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Direct3D and OpenGL are competing application programming interfaces (APIs) which can be used in applications to render 2D and 3D computer graphics. Hardware acceleration of this process has been commonplace since approximately . , graphics processing units (GPUs) almost always implement a particular version of both of these APIs, such as these examples: DirectX 9 and OpenGL 2 circa 2004; DirectX 10 and OpenGL 3 circa 2008; and most recently, DirectX 11 and OpenGL 4 circa 2011. GPUs that support more recent versions of the standards are backwards-compatible with applications that utilize the older standards; for example, one can run older DirectX 9 games on a more recent DirectX 11-certified GPU. == Availability == Direct3D application development generally targets the Microsoft Windows platform. The OpenGL API is an open standard, and implementations exist for a wide variety of platforms. In more detail, the two computer graphics APIs are the following: # Direct3D is a proprietary〔()〕 API by Microsoft that provides functions to render two-dimensional (2D) and three-dimensional (3D) graphics, and uses hardware acceleration if available on the graphics card. It was designed by Microsoft Corporation for use on the Windows platform. Direct3D can also be used on other operating systems through Win32 api layer such as Wine, although the subset of features provided is not as complete as the reference implementation. # OpenGL is an open standard API that provides a number of functions to render 2D and 3D graphics, and is available on most modern operating systems including but not limited to Windows, Mac OS X and Linux. Note that many essential OpenGL extensions and methods, although documented, are actually patented, thus imposing serious legal troubles to implement them (see issues with Mesa〔idr: OpenGL 3 and Mesa: (X.Org Wiki - Events/XDC2009/Notes ). Retrieved 28 October 2011.〕). OpenGL and Direct3D are both implemented in the display driver. A significant difference however is that Direct3D implements the API in a common runtime (supplied by Microsoft), which in turn talks to a low-level Device Driver Interface (DDI). With OpenGL, every vendor implements the entire API in the driver itself. This means that some API functions may have slightly different behavior from one vendor to the next. The GLSL shader compilers of different vendors also show slightly different behavior. The following compares the two APIs, structured around various considerations mostly relevant to game development. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Comparison of OpenGL and Direct3D」の詳細全文を読む スポンサード リンク
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