DirectX

Microsoft DirectX is a collection of application programming interfaces (APIs) for handling tasks related to multimedia, especially game programming and video, on Microsoft platforms. Originally, the names of these APIs all began with "Direct", such as Direct3D, DirectDraw, DirectMusic, DirectPlay, DirectSound, and so forth. The name DirectX was coined as a shorthand term for all of these APIs (the X standing in for the particular API names) and soon became the name of the collection. When Microsoft later set out to develop a gaming console, the X was used as the basis of the name Xbox to indicate that the console was based on DirectX technology. The X initial has been carried forward in the naming of APIs designed for the Xbox such as XInput and the Cross-platform Audio Creation Tool (XACT), while the DirectX pattern has been continued for Windows APIs such as Direct2D and DirectWrite.

Direct3D (the 3D graphics API within DirectX) is widely used in the development of video games for Microsoft Windows and the Xbox line of consoles. Direct3D is also used by other software applications for visualization and graphics tasks such as CAD/CAM engineering. As Direct3D is the most widely publicized component of DirectX, it is common to see the names "DirectX" and "Direct3D" used interchangeably.

The DirectX software development kit (SDK) consists of runtime libraries in redistributable binary form, along with accompanying documentation and headers for use in coding. Originally, the runtimes were only installed by games or explicitly by the user. Windows 95 did not launch with DirectX, but DirectX was included with Windows 95 OEM Service Release 2. Windows 98 and Windows NT 4.0 both shipped with DirectX, as has every version of Windows released since. The SDK is available as a free download. While the runtimes are proprietary, closed-source software, source code is provided for most of the SDK samples. Starting with the release of Windows 8 Developer Preview, DirectX SDK has been integrated into Windows SDK.

In late 1994, Microsoft was ready to release Windows 95, its next operating system. An important factor in its value to consumers was the programs that would be able to run on it. Microsoft employee Alex St. John had been in discussions with various game developers asking how likely they would be to bring their MS-DOS games to Windows 95, and found the responses mostly negative, since programmers had found that the Windows environment did not provide the necessary features which were available under MS-DOS using BIOS routines or direct hardware access. There were also strong fears of compatibility; a notable case of this was from Disney's Animated Storybook: The Lion King which was based on the WinG programming interface. Due to numerous incompatible graphics drivers from new Compaq computers that were not tested with the WinG interface which came bundled with the game, it crashed so frequently on many desktop systems that parents had flooded Disney's call-in help lines.

Another Microsoft employee, Craig Eisler, had joined the Windows 95 multimedia team to work on game technology. Hearing from St. John that the technology Microsoft had was not resonating with developers, Eisler set out to build a new set of APIs and a driver model that would allow developers to access the native capabilities of graphics hardware, and gave graphics hardware companies the ability to innovate in ways that developers could use. Needing program management support, Eisler recruited Eric Engstrom, and together they were granted 11 patents for their DirectX work. The project was codenamed the Manhattan Project, like the World War II project of the same name, and the idea was to displace the Japanese-developed video game consoles with personal computers running Microsoft's operating system. It had initially used the radiation symbol as its logo but Microsoft asked the team to change the logo. Management did not agree to the project as they were already writing off Windows as a gaming platform, but the three committed towards this project's development. Their rebellious nature led Brad Silverberg, the senior vice president of Microsoft's office products, to name the trio the "Beastie Boys".

Most of the work by the three was done among other assigned projects starting near the end of 1994. Within four months and with input from several hardware manufacturers, the team had developed the first set of application programming interfaces (APIs) which they presented at the 1995 Game Developers Conference. The SDK included libraries implementing DirectDraw for bit-mapped graphics, DirectSound for audio, and DirectPlay for communication between players over a network. Furthermore, an extended joystick API already present in Windows 95 was documented for the first time as DirectInput, while a description of how to implement the immediate start of the installation procedure of a software title after inserting its CD-ROM, a feature called AutoPlay, was also part of the SDK. The "Direct" part of the library was so named as these routines bypassed existing core Windows 95 routines and accessed the computer hardware only via a hardware abstraction layer (HAL). Though the team had named it the "Game SDK" (software development kit), the name "DirectX" came from one journalist that had mocked the naming scheme of the various libraries. The team opted to continue to use that naming scheme and call the project DirectX.

The first version of DirectX was released in September 1995 as the Windows Game SDK. Its DirectDraw component was the Win32 replacement for the DCI and WinG APIs for Windows 3.1. DirectX 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.

To get more developers on board DirectX, Microsoft approached id Software's John Carmack and offered to port Doom and Doom 2 from MS-DOS to DirectX, free of charge, with id retaining all publishing rights to the game. Carmack agreed, and Microsoft's Gabe Newell led the porting project. The first game was released as Doom 95 in August 1996, the first published DirectX game. Microsoft promoted the game heavily with Bill Gates appearing in ads for the title.