Framebuffer: Difference between revisions

Revision as of 16:49, 12 October 2020

Revision as of 02:56, 25 December 2020

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[[File:Sun sbus cgsix framebuffer.jpg|thumb|Sun TGX Framebuffer]]

A '''framebuffer''' ('''frame buffer''', or sometimes '''framestore''') is a portion of [[random-access memory]] (RAM)<ref>{{cite web|url=http://www.webopedia.com/TERM/F/frame_buffer.html|title=What is frame buffer? A Webopedia Definition|work=webopedia.com}}</ref> containing a [[bitmap]] that drives a video display. It is a [[Data buffer|memory buffer]] containing data representing all the [[pixel]]s in a complete [[video frame]].<ref>{{cite web |url=http://www.sunhelp.org/faq/FrameBuffer.html#00 |title=Frame Buffer FAQ |accessdateaccess-date=14 May 2014 }}</ref> Modern [[video card]]s contain framebuffer circuitry in their cores. This circuitry converts an in-memory bitmap into a [[video signal]] that can be displayed on a computer monitor.

In [[computing]], a '''screen buffer''' is a part of [[computer memory]] used by a computer application for the representation of the content to be shown on the [[computer display]].<ref name="google">{{cite book|title=.NET Framework Solutions: In Search of the Lost Win32 API|author=Mueller, J.|date=2002|publisher=Wiley|isbn=9780782141344|url=https://books.google.com/books?id=XYQruTc6_44C|page=160|accessdateaccess-date=2015-04-21}}</ref> The screen buffer may also be called the '''video buffer''', the '''regeneration buffer''', or '''regen buffer''' for short.<ref name="smartcomputing">{{cite web|url=http://www.smartcomputing.com/editorial/dictionary/detail.asp?searchtype=2&DicID=10421&RefType=Dictionary&guid=|archive-url=https://web.archive.org/web/20120324192310/http://www.smartcomputing.com/editorial/dictionary/detail.asp?searchtype=2&DicID=10421&RefType=Dictionary&guid= |archive-date=2012-03-24 |url-status=dead|title=Smart Computing Dictionary Entry - video buffer|accessdateaccess-date=2015-04-21}}</ref> Screen buffers should be distinguished from [[video memory]]. To this end, the term '''off-screen buffer''' is also used.

The information in the buffer typically consists of color values for every [[pixel]] to be shown on the display. Color values are commonly stored in 1-bit [[binary image|binary]] (monochrome), 4-bit [[palette (computing)|palettized]], 8-bit palettized, 16-bit [[high color]] and 24-bit [[Color depth#True color .2824-bit.29|true color]] formats. An additional [[Alpha compositing|alpha channel]] is sometimes used to retain information about pixel transparency. The total amount of memory required for the framebuffer depends on the [[Display resolution|resolution]] of the output signal, and on the [[color depth]] or [[Palette (computing)|palette]] size.

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In the early 1970s, the development of [[MOS memory]] ([[metal-oxide-semiconductor]] memory) [[Integrated circuit|integrated-circuit]] chips, particularly [[large-scale integration|high-density]] [[DRAM]] (dynamic [[random-access memory]]) chips with at least 1{{nbsp}}[[kibibit|kb]] memory, made it practical to create, for the first time, a [[digital memory]] system with framebuffers capable of holding a standard video image.<ref name="Shoup_SuperPaint"/><ref>{{cite conference |last1=Goldwasser |first1=S.M. |title=Computer Architecture For Interactive Display Of Segmented Imagery |conference=Computer Architectures for Spatially Distributed Data |date=June 1983 |publisher=[[Springer Science & Business Media]] |isbn=9783642821509 |pages=75-94 (81) |url=https://books.google.com/books?id=8MuoCAAAQBAJ&pg=PA81}}</ref> This led to the development of the [[SuperPaint]] system by [[Richard Shoup (programmer)|Richard Shoup]] at [[Xerox PARC]] in 1972.<ref name="Shoup_SuperPaint">{{cite web |url=http://accad.osu.edu/~waynec/history/PDFs/Annals_final.pdf |archive-url=https://web.archive.org/web/20040612215245/http://accad.osu.edu/~waynec/history/PDFs/Annals_final.pdf |archive-date=2004-06-12 |title=SuperPaint: An Early Frame Buffer Graphics System |author=Richard Shoup |publisher=IEEE |work=Annals of the History of Computing |year=2001 |url-status=dead }}</ref> Shoup was able to use the SuperPaint framebuffer to create an early digital video-capture system. By synchronizing the output signal to the input signal, Shoup was able to overwrite each pixel of data as it shifted in. Shoup also experimented with modifying the output signal using color tables. These color tables allowed the SuperPaint system to produce a wide variety of colors outside the range of the limited 8-bit data it contained. This scheme would later become commonplace in computer framebuffers.

In 1974, [[Evans & Sutherland]] released the first commercial framebuffer, the Picture System,<ref>{{citation |title=Picture System |url=http://s3data.computerhistory.org/brochures/evanssutherland.3d.1974.102646288.pdf |publisher=Evans & Sutherland |access-date=2017-12-31}}</ref> costing about $15,000. It was capable of producing resolutions of up to 512 by 512 pixels in 8-bit [[grayscale]], and became a boon for graphics researchers who did not have the resources to build their own framebuffer. The [[New York Institute of Technology]] would later create the first 24-bit color system using three of the Evans & Sutherland framebuffers.<ref name="NYIT-History">{{cite web |url=https://www.cs.cmu.edu/~ph/nyit/masson/nyit.html |title=History of the New York Institute of Technology Graphics Lab |accessdateaccess-date=2007-08-31}}</ref> Each framebuffer was connected to an [[RGB color model|RGB]] color output (one for red, one for green and one for blue), with a Digital Equipment Corporation PDP 11/04 [[minicomputer]] controlling the three devices as one.

In 1975, the UK company [[Quantel]] produced the first commercial full-color broadcast framebuffer, the Quantel DFS 3000. It was first used in TV coverage of the [[1976 Summer Olympics|1976 Montreal Olympics]] to generate a [[picture-in-picture]] inset of the Olympic flaming torch while the rest of the picture featured the runner entering the stadium.

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{{Reflist}}

{{Refbegin}}

* {{cite web |url=http://accad.osu.edu/~waynec/history/PDFs/14_paint.pdf |title=Digital Paint Systems: Historical Overview |author=Alvy Ray Smith |work=Microsoft Tech Memo 14 |date=May 30, 1997 |url-status=dead |archiveurlarchive-url=https://web.archive.org/web/20120207124911/https://design.osu.edu/carlson/history/PDFs/14_paint.pdf |archivedatearchive-date=February 7, 2012 }}

* {{cite web |url=http://accad.osu.edu/~waynec/history/lesson15.html |title=Hardware advancements |work=A Critical History of Computer Graphics and Animation |publisher=The Ohio State University |author=Wayne Carlson |year=2003 |url-status=dead |archiveurlarchive-url=https://web.archive.org/web/20120314015613/http://design.osu.edu/carlson/history/lesson15.html |archivedatearchive-date=2012-03-14 }}

* {{cite web |url=http://accad.osu.edu/~waynec/history/PDFs/paint.pdf |title=Digital Paint Systems: An Anecdotal and Historical Overview |author=Alvy Ray Smith |publisher=IEEE Annals of the History of Computing |year=2001 |url-status=dead |archiveurlarchive-url=https://web.archive.org/web/20120205050230/https://design.osu.edu/carlson/history/PDFs/paint.pdf |archivedatearchive-date=2012-02-05 }}

{{Refend}}