<s>
A	O
virtual	B-Application
reality	I-Application
game	I-Application
or	O
VR	B-Application
games	I-Application
is	O
a	O
video	O
game	O
played	O
on	O
virtual	B-Application
reality	I-Application
(	O
VR	O
)	O
hardware	O
.	O
</s>
<s>
Most	O
VR	B-Application
games	I-Application
are	O
based	O
on	O
player	O
immersion	O
,	O
typically	O
through	O
head-mounted	B-Device
display	I-Device
unit	I-Device
or	I-Device
headset	I-Device
with	O
stereoscopic	B-Algorithm
displays	I-Algorithm
and	O
one	O
or	O
more	O
controllers	B-Device
.	O
</s>
<s>
The	O
video	O
game	O
industry	O
made	O
early	O
attempts	O
at	O
VR	O
in	O
the	O
1980s	O
,	O
most	O
notably	O
with	O
Mattel	O
's	O
Power	B-General_Concept
Glove	I-General_Concept
and	O
Nintendo	O
's	O
Virtual	B-Device
Boy	I-Device
.	O
</s>
<s>
With	O
the	O
introduction	O
of	O
the	O
first	O
consumer-ready	O
VR	O
product	O
,	O
the	O
Oculus	B-Device
Rift	I-Device
,	O
in	O
2013	O
,	O
VR	B-Application
games	I-Application
soon	O
followed	O
,	O
including	O
existing	O
games	O
adapted	O
for	O
the	O
VR	O
hardware	O
,	O
and	O
new	O
games	O
designed	O
directly	O
for	O
VR	O
.	O
</s>
<s>
While	O
VR	O
hardware	O
and	O
games	O
grew	O
modestly	O
for	O
the	O
remainder	O
of	O
the	O
2010s	O
,	O
Half-Life	B-Application
:	I-Application
Alyx	I-Application
,	O
a	O
full	O
VR	B-Application
game	I-Application
developed	O
by	O
Valve	O
,	O
was	O
considered	O
the	O
killer	O
application	O
for	O
VR	B-Application
games	I-Application
.	O
</s>
<s>
Research	O
into	O
virtual	B-Application
reality	I-Application
(	O
VR	O
)	O
hardware	O
and	O
software	O
started	O
as	O
early	O
as	O
1968	O
by	O
Ivan	O
Sutherland	O
and	O
his	O
student	O
Bob	O
Sproull	O
,	O
but	O
most	O
equipment	O
was	O
too	O
expensive	O
for	O
consumer	O
use	O
,	O
and	O
its	O
use	O
for	O
games	O
was	O
limited	O
.	O
</s>
<s>
In	O
the	O
late	O
1980s	O
,	O
Jaron	O
Lanier	O
and	O
Thomas	O
G	O
.	O
Zimmerman	O
,	O
former	O
programmers	O
for	O
Atari	O
,	O
Inc.	O
,	O
began	O
developing	O
hardware	O
under	O
the	O
name	O
VPL	O
Research	O
,	O
with	O
Lanier	O
coining	O
the	O
term	O
"	O
virtual	B-Application
reality	I-Application
"	O
for	O
their	O
products	O
.	O
</s>
<s>
The	B-General_Concept
Power	I-General_Concept
Glove	I-General_Concept
was	O
released	O
in	O
1989	O
.	O
</s>
<s>
The	O
games	O
Super	B-Device
Glove	I-Device
Ball	I-Device
and	O
Bad	B-Application
Street	I-Application
Brawler	I-Application
were	O
specifically	O
designed	O
to	O
use	O
the	B-General_Concept
Power	I-General_Concept
Glove	I-General_Concept
,	O
while	O
other	O
NES	O
games	O
could	O
be	O
played	O
using	O
the	B-General_Concept
Power	I-General_Concept
Glove	I-General_Concept
by	O
mapping	O
its	O
output	O
to	O
various	O
controls	O
.	O
</s>
<s>
About	O
one	O
million	O
Power	B-General_Concept
Glove	I-General_Concept
units	O
were	O
sold	O
before	O
Mattel	O
discontinued	O
it	O
in	O
1990	O
.	O
