<s>
Parallel	B-Operating_System
rendering	I-Operating_System
(	O
or	O
distributed	B-Operating_System
rendering	I-Operating_System
)	O
is	O
the	O
application	O
of	O
parallel	B-Operating_System
programming	I-Operating_System
to	O
the	O
computational	O
domain	O
of	O
computer	O
graphics	O
.	O
</s>
<s>
Rendering	O
graphics	O
can	O
require	O
massive	O
computational	O
resources	O
for	O
complex	O
scenes	O
that	O
arise	O
in	O
scientific	B-Application
visualization	I-Application
,	O
medical	B-Application
visualization	I-Application
,	O
CAD	B-Application
applications	O
,	O
and	O
virtual	B-Application
reality	I-Application
.	O
</s>
<s>
Recent	O
research	O
has	O
also	O
suggested	O
that	O
parallel	B-Operating_System
rendering	I-Operating_System
can	O
be	O
applied	O
to	O
mobile	B-Application
gaming	I-Application
to	O
decrease	O
power	O
consumption	O
and	O
increase	O
graphical	O
fidelity	O
.	O
</s>
<s>
Rendering	O
is	O
an	O
embarrassingly	B-Operating_System
parallel	I-Operating_System
workload	O
in	O
multiple	O
domains	O
(	O
e.g.	O
,	O
pixels	O
,	O
objects	O
,	O
frames	O
)	O
and	O
thus	O
has	O
been	O
the	O
subject	O
of	O
much	O
research	O
.	O
</s>
<s>
There	O
are	O
two	O
,	O
often	O
competing	O
,	O
reasons	O
for	O
using	O
parallel	B-Operating_System
rendering	I-Operating_System
.	O
</s>
<s>
There	O
can	O
also	O
be	O
other	O
advantages	O
and	O
disadvantages	O
such	O
as	O
latency	O
and	O
load	B-Application
balancing	I-Application
issues	O
.	O
</s>
<s>
triangle	B-Algorithm
meshes	I-Algorithm
)	O
.	O
</s>
<s>
The	O
frames	O
rendered	O
from	O
different	O
points	O
of	O
view	O
can	O
improve	O
image	O
quality	O
with	O
anti-aliasing	O
or	O
add	O
effects	O
like	O
depth-of-field	O
and	O
three-dimensional	B-Algorithm
display	I-Algorithm
output	O
.	O
</s>
<s>
Distributing	O
interlaced	O
lines	O
of	O
pixels	O
gives	O
good	O
load	B-Application
balancing	I-Application
but	O
makes	O
data	O
scaling	O
impossible	O
.	O
</s>
<s>
Distributing	O
contiguous	O
2D	O
tiles	O
of	O
pixels	O
allows	O
for	O
data	O
scaling	O
by	O
culling	O
data	O
with	O
the	O
view	B-General_Concept
frustum	I-General_Concept
.	O
</s>
<s>
Dynamic	O
load	B-Application
balancing	I-Application
is	O
also	O
needed	O
to	O
maintain	O
performance	O
scaling	O
.	O
</s>
<s>
It	O
provides	O
good	O
data	O
scaling	O
and	O
can	O
provide	O
good	O
performance	O
scaling	O
,	O
but	O
it	O
requires	O
the	O
intermediate	O
images	O
from	O
processing	O
nodes	O
to	O
be	O
alpha	B-Algorithm
composited	I-Algorithm
to	O
create	O
the	O
final	O
image	O
.	O
</s>
<s>
As	O
the	O
image	O
resolution	O
grows	O
,	O
the	O
alpha	B-Algorithm
compositing	I-Algorithm
overhead	O
also	O
grows	O
.	O
</s>
<s>
A	O
load	B-Application
balancing	I-Application
scheme	O
is	O
also	O
needed	O
to	O
maintain	O
performance	O
regardless	O
of	O
the	O
viewing	O
conditions	O
.	O
</s>
<s>
This	O
can	O
be	O
achieved	O
by	O
over	O
partitioning	O
the	O
object	O
space	O
and	O
assigning	O
multiple	O
pieces	O
to	O
each	O
processing	O
unit	O
in	O
a	O
random	O
fashion	O
,	O
however	O
this	O
increases	O
the	O
number	O
of	O
alpha	B-Algorithm
compositing	I-Algorithm
stages	O
required	O
to	O
create	O
the	O
final	O
image	O
.	O
</s>
<s>
Object	O
distributions	O
can	O
try	O
to	O
minimize	O
their	O
overlap	O
in	O
screen	O
space	O
in	O
order	O
to	O
reduce	O
alpha	B-Algorithm
compositing	I-Algorithm
costs	O
,	O
or	O
even	O
use	O
a	O
pixel	O
distribution	O
to	O
render	O
portions	O
of	O
the	O
object	O
space	O
.	O
</s>
<s>
The	O
open	O
source	O
software	O
package	O
Chromium	B-Library
provides	O
a	O
parallel	B-Operating_System
rendering	I-Operating_System
mechanism	O
for	O
existing	O
applications	O
.	O
</s>
<s>
It	O
intercepts	O
the	O
OpenGL	B-Application
calls	O
and	O
processes	O
them	O
,	O
typically	O
to	O
send	O
them	O
to	O
multiple	O
rendering	O
units	O
driving	O
a	O
display	B-Device
wall	I-Device
.	O
</s>
<s>
Equalizer	O
is	O
an	O
open	O
source	O
rendering	O
framework	B-Architecture
and	O
resource	O
management	O
system	O
for	O
multipipe	O
applications	O
.	O
</s>
<s>
Equalizer	O
provides	O
an	O
API	B-Application
to	O
write	O
parallel	O
,	O
scalable	O
visualization	O
applications	O
which	O
are	O
configured	O
at	O
run-time	O
by	O
a	O
resource	O
server	O
.	O
</s>
<s>
OpenSG	O
is	O
an	O
open	O
source	O
scenegraph	B-Data_Structure
system	O
that	O
provides	O
parallel	B-Operating_System
rendering	I-Operating_System
capabilities	O
,	O
especially	O
on	O
clusters	O
.	O
</s>
<s>
It	O
hides	O
the	O
complexity	O
of	O
parallel	O
multi-threaded	B-Operating_System
and	O
clustered	O
applications	O
and	O
supports	O
sort-first	O
as	O
well	O
as	O
sort-last	O
rendering	O
.	O
</s>
<s>
Golem	O
is	O
an	O
open	O
source	O
decentralized	B-Application
application	I-Application
used	O
for	O
parallel	B-Operating_System
computing	I-Operating_System
that	O
currently	O
works	O
with	O
rendering	O
in	O
Blender	O
and	O
has	O
plans	O
to	O
incorporate	O
more	O
uses	O
.	O
</s>
