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QUICKREF.TXT
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1996-04-28
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The Fractal Engine v2 for the Atari ST family by Dan Grace
Reference Guide and Quick-Start Tutorial by Mike Harris
(c) gh Fractals July 1993
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Reference Guide.
---------------
The Fractal Engine is run by double clicking on the item FRACENG2.PRG from the
GEM desktop. Once the application has loaded, you are presented with the main
screen. This is known as the main menu and is the root from which all
operations available are selected and performed. The main menu screen has three
main regions:
Top window - displays the title and any other relevant information.
Menu window - this contains the current menu in operation.
julia - select new parameters for drawing Julia sets.
zoom - magnify the current image, if it exists.
draw - transforms the current co-ordinates into an image.
methods - select a different drawing method for current fractal type
- go to methods menu options.
edit cd - edit the current co-ordinates (parameters).
copy cd - transforms the current image into textural co-ordinates.
load cd - load co-ordinates from file into parameters window.
save cd - store co-ordinates in parameters window to file.
load pic - load image and co-ordinates from file.
save pic - save image and co-ordinates to file.
storepic - store the current image in memory.
restore - recall a previously stored image from memory.
batch - menu of operations for multiple drawing of images
- go to batch menu options.
view - view the current image.
types - select a new fractal type with default co-ordinates
- go to types menu options.
palettes - palette operations to change image colours
- go to palettes menu options.
save pal - saves all palette data to disk.
quit - why would you want to do that?
Parameters window - displays the current co-ordinates which will take effect
next time draw is selected.
Methods menu - displays the drawing methods available to the current fractal
type. This is dependant on the fractal type selected. The methods are as
follows for the complex fractals types:
normal - fast two-dimensional image of fractal.
LEM - slower than normal but with more control over image.
sphere - a three-dimensional sphere with your fractal on the surface.
scape - a three-dimensional landscape of your fractal.
sml nrml - quarter-size image using normal method.
sml LEM - quarter-size image using normal method.
Types menu - displays the different fractal types available, as follows:
quad - quadratic complex fractal type - the beetle.
conj - conjugate of quadratic complex fractal.
cub1 - complex fractal of standard cubic equation.
cub2 - our very own cubic complex fractal.
spid - complex fractal which looks like a spider!
fish - complex fractal which looks like a jellyfish!
cosn - complex fractal using the cosine function.
sine - complex fractal using the sine function.
newt - quadratic complex fractal using Newton's method.
barn - one of Michael Barnsley's complex alternatives.
deg4 - complex fractal based on model of magnetism.
popcorn - strange attractors looking like popcorn, wood or your skin!
p-dla - diffusion limited aggregation grows your own plants!
l-dla - looks a bit like chromatography (?)
clouds - random fractal plasma clouds or sky for mountains.
mntns - random fractal mountains with sea!
choose - select new fractal type and return to main menu.
exit - return to main menu without selecting new type.
Palettes menu - allows you to select between different palettes and modes,
rotate the current palette or choose to edit the palette.
pal - / pal + - decrement and increment the current palette number.
mode - / mode + - decrement and increment the current mode number.
swirl - rotate the current colour palette.
hide - hide the palette menu to view the screen beneath.
edit - edit the current palette - go to edit palette menu.
exit - return to the main menu.
Edit Palette menu - allows you to edit the amount of red, green and blue for
each colour of the current palette.
red - / red + - adjusts the amount of red in the current colour.
green - / green + - adjusts the amount of green in the current colour.
blue - / blue + - adjusts the amount of blue in the current colour.
colour - selects a new current colour with mouse.
exit - back to the palette menu for you, sonny.
Batch menu - operations for drawing loads of images all at once. As a folder of
separate images, an animation sequence or a poster to liven up your drab
surroundings.
zoomanim - zoom animation of complex fractals.
jul anim - Julia set animation of complex fractals.
convert - convert a folder of co-ordinate files into images.
poster - produce a poster to disk or printer from any image or file.
exit - return to main menu.
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Quick-start Tutorial - Julia sets, zooming and 3D Landscapes.
--------------------
Let's try searching for a Julia set and producing a three-dimensional landscape:
1. First of all, we need select a fractal type to draw images from. For this
example we shall use the quadratic (quad) complex fractal type. This is the
default type selected when you first run the program. If you've been playing
around a bit and this is no longer the current type then click on the types
button from the main menu, then quad and choose buttons from the types menu.
You are now back at the main menu.
2. Click on the methods button and select sml nrml for the quarter-size screen
basic drawing method.
3. Next click on draw. FE2 draws a quarter-size picture of the quadratic
Mandelbrot set and returns you to the main menu. You can use view to see it
again. Now what we need to do is select a decent Julia set for our landscape.
As the Mandelbrot set represents a directory of all our possible Julia set
images, choosing a set from the screen visually makes the task easier.
4. Before we do this, let's zoom-in on the Mandelbrot set so that we can be
more accurate about choosing our Julia set co-ordinates. Click on the zoom
option and you are flipped to the Mandelbrot set image and the zoom-box is
displayed. This can be manipulated by pressing the left mouse button to make it
smaller and the right button to make it larger; Moving the mouse around
correspondingly moves the zoom-box around. Let's put the zoom-box over the
second-largest disk of the Mandelbrot set (the black bit). Once your happy with
this, press the spacebar which selects the new window size and click on draw.
Once again your image is drawn.
(A good point to note at this juncture is if your picture looks a little
bit blocky around the edges of the black, you may be running out iterations.
This is indicated by the outside colours looking rather like blobby fingers and
can be remedied by increasing the iterations value. Use edit cd and press the
return key until you are at the iters field. The default value is thirty, so
try something like fifty. If you zoom in even further, a value of eighty or
even a hundred may be needed - best experimenting.)
5. One last thing to do before we start drawing a Julia set: Click on
storepic. This saves your Mandelbrot zoom in memory so that if you make a
mistake or are unhappy with your Julia set, you can recall it and try again.
6. Click on julia, you are asked whether you want to enter the Julia set
parameters from keyboard or visually. Click on visually and your Mandelbrot
zoom appears and you can move the mouse pointer around the screen. You select a
Julia set by clicking the left mouse button. Go for one somewhere in the set or
close to the boundary (between the black and colour bands outside). Once you
have selected a Julia set, click on draw and a quarter-size image appears.
If you don't like the look of it, click on restore to bring back the
Mandelbrot set image saved in memory and do step 6 again until you are happy.
7. Right, at last we can go for a 3-D landscape of our Julia set: Click on
methods and select scape. Back to the main menu, click on draw. You will be
asked whether you wish to overlay over an existing screen, select no. The 3-D
scape will take longer to draw as the mathematics involved in ray-tracing and
rendering landscapes is a lot more complicated and they're always full-sized
pictures. Remember that all good things come in time, so be patient! 8. Your
finished Julia set! At this point, I would save the image to disk by clicking on
save pic. When asked which file format to save the image in, choose .FE2; this
will allow to picture to be re-loaded at a later date. FE2 will suggest a file
name for you; FRAC_000.FUL, for example. If this is a little anonymous for your
tastes, enter one of your own. Once saved, it can be loaded back in with load
pic.
Remember, you still have your Mandelbrot zoom saved in memory and it
stays there until you overwrite it with another storepic or you quit from FE2.
Try experimenting with Julia sets from different regions to get a feel of their
relationships with Mandelbrot sets.
This may seem a little complicated, but it's not and you'll soon get used to
it. We've covered a lot in this example so it's a good idea to follow it
several times to get a clear picture of what exactly is going on in all the
chaos!