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DirectX

DirectX is a collection of APIs for handling tasks related to multimedia, especially game programming, on Microsoft platforms. It is widely used in the development of computer games for Windows, the Xbox and Xbox 360.

Both the DirectX runtime and SDK are available free of charge from Microsoft. The DirectX runtime was originally redistributed by computer game developers along with their games, but later it was included in Windows. Game developers still often include an updated version of DirectX that prompts installation automatically after the game installation to ensure proper program functionality.

The latest release version of DirectX is the October 2006 version of DirectX 9.0c. Direct3D 10 Beta is available as of Windows Vista build 5238.

DirectX APIs

The various components of DirectX are in the form of COM-compliant objects.

The components comprising DirectX are

For Windows Vista and DirectX 10, DirectInput will be deprecated in favor of XInput, from the Xbox team. Likewise, DirectSound will also be deprecated in favor of XACT. As of DirectX 9.0c, however, neither XInput nor XACT have all of the capabilities of DirectInput or DirectSound, and according to MS documentation on XInput, XInput is specifically designed for the Xbox 360 controllers. DirectPlay is deprecated in favor of Xbox Live whereas DirectShow will be deprecated in favor of Media Foundation, a different set of APIs debuting with Windows Vista to handle audio and video playback. DirectMusic will probably remain the only component intact.

History

This is from a post by Phil Taylor of Microsoft on the Directxdev mailing list. I have edited it slightly for readability:

" Some one should store this somewhere for when it gets asked again :-).

Alex, Craig, and Eric burst onto stage at CGDC 1995 and showed a beta of the GamesSDK v1, with DDraw, DSound, DInput, and DPlay. The logo used was the radiation symbol, the internal code-name was "The Manhattan Project" and the technology was smoking hot compared to any previous Windows graphics API.

They got a standing o, as no one had ever seen an MS library delivering refresh-rate graphics. It was quite a scene, and the BBQ and open rides at Great America contributed to the feeling that something great was happening.

Summer of 1995 MS bought RenderMorphics with the intent of adding a 3D API to the GSDK. I know this because I was at Kaleida labs who was a source licensee of RL, and I was the 3D developer for ScriptX, both Mac and Windows. Thus Kaleida and I was notified about the transaction.

GSDK v1 shipped in Oct 1995, just after Windows 95 shipped in August 1995.

The famous Judgement day Halloween party complete with Gwar in the Haunted House at the Redwest parking lot celebrated the event.

The day after Judgement day, "The Aftermath" was held to brief developers on D3D. At that time a beta of D3D was made available. The immediate mode API was always called D3D. The higher-level RL API was renamed to be D3D Retained Mode.

At some point a 2nd version of RL was indeed made available, but at the cost of being COM-ified. RL lost a bit of its performance with this architectural change. But D3D IM and accessing 3D HW is where the action was anyway.

DX 2.0 shipped in June 1996. The Games SDK was indeed renamed at this point, but still used the old radiation symbol logo. It contained updates to the original 4 APIs. D3D IM and RM were aimed at DX 3.0.

DX 3.0 shipped August "43" ( Sept 12 to the rest of us ) because Eric promised it would ship in August. D3D IM with execute buffers and D3D RM were in that release.

The release plan Alex, Craig, and Eric had outlined before the community at CGDC 96 and again at Meltdown Aug '96 showed:

   *   DX 3 Aug 96
   *   DX 4 Dec 96
   *   DX 5 June 97
DX 4 was basically a bug fix release to make sure DX 3 actually worked on real 3D HW since the Voodoo 1 HW release was going to be after DX 3 shipped.

Similar fix-ups have happened since. After a lot of discussion, saner heads prevailed and convinced the 3 that a release right before Christmas would be a bad idea in terms of consumer satisfaction and game developer sales, since there would be little testing and a high likelihood of bad experiences and returns.

So the question was what to do about release numbers. Since a DX 5 release in 97 was already on tap, it was decided to skip DX 4 and go to DX 5. That way the community got the expected release in 97.

At the same time, both Japanese and German geographies provided feedback that the radiation symbol logo was not appropriate for those geographies.

