All about DirectX 10

Atomic talks DirectX 10 with Chas Boyd to find out why it's Vista only, what it can do and if it's as good as we've heard.

Atomic talks DirectX 10 with Chas Boyd to find out why it's Vista only, what it can do and if it's as good as we've heard.

Atomic: Could you explain the new features available in DX10?
Chas Boyd: New features in DirectX 10 maximise the power of the GPU, allowing games to more efficiently use powerful modern video cards to their fullest potential, while freeing up the CPU for improved artificial intelligence in games and bigger game worlds. The programmability and power of DirectX 10 allows developers to create more complex environments and detailed characters, as well as more powerful physics and artificial intelligence. We also re-architected the Windows Display Driver Model to provide more stability and better performance.

Atomic: What are the major differences with DX10 and DX9?
Boyd: We took a dramatic new approach with DirectX 10 in Windows Vista, rebuilding it from the ground up in order to provide a rich, incredibly detailed experience, while delivering many times the graphics performance potential.

Atomic: What’s new in Shader Model 4.0?
Boyd: Support for longer unified shaders creates more flexibility for developers and allows programmers to use the GPU for features such as physics calculations and audio processing. Shader Model 4.0 includes a stringent specification designed to simplify development, with features such as 32-bit colour depth precision. The features in Shader Model 4.0 also make DirectX 10 more effective for audiences such as CAD/CAM designers or creators of movie special effects.

Atomic: At this point, what do you see as being the best showcase of DX10 technology?
Boyd: Our partner publishers have done some amazing things with DirectX 10 technology. The award-winning Crysis has been almost universally declared the most visually advanced game available, due in no small part to Crytek’s use of DirectX 10. Other titles, including Gears of War for Windows, BioShock, World in Conflict and Flight Simulator demonstrate what DirectX 10 can offer to games in a variety of genres.

The majority of games out today (even console games) are built with DirectX 9, which has had more than five years to mature. DirectX 10 games look great now, but in five years developers are going to stun people with the graphic fidelity. We opened up the API for developers to do more with it, and as for hardware vendors, they have all agreed to support all of the features DirectX 10 has to offer. With the new generation of GPUs gamers will no longer have to worry about whether their cards will support certain features or not.

Atomic: Why can DX10 never run on XP/2000?
Boyd: DirectX 10 requires specific features of the Windows Vista operating system in order to take full advantage of graphics hardware, specifically the functionality offered by the new display driver model, WDDM.

Atomic: Was the public backlash about DX10 being Vista-exclusive expected? How do you feel about it?
Boyd: The adoption period associated with any new technology can cause some users to feel left behind. We’ve done our best to limit complexity for users by assuring that all DirectX 10 titles are backwards compatible with DirectX 9 hardware and Windows XP. As Windows Vista rapidly becomes the platform of choice for PC gamers, we feel confident that Windows gamers will appreciate the quality and features Windows Vista brings to gaming, and to DirectX 10.

Atomic: What sort of performance/quality differences will gamers see on DirectX 10 and DirectX 9 hardware?
Boyd: Right about now we are seeing performance parity between DirectX9 and DirectX10 implementations, and from here on DirectX10 performance will grow. We are already seeing some image quality improvements due to DirectX10’s more precise specification of how the hardware should work, which helps both DirectX9 and DirectX10 games visually. DirectX10’s advanced features will enable games to use visual techniques that would be more complicated to implement under DirectX9. For example, improved interfaces allow higher scene complexity for richer, more detailed worlds at a given performance level. At a practical level, DirectX10’s more consistent feature set also means more games shipping sooner because of reduced game development times.

Atomic: What advantages are there working with DirectX 10 over DirectX 9?
Boyd: As I mentioned earlier, DirectX 10 includes new features that help developers take better advantage of the GPU, including Shader Model 4.0, as well as providing for a more stable platform all together. Whether a game is built for Xbox 360, Windows, or both, we want to make sure there is as much efficiency as possible. We receive regular input from hardware vendors and constantly update the DirectX SDK to ensure developers can use the latest programming innovations in their applications.

Atomic: When do you think we’ll be seeing the full extent of DX10’s capabilities?
Boyd: As new technology enters the market, it takes time for adoption to grow and the full realisation of the potential to unfold. We’ve seen our development partners do some amazing things with DirectX 10, and with additional driver and hardware support, we’re confident that DirectX 10 technology is on its way to changing the way the world looks at computer graphics.

Atomic: When do you believe we’ll have reached the point when the majority of gamers have moved onto DX10 hardware?
Boyd: With more than 80 million copies of Windows Vista in use in the first year and a projected 60 million DirectX 10 GPUs shipped through January 2008, I’d say we have a great start. We are confident that the gaming community understands and appreciates what DirectX 10 offers, and will continue to adopt it.

Atomic: Some gamers have complained about experiencing reduced performance in DX9 applications in Vista. Is this something that can/will be addressed in Service Pack 1?
Boyd: As of yet we have no information to share on the contents of Windows Vista Service Pack 1. Additionally, game developers and hardware vendors are regularly updating and optimising their games and drivers respectively to continuously improve performance.

Atomic: Does the fact that current-gen consoles use an older version of DirectX than Vista PCs make multi platform development tricky?
Boyd: Basically, no. There are some new features in DirectX 10 that differ from the DirectX 9 Application Programming Interface, but for the most part we aim to provide developers with a common set of APIs for both the Xbox and Windows platforms. For example, XInput is a common API that allows for easy implementation of support for the Xbox 360 Controller for both Xbox and Windows games. Another example is XACT Microsoft cross-platform audio creation tool, similarly it allows for one API to be used across both the Xbox and Windows platforms.

We are also taking steps to ensure easier development for everyone including students, hobbyists and independent game developers. XNA Game Studio Express is based on Visual C# Express 2005 and lets developers create games for both Windows and Xbox 360.

Atomic: Is there a Microsoft DX10 game console in development? Can you provide a rough idea of when it will be released?
Boyd: We have nothing to announce at this time.

Atomic: What can gamers expect from DX10.1? Could you explain why the update isn’t compatible with DX10 hardware?
Boyd: Unlike DirectX 10.0, which provided major new features that had significant impact on game engines and art pipelines, DirectX 10.1 is a minor update that provides support for incremental new features with minimal code change.

The features included in DirectX 10.1 are an incremental extension; we do not expect applications to depend on these exclusively. All of the features in DirectX 10.1 have fallbacks that are straightforward to implement if native hardware support is not available. We fully expect that all games that leverage the new features will also run on DirectX 10.0 hardware.