A set of Windows interfaces from Microsoft for programming graphics and sound. Windows developers program to the DirectX APIs, and the manufacturers of sound and graphics cards write DirectX drivers to be included with their hardware. DirectX provides a high-level interface for accessing low-level functions "directly." It accesses the hardware abstraction layer in Windows (see
HAL).
The first DirectX API was introduced in late 1995 to encourage game developers to move their software to Windows. Before DirectX, games for the PC were written in DOS in order to redraw the screen fast enough for real-time animation. To obtain the speed, gaming companies had to write drivers for a variety of graphics cards, which was a development headache.
A Single Graphics Interface for Windows
DirectX provides the interface to access the frame buffer and advanced features of the graphics card, which are not provided in the standard Windows GDI graphics interface. When DirectX was introduced, vendors quickly developed drivers that exposed low-level functions of their graphics hardware to the application.
Emulate Graphics Functions in Software
Through the Hardware Emulation Layer (HEL), DirectX is capable of emulating graphics functions in software that are not built into the graphics card. See
graphics pipeline.
Which DirectX Version Is Running?
To determine which version of DirectX is installed in your PC, select Run from the Start menu, type in
dxdiag and click OK. Look under System Information for the DirectX Version number. See
DirectX 12,
GDI,
video accelerator and
DirectSound.
DirectX
Interface Purpose
DirectCompute GPGPU computing
DirectDraw 2D graphics
Direct3D 3D graphics
DirectSound audio
DirectSound3D game audio
DirectPlay multi-player games
DirectInput game input
DirectVoice game audio chat
DirectShow streaming media
DirectVideo earlier video API