Swap chain: Difference between revisions

Revision as of 15:56, 29 March 2014

Revision as of 22:01, 27 May 2014

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In [[computer graphics (computer science)|computer graphics]], a '''swap chain''' is a series of virtual [[framebuffer]]s utilized by the [[graphics card]] and graphics [[API]] for [[frame rate]] stabilization and several other functions. The swap chain usually exists in [[Video card#Video memory|graphics memory]], but it can exist in system memory as well. The non-utilization of a swap chain willmay result in stuttering [[real Time rendering|rendering]], but its existence and utilization are required by many graphics APIs. A swap chain with two buffers is a [[double buffer]], and one with three is a [[triple buffer]].

==Function==

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| url = http://nexe.gamedev.net/directKnowledge/default.asp?p=Swap%20Chains

| accessdate = 30 October 2009

}}</ref>

===Comparison with Triple Buffering===

Outside the context of Direct3D, [[Multiple buffering#Triple buffering|triple buffering]] refers to the technique of allowing an application to draw to whichever back buffer was least recently updated. This allows the application to always proceed with rendering, regardless of the pace at which frames are being drawn by the application or the pace at which frames are being sent to the display. Triple Buffering may result in a frame being discarded without being displayed if two or more newer frames are completely rendered in the time it takes for one frame to be sent to the display. By contrast, Direct3D swap chains are a strict [[Queue (abstract data type)|first-in, first-out queue|]], so every frame that is drawn by the application will be displayed even if newer frames are available. Direct3D does not implement a most-recent buffer swapping strategy, and Microsoft's documentation calls a Direct3D swap chain of three buffers "triple buffering". Triple Buffering as described above is superior for interactive purposes such as gaming, but Direct3D swap chains of more than three buffers can be better for tasks such as presenting frames of a video where the time taken to [[Data Compression#Video|decode]] each frame may be highly variable. <ref name="anandtech 0">

{{Cite web

| title = Triple Buffering: Why We Love It

| publisher = AnandTech

| url = http://www.anandtech.com/show/2794/4

| accessdate = 27 May 2014

}}</ref>