Kevin Dalles was product manager at the time ( before Kevin Bachus ) and produced the 4-arm logo over winter 96-97. The logo change was unrelated to any release vehicle.

As a retrospective flashback, Alex started appearing down in the valley at Ken Nicholsons "GamePC Consortium" meetings ( which I attended ) and was talking about graphics acceleration, "Funstones" as a benchmark to measure graphics performance, etc - all a huge big hint he was cooking something up back in Redmond. http://www4.tomshardware.com/smoke/20000120/smoke-01.html captures some of that perspective. Although I have to say WinG wasnt that laughable, just limited to 8-bit modes which wasn't enough. DDraw accelerated all modes by comparison, which made it way more valuable. And the perspective on how RL become D3D IM is a bit limited in that its accurate enough for RM but doesn't hit enough data points for the IM API. And D3D definitely was not "jumped on" by 3Dfx, ATI, and nVidia. 3Dfx did all they could to counter-evangelise Glide. ATI and nVidia were helpful true. Nor is Rich Seidner's "Crushed by MS" totally true - I worked with Rich at Kaleida and thus know quite a bit about what really happened. So don't read Omits' article or any of these articles and believe all of it.

All that and I didn't mention the spaceship at all :-) " Phil Taylor, 20 October 2004,

When directX was first launched they were in direct competition with the Japanese developers who were beating the Americans in almost all aspects of technology and especially gaming, so Microsoft -led by Alex st. John-, in a sort of sick retort called DirectX "The Manhattan Project".

Originally targeted at the game development industry, DirectX has become more widely used among other software production industries. Most notably, Direct3D is becoming more popular among the engineering sector because of its ability to quickly render high-quality 3D graphics using the latest 3D graphics hardware.

In 1994, Microsoft was just on the verge of releasing its next operating system, Windows 95. The main factor that would determine the value consumers would place on their new operating system very much rested on what programs would be able to run on it. Three Microsoft employees — Craig Eisler, Alex St. John, and Eric Engstrom — were concerned, because programmers tended to see Microsoft's previous operating system, DOS, as a better platform for game programming, meaning few games would be developed for Windows 95 and the operating system would not be as much of a success.

DOS allowed direct access to video cards, keyboards and mice, sound devices and all other parts of the system, while Windows 95, with its protected memory model, restricted access to all of these, working on a much more standardized model. Microsoft needed a way that would let programmers get what they wanted, and they needed it quickly; the operating system was only months away from being released. Eisler, St. John, and Engstrom conspired together to fix this problem, with a solution that they eventually named DirectX.

DirectX was built upon the concepts of a development system known as "Exodus" developed by Kinesoft Development under the direction of the their Founder, Peter Sills and their Director of Technology, Andrew Glaister. Exodus was first shown to Eric Engstrom early in 1994, thus sparking the concept that games could indeed be developed directly for Microsoft's forthcoming operating system, Windows 95. In fact, the first commercial game to ship using Exodus, was Pitfall for Windows 95 (from Activision). It was this title which Bill Gates showed off at that year's COMDEX tradeshow - announcing that Windows 95 would be a top-notch gaming platform. Microsoft worked closely with Kinesoft during that year to develop DirectX 1.0 Earthworm Jim (Activision) and Gex (Microsoft) were also shipped shortly after the release of Windows 95, both using the Exodus engine, which then evolved into DirectX.

Andrew Glaister later went on to be the Development Manager of the Microsoft Game Studios in Redmond, Washington.

The first version of DirectX released was shipped September of 1995 as the Windows Games SDK. It was the Win32 replacement for the poorly designed APIs for the Win16 operating system (DCI and WinG). A development team at ATI brought fundamental game graphics technology to the attention of Microsoft. The development of DirectX was led by the team of Eisler (development lead), St. John, and Engstrom (program manager). Simply put, it allowed all versions of Microsoft Windows, starting with Windows 95, to incorporate high-performance multimedia. Eisler wrote about the frenzy to build DirectX 1 through 5 in his blog.

