Microsoft continues to say a firm no to backporting DirectX 10 to Windows XP. Furthermore, the Redmond company is also denying claims from third parties that Windows Vista's DirectX 10 will be hacked and transitioned to Windows XP. According to Microsoft, DirectX 10 is connected with the new overhauled graphics API and driver model introduced into Windows Vista. Also, DirectX 10 is irremediably tied to graphics cards with support for Shader Model 4.0. In Microsoft's perspective, this means that gamers that want access to DirectX 10 will not only have to migrate to Windows Vista but also upgrade their graphics card accordingly.
Phil Taylor, Senior Program Manager of the Flight Sim team at Microsoft says that projects such as the FallingLeafSystems have no chance whatsoever to make DirectX 10 work without DirectX 10 hardware. "FallingLeafSystems is claiming to enable DX10 on XP, and further, to quote the AlkyProject blog "No longer will you have to upgrade your OS and video card(s) to play the latest games." Can they make that work? Not at all. The FallingLeafSystems approach is to write a wrapper around the OpenGL extensions for DX10 class hardware that are already available on XP. And to claim this can work without proper hardware. That by itself means this isn’t some monumental hack. No reverse engineering of DX10 is involved. What is involved is eyeballing the D3D10 API and mapping those calls to their OGL equivalent," Taylor commented.
In this manner Microsoft responded to announcements that Halo 2 and Shadowrun, Windows Vista exclusive gaming titles, have been cracked to work on Windows XP and that FallingLeafSystems will backport DirectX 10 to XP. Taylor explained that taking DirectX 10 back to XP would be equivalent with rewriting the operating system's kernel in order to be similar to Vista's.
"A couple key parts of the Vista kernel-WDDM driver work are GPU interruptability and GPU memory management. Yes, in Vista the OS is managing the GPU to make applications play nice, as opposed to the DX9 style "last application in owns the card" style. And 10.1 and 10.2 will expand on those capabilities with more fine-grained interruptability and GPU memory paging behaviors. So there is a lot of work left to do before this is anything like ready for prime time. And it should be pretty clear that without DX10 class hardware this approach is doomed to failure. So that limits it out of the box," Taylor added.
As a conclusion Taylor revealed his circumspection over if backporting DirectX 10 to XP would work at all. Instead he said "full DX10 support requires Vista. There is no such thing as a free lunch."
Microsoft, Windows Vista, Windows XP, DirectX 1o, DX10