<s>
Simple	B-Operating_System
DirectMedia	I-Operating_System
Layer	I-Operating_System
(	O
SDL	O
)	O
is	O
a	O
cross-platform	B-Operating_System
software	I-Operating_System
development	O
library	B-Library
designed	O
to	O
provide	O
a	O
hardware	B-Operating_System
abstraction	I-Operating_System
layer	I-Operating_System
for	O
computer	O
multimedia	O
hardware	B-Architecture
components	I-Architecture
.	O
</s>
<s>
Software	O
developers	O
can	O
use	O
it	O
to	O
write	O
high-performance	O
computer	O
games	O
and	O
other	O
multimedia	O
applications	O
that	O
can	O
run	O
on	O
many	O
operating	B-General_Concept
systems	I-General_Concept
such	O
as	O
Android	B-Application
,	O
iOS	B-Application
,	O
Linux	B-Application
,	O
macOS	B-Application
,	O
and	O
Windows	B-Application
.	O
</s>
<s>
SDL	O
manages	O
video	O
,	O
audio	B-Device
,	O
input	B-Device
devices	I-Device
,	O
CD-ROM	B-Device
,	O
threads	B-Operating_System
,	O
shared	O
object	O
loading	O
,	O
networking	B-Architecture
and	O
timers	O
.	O
</s>
<s>
For	O
3D	O
graphics	O
,	O
it	O
can	O
handle	O
an	O
OpenGL	B-Application
,	O
Vulkan	B-Application
,	O
Metal	B-Library
,	O
or	O
Direct3D11	O
(	O
older	O
Direct3D	O
version	O
9	O
is	O
also	O
supported	O
)	O
context	O
.	O
</s>
<s>
However	O
,	O
the	O
library	B-Library
is	O
suited	O
to	O
building	O
games	O
directly	O
,	O
or	O
is	O
usable	O
indirectly	O
by	O
engines	O
built	O
on	O
top	O
of	O
it	O
.	O
</s>
<s>
The	O
library	B-Library
is	O
internally	O
written	O
in	O
C	B-Language
and	O
possibly	O
,	O
depending	O
on	O
the	O
target	O
platform	O
,	O
C++	B-Language
or	O
Objective-C	B-Language
,	O
and	O
provides	O
the	O
application	B-Application
programming	I-Application
interface	I-Application
in	O
C	B-Language
,	O
with	O
bindings	O
to	O
other	O
languages	O
available	O
.	O
</s>
<s>
It	O
is	O
free	B-License
and	I-License
open-source	I-License
software	I-License
subject	O
to	O
the	O
requirements	O
of	O
the	O
zlib	B-License
License	I-License
since	O
version	O
2.0	O
,	O
and	O
with	O
prior	O
versions	O
subject	O
to	O
the	O
GNU	B-Application
Lesser	I-Application
General	I-Application
Public	I-Application
License	I-Application
.	O
</s>
<s>
Under	O
the	O
zlib	B-License
License	I-License
,	O
SDL	O
2.0	O
is	O
freely	O
available	O
for	O
static	B-Library
linking	I-Library
in	O
closed-source	B-Application
projects	O
,	O
unlike	O
SDL	O
1.2	O
.	O
</s>
<s>
SDL	O
2.0	O
,	O
released	O
in	O
2013	O
,	O
was	O
a	O
major	O
departure	O
from	O
previous	O
versions	O
,	O
offering	O
more	O
opportunity	O
for	O
3D	O
hardware	B-Architecture
acceleration	O
,	O
but	O
breaking	O
backwards-compatibility	B-General_Concept
.	O
</s>
<s>
Over	O
700	O
games	O
,	O
180	O
applications	O
,	O
and	O
120	O
demos	O
have	O
been	O
posted	O
on	O
the	O
library	B-Library
website	O
.	O
</s>
<s>
Sam	O
Lantinga	O
created	O
the	O
library	B-Library
,	O
first	O
releasing	O
it	O
in	O
early	O
1998	O
,	O
while	O
working	O
for	O
Loki	O
Software	O
.	O
</s>
<s>
He	O
got	O
the	O
idea	O
while	O
porting	O
a	O
Windows	B-Application
application	O
to	O
Macintosh	O
.	O
</s>
<s>
He	O
then	O
used	O
SDL	O
to	O
port	O
Doom	B-Application
to	O
BeOS	B-Application
(	O
see	O
Doom	B-Application
source	O
ports	O
)	O
.	O
</s>
<s>
Several	O
other	O
free	O
