This fat After Dark module for the Macintosh draws animated, fractal clouds. Like the real thing, they come in an almost infinite variety of shapes. Just wait and see...
Shareware notice
Clouds 2.0.1 is shareware. Please pay a fee of US$ 5 if you use it. This fee includes all future updates.
Payments (check, cash, or credit card) are handled by the Kagi Shareware Service. Please create a form for your payment with the enclosed "Register" application, print it or copy it to an E-mail message, and send it to the address indicated on the form.
If the "Register" application is missing, or you have any questions or comments about the module, please contact me at: geisler@kagi.com
⌐1993-1995, Robert Geisler. Arrow CDEF ⌐1994, David Hay. Permission required for commercial distribution - may be included in the Info-Mac CD-ROM.
Robert Geisler hereby disclaims all warranties relating to this software, whether express or implied, including without limitation any implied warranties of merchantability or fitness for a particular purpose. Robert Geisler will not be liable for any special, incidental, consequential, indirect or similar damages due to loss of data or any other reason, even if Robert Geisler or an agent of his has been advised of the possibility of such damages. In no event shall Robert Geisler be liable for any damages, regardless of the form of the claim.
System requirements
Clouds requires a monitor with at least 256 colors, and looks best with thousands or millions of colors. Clouds can be used with After Dark or with the freeware screensaver, DarkSide.
Depending on the screen size and resolution, Clouds may need several megabytes of temporary memory.
IMPORTANT! To use Clouds with DarkSide on a Power Mac running Mac OS 7.5.2, you must increase the partition size of DarkSide (through the Finder's Get Info command). 200 KB should be safe.
Control panel settings
Styles control colors, wispiness, wind, and sunshine. Select "Random" to use styles in random order.
"Redraw Speed" controls how often the display changes.
Select "Fade in and out" for soft transitions.
Click on "Edit" to create or modify styles.
Editing presets
Select the style that you would like to edit from the menu on top.
The color bar contains the 254 available colors, ordered from lowest to highest cloud density. Click in it to select a color to edit, or drag to select a range of colors. Click on "Change..." to change the selected color, or on "Blend" to interpolate between the first and the last color in a range. (Most of the included color tables were created by editing only a few colors such as #1, #80, #144, and #254, and interpolating between them.)
Click on the arrows next to "Fractal dimension" to change the fractal dimension. A higher fractal dimension results in wispier clouds. Values around 2.3 look most natural.
Select the wind direction from the "Wind" menu. A southwest wind moves the clouds up and to the right.
Click on the arrows next to "Stars" to set the number of stars in the sky.
Click on the "Picture" button to add or remove a picture of a celestial body.
Click on the "Duplicate..." button to duplicate the selected style, or on "Delete" to delete it. Click on "Import" to import styles from a file or from another copy of Clouds. Click on "Export" to export the selected style to a file.
Technical notes
Clouds uses a simplified version of the MidPointFM2D random midpoint displacement algorithm by D. Saupe (without random additions, with circularized boundaries, and fixed initial values). Fractal values are used as color indices without any scaling.
Resolution does not increase gradually like in the previous version of Clouds. However, the first image is drawn at half of the resolution of the following images. (Wait for the second image if you want to save the clouds as a desktop background.) Final resolution is 512 x 512 if screen height is ▓ 256 pixels, 1024 x 1024 if it is ▓ 512, etc.
On portrait monitors only half of the image is displayed to maintain an appropriate aspect ratio. On systems with multiple monitors clouds are displayed only on the main monitor. On 256 color monitors the screen's color table is set to that of the preset, except on PowerBooks (which can display only a limited range of colors) and in MultiModules.
Contributions welcome
If you feel you have created a particularly nice style, export it to a file, and send it as an E-mail attachment to geisler@kagi.com. PICTs must be copyright-free. Contributed styles may eventually be released as freeware.
Changes in version 2.0.1
Ñ Won't crash anymore when displaying stars together with a "Please wake up" message.
Clouds 2.0 was created with Metrowerks C 1.2.2, the After Dark SDK 3.0, and Adobe Photoshop 3.0.
The algorithm is based on: Saupe, D. (1988). Algorithms for random fractals. In: The Science of Fractal Images, H.O. Peitgen and D. Saupe, eds. (New York: Springer-Verlag), pp. 71-113.
Thanks to everyone who sent comments and suggestions, to subscribers of the After Dark mailing list for advice on temporary memory, and to GR and JosÄ Casal for testing of the first version.