</s>
<s>
Interest	O
in	O
VR	O
grew	O
in	O
the	O
1990s	O
,	O
particularly	O
after	O
the	O
1992	O
film	O
Lawnmower	O
Man	O
,	O
which	O
helped	O
popularize	O
the	O
idea	O
of	O
VR	B-Device
headsets	I-Device
with	O
the	O
general	O
public	O
.	O
</s>
<s>
Reflection	O
Technology	O
,	O
Inc	O
.	O
(	O
RTI	O
)	O
had	O
been	O
developing	O
a	O
head-mounted	O
,	O
stereoscopic	B-Algorithm
head-tracking	B-Operating_System
system	O
using	O
light-emitting	O
diode	O
(	O
LED	O
)	O
displays	O
,	O
the	O
Private	O
Eye	O
.	O
</s>
<s>
Seeking	O
funding	O
for	O
larger	O
production	O
,	O
RTI	O
licensed	O
the	O
technology	O
to	O
Nintendo	O
,	O
and	O
under	O
Gunpei	O
Yokoi	O
,	O
Nintendo	O
developed	O
the	O
Virtual	B-Device
Boy	I-Device
,	O
released	O
in	O
1995	O
.	O
</s>
<s>
The	O
Virtual	B-Device
Boy	I-Device
used	O
red	O
LED	O
displays	O
rather	O
than	O
full-color	O
ones	O
,	O
as	O
they	O
were	O
the	O
most	O
inexpensive	O
to	O
produce	O
,	O
and	O
required	O
mounting	O
to	O
a	O
stand	O
to	O
be	O
played	O
,	O
rather	O
than	O
head-mounted	O
.	O
</s>
<s>
Only	O
22	O
games	O
were	O
produced	O
for	O
the	O
Virtual	B-Device
Boy	I-Device
,	O
and	O
it	O
was	O
considered	O
to	O
be	O
one	O
of	O
Nintendo	O
's	O
commercial	O
failures	O
.	O
</s>
<s>
Sega	O
developed	O
a	O
low-cost	O
VR	O
device	O
,	O
the	O
Sega	B-Device
VR	I-Device
,	O
in	O
the	O
early	O
1990s	O
,	O
for	O
its	O
arcade	O
games	O
and	O
home	O
consoles	O
;	O
the	O
unit	O
did	O
not	O
advance	O
beyond	O
the	O
prototype	O
stage	O
,	O
though	O
Sega	O
incorporated	O
some	O
of	O
its	O
head-tracking	B-Operating_System
technology	O
into	O
its	O
arcade	O
cabinets	O
.	O
</s>
<s>
VR	O
systems	O
without	O
head-mounted	O
hardware	O
were	O
also	O
developed	O
in	O
the	O
1990s	O
,	O
including	O
the	O
Cave	B-General_Concept
automatic	I-General_Concept
virtual	I-General_Concept
environment	I-General_Concept
(	O
CAVE	O
)	O
.	O
</s>
<s>
For	O
example	O
,	O
the	O
Virtuality	B-Application
Group	I-Application
produced	O
its	O
Virtuality	B-Application
line	O
of	O
arcade	O
games	O
starting	O
in	O
the	O
early	O
1990s	O
that	O
typically	O
included	O
a	O
VR	B-Device
headset	I-Device
with	O
head-tracking	B-Operating_System
and	O
other	O
features	O
.	O
</s>
<s>
There	O
remained	O
strong	O
interest	O
from	O
academics	O
to	O
explore	O
what	O
VR	O
,	O
along	O
with	O
augmented	B-General_Concept
reality	I-General_Concept
and	O
other	O
mixed	B-General_Concept
reality	I-General_Concept
systems	O
,	O
could	O
bring	O
to	O
video	O
games	O
,	O
through	O
the	O
2000s	O
,	O
but	O
these	O
games	O
were	O
mostly	O
prepared	O
for	O
research	O
proof-of-concepts	O
to	O
demonstrate	O
the	O
interaction	O
of	O
VR	O
hardware	O
,	O
software	O
,	O
and	O
human	O
motion	O
rather	O
than	O
for	O
commercial	O
release	O
,	O
since	O
hardware	O
costs	O
were	O
still	O
high	O
.	O
</s>
<s>
The	O
Oculus	B-Device
Rift	I-Device
is	O
considered	O
