The rich graphics of video games are enhanced by Direct3D and OpenGL.
Photoshop CS5 and CS4 leverage the video adapter’s chip (the graphics processing unit (GPU)) instead of the computer’s main chip, the central processing unit (CPU), to speed some functions. Direct3D and OpenGL are competing application programming interfaces (APIs) which can be used by applications to render two-dimensional (2-D) and three-dimensional (3-D) computer graphics, taking advantage of hardware acceleration when available.
Direct3D is Microsoft’s proprietary DirectX API. Direct3D is only available for Microsoft’s Windows operating systems, although it also runs on the open source software, Wine. It is the foundation for the graphics API on the Xbox and Xbox 360 game systems, and allows applications to run full screen instead of window-sized, though it can also be customized to run in a window. Direct3D uses hardware acceleration from the available graphics card to further speed graphics rendering.
OpenGL is an open source API that provides many of the same functions as Direct3D to render 2-D and 3-D graphics, and will run on most operating systems including Windows; Mac OS X and GNU/Linux, most importantly. OpenGL therefore accelerates video processing for working with large or complex images, including 3-D. OpenGL settings and
GPU acceleration continue to work on Photoshop, but Photoshop on 64-bit Windows XP systems doesn’t support them.
Photoshop Memory Usage
Photoshop borrows much of the available memory on your computer to dynamically render all facets of the program. This ensures that Photoshop can successfully run the plug-ins and filters that are part of Photoshop and load large images in acceptable time frames. If possible on your computer, Photoshop uses OpenGL by default on Mac OS, Windows, Vista and Windows 7. In the 32-bit processing Windows XP, you can turn on the option manually so long as your video adapter supports it.
On Windows-based systems, improvements in both Direct3D and later Photoshop versions mean that Photoshop uses DirectX acceleration as well as OpenGL. It should be remembered that graphics rendering in Photoshop is more dependent on the operating system and the graphics hardware of the computer system, rather than the other way around. This is markedly valid since the migration of Photoshop and other graphics software to the PC platform.