Prior to DirectX's existence, Microsoft had already included OpenGL on their Windows NT platform. At the time, OpenGL required "high-end" hardware and was limited to engineering and CAD uses. Direct3D (introduced by Eisler, Engstrom, and St. John as an alternative to SGI's OpenGL) was intended to be a lightweight partner to the back then slower OpenGL for game use. As the power of graphics cards and the computers running them grew, OpenGL became the de-facto standard and a mainstream product. At that point a "battle" began between supporters of the cross-platform OpenGL and the Windows-only Direct3D, which many argued was another example of Microsoft's embrace, extend and extinguish business tactic (see Fahrenheit or Direct3D vs. OpenGL). Nevertheless, the other APIs of DirectX are often combined with OpenGL in many computer games because OpenGL does not include all of DirectX's functionality (such as sound or joystick support).

In a console specific version, DirectX was used as a basis for Microsoft's Xbox and xbox360 console API. The API was developed jointly between Microsoft and NVIDIA, who developed the custom graphics hardware used by the console. The Xbox API is similar to DirectX version 8.1, but is non-updateable like other console technologies. The Xbox was code named DirectXbox, but this was shortened to Xbox for its commercial name. (J. Allard, PC Pro Interview, April 2004)

In 2002, Microsoft released DirectX 9 with support for the use of much longer shader programs than before with pixel and vertex shader version 2.0. Microsoft has continued to update the DirectX suite since then, introducing shader model 3.0 in DirectX 9.0c, released in August 2004.

As of April 2005, DirectShow was removed from DirectX and moved to the Microsoft Platform SDK instead. DirectX is, however, still required to build the DirectShow samples [1].

Release history

DirectX version Logo Version number Operating system Date released
DirectX 1.0 4.02.0095   September 30, 1995
DirectX 2.0 / 2.0a   4.03.00.1096 Windows 95 OSR2 and NT 4.0 June 5, 1996
DirectX 3.0 / 3.0a   4.04.0068 / 70 Windows NT 4.0 SP3
last supported version of DirectX for Windows NT 4.0 		September 15, 1996
DirectX 4.0   Never launched  
DirectX 5.0   4.05.00.0155 Available as a beta for Windows NT 5.0 that would install on Windows NT 4.0 July 16, 1997
DirectX 5.1       December 1, 1997
DirectX 5.2   4.05.01.1600 DirectX 5.2 release for Windows 95 May 5, 1998
DirectX 5.2   4.05.01.1998 Windows 98 May 5, 1998
DirectX 6.0   4.06.00.0318 last version of DirectX Media for Windows NT 4.0 August 7, 1998
DirectX 6.1   4.06.02.0436 Windows 98 SE February 3, 1999
DirectX 7.0 4.07.00.0700 Windows 2000 September 22, 1999
DirectX 7.0a   4.07.00.0716   ???, 1999
DirectX 7.1   4.07.01.3000 Windows ME September 16, 1999
DirectX 8.0 4.08.00.???? (RC0)   September 30, 2000
DirectX 8.0 4.08.00.0400 (RC14) Xbox
  		November 3, 2000
DirectX 8.0a 4.08.00.0400 (RC14) + installer fixes Last supported version
for Windows 95 		November 7, 2000
DirectX 8.1   4.08.01.0810
4.08.01.0881 (RC7) 		Windows XP November 12, 2001
DirectX 9.0 4.09.0000.0900 Windows Server 2003 December 19, 2002
DirectX 9.0a   4.09.0000.0901   March 26, 2003
DirectX 9.0b   4.09.0000.0902 (RC2)   August 13, 2003
DirectX 9.0c   4.09.0000.0904 (RC0) Windows XP SP2 and Xbox 360 August 9, 2004
DirectX 9.0c   4.09.0000.0904 Compatible with all Windows OS versions that 9.0c (RC0) was compatible with
First version to include D3DX DLLs 		December 9, 2005
DirectX 9.0c - bimonthly updates   4.09.0000.0904 Windows XP
August 2005 was the last build to support Windows 98, Windows 98 SE, Windows ME and Windows 2000.
The December '05, and February '06 updates also add the XML format to some classes. These updates are primarily to D3DX and are only intended for developers and redistributable packages, but not the core runtime. They come bimonthly; official recommendation seems to be they should not be downloaded unless a piece of software specifically asks for them, despite user reports of increased performance with the newer versions. 		Bimonthly from 2005-08 until present
DirectX 9.0L   Windows Vista Only. (L for Longhorn) Provides DirectX 9 API for Vista
DirectX 10.0 New version of DirectX which is only available with Windows Vista.

