Original sentence: Microsoft's OpenGL driver bundled with Windows versions before Windows Vista provides no hardware acceleration or direct support for extensions.OpenGL, on the other hand, has implementations available across a wide variety of platforms including Microsoft Windows, UNIX-based systems such as Linux and Mac OS X, and the PlayStation 3 game console.These ICDs are, in virtually all cases, bundled with the standard driver download package from IHVs, so simply installing recent graphics drivers is sufficient to provide hardware OpenGL support.These versions of Windows thus require that user install installable client drivers (ICD's) developed by GPU manufacturers for OpenGL hardware support.This allow for hardware acceleration through OpenGL from a standard install, but this implementation only implements OpenGL 1.4 without any of the extensions or versions since then.Windows Vista will include an OpenGL implementation that maps OpenGL calls to Direct3D ones.With the exception of Windows, all operating systems that allow for hardware-accelerated 3D graphics have chosen OpenGL as their only graphics API
Edited sentence: Being a proprietary Microsoft product intended for use only on Microsoft-supported platforms, one natural limitation of Direct3D is its lack of portability.For some applications this is irrelevant: computer game developers, for example, may decide that as the non-Windows segment of the computer gaming market is as of 2006 much smaller than the Windows segment, porting their games to non-Windows platforms is not a priority, and hence lack of portability is not a concern...Microsoft's OpenGL driver bundled with Windows versions from 95 to Vista provides no hardware acceleration or direct support for extensions.Microsoft's stance on this is that eliminating OpenGL inconveniences few and allows them to support more hardware in the same testing time.OpenGL, on the other hand, has implementations available across a wide variety of platforms including Microsoft Windows, UNIX-based systems such as Linux and Mac OS X, and game consoles by Nintendo and Sony such as the PlayStation 3 and Wii.Windows thus requires installable client drivers (ICD's) developed by GPU manufacturers for OpenGL hardware support; these ICD's also enable full Direct3D support.With the exception of Windows, all operating systems that allow for hardware-accelerated 3D graphics have chosen OpenGL as the primary API