Three-dimensional Light Source Parameters

This one deals with all the aspects of light source and Targa files.

You must choose the direction of the light from the light source. This will
be scaled in the x, y, and z directions the same as the image. For
example, 1,1,3 positions the light to come from the lower right front of
the screen in relation to the untransformed image. It is important to
remember that these coordinates are scaled the same as your image. Thus,
"1,1,1" positions the light to come from a direction of equal distances to
the right, below and in front of each pixel on the original image.
However, if the x,y,z scale is set to 90,90,30 the result will be from
equal distances to the right and below each pixel but from only 1/3 the
distance in front of the screen i.e.. it will be low in the sky, say,
afternoon or morning.

Then you are asked for a smoothing factor. Unless you used "Continuous
Potential" when generating the starting image, the illumination when using
light source fills may appear "sparkly", like a sandy beach in bright sun.
A smoothing factor of 2 or 3 will allow you to see the large-scale
shapes better.

Smoothing is primarily useful when doing light source fill types with plasma
clouds. If your fractal is not a plasma cloud and has features with
sharply defined boundaries (e.g. Mandelbrot Lake), smoothing may cause
the colors to run. This is a feature, not a bug. (A copyrighted response
of [your favorite commercial software company here], used by permission.)

The ambient option sets the minimum light value a surface has if it has no
direct lighting at all. All light values are scaled from this value to
white. This effectively adjusts the depth of the shadows and sets the
overall contrast of the image.

If you selected the full color option, you have a few more choices.
The next is the haze factor. Set this to make distant objects more hazy.
Close up objects will have little effect, distant objects will have most.
0 disables the function. 100 is the maximum effect, the farthest objects
will be lost in the mist. Currently, this does not really use distance
from the viewer, we cheat and use the y value of the original image. So
the effect really only works if the y-rotation (set earlier) is between
+/- 30.

Next, you can chose the name under which to save your Targa file. If you
have a ram disk handy, you might want to create the file on it, for speed.
So include its  full path name in this option. If you have not set
"overwrite=yes" then the file name will be incremented to avoid over-writing
previous files. If you are going to overlay an existing Targa file, enter
its name here.

Next, you may select the background color for the Targa file. The default
background on the Targa file is sky blue. Enter the Red, Green, and Blue
component for the background color you wish.

Finally, absolutely the last option (this time we mean it): you can now
choose to overlay an existing Targa-24, type 2, non mapped, top-to-bottom
file, such as created by Fractint or PVRay. The Targa file specified above
will be overlayed with new info just as a GIF is overlayed on screen. Note:
it is not necessary to use the "O" overlay command to overlay Targa files.
The Targa_Overlay option must be set to yes, however.

You'll probably want to adjust the final colors for monochrome fill types
using light source via color cycling.

Now, lie down for a while in a quiet room with a damp washcloth on your
forehead.