DirectX 10 port for Windows XP users?

Teenage coder reverse engineers DX10 graphics API

Microsoft's new DirectX 10 graphics API will run on the aging Windows XP operating system. This is the bold claim being made by a 19-year-old software developer today.

If successful, the Alky Project will cast doubt on Microsoft's assertion that making DirectX 10 available to users of Windows XP was impossible due to engineering reasons. DirectX 10 is currently exclusive to the recently released Windows Vista operating system.

The Alky Project itself consists of a set of compatibility libraries designed to allow games made for the DirectX 10 API to run on operating systems other than Windows Vista. The coder behind the project is a self-styled specialist in compiler and inter-operating system compatibility. He goes under the name Cody Brocious.

Microsoft has previously claimed that it is impossible to offer the new API as an upgrade for Windows XP. This is down to changes to the way the latest revision of DirectX is architected. DX10 portability is also hampered by the API's close relationship with the new Windows Display Driver Model in Vista.

Exclusive Vista

Some industry observers have claimed Microsoft only made DirectX 10 an exclusive feature of Vista to force gaming enthusiasts to upgrade. Consequently, the full graphical wonder of several hotly anticipated new 3D gaming titles will only be available on PCs running Windows Vista. Games such as Crysis, Alan Wake and Unreal Tournament 3 also require the latest 3D hardware with full DirectX 10 support.

The Alky Project also claims to enable DirectX 10 software to run on existing DirectX 9 graphics hardware. One of the key new features of DirectX 10 is a new hardware graphics shader definition known as the geometry shader. The DirectX 9 3D chips, by contrast, only support pixel and vertex shader instructions.

However, the Alky Project reportedly reduces geometry shader instructions to native machine code for execution. In simple terms, the CPU is used to emulate missing GPU features.

A number of other projects designed to enable games coded for Microsoft's DirectX APIs to run on third party operating systems already exist. Perhaps the best known is Cedega . Cedega enables games made for Windows to run on many of the leading Linux distributions.

Preview versions of the compatibility libraries are available from the Alky Project website. But we would strongly advise against dabbling with such experimental software with any PC that is remotely mission critical. Early reports suggest the software is functional but extremely rudimentary.

"The current preview allows you to run a number of examples from the DirectX SDK on Windows XP," says a post on the Alky Project website. "They're not the greatest thing since sliced bread, but we want to whet your appetite."

If the project does end up offering anything approaching full functionality, Microsoft will have some serious explaining to do.

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