libraries	O
were	O
developed	O
to	O
work	O
alongside	O
SDL	O
,	O
such	O
as	O
SMPEG	B-Application
and	O
OpenAL	B-Application
.	O
</s>
<s>
Soon	O
after	O
putting	O
Galaxy	O
Gameworks	O
on	O
hold	O
,	O
Lantinga	O
announced	O
that	O
SDL	O
1.3	O
(	O
which	O
would	O
then	O
later	O
become	O
SDL	O
2.0	O
)	O
would	O
be	O
licensed	O
under	O
the	O
zlib	B-License
License	I-License
.	O
</s>
<s>
SDL	O
2.0	O
is	O
a	O
major	O
update	O
to	O
the	O
SDL	O
1.2	O
codebase	B-General_Concept
with	O
a	O
different	O
,	O
not	O
backwards-compatible	B-General_Concept
API	B-General_Concept
.	O
</s>
<s>
It	O
replaces	O
several	O
parts	O
of	O
the	O
1.2	O
API	B-General_Concept
with	O
more	O
general	O
support	O
for	O
multiple	O
input	O
and	O
output	O
options	O
.	O
</s>
<s>
Some	O
feature	O
additions	O
include	O
multiple	O
window	O
support	O
,	O
hardware-accelerated	O
2D	O
graphics	O
,	O
and	O
better	O
Unicode	O
support	O
.	O
</s>
<s>
Support	O
for	O
Mir	B-Language
and	O
Wayland	B-Language
was	O
added	O
in	O
SDL	O
2.0.2	O
and	O
enabled	O
by	O
default	O
in	O
SDL	O
2.0.4	O
.	O
</s>
<s>
Version	O
2.0.4	O
also	O
provided	O
better	O
support	O
for	O
Android	B-Application
.	O
</s>
<s>
SDL	O
is	O
a	O
wrapper	B-Library
around	O
the	O
operating-system-specific	O
functions	O
that	O
the	O
game	O
needs	O
to	O
access	O
.	O
</s>
<s>
The	O
only	O
purpose	O
of	O
SDL	O
is	O
to	O
provide	O
a	O
common	O
framework	O
for	O
accessing	O
these	O
functions	O
for	O
multiple	O
operating	B-General_Concept
systems	I-General_Concept
(	O
cross-platform	B-Operating_System
)	O
.	O
</s>
<s>
It	O
is	O
often	O
used	O
to	O
complement	O
OpenGL	B-Application
by	O
setting	O
up	O
the	O
graphical	O
output	O
and	O
providing	O
mouse	O
and	O
keyboard	O
input	O
,	O
since	O
OpenGL	B-Application
comprises	O
only	O
rendering	O
.	O
</s>
<s>
A	O
game	O
using	O
the	O
Simple	B-Operating_System
DirectMedia	I-Operating_System
Layer	I-Operating_System
will	O
not	O
automatically	O
run	O
on	O
every	O
operating	B-General_Concept
system	I-General_Concept
;	O
further	O
adaptations	O
must	O
be	O
applied	O
.	O
</s>
<s>
These	O
are	O
reduced	O
to	O
the	O
minimum	O
,	O
since	O
SDL	O
also	O
contains	O
a	O
few	O
abstraction	O
APIs	B-General_Concept
for	O
frequent	O
functions	O
offered	O
by	O
an	O
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
These	O
comprise	O
the	O
"	O
standard	O
library	B-Library
"	O
,	O
and	O
are	O
provided	O
on	O
the	O
official	O
website	O
and	O
included	O
in	O
the	O
official	O
documentation	O
:	O
</s>
<s>
The	O
SDL	O
2.0	O
library	B-Library
has	O
language	B-Application
bindings	I-Application
for	O
:	O
</s>
<s>
Java	B-Language
(	O
e.g.	O
</s>
<s>
Python	B-Language
(	O
several	O
,	O
e.g.	O
</s>
<s>
Because	O
of	O
the	O
way	O
SDL	O
is	O
designed	O
,	O
much	O
of	O
its	O
source	O
code	O
is	O
split	O
into	O
separate	O
modules	O
for	O
each	O
operating	B-General_Concept
system	I-General_Concept
,	O
to	O
make	O
calls	O
to	O
the	O
underlying	O
system	O
.	O
</s>
<s>
GDI	B-Operating_System
back-end	O
for	O
Microsoft	B-Application
Windows	I-Application
.	O
</s>
<s>
DirectX	B-Application
back-end	O
;	O
older	O
SDL	O
1.2	O
uses	O
DirectX	B-Application
7	I-Application
by	O
default	O
,	O
while	O
2.0	O
defaults	O
to	O
DirectX	B-Application
