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 shorthand term for all of these APIs (the X standing in for the particular API names) and soon became the name of the collection. 

Windows supports DirectX 8.0, which enhances the multimedia capabilities of your computer. DirectX provides access to the capabilities of your display and audio cards, which enables programs to provide realistic three-dimensional (3-D) graphics and immersive music and audio effects. DirectX is a set of low-level Application Programming Interfaces (APIs) that provides Windows programs with high-performance hardware-accelerated multimedia support.

DirectX enables the program to easily determine the hardware capabilities of your computer, and then sets the program parameters to match. This allows multimedia software programs to run on any Windows-based computer with DirectX compatible hardware and drivers and ensures that the multimedia programs take full advantage of high-performance hardware.

DirectX contains a set of APIs that provide access to the advanced features of high-performance hardware, such as 3-D graphics acceleration chips and sound cards. These APIs control low-level functions, including two-dimensional (2-D) graphics acceleration; support for input devices such as joysticks, keyboards, and mice; and control of sound mixing and sound output.

DirectX is composed of multiple APIs:

• Direct3D (D3D): for drawing 3D graphics.
• DXGI: for enumerating adapters and monitors and managing swap chains for Direct3D 10 and up.
• Direct2D: for 2D graphics.
• DirectWrite: for fonts.
• DirectCompute: for GPU Computing.
• DirectSound3D (DS3D): for the playback of 3D sounds.
• DirectX Media: comprising DirectAnimation for 2D/3D[14] web animation, DirectShow for multimedia playback and streaming media, DirectX Transform for web interactivity, and Direct3D Retained Mode for higher level 3D graphics. DirectShow contains DirectX plugins for audio signal processing and DirectX Video Acceleration for accelerated video playback.
• DirectX Diagnostics (DxDiag): a tool for diagnosing and generating reports on components related to DirectX, such as audio, video, and input drivers.
• DirectX Media Objects: support for streaming objects such as encoders, decoders, and effects.
• DirectSetup: for the installation of DirectX components, and the detection of the current DirectX version.
• XACT3 higher-level audio API
• XAudio2: low-level API for audio