<P> A major update to DirectX API, DirectX 10 ships with and is only available with Windows Vista and later; previous versions of Windows such as Windows XP are not able to run DirectX 10 - exclusive applications . Rather, programs that are run on a Windows XP system with DirectX 10 hardware simply resort to the DirectX 9.0 c code path, the latest available for Windows XP computers . </P> <P> Changes for DirectX 10 were extensive . Many former parts of DirectX API were deprecated in the latest DirectX SDK and are preserved for compatibility only: DirectInput was deprecated in favor of XInput, DirectSound was deprecated in favor of the Cross-platform Audio Creation Tool system (XACT) and additionally lost support for hardware accelerated audio, since the Vista audio stack renders sound in software on the CPU . The DirectPlay DPLAY. DLL was also removed and was replaced with dplayx. dll; games that rely on this DLL must duplicate it and rename it to dplay. dll . </P> <P> In order to achieve backwards compatibility, DirectX in Windows Vista contains several versions of Direct3D: </P> <Ul> <Li> Direct3D 9: emulates Direct3D 9 behavior as it was on Windows XP . Details and advantages of Vista's Windows Display Driver Model are hidden from the application if WDDM drivers are installed . This is the only API available if there are only XP graphic drivers (XDDM) installed, after an upgrade to Vista for example . </Li> <Li> Direct3D 9Ex (known internally during Windows Vista development as 9.0 L or 9. L): allows full access to the new capabilities of WDDM (if WDDM drivers are installed) while maintaining compatibility for existing Direct3D applications . The Windows Aero user interface relies on D3D 9Ex . </Li> <Li> Direct3D 10: Designed around the new driver model in Windows Vista and featuring a number of improvements to rendering capabilities and flexibility, including Shader Model 4 . </Li> </Ul>

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