9	I-Application
and	O
can	O
access	O
up	O
to	O
DirectX	B-Application
11	O
.	O
</s>
<s>
Quartz	B-Operating_System
back-end	O
for	O
macOS	B-Application
(	O
dropped	O
in	O
2.0	O
)	O
.	O
</s>
<s>
Metal	B-Library
back-end	O
for	O
macOS	B-Application
/	O
iOS	B-Application
/	O
tvOS	B-Operating_System
since	O
2.0.8	O
;	O
older	O
versions	O
use	O
OpenGL	B-Application
by	O
default	O
.	O
</s>
<s>
Xlib	B-Language
back-end	O
for	O
X11-based	O
windowing	B-Application
system	I-Application
on	O
various	O
operating	B-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
OpenGL	B-Application
contexts	O
on	O
various	O
platforms	O
.	O
</s>
<s>
EGL	B-Application
back-end	O
when	O
used	O
in	O
conjunction	O
with	O
Wayland-based	O
windowing	O
system.	O
,	O
Raspberry	B-Operating_System
Pi	I-Operating_System
and	O
other	O
systems	O
.	O
</s>
<s>
Vulkan	B-Application
contexts	O
on	O
platforms	O
that	O
support	O
it	O
.	O
</s>
<s>
sceGu	O
back-end	O
,	O
a	O
Sony	O
OpenGL-like	O
backend	O
native	O
to	O
the	O
PSP	B-Operating_System
.	O
</s>
<s>
SDL	O
1.2	O
has	O
support	O
for	O
RISC	B-Operating_System
OS	I-Operating_System
(	O
dropped	O
in	O
2.0	O
)	O
.	O
</s>
<s>
The	O
Rockbox	B-Application
MP3	O
player	O
firmware	O
also	O
distributes	O
a	O
version	O
of	O
SDL	O
1.2	O
,	O
which	O
is	O
used	O
to	O
run	O
games	O
such	O
as	O
Quake	B-Application
.	O
</s>
<s>
For	O
instance	O
,	O
MobyGames	B-Application
listed	O
120	O
games	O
using	O
SDL	O
in	O
2013	O
,	O
and	O
the	O
SDL	O
website	O
itself	O
listed	O
around	O
700	O
games	O
in	O
2012	O
.	O
</s>
<s>
Important	O
commercial	O
examples	O
are	O
Angry	B-Application
Birds	I-Application
,	O
Unreal	B-Operating_System
Tournament	I-Operating_System
,	O
and	O
games	O
developed	O
using	O
Valve	O
's	O
Source	B-Application
Engine	I-Application
,	O
which	O
uses	O
SDL	O
extensively	O
for	O
cross-platform	B-Operating_System
compatibility	O
;	O
ones	O
from	O
the	O
open-source	O
domain	O
are	O
OpenTTD	B-Application
,	O
The	B-Application
Battle	I-Application
for	I-Application
Wesnoth	I-Application
or	O
Freeciv	B-Application
.	O
</s>
<s>
The	O
cross-platform	B-Operating_System
game	O
releases	O
of	O
the	O
popular	O
Humble	O
Indie	O
Bundles	O
for	O
Linux	B-Application
,	O
Mac	O
and	O
Android	B-Application
are	O
often	O
SDL-based	O
.	O
</s>
<s>
For	O
instance	O
,	O
the	O
PC	O
game	O
Homeworld	B-Application
was	O
ported	O
to	O
the	O
Pandora	B-Device
handheld	B-Application
and	O
Jagged	B-Application
Alliance	I-Application
2	I-Application
for	O
Android	B-Application
via	O
SDL	O
.	O
</s>
<s>
Also	O
,	O
several	O
non	O
video	O
game	O
programs	O
use	O
SDL	O
;	O
examples	O
are	O
the	O
emulators	B-Application
,	O
such	O
as	O
DOSBox	B-Application
,	O
FUSE	B-Language
ZX	I-Language
Spectrum	I-Language
emulator	I-Language
and	O
VisualBoyAdvance	B-Device
.	O
</s>
<s>
SDL	O
is	O
used	O
in	O
university	O
courses	O
teaching	O
multimedia	O
and	O
computer	B-General_Concept
science	I-General_Concept
,	O
for	O
instance	O
,	O
in	O
a	O
workshop	O
about	O
game	O
programming	O
using	O
libSDL	B-Operating_System
at	O
the	O
University	O
of	O
Cadiz	O
in	O
2010	O
,	O
or	O
a	O
Game	O
Design	O
discipline	O
at	O
UTFPR	O
(	O
Ponta	O
Grossa	O
campus	O
)	O
in	O
2015	O
.	O
</s>
