2.11 Plasma Clouds
(type=plasma)
Plasma clouds ARE real live fractals, even though we didn't know it at
first. They are generated by a recursive algorithm that randomly picks
colors of the corner of a rectangle, and then continues recursively
quartering previous rectangles. Random colors are averaged with those of
the outer rectangles so that small neighborhoods do not show much
change, for a smoothed-out, cloud-like effect. The more colors your
video mode supports, the better. The result, believe it or not, is a
fractal landscape viewed as a contour map, with colors indicating
constant elevation. To see this, save and view with the <3> command
(see "3D" Images (p. 106)) and your "cloud" will be converted to a
mountain!
You've GOT to try color cycling (p. 23) on these (hit "+" or "-"). If
you haven't been hypnotized by the drawing process, the writhing colors
will do it for sure. We have now implemented subliminal messages to
exploit the user's vulnerable state; their content varies with your bank
balance, politics, gender, accessibility to a Fractint programmer, and
so on. A free copy of Microsoft C to the first person who spots them.
This type accepts four parameters.
The first determines how abruptly the colors change. A value of .5
yields bland clouds, while 50 yields very grainy ones. The default value
is 2.
The second determines whether to use the original algorithm (0) or a
modified one (1). The new one gives the same type of images but draws
the dots in a different order. It will let you see what the final image
will look like much sooner than the old one.
The third determines whether to use a new seed for generating the next
plasma cloud (0) or to use the previous seed (1).
The fourth parameter turns on 16-bit .POT output which provides much
smoother height gradations. This is especially useful for creating
mountain landscapes when using the plasma output with a ray tracer such
as POV-Ray.
With parameter three set to 1, the next plasma cloud generated will be
identical to the previous but at whatever new resolution is desired.
Zooming is ignored, as each plasma-cloud screen is generated randomly.
The random number seed used for each plasma image is displayed on the
<tab> information screen, and can be entered with the command line
parameter "rseed=" to recreate a particular image.
The algorithm is based on the Pascal program distributed by Bret Mulvey
as PLASMA.ARC. We have ported it to C and integrated it with Fractint's
graphics and animation facilities. This implementation does not use
floating-point math. The algorithm was modified starting with version 18
so that the plasma effect is independent of screen resolution.
Saved plasma-cloud screens are EXCELLENT starting images for fractal
"landscapes" created with the "3D" commands (p. 32).