CompTIA A+ Certification All-in-One Exam Guide

Although they might accomplish the same task (for instance, translating
instructions and passing them on to the video driver), every API handles
things just a little bit differently. In some 3-D games, the OpenGL standard
might produce more precise images with less CPU overhead than the DirectX
standard. In general, however, you won’t notice a large difference between
the images produced by OpenGL and those produced by DirectX.
1002
DirectX and Video Cards
In the old days, many applications communicated directly with much of the
PC hardware and, as a result, could crash your computer if not written well
enough. Microsoft tried to fix this problem by placing all hardware under the
control of Windows, but programmers balked because Windows added too
much work for the video process and slowed everything down. For the most
demanding programs, such as games, only direct access to hardware would
work.
This need to “get around Windows” motivated Microsoft to unveil a new
set of protocols called DirectX. Programmers use DirectX to take control of
certain pieces of hardware and to talk directly to that hardware; it provides
the speed necessary to play the advanced games so popular today. The
primary impetus for DirectX was to build a series of products to enable
Windows to run 3-D games. That’s not to say that you couldn’t run 3-D
games in Windows before DirectX; rather, it’s just that Microsoft wasn’t
involved in the API rat race at the time and wanted to be. Microsoft’s goal in
developing DirectX was to create a 100-percent-stable environment, with
direct hardware access, for running 3-D applications and games within
Windows.
Microsoft regularly updates DirectX. The latest games require the latest
version of DirectX. Windows updates automatically, so you don’t have to do
anything. But if you want to look at the DirectX version installed on a
computer (because you’ll see this on the 1002 exam), use the DirectX
Diagnostic Tool (dxdiag) (see Figure 17-64). In Windows 10, type dxdiag in
the Type here to search box. Press ENTER to run the program. The System tab
gives the version of DirectX. The system pictured in Figure 17-64 runs