I'm not the original author of this program; it was originally written for the
PC in GW-Basic in 1996, with a revision in 1998. The original author(s) are
unknown.

I initially found mention of the GW-Basic version here, while googling "BASIC 
3D Engines":

http://www.petesqbsite.com/sections/zines/qbcm/issues/1-2/default.html

The, googling "SHUTTLE.BAS" led me to this archive:

http://www.w0btu.com/files/misc/software/hamcalc/PROG/

I downloaded SHUTTLE.BAS and GWBASIC.EXE; I tried to load SHUTTLE.BAS in a text 
editor, but it had been saved in GWBASIC's binary format. To convert it to ASCII
I would need to boot into GWBASIC, load the file, then re-save it using:

    SAVE "filename", A

So thats what I did - see "SHUTTLE.TXT" for the converted version. I also ran it
to see what it looked like. I found that it runs in the EGA mode 8 (640x200x16 
colors).

I then decided that a CoCo version needed to be made - so I converted it using
MESS and the CoCo 3 emulation. At first I wasn't sure if I wanted to convert it
to run on the CoCo 3 or if I wanted all CoCo's to be able to run it. I event-
ually decided on the latter.

When you run it, it loads up the data, then goes into a loop to draw the
shuttle, clearing the screen between each iteration. I decided to use PMODE 4,
with the "secondary" colorset because it had a more "retro" feel about it,
evoking a green-screen terminal (VT-100 yay!). There is a line, commented out,
that would allow you to enter initial rotation parameters (after which it would
start to rotate from that angle).

I found it was much more enjoyable in MESS to pop the high-speed poke, then
using F11 to disable throttling of the emulator, for the highest speed redrawing
in BASIC.

I'd like to see or create a version that renders to a background page, and then
PCOPY the finished drawing to the foreground, or flip between the two pages (in
other words, implement double-buffering). I think there's a way to do this,
perhaps something in one of the PEEKs, POKEs, EXECs books can help?

Anyhow - play around with it, and have some fun with it!

Andrew L. Ayers
Glendale, Arizona
https://www.github.com/andrew-ayers
June 2018

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!! UPDATE !! UPDATE !! UPDATE !! UPDATE !!

I've updated the ZIP file in a couple of ways:

1. The DSK image now has four versions of the BAS file for the Color Computer:

    a. SHUTTLE1.BAS - The original conversion for the CoCo 1,2,3 (ECB, PMODE 4)
                      that renders a rotating view, clearing the screen between
                      each view

    b. SHUTTLE2.BAS - A modified version for the CoCo 1,2,3 (ECB, PMODE 4) that
                      renders a fixed orientation, for a screenshot

    c. SHUTTLEP.BAS - A modified version for the CoCo 1,2,3 (ECB, PMODE 4) that
                      works in a similar manner as SHUTTLE1.BAS, rendering a
                      rotating view, but does it using double buffering
    
    d. SHUTTLE3.BAS - Same as SHUTTLE2.BAS, but for the CoCo 3 only! Uses the
                      640x192x4 color mode (HSCREEN 4). Please note that this 
                      version also uses the high-speed poke for the CoCo 3 (POKE 
                      65497,0) - it catches the BREAK key, though, and restores the 
                      normal speed and palette.

2. I included screenshots from SHUTTLE2.BAS and SHUTTLE3.BAS. Note that these were
   generated using the OVCC emulator and thea CoCo 3 ROM; things may look different
   using a real CoCo or a different emulator.

3. Changes to this file, of course... :)

It's something I've wanted to do, and after posting things a couple of times on the
FB CoCo group, and requests for screenshots, I decided adding a CoCo 3 version was
something that needed to be done. In the course of all of this, I also decided that
a double-buffered version for PMODE 4 should be implemented, too.

Hint: If you are using an emulator or other "non-standard" Color Computer, increase
the speed/framerate/overclocking to max, and enjoy the show...

-- AndrewA, July 22-26, 2021

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What the future might bring...

Needless to say, after all of these changes and updates, the code is a mess, and
there are too many versions, that all do basically the same thing. My future
goals for this code:

1. Unify everything - bring it all under a single codebase
2. Modularization of code?
3. Menu and configuration options?
4. Save and load a view?
5. Get rid of DATA statements (maybe a file generator)?
6. Allow for custom models?
7. Documentation of the code (it desperately needs this)...
8. HSCREEN double buffering?

I can't guarantee any or some of this will happen, but they are all nice to 
think about. Of course, that's what I thought after my first conversion of the 
code, and now here we are, right?

-- AndrewA, July 26, 2021