Providing Guidelines for Hardware Development

When Microsoft created DirectX, one of its primary goals was to promote games development for the Windows operating environment. Prior to DirectX, the majority of games developed for the personal computer were MS-DOS-based. Developers of these games had to conform to a number of hardware implementations for a variety of cards. With DirectX, games developers get the benefits of device independence without losing the benefits of direct access to the hardware.

Another important goal was to provide guidelines for hardware companies based on feedback from developers of high-performance applications and independent hardware vendors (IHVs). As a result, the DirectX SDK components might provide specifications for hardware-accelerator features that do not yet exist. In many cases, the software emulates these features. In other cases, the software polls the hardware regarding its capabilities and bypasses the feature if it is not supported.

Display-hardware features that will be available soon include:

·Overlays, which will be supported so page flipping will be enabled within a window in a graphic device interface (GDI). Page flipping is the double-buffer scheme used to display frames on the entire screen.

·Sprite engines, which make overlaying sprites easier.

·Stretching with interpolation, which efficiently conserve display memory because it stretches a smaller frame to fit the entire screen.

·Alpha blending, which mixes colors at the hardware-pixel level.

·Three-dimensional (3D) accelerators with perspective-correct textures, which allow you to display textures on a 3D surface. For example, you can texture hallways in a castle generated by 3D software with a brick-wall bitmap that maintains the correct perspective.

·Blits for 3D graphics that take z-buffers into account.

·Standard 2 megabytes (MB) of display memory, which is typically the minimum required by 3D games.

·Compression standard, which allows you to store more data in display memory. This standard will be very fast when implemented in either software or hardware. It will be used for textures and will include transparency compression.

Audio-hardware features that will be available soon include:

·Hardware and enhancers that provide a 3D spatial placement for different sounds.

·On-board memory for audio boards.

·Audio-video combination boards that share on-board memory.

In addition, video playback will benefit from future DirectX-compatible hardware accelerators. One of the features that future releases of DirectX will support is hardware-accelerated decompression of YUV video.