the	O
first	O
consumer-ready	O
VR	B-Device
headset	I-Device
and	O
was	O
first	O
released	O
in	O
2016	O
.	O
</s>
<s>
During	O
testing	O
,	O
Luckey	O
had	O
gained	O
the	O
help	O
of	O
id	O
Software	O
's	O
John	O
Carmack	O
to	O
develop	O
a	O
VR	O
version	O
of	O
Doom	B-Application
3	I-Application
for	O
Oculus	O
.	O
</s>
<s>
While	O
this	O
helped	O
to	O
successfully	O
demonstrate	O
the	O
Oculus	O
,	O
which	O
led	O
to	O
Facebook	B-Application
acquiring	O
Oculus	O
in	O
2014	O
for	O
,	O
it	O
also	O
led	O
to	O
a	O
lawsuit	O
between	O
ZeniMax	O
Media	O
,	O
id	O
's	O
parent	O
company	O
,	O
against	O
Oculus	O
over	O
intellectual	O
property	O
theft	O
over	O
Carmack	O
's	O
participation	O
.	O
</s>
<s>
The	O
Oculus	B-Device
Rift	I-Device
announcement	O
led	O
to	O
other	O
VR	O
developments	O
.	O
</s>
<s>
Sony	O
Computer	O
Entertainment	O
developed	O
the	O
PlayStation	B-Device
VR	I-Device
system	O
for	O
the	B-Operating_System
PlayStation	I-Operating_System
4	I-Operating_System
,	O
while	O
Valve	O
partnered	O
with	O
HTC	O
to	O
develop	O
the	O
HTC	O
Vive	O
;	O
both	O
of	O
these	O
units	O
were	O
released	O
in	O
2016	O
.	O
</s>
<s>
Valve	O
later	O
developed	O
their	O
own	O
headset	O
without	O
HTC	O
,	O
the	O
Valve	B-Device
Index	I-Device
,	O
which	O
was	O
released	O
in	O
2019	O
.	O
</s>
<s>
Headsets	O
designed	O
to	O
accommodate	O
mobile	O
devices	O
were	O
also	O
released	O
,	O
using	O
the	O
devices	O
to	O
create	O
the	O
stereoscopic	B-Algorithm
display	I-Algorithm
,	O
some	O
of	O
the	O
positioning	O
functions	O
,	O
and	O
other	O
VR	O
tracking	O
embedded	O
in	O
the	O
additional	O
hardware	O
.	O
</s>
<s>
In	O
2014	O
,	O
Google	B-Application
introduced	O
Google	B-Device
Cardboard	I-Device
,	O
a	O
inexpensive	O
headset	O
package	O
that	O
constructed	O
from	O
cardboard	O
for	O
use	O
with	O
Android	O
phones	O
;	O
the	O
completed	O
headset	O
creates	O
the	O
necessary	O
visual	O
space	O
to	O
support	O
stereoscopic	B-Algorithm
view	I-Algorithm
from	O
the	O
phone	O
's	O
display	O
.	O
</s>
<s>
Samsung	B-Application
,	O
in	O
conjunction	O
with	O
Oculus	O
,	O
released	O
the	O
Samsung	B-Device
Gear	I-Device
VR	I-Device
in	O
2015	O
to	O
support	O
its	O
Samsung	B-Operating_System
Galaxy	I-Operating_System
smartphones	O
;	O
services	O
for	O
the	O
Gear	B-Device
VR	I-Device
ended	O
in	O
2020	O
.	O
</s>
<s>
Nintendo	O
released	O
the	O
Nintendo	B-Application
Labo	I-Application
VR	B-Device
Kit	I-Device
in	O
2019	O
as	O
part	O
of	O
its	O
Labo	B-Application
series	O
of	O
toys-to-life	O
cardboard	O
products	O
.	O
</s>
<s>
A	O
handful	O
of	O
Nintendo	B-Application
Switch	I-Application
games	O
support	O
Labo	B-Application
VR	O
functionality	O
,	O
such	O
as	O
the	O
2017	O
games	O
Super	B-Application
Mario	I-Application
Odyssey	I-Application
and	O
The	B-Application
Legend	I-Application
of	I-Application
Zelda	I-Application
:	I-Application
