	O
via	O
mechanisms	O
like	O
VNC	B-Protocol
)	O
.	O
</s>
<s>
Microsoft	O
developed	O
a	O
similar	O
technology	O
based	O
on	O
DirectX	B-Application
,	O
named	O
the	O
DWM	O
,	O
as	O
part	O
of	O
its	O
Windows	B-Application
Vista	I-Application
operating	I-Application
system	I-Application
.	O
</s>
<s>
,	O
the	O
Xgl	B-Application
X	B-Protocol
Server	I-Protocol
(	O
and	O
related	O
components	O
including	O
the	O
Compiz	B-Language
compositing	B-Operating_System
manager	I-Operating_System
and	O
associated	O
graphical	O
config	O
tools	O
)	O
ships	O
as	O
a	O
non-default	O
in	O
one	O
major	O
Linux	O
distribution	O
,	O
SUSE	O
10.1	O
,	O
and	O
is	O
included	O
in	O
Frugalware	O
Linux	O
or	O
SUSE	O
Linux	O
Enterprise	O
Desktop	O
10	O
.	O
</s>
<s>
Xgl	B-Application
can	O
be	O
set	O
up	O
fairly	O
easily	O
for	O
Ubuntu	B-Operating_System
6.06	O
LTS	O
(	O
Dapper	O
Drake	O
)	O
and	O
6.10	O
(	O
Edgy	O
Eft	O
)	O
and	O
for	O
Freespire	O
with	O
binary	O
packages	O
from	O
unofficial	O
repositories	B-Application
.	O
</s>
<s>
Xgl	B-Application
is	O
also	O
available	O
as	O
an	O
overlaid	O
package	O
in	O
Gentoo	B-Application
Linux	I-Application
,	O
and	O
as	O
a	O
PKGBUILD	O
for	O
Arch	O
Linux	O
.	O
</s>
<s>
Mandriva	O
Linux	O
2007	O
includes	O
official	O
packages	O
to	O
run	O
Compiz	B-Language
,	O
using	O
Xgl	B-Application
and	O
AIGLX	B-Application
.	O
</s>
<s>
Ubuntu	B-Operating_System
6.10	O
"	O
Edgy	O
Eft	O
"	O
and	O
later	O
use	O
AIGLX	B-Application
,	O
not	O
Xgl	B-Application
,	O
by	O
default	O
.	O
</s>
<s>
Xgl	B-Application
was	O
removed	O
from	O
X11R7.5	O
in	O
2009	O
due	O
to	O
its	O
being	O
an	O
unmaintained	O
server	O
variant	O
.	O
</s>
