Jump to content

DirectX

From Wikipedia, the free encyclopedia

This is an old revision of this page, as edited by 72.11.40.154 (talk) at 21:08, 1 March 2007. The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

You must add a |reason= parameter to this Cleanup template – replace it with {{Cleanup|November 2006|reason=<Fill reason here>}}, or remove the Cleanup template.

DirectX
Developer(s)Microsoft
Stable release
Operating systemMicrosoft Windows
TypeApplication framework
LicenseEULA
WebsiteDirectX Homepage

Editing of this article by unregistered or newly registered users is currently disabled.
Such users may discuss changes, request unprotection, log in, or create an account. DirectX is a collection of Application Programming Interfaces (APIs) for handling tasks related to multimedia, especially game programming, on Microsoft platforms. It is competing with OpenGL and with SDL and is widely used in the development of computer games for Microsoft Windows, Sega Dreamcast, Microsoft Xbox, and Microsoft Xbox 360.

DirectX is also used among other software production industries, most notably among the engineering sector because of its ability to quickly render high-quality 3D graphics using the latest 3D graphics hardware.

Both the DirectX runtime and software development kit are proprietary closed-source software but available free of charge. The DirectX runtime was originally redistributed by computer game developers along with their games, but later it was included in Microsoft 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, DirectX 10 is exclusive to Microsoft Windows Vista.

DirectX APIs

DXDiag running in XP Service Pack 2

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

The components comprising DirectX are

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, one must install DirectX in order 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. Prior to DirectX 10, DirectX was considered backward compatible, which means that newer versions supported the older versions. For example, if one had DirectX 9 installed on one's system and ran a game that was written for DirectX 6, it would still work. The game used what was called the DirectX 6 "interface". Every version of DirectX supported every previous version of DirectX. This is a positive consequence of the COM model used for this API.

With Windows Vista and the radically changed Direct3D 10, this is no longer possible for handling 3D graphics. DirectX 10 therefore also supplies the Direct3D 9 API so older games and applications can still use graphics hardware..

DirectX 10

Windows Vista ships with DirectX 10 and is the only version of Windows which it is offered for, and it has a large number of changes: DirectInput will be deprecated in favor of XInput, from the Xbox team. Likewise, DirectSound will also be deprecated in favor of XACT. DirectX 10 has also dropped support for hardware accelerated audio, opting instead to render sound in software on the CPU. 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.[citation needed]

Direct3D

A major new feature of DirectX 10 is Direct3D 10 (originally called Windows Graphics Foundation). By using the new Windows Display Driver Model, Shader Model 4 and new, more strict requirements for GPU manufacturers to claim Direct3D 10 compatibility,[1] version 10 of Direct3D represents a departure from the practices of previous versions. In order to achieve backwards compatibility with previous versions of Direct3D, DirectX 10 actually contains three versions of Direct3D:[2]

  • Direct3D 9: this API emulates all Direct3D 9 on Windows XP behavior (and it's quirks) in order to achieve full compatibility with older applications. All the details and advantages of Vista's Windows Display Driver Model are hidden from the application if WDDM drivers are installed. This is the only API available if there are only XP graphic drivers (XPDM) installed, after an upgrade to Vista for example.
  • Direct3D 9Ex (previously known as 9.0L): allows full access to the new capabilities of WDDM while maintaining compatibility for existing Direct3D applications by putting it in a seperate API. The transparency ("Glass") effects in Windows Aero rely on the D3D 9Ex code path. When 9Ex was still codenamed 9.0L, there were rumors that this would be Direct3D 10 for Windows XP.[3] It was quickly pointed out that this was not the case, mainly due to lack of support for WDDM in Windows XP.[4]
  • Direct3D 10

Currently, the only graphics hardware compatible with Direct3D 10 is the NVIDIA GeForce 8 Series which has thus far limited the advent of Direct3D 10-capable applications. Contrary to rumors surrounding the issue, Direct3D 10 will not be released on the Xbox 360 via a firmware update due to incompatibilities with its graphics hardware.[5]

Other information

Microsoft developed XNA, 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 still 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" (or MDX for short) and performance is claimed to be 98% of that of native DirectX software. The design ideas behind Managed DirectX can be seen in the newer framework XNA which also implements Managed DirectX along with other technologies aimed at making game development easier.

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, as 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 RTM was made available on Dec. 11, 2006, as a free download on Windows XP

Alternatives

There are alternatives to this framework, some more complete than others. An example of an increasingly popular cross platform alternative that provides some of the functionality is the combination of OpenGL and OpenAL. Other alternatives are SDL or openML.

See also

References

  1. ^ http://www.extremetech.com/article2/0,1697,2000442,00.asp
  2. ^ Chuck Walbourn (August 2006). "Graphics APIs in Windows Vista". MSDN. Retrieved 2007-02-26. {{cite web}}: Check date values in: |date= (help)
  3. ^ Fuad Abazovic (October 16 2006). "DirectX 9.L will be a DirectX 10 for Windows XP, apparently". Retrieved 2007-02-26. {{cite web}}: Check date values in: |date= (help)
  4. ^ David Weller (October 17 2006). "DirectX 10 for Windows XP? Repeat after me: No. No. No". Let's Kill Dave!. Retrieved 2006-12-31. {{cite web}}: Check date values in: |date= (help)
  5. ^ Patrick Klepek (August 23 2006). "Xbox 360 Not Upgradable to DirectX 10". 1UP.com. Retrieved 2006-12-31. {{cite web}}: Check date values in: |date= (help)

Programmer resources

Retrieved from "https://en.wikipedia.org/enwiki/w/index.php?title=DirectX&oldid=111912987"