Custom PC - UK (2020-02)

FEAATURE//ANALYSSIS

At least that’s the theory. In practice, FXA
can look a bit blurry, and in a way that isn’t
offset by the significant step up in realism and
depth of full-scene super sampling. On the
flip side, it’s astonishingly efficient in terms of
performance.It takesupsolittleprocessing
powerthatyoucanenableit onallgames
andatallresolutionsessentiallyforfree.In
ourCS:GOtesting,enablingFXAAdropped
performancebyjust8 percent.
Therearefurtherkeybenefitstoo.One
is thatit worksonallpartsofa scene,such
astheedgesoftransparenttextures.More
importantly,FXAAcanbeprocessedontop
ofanyotherrenderingprocesses,including
othertypesofAA.Thisis particularly
importantformanymoderngamesthat
usesophisticatedpixelshaders,asnormal
AAtechniquescan’tbeappliedafterthese
shadershavedonetheirwork.
Alltold,though,theresultsofthistechnique
aren’tparticularlyattractive,especiallyasit
doesn’tdoa lottofixflickeringand
shimmeringissues,wherepixelsrapidly
changecolourinanunnatural-lookingway
whenthere’smovementonscreen– an
effectthat’softenfixedbyanti-aliasing.The
changesincolourareslightlysubtlerthanwith
noAA,duetotheblurring,butyoustillseethe
suddenchangesbecausetheunderlying
sceneisn’ttrulyanti-aliased.

ook particularly bad in complex

scenes where there’s a lot foliage or other

transparent textures. It just blurs into an

indistinct mass that lacks the sense of depth

that other conventional AA techniques provide,

whilealsodoinglittletoresolveflickering.

Ata push,if you’rereallysqueezedfor

performance,youcouldapply2xMSAAand

FXAAorperhaps2xadaptiveAAandFXAA.

The2xMSAAandadaptiveAAwilltakecareof

theworstjaggiesandshimmering,whilethe

FXAAwillhelpsoftenuptherestofthescene.

EnhancedSubpixel

MorphologicalAA(SMAA)

SMAAis animprovementonFXAAthatmore

effectivelydetectspatternsintheunderlying

image,suchasthelinesandcurvesthatdefine

theboundariesofobjectsthatneedanti-

aliasing.It thenblurstheseboundariesinthe

directionofthepattern.Thisapproachgreatly

enhancesthistechnique’s abilitytoreduce

bothjaggiesandtheshimmeringeffectthat

plaguesFXAAandnon-anti-aliasedscenes.

The downside is that enabling it results in a

greater performance hit than FXAA, although

SMAA is still far less demanding than

conventional AA. Unfortunately, we didn’t

have a way of enabling SMAA in CS:GO for a

directcomparisontoourothertests,butwe

couldtestit inRiseoftheTombRaider.Here,

thegamedelivered53.6fpswithnoAA,

52.5fpswithFXAAand48.6fpswithSMAA.

That’salmostcertainlya performancehit

mostofuswouldbewillingtotake.

Moreover,thisgameprovideda particularly

goodwaytoshowthedifferencein quality

betweenFXAAandSMAA.Itsdensefoliage

andparticleeffects,suchasrainandsnowreally

showedupFXAA’stendencytojustmakethe

imagelookblurry,whereasSMAAdida better

jobofpreservingdetail.In thescreenshots

below,there’slessofthefoliage,butyoucan

clearlyseehow,withnoAA,theoutlineofLara

Croft’sheadis jaggedand,withSMAA,the

imageis smoothedoff.WithFXAA,though,

thewholeimagelooksfarmuddier,although

theoverallAAeffectis admittedlystronger.

From left to right: No AA, FXAA, SMAA

BASICALLY, IT LOOKS FOR PLACES WHERE THERE’S A

HIGH CONTRAST BETWEEN NEIGHBOURING PIXELS, AND

THEN BLENDS THOSE AREAS