Breath	I-Application
of	I-Application
the	I-Application
Wild	I-Application
.	O
</s>
<s>
Despite	O
the	O
availability	O
of	O
low-cost	O
hardware	O
for	O
VR	O
,	O
the	O
technology	O
had	O
still	O
not	O
taken	O
off	O
for	O
video	O
games	O
by	O
2018	O
as	O
had	O
been	O
expected	O
when	O
the	O
Oculus	B-Device
Rift	I-Device
was	O
announced	O
.	O
</s>
<s>
There	O
had	O
been	O
several	O
games	O
from	O
smaller	O
studios	O
that	O
had	O
been	O
considered	O
successful	O
,	O
such	O
as	O
Superhot	O
VR	O
and	O
Beat	B-Application
Saber	I-Application
,	O
but	O
the	O
triple-A	O
studios	O
had	O
not	O
ventured	O
into	O
the	O
area	O
.	O
</s>
<s>
Many	O
journalists	O
stated	O
that	O
the	O
first	O
"	O
killer	O
app	O
"	O
VR	B-Application
game	I-Application
was	O
Half-Life	B-Application
:	I-Application
Alyx	I-Application
,	O
developed	O
by	O
Valve	O
and	O
released	O
in	O
March	O
2020	O
.	O
</s>
<s>
Alyx	O
includes	O
a	O
number	O
of	O
novel	O
control	O
schemes	O
to	O
avoid	O
the	O
motion	B-Application
sickness	I-Application
problems	I-Application
of	O
previous	O
VR	B-Application
games	I-Application
,	O
such	O
as	O
the	O
2019	O
indie	O
title	O
Boneworks	B-Application
.	O
</s>
<s>
Nearly	O
all	O
VR	B-Application
games	I-Application
,	O
as	O
generally	O
defined	O
,	O
require	O
the	O
use	O
of	O
a	O
VR	B-Device
headset	I-Device
that	O
provides	O
stereoscopic	B-Algorithm
displays	I-Algorithm
that	O
simulate	O
three	O
dimensional	O
reality	O
and	O
create	O
immersion	O
for	O
the	O
player	O
.	O
</s>
<s>
Most	O
headsets	O
include	O
some	O
means	O
of	O
positional	B-Operating_System
tracking	I-Operating_System
as	O
to	O
provide	O
head-tracking	B-Operating_System
(	O
that	O
is	O
,	O
as	O
to	O
tell	O
which	O
direction	O
a	O
player	O
's	O
head	O
is	O
looking	O
)	O
,	O
either	O
through	O
sensors	O
built	O
into	O
the	O
unit	O
or	O
from	O
external	O
sensors	O
or	O
cameras	O
that	O
are	O
placed	O
at	O
the	O
corners	O
of	O
the	O
play	O
area	O
.	O
</s>
<s>
Some	O
headsets	O
further	O
provide	O
eye	B-General_Concept
tracking	I-General_Concept
.	O
</s>
<s>
To	O
provide	O
immersive	O
audio	O
,	O
either	O
surround	O
sound	O
speaker	O
systems	O
are	O
used	O
,	O
or	O
headsets	O
may	O
be	O
outfitted	O
with	O
speakers	O
or	O
headphones	O
for	O
the	O
player	O
that	O
provide	O
3D	B-Application
audio	I-Application
effects	I-Application
.	O
</s>
<s>
This	O
is	O
most	O
commonly	O
provided	O
through	O
the	O
use	O
of	O
one	O
or	O
more	O
game	B-Device
controllers	I-Device
.	O
</s>
<s>
A	O
controller	O
can	O
be	O
as	O
simple	O
as	O
a	O
keyboard-and-mouse	O
(	O
KBM	O
)	O
or	O
a	O
standard	O
game	B-Device
controller	I-Device
,	O
or	O
may	O
be	O
specialized	O
hardware	O
that	O
includes	O
positional	B-Operating_System
tracking	I-Operating_System
.	O
</s>
<s>
Most	O
often	O
for	O
specialized	O
VR	O
hardware	O
,	O
the	O
player	O
will	O
have	O
two	O
controllers	B-Device
