DirectX

From Freepedia

 

Maintainer: Microsoft
Latest release: 9.0c / August 8, 2004
OS: Windows
Genre: Application framework
License: EULA
Website: DirectX Homepage

DirectX is a collection of APIs for easily handling tasks related to game programming on Microsoft Windows. It is most widely used in the development of computer games for Windows. The DirectX SDK is available free from Microsoft. The DirectX runtime was originally redistributed by computer game developers along with their games, but later it was included in Windows. DirectX 9.0c is the latest version of DirectX. The latest versions of DirectX are still usually included with PC games, since the API is updated so often.

Contents

DirectX APIs

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

The components comprising DirectX are :

History

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.

See also RenderMorphics

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.

The first release version of DirectX was shipped September of 1995 as the Windows Games SDK. It was the Win32 replacement for poorly designed, ill-conceived APIs for the Win16 operating system (DCI and WinG). The development of DirectX was lead by the team of Eisler (development lead), St. John (evangelist), and Engstrom (program manager). Simply put, it allowed all versions of Microsoft Windows, starting with Windows 95, to incorporate high-performance multimedia.

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 OpenGL for game use. As the power of graphics cards and the computers running them grew, OpenGL became 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 in itself include all of DirectX's functionality (such as sound or joystick support). Several attempts to address this have generally failed.

DirectX was used as a basis for Microsoft's Xbox 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.

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 
DirectX 2.0 / 2.0a 4.03.00.1096Windows 95 OSR2 and NT 4.0
DirectX 3.0 / 3.0a 4.04.0068 / 69Windows NT 4.0 SP3
last supported version of DirectX for Windows NT 4.0
DirectX 4.0 Never launched 
DirectX 5.0 4.05.00.0155Available as a beta for Windows NT 5.0 that would install on Windows NT 4.0
DirectX 5.0 4.05.01.1721 / 1998Windows 98
DirectX 6.0 4.06.02.0436Windows 98 SE
last version of DirectX Media for Windows NT 4.0
DirectX 7.0
Image:Dx7logo.gif
4.07.00.0700Windows 2000 and ME
DirectX 7.0a 4.07.00.0716 
DirectX 8.0
Image:Dx8logo.gif
4.08.00.0400 
DirectX 8.1 4.08.01.0810
4.08.01.0881		Windows XP and 2003 Server
Last supported version
for Windows 95		November 12, 2001
DirectX 9.0 4.09.0000.0900 December 24, 2002
DirectX 9.0a 4.09.0000.0901 March 26, 2003
DirectX 9.0b 4.09.0000.0902 August 13, 2003
DirectX 9.0c 4.09.0000.0904Maybe the last supported version
for Windows 98SE and Windows Me		August 9, 2004
DirectX 9.0L (coming with Windows Vista) 4.09.0000.0905 (?)Adds the extended IDirect3DDevice9Ex interface with additional functions only available with LDDM drivers for Windows Vista.
DirectX 10 (coming with Windows Vista) (?)First version for Windows Vista 

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.

The future of DirectX

Microsoft is currently working on a large update to DirectX. Originally called Windows Graphics Foundation, but later renamed to DirectX 10, it will appear as part of Windows Vista. Version 10 will represent a departure from the driver model of DirectX 9.0, with the addition of a scheduler and memory virtualization system. DirectX 10 will forego the current DirectX practice of using "capability bits" to indicate which features are active on the current hardware. Instead, DirectX 10 will define a minimum standard of hardware capabilities which must be supported for a display system to be "DirectX 10 compatible".

Another tool Microsoft is working on is XNA which is a framework designed to assist development of games by making it easier to integrate DirectX, HLSL and other tools in one package.

See also

External links

Programmer resources

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