DDHAL Customization

Once you implement a basic display driver with DirectDraw support, you may want to customize it to take full advantage of the hardware you are using. Before you try to extend your new DDHAL implementation, familiarize yourself with the DirectDraw hardware abstraction layer specification that is part of the DirectDraw driver documentation.

Performance Enhancements

The basic DDHAL implementation has no internal hardware acceleration. All hardware acceleration is performed through extensions you make to DDGPE. While acceleration accomplished in this way is acceptable, copying some or all of the acceleration into the DDHAL can make your driver even faster.

Once you identify a function that you want to accelerate, you can decide whether you want to implement acceleration in your DDGPE, in your DDHAL, or in both. The DDGPE implementation and sample code allow you to perform your HAL acceleration in your DDGPE-based class. The DDGPE model also allows you to move many acceleration functions, excluding acceleration of some line drawing functions, into the DDHAL and to use these DDHAL functions from within your DDGPE class.

Adding New Functionality

You can add new functionality to your DDHAL implementation by modifying the device capabilities and callback structures, and by implementing new callbacks. For more information on extending your DDHAL, consult the DirectDraw hardware abstraction layer specification.

See Also

DirectDraw Driver Extension | DirectDraw Display Driver Creation | DDHAL Functionality Implementation | DDHAL Resources

 Last updated on Tuesday, May 18, 2004

© 1992-2003 Microsoft Corporation. All rights reserved.