Microsoft Corp. has issued DirectX software development kit (SDK) that contains basic technical preview of Direct3D 11. Even though the preview does not expose all the features of DirectX 11, it gives a signal to software developers that Direct3D 11 is around the corner and that they can take advantage of appropriate functionality.

The new version of performance investigator (PIX) tool for Windows, which is a part of DirectX SDK, supports basic stream capture and single frame capture for Direct3D 11, however the new Direct3D 11 hardware features like tessellation, compute shader, dynamic shader linkage, and new resource formats, are not supported. In addition, advanced features like shader debugging and mesh viewing are not supported, according to Microsoft.

The key API difference from Direct3D 10 in Direct3D 11 is the addition of deferred contexts, which enables scalable execution of Direct3D commands distributed over multiple cores. A Deferred Context captures and assembles actions like state changes and draw submissions that can be executed on the actual device at a later time. By utilizing Deferred Contexts on multiple threads, an application can distribute the CPU overhead needed in the Direct3D 11 runtime and the driver to multiple cores, enabling better use of an end-user's machine configuration.

Direct3D 11 also extends and enhances Direct3D 10 with new hardware and API calls. For example, Direct3D 11 introduces the Compute Shader as a way to access this computational capability without so many constraints. It opens the door to operations on more general data-structures than just arrays, and to new classes of algorithms as well. Key features of compute shader include: communication of data between threads, and a rich set of primitives for random access and streaming I/O operations. These features enable faster and simpler implementations of techniques already in use, such as imaging and post-processing effects, and also open up new techniques that become feasible on Direct3D 11–class hardware.

Other key capability of the Direct3D 11 is additional pipeline stages to support real-time Tessellation of high order primitives. In addition, Direct3D 11 introduces a limited form of Runtime Shader Linkage that allows for near-optimal shader specialization during execution of an application.

The first DirectX 11-compatible graphics processing units are set to become available in 2009.

Tags: Microsoft, DirectX, ATI, AMD, Nvidia, Geforce, Radeon, Intel, Larrabee