,	O
one	O
for	O
each	O
hand	O
.	O
</s>
<s>
These	O
controllers	B-Device
may	O
also	O
provide	O
haptic	B-Device
feedback	I-Device
to	O
the	O
user	O
.	O
</s>
<s>
Nearly	O
all	O
VR	B-Application
games	I-Application
are	O
played	O
from	O
a	O
first-person	O
perspective	O
as	O
to	O
take	O
advantage	O
of	O
the	O
level	O
of	O
immersion	O
created	O
by	O
the	O
headset	O
.	O
</s>
<s>
While	O
games	O
can	O
be	O
controlled	O
through	O
traditional	O
controls	O
such	O
as	O
KBM	O
or	O
standard	O
console	O
controller	O
,	O
these	O
interfaces	O
break	O
the	O
level	O
of	O
immersion	O
,	O
and	O
instead	O
,	O
more	O
specialized	O
controllers	B-Device
,	O
typically	O
designed	O
to	O
fit	O
naturally	O
into	O
a	O
player	O
's	O
hand	O
.	O
</s>
<s>
VR	O
offers	O
several	O
novel	O
control	O
schemes	O
-	O
how	O
the	O
player	O
manipulates	O
their	O
in-game	O
character	O
through	O
the	O
game	O
world	O
and	O
the	O
direction	O
they	O
are	O
looking	O
-	O
compared	O
to	O
the	O
traditional	O
free	B-General_Concept
look	I-General_Concept
or	I-General_Concept
mouselook	I-General_Concept
offered	O
by	O
the	O
traditional	O
KBM	O
or	O
standard	O
controller	O
.	O
</s>
<s>
Movement	O
and	O
aim	O
may	O
be	O
coupled	O
between	O
the	O
headset	O
and	O
the	O
controllers	B-Device
or	O
may	O
be	O
decoupled	O
,	O
typically	O
with	O
the	O
headset	O
controlling	O
the	O
direction	O
of	O
movement	O
and	O
controller	O
the	O
aim	O
,	O
which	O
generally	O
leads	O
to	O
more	O
immersive	O
experiences	O
.	O
</s>
<s>
Some	O
VR	O
systems	O
such	O
as	O
the	O
HTC	O
Vive	O
and	O
Oculus	O
offer	O
room	B-General_Concept
scale	I-General_Concept
tracking	O
,	O
which	O
not	O
only	O
incorporate	O
the	O
motions	O
of	O
the	O
player	O
but	O
where	O
they	O
are	O
physically	O
located	O
within	O
a	O
given	O
area	O
and	O
the	O
physical	O
positioning	O
of	O
their	O
body	O
.	O
</s>
<s>
Example	O
of	O
games	O
that	O
support	O
room	B-General_Concept
scale	I-General_Concept
tracking	O
include	O
Job	B-Application
Simulator	I-Application
and	O
Rec	B-Application
Room	I-Application
.	O
</s>
<s>
When	O
room	B-General_Concept
scale	I-General_Concept
is	O
not	O
available	O
,	O
alternate	O
movement	O
schemes	O
have	O
been	O
developed	O
when	O
character	O
movement	O
is	O
required	O
.	O
</s>
<s>
VR	B-Application
games	I-Application
are	O
designed	O
to	O
enhance	O
immersionthe	O
perception	O
that	O
one	O
is	O
actually	O
in	O
the	O
virtual	O
worldand	O
presencethe	O
psychological	O
effect	O
that	O
they	O
are	O
actually	O
interacting	O
with	O
the	O
virtual	O
world	O
outside	O
of	O
their	O
physical	O
bodiesconcepts	O
which	O
cannot	O
readily	O
be	O
done	O
with	O
traditional	O
"	O
flat	O
screen	O
"	O
games	O
played	O
on	O
a	O
computer	O
monitor	O
or	O
television	O
.	O
</s>
<s>
A	O
limiting	O
factor	O
for	O
VR	B-Application
games	I-Application
until	O
the	O
2010s	O
was	O
the	O
overall	O
system	O