Note that the version number as reported by Microsoft's DXDiag tool may use the x.xx.xxxx.xxxx format for version numbers; however Microsoft's site at http://msdn.microsoft.com/archive/default.asp?url=/archive/en-us/directx9_c_Dec_2004/directx/directxsdk/dxandxp.asp claims that the registry always has data in x.xx.xx.xxxx format. Put another way, when the above table lists a version as '4.09.0000.0904', the registry may have it as '4.09.00.0904'.

Compatibility

Hardware manufacturers have to write drivers for and test each individual piece of hardware to make them DirectX compatible. Many modern hardware devices only have DirectX compatible drivers (in other words, you must install DirectX before you will be able to use that hardware). Early versions of DirectX included an up-to-date library of all of the DirectX compatible drivers currently available. This practice was stopped however, in favor of the web-based Windows Update driver-update system, which allowed users to download only the drivers relevant to their hardware, rather than the entire library.

Some drivers only support one version of DirectX. But DirectX is backward compatible, which means that newer versions support the older versions. For example, if one has DirectX 9 installed on one's system and runs a game that was written for DirectX 6, it should still work. The game will use what is called the DirectX 6 "interface." Every version of DirectX must support every previous version of DirectX. This is a positive consequence of the COM model used for this API.

The future of DirectX

''See also: Direct3D 10 section at the Direct3D article

Microsoft has several development projects related to DirectX underway.

Microsoft is currently working on a large update to the Direct3D API. Originally called Windows Graphics Foundation, DirectX 10, and later DirectX Next, but currently referred to as Direct3D 10, it will appear as part of Windows Vista. Version 10 will represent a departure from the driver model of DirectX Graphics 9.0, with the addition of a scheduler and memory virtualization system. Direct3D 10 will forego the current DirectX practice of using "capability bits" to indicate which features are active on the current hardware. Instead, Direct3D 10 will define a minimum standard of hardware capabilities which must be supported for a display system to be "Direct3D 10 compatible". According to Microsoft, Direct3D 10 will be able to display graphics up to 8 times faster than DirectX Graphics 9.0c. In addition, Direct3D 10 will incorporate Microsoft Shader Model 4.0.

Microsoft is also developing XNA, which is a framework designed to assist development of games by making it easier to integrate DirectX, High Level Shader Language (HLSL) and other tools in one package.

Although somewhat in its infancy, during 2002 Microsoft released a version of DirectX compatible with the Microsoft .NET Framework, thus allowing programmers to take advantage of .NET features (such as the use of the C# and Visual Basic programming languages) simultaneously with DirectX development. This API is known as "Managed DirectX" and performance is claimed to be 98% of that of native DirectX software.

In December 2005, February 2006, April 2006 and August 2006 Microsoft released a version of DirectX that is designed for the .NET 2.0 framework. In older versions DirectX was split apart into different modules, this has changed with the .NET 2.0 version, it is now a single file and is much easier to use. However, the .NET 2.0 version of DirectX is not a finalized version; it is still a beta. During the GDC 2006 Microsoft presented the XNA Framework, which this 2.0 version will be merged into and which will allow for the execution of managed code on the Xbox 360. The XNA Game Studio Express beta was made available on Aug. 30, 2006, as a free download on Windows XP.

Microsoft will also make the requirements for GPU manufacturers to claim to be DirectX 10 compatible much stricter, with only three features optional. http://www.extremetech.com/article2/0,1697,2000442,00.asp. The intention of this is so that game developers will know all the features that the graphics cards have, and so they will be able to make games more effectively, by utilising all the features of DirectX without worrying about making their games be able to function without certain features.

DirectX 10 is available exclusively to Vista, which means that computers that aren't running Vista will not be able to run later applications which require DirectX 10. Although Wine developers have plans about porting their upcoming DirectX 10 implementation to older windows versions. [2] [3]

See also

External links

Programmer resources

This article is from Wikipedia and is available under the terms of the GNU Free Documentation License.