DirectX |
DirectX is a collection of Application Programming Interface for easily handling tasks related to game programmer on Microsoft Windows. It is most widely used in the development of computer games for Windows. The DirectX Software development kit is available free from Microsoft. The DirectX runtime was originally redistributed by video game developer 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 computer game, since the API is updated so often.
=DirectX APIs=
The various components of DirectX are in the form of Component Object Model-compliant objects.
The components comprising DirectX are :
=History=
Originally targeted at the video game 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 card.
: 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 game programmer 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, computer keyboard and computer mouse, sound card 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 Windows API replacement for poorly designed, ill-conceived APIs for the Windows API 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 graphics API 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 video game 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 [http://msdn.microsoft.com/directx/sdk/readmepage/default.aspx].
== Release history ==
=Compatibility=
Hardware manufacturers have to write Device driver 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 (Microsoft) 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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