Editing Spatial anti-aliasing (section)

==Super sampling / full-scene anti-aliasing==

[[Supersampling|Super sampling anti-aliasing (SSAA)]],<ref>{{cite web |url=http://www.anandtech.com/show/2841/14 |title=AMD's Radeon HD 5870: Bringing About the Next Generation Of GPUs |publisher=AnandTech.com }}</ref> also called full-scene anti-aliasing (FSAA),<ref>
{{cite book
 | title = Game Engine Architecture
 | author = Jason Gregory, [[Jeff Lander]]
 | publisher = A K Peters, Ltd.
 | year = 2009
 | isbn = 978-1-56881-413-1
 | page = 39
 | url = https://books.google.com/books?id=LJ20tsePKk4C&pg=PA442
 }}</ref> is used to avoid aliasing (or "[[jaggies]]") on full-screen images.<ref>
{{cite journal
 | journal =Crossroads
 | title = Graphic libraries for Windows programming
 | author = M. Carmen Juan Lizandra
 | volume = 6
 | issue = 4
 | pages = 14–18
 | publisher = ACM
 | doi = 10.1145/333424.333433
 | date = June 2000
 | s2cid = 15786664
 }}</ref> SSAA was the first type of anti-aliasing available with early video cards. But due to its tremendous computational cost and the advent of [[multisample anti-aliasing]] (MSAA) support on GPUs, it is no longer widely used in real time applications. MSAA provides somewhat lower graphic quality, but also tremendous savings in computational power.

The resulting image of SSAA may seem softer, and should also appear more realistic. However, while useful for photo-like images, a simple anti-aliasing approach (such as super-sampling and then averaging) may actually worsen the appearance of some types of line art or diagrams (making the image appear fuzzy), especially where most lines are horizontal or vertical.  In these cases, a prior grid-fitting step may be useful (see [[hinting]]).

In general, super-sampling is a technique of collecting data points at a greater resolution (usually by a power of two) than the final data resolution. These data points are then combined (down-sampled) to the desired resolution, often just by a simple [[average]]. The combined data points have less visible aliasing artifacts (or [[moiré pattern]]s).

Full-scene anti-aliasing by super-sampling usually means that each full frame is rendered at double (2x) or quadruple (4x) the [[computer display|display]] resolution, and then down-sampled to match the display resolution. Thus, a 2x FSAA would render 4 super-sampled [[pixels]] for each single pixel of each frame. Rendering at larger resolutions will produce better results; however, more processor power is needed, which can degrade performance and frame rate. Sometimes FSAA is implemented in hardware in such a way that a graphical application is unaware the images are being super-sampled and then down-sampled before being displayed.