Well, *if* it would be a java program, it would have been quite easy.
However, it's much more difficult to implement it with a very simple
scripting language  to *describe* the model. That's it, I'm just describing
the scene, after it was created, there is no interaction with the scene.
However, I'm thinking if it's not possible to *precalculate* the eclipse
times and positions, so that the shadow can be attached to a behavior. *If*
I'll manage it, I'll let you know ;)

Florin

-----Urspr�ngliche Nachricht-----
Von: Wolfgang Kienreich [mailto:[EMAIL PROTECTED]]
Gesendet: Montag, 20. Januar 2003 15:04
An: [EMAIL PROTECTED]
Betreff: [JAVA3D] AW: [JAVA3D] R�f. : [JAVA3D] Again about the solar
system.


Hey, nice idea ... Could work as follows (couldn't it - I'm asking you?)
:

+ Line from sun to earth through moon

+ Check for intersect (perhaps with a somewhat larger sphere to take
into account half shadows), proceed if yes

+ Get intersection texture coords

+ Calculate size of shadow on earth (with a scale factor to give nice
optical appearance, doesnt have to follow physics)

+ Overlay a disc-shaped dark area onto the earth texture, centered at
the given texture coordinates, scaled to the calculated size

That's it. Not joking, just checking. And - Florin please don't send me
the bill for the nightshift hours resulting from this ;-)

Wolfgang

==================================================================== 
Wolfgang Kienreich
Technical Research 
Knowledge Retrieval / Knowledge Visualization 
Know-Center  http://www.know-center.at
Inffeldgasse 16c, 8010 Graz, Austria 
email : [EMAIL PROTECTED] 
phone : +43 316 820918 647 
fax   : +43 316 873 5688 
==================================================================== 


-----Urspr�ngliche Nachricht-----
Von: Discussion list for Java 3D API
[mailto:[EMAIL PROTECTED]] Im Auftrag von Jacky Rymasz
Gesendet: Montag, 20. J�nner 2003 14:35
An: [EMAIL PROTECTED]
Betreff: [JAVA3D] R�f. : [JAVA3D] Again about the solar system.


I love it... nice job! :)
Just one thing... is it possible to add shadows (ie: shadow of the moon
on earth)? ;)

Jack


 

                      Florin Herinean

                      <fherinean@PUBLITY.        Pour :
[EMAIL PROTECTED]

                      DE>                        cc :

                      Envoy� par :               Objet :   [JAVA3D]
Again about the solar system.                                        
                      Discussion list for

                      Java 3D API

                      <JAVA3D-INTEREST@JA

                      VA.SUN.COM>

 

 

                      20/01/03 13:42

                      Veuillez r�pondre �

                      Discussion list for

                      Java 3D API

 

 





Hello everybody,

Maybe some of you got bored because of my emails, but I have just added
some new nice features to my solar system model.

http://www.seelenbinder-schule.de/~fherinean/solar_system_applet.html

1. All the planets display now correct textures, so they look quite
similar to what you see in the pictures.

2. The light is correctly comming from the sun and not from an arbitrary
position. Now you can watch the phases of the planets.

3. The orbits of Mercury and Pluto are tilted with the correct angles.

4. Mercury, Mars and Pluto features correct elliptical orbits.

5. All the planets are spinning with proportional speeds.

6. The spinning axes of the planets are tilted at the correct angles.
You can watch Uranus spinning at 97 degrees.

7. *right* clicking on a planet in the left list shows an information
dialog where astronomical information is provided. Further clicking on
the "View" button, will bring into the main view that planet featuring a
high resolution texture. Warning: that operation may be longer because
of the size of the textures, some of them of 250 kb.

I hope you'll enjoy playing with it, it makes a good didactical program,
nice to show to your children. Good to notice, I haven't remarked any
significant reducing of the performances, despite the use of the
textures and additional behaviors. My favourite watching position is the
"left" view, no orbits, zoomed in somewhere close to the Saturn orbit.

What was left out intentionally, for the sake of observability, so that
it doesn't make a real simulator:

a) the planets are moving too fast compared to the spinning time.
b) the sizes of the planets are not proportional. All the planets have
been magnified compared to the sun, the magnification factor the bigger
the smaller the planet.
c) the orbits are too close to the sun.
d) the intensity of the light of the sun is constant, regardles of the
distance.

Cheers,

Florin

========================================================================
===
To unsubscribe, send email to [EMAIL PROTECTED] and include in the
body of the message "signoff JAVA3D-INTEREST".  For general help, send
email to [EMAIL PROTECTED] and include in the body of the message
"help".




To unsubscribe, send email to [EMAIL PROTECTED] and include in the
body of the message "signoff JAVA3D-INTEREST".  For general help, send
email to [EMAIL PROTECTED] and include in the body of the message
"help".

==========================================================================To
unsubscribe, send email to [EMAIL PROTECTED] and include in the body
of the message "signoff JAVA3D-INTEREST".  For general help, send email to
[EMAIL PROTECTED] and include in the body of the message "help".

==========================================================================To 
unsubscribe, send email to [EMAIL PROTECTED] and include in the body
of the message "signoff JAVA3D-INTEREST".  For general help, send email to
[EMAIL PROTECTED] and include in the body of the message "help".

Reply via email to