latency	O
between	O
a	O
player	O
's	O
actions	O
and	O
the	O
feedback	O
they	O
saw	O
on	O
the	O
headset	O
.	O
</s>
<s>
Since	O
then	O
,	O
improvements	O
in	O
graphics	B-Architecture
processor	I-Architecture
technology	O
and	O
game	O
engines	O
with	O
optimized	O
rendering	O
systems	O
give	O
consumer-grade	O
hardware	O
the	O
capacity	O
to	O
perform	O
high-speed	O
real-time	O
3D	O
rendering	O
at	O
60	O
Hz	O
or	O
greater	O
at	O
resolutions	O
appropriate	O
for	O
VR	O
applications	O
.	O
</s>
<s>
Improvements	O
have	O
been	O
made	O
since	O
in	O
sensor	O
technology	O
and	O
the	O
software	O
libraries	O
to	O
register	O
movements	O
,	O
and	O
VR	B-Application
games	I-Application
can	O
also	O
include	O
other	O
methods	O
such	O
as	O
limited	O
prediction	O
of	O
a	O
player	O
's	O
movements	O
,	O
to	O
bring	O
sense	O
feedback	O
to	O
the	O
same	O
timescale	O
as	O
rendering	O
.	O
</s>
<s>
While	O
many	O
of	O
the	O
latency	O
problems	O
are	O
resolved	O
with	O
the	O
VR	O
hardware	O
of	O
the	O
2010s	O
,	O
VR	B-Application
games	I-Application
still	O
must	O
be	O
programmed	O
with	O
these	O
concerns	O
in	O
mind	O
.	O
</s>
<s>
In	O
its	O
current	O
meaning	O
,	O
"	O
virtual	B-Application
reality	I-Application
"	O
generally	O
has	O
been	O
taken	O
to	O
creating	O
immersion	O
and	O
presence	O
with	O
the	O
player	O
by	O
creating	O
a	O
new	O
visual	O
stimulus	O
(	O
through	O
a	O
VR	B-Device
headset	I-Device
for	O
example	O
)	O
that	O
obscures	O
to	O
real	O
world	O
view	O
.	O
</s>
<s>
This	O
definition	O
distinguishes	O
VR	O
from	O
augmented	B-General_Concept
reality	I-General_Concept
where	O
additional	O
visual	O
information	O
is	O
added	O
atop	O
the	O
real	O
world	O
view	O
.	O
</s>
<s>
A	O
broader	O
definition	O
of	O
virtual	B-Application
reality	I-Application
can	O
be	O
taken	O
to	O
be	O
any	O
application	O
that	O
replaces	O
one	O
or	O
more	O
of	O
the	O
human	O
senses	O
with	O
a	O
virtual	O
one	O
.	O
</s>
<s>
Thus	O
,	O
games	O
featuring	O
any	O
alternative	O
control	O
scheme	O
compared	O
to	O
a	O
typical	O
game	B-Device
controller	I-Device
or	O
keyboard-and-mouse	O
system	O
could	O
be	O
considered	O
as	O
a	O
virtual	B-Application
reality	I-Application
game	I-Application
,	O
where	O
the	O
sense	O
of	O
touch	O
of	O
these	O
traditional	O
controls	O
is	O
replaced	O
with	O
a	O
novel	O
scheme	O
.	O
</s>
<s>
Such	O
games	O
would	O
include	O
those	O
with	O
alternate	O
peripherals	O
such	O
as	O
Dance	B-Application
Dance	I-Application
Revolution	I-Application
and	O
Guitar	B-Application
Hero	I-Application
,	O
or	O
games	O
featuring	O
motion	O
controls	O
such	O
as	O
many	O
Wii-based	O
games	O
.	O
</s>
<s>
However	O
,	O
with	O
the	O
expansion	O
of	O
VR	O
hardware	O
in	O
the	O
2010s	O
,	O
the	O
use	O
of	O
"	O
virtual	B-Application
reality	I-Application
"	O
to	O
include	O
these	O
types	O
of	O
games	O
has	O
been	O
deprecated	O
.	O
</s>
