DirectX is probably the best known collection of Application Programming Interfaces (APIs) out there. Originally developed to transition game development from MS-DOS to Windows 95, it allows game developers to easily program for a wide variety of hardware.

The development of DirectX over the last 14 years has paralleled the development of Windows. There were many frequent updates to DirectX from the release of version 5.0 to DirectX 9.0, with gamers eagerly downloading each update in order to unlock higher performance or better features. That was because there were dozens of video card companies developing hardware during the turn of the century. With only three major players today, most performance boosts have come from GPU manufacturers themselves.

Nonetheless, Microsoft still understands the importance of driving the baseline for graphics technology. Every major release of Windows since Windows 95 has come with at least a DirectX update. Windows XP came with DirectX 8.1, XP Service Pack 2 included DirectX 9.0c, Vista launched with DirectX 10, and Windows 7 will launch with DirectX 11 on October 22.

Windows Vista introduced the Windows Display Driver Model, which allowed new features such as virtualized video memory and scheduling of concurrent graphics contexts. Since DirectX 10 was so closely integrated with Vista, it could not be easily used with older versions of Windows. Along with poor consumer satisfaction, this led to a dearth of game developers programming for DirectX 10, despite its many features. Game developers target the largest number of consumers possible, and none of them wanted to program exclusively for DirectX 10 if nobody had hardware for it.

Microsoft has learned its lesson, and the situation is very different with DirectX 11. It is essentially a superset of DirectX 10.1, itself a superset of DirectX 10. This means that game developers will be able to design their games for DirectX 11, but the Direct3D 11 runtime will scale back graphics features that are not supported by the hardware. This also means that Windows Vista users will be able to install DirectX 11, which means a bigger market for game developers.

There are several key features in DirectX 11 that will make graphics on the screen look closer to reality. Tessellation is used to increase the polygon count in an image. The more polygons, the more realistic the image will look. Gone will be the days of blocky looking characters as the polygon count will increase significantly with the next generation of DirectX 11 hardware.

Multithreaded rendering will allow Direct3D processes to run across multiple CPU cores. Most games are using dual core CPUs, but multithreaded rendering will make gaming on triple and quad cores finally worth the cost. A faster processing pipeline and increased scaling are only some of the benefits.

DirectCompute allows access to the shader cores and pipeline. It allows for non-proprietary physics implementations, which some open-source physics projects are looking to take advantage of. Video transcoding will also take a significant leap due to access to the many processors on a modern GPU.

Many improvements to image quality and realism were already made available in DirectX 10 with Shader Model 4.0, and Shader Model 5.0 in DirectX 11 will bring even more improvements. A new type of texture compression will bring higher image quality as well.

Game developers are very excited about the possibilities that DirectX 11 hardware brings. There are over three dozen DirectX 11 titles currently in development, and some of them will be available for the Windows 7 launch.

Finally, graphics cards will have something to challenge them.