To quote the developers from Berkeley Systems, Inc.
"After Dark is a screen saving shell. It provides all of the support and tools a programmer needs to quickly create unique screen saving graphics. To create a new screen saver, you simply write a new graphics module. A screen saver graphics module is a small, separately compiled dynamically linked library (DLL). You can produce a graphics module with any development system that can produce DLLs and which supports the Windows SDK."
To be able to use an AfterDark module you must have purchased a full version of one of the AfterDark screensavers.
You can only develop screensaver modules for After Dark 3.0, however these can also be run under the After Dark 4.0 engine. The screensaver is basically a 16bit DLL which has been renamed to have the .AD extention. The version 4.0 savers are a 32 bit DLL but these are not currently supported by the SDK.
To develop new modules you only need a few things.
The SDK is supplied as a self extracting executable. Use the -D option to expand it into directories or use Winzip or a similar tool.
Having tried out the SDK I was very impressed with the quality of the instruction and there are some easy to follow example and some exercises to try. You are basically provided with a framework of the basic operations which are needed by a screensaver, including the starting and stoping, configuration which uses a standard dialog so your module has the look and feel of a Berkeley Systems module, default functions for all of the basic operations, pallette and sound handling and easy access to the values set during the configuration.
Read the documentation carefully or you will have problems compiling the resources under Microsoft VC
The only problem I have discovered is that the ADRES utility used to help edit the AfterDark custom resources does not run under Windows 95. It does however run under other Windows versions.
The following sites also have details on developing modules for AfterDark
