Celestia Forums

I have written a script (well it worked for 1.2.4) on retrograde rotation.



http://explorer.arc.nasa.gov/Celestia/jovian.cel



I plan to write some other scripts to illustrate common phenomena such as seasonal change, lunar phases, etc. If you have some scripts you'd like to share, please post them.

AND - if anyone has a document that explains and lists the new scripting
options (duration and row number) in print directives, please share the wealth!

Finally 1.2.5 seems to run well, but I have found that some machines happy with 4, crash with 5. Also scripts need to be modified.

Here is a script that I wrote a little while ago. It's about Pan, a little moon of Saturn orbiting in the Encke division...

I hacked it to debug various scripting commands like 'move', ...

Bye Fridger

-----------------------------------
{
labels {clear "moons" }
setambientlight {brightness 0.15}
setfaintestautomag45deg { magnitude 10.5 }
time { jd 2452452.20 }
renderflags { set "galaxies" }
time { jd 2452452.68056 }
select { object "Sol/Saturn/Pan" }
gotolonglat { time 5 distance 50000 up [ 0 1 0 ] longitude 145.462 latitude 37.168 }
print { text "Looking for the tiny Saturn moon Pan in the outer Encke ring division. . ." row -3 duration 5 }
wait {duration 5}
changedistance { rate -1.3 duration 2 }
setambientlight {brightness 0.3}
print { text "Can you see now the little bright dot?. . ." row -3 duration 5 }
labels { set "moons" }
wait { duration 0.5 }
labels {clear "moons" }
wait { duration 0.5 }
labels { set "moons" }
wait { duration 0.5 }
labels {clear "moons" }
wait { duration 0.5 }
labels { set "moons" }
chase {}
wait { duration 2 }
print { text "Closing in. . ." row -3 duration 5 }
gotolonglat { time 6 distance 1.5 up [ -1 1 0 ] longitude 160.997 latitude 43.628 }
wait { duration 6 }
setambientlight {brightness 0.15}
labels {clear "moons" }
rotate { axis [-1 0 0] rate 10 duration 3 }
wait { duration 4 }
print { text "Accelerate time by a factor of 1000 " row -3 duration 5 }
timerate { rate 1000 }
wait { duration 10 }
move { velocity [ -0.5 2.0 0 ] duration 2.2 }
wait { duration 3 }
print { text "Slow down time again" row -3 duration 5 }
timerate { rate 100 }
move { velocity [ 0.5 -2.0 0 ] duration 2.2 }
wait { duration 2.2 }
chase {}
print { text "Chasing mode to display Pan's irregular motion. . ." row -3 duration 5 }
timerate { rate -5000 }
wait {duration 8 }
print { text "Locking mode. . ." row -3 duration 5 }
timerate { rate -500 }
lock {}
wait { duration 6.5 }
setframe { coordsys "observer" ref "Sol/Saturn/Pan" target "Sol/Saturn/Pan" }
timerate { rate 5000 }
wait { duration 6 }
select {object "Sol/Saturn" }
timerate { rate 1000 }
center { time 2 }
changedistance { rate 2.5 duration 2 }
wait { duration 4 }
select {object "Sol" }
print { text "Now leaving the ring system. . ." row -3 duration 5 }
follow {}
wait {duration 12 }
select {object "Sol/Saturn" }
goto { time 2 distance 5 }
wait {duration 2}
orbit { duration 3 rate 5.5 axis [1 0 0] }
print { text "Leaving Saturn . . . end of demo" row -3 duration 10 }
changedistance { rate 2 duration 12 }
setfaintestautomag45deg { magnitude 8.5 }
setambientlight { brightness 0 }
}

It is a very good idea.
But your script doesn't work well on my Celestia.
First you need to reset all parameters (like FOV to 45, speed, etc...).
I can't see your comments. You have to add the "row -3" command in the print brakets.

I'm looking forward to running all your scenarii.

Calculus wrote:It is a very good idea.
But your script doesn't work well on my Celestia.
First you need to reset all parameters (like FOV to 45, speed, etc...).
I can't see your comments. You have to add the "row -3" command in the print brakets.

I'm looking forward to running all your scenarii.

Strange, the script is definitely for 1.2.5 and runs excellently on my machine. Usually Celestia starts off with FoV=45 deg's. Clearly, the script is not polished, since I hacked it for debugging purposes, but I have not set anything special in my start.cel. Hence with a default 1.2.5 setup it should work well.

Perhaps, there was some mistake in copying the script from the WEB?

Try getting it from here:

http://www.celestiaproject.net/~t00fri/images/ ... andemo.cel

Bye Fridger

Strange, the script is definitely for 1.2.5 and runs excellently on my machine. Usually Celestia starts off with FoV=45 deg's. Clearly, the script is not polished, since I hacked it for debugging purposes, but I have not set anything special in my start.cel. Hence with a default 1.2.5 setup it should work well.

Perhaps, there was some mistake in copying the script from the WEB?

I actually launched the script with a 3" FOV set in Celestia. I couldn't see anything. About the text, I was able to see it only after I added "row -3" in the file!
I don't know why. Maybe its because of the screen resolution (1024*768*32).

Calculus wrote:

Strange, the script is definitely for 1.2.5 and runs excellently on my machine. Usually Celestia starts off with FoV=45 deg's. Clearly, the script is not polished, since I hacked it for debugging purposes, but I have not set anything special in my start.cel. Hence with a default 1.2.5 setup it should work well.

Perhaps, there was some mistake in copying the script from the WEB?

I actually launched the script with a 3" FOV set in Celestia. I couldn't see anything. About the text, I was able to see it only after I added "row -3" in the file!
I don't know why. Maybe its because of the screen resolution (1024*768*32).

Resolutions were definitely different, since I use 1600x1200x16. Yet in each of my print statements, there is a "row -3". What else are you suggesting??

Bye Fridger

Sorry Fridger, I was not reffering to your script but alan's one.
I haven't tried yours yet.

The set FOV command doesn't work in Celestia 1.2.5...

Unless I mistyped it ! -> set { FOV 35.0 }

I have also tried set { "FOV" 35 } and some others tries...

Nothing works...

As well as the Autofaintestmag feature (changing with the FOV) that doesn't work too !

Kendrix wrote:The set FOV command doesn't work in Celestia 1.2.5...

Unless I mistyped it ! -> set { FOV 35.0 }

I have also tried set { "FOV" 35 } and some others tries...

Nothing works...

As well as the Autofaintestmag feature (changing with the FOV) that doesn't work too !

set {FOV float} is indeed not yet implemented.

setfaintestautomag45deg{ magnitude float} I have coded and it /does/ work. You can convince yourself by running my script above.

Nothing else in this context has ever been implemented, hence it cannot work;-).

The toggling of Automag so far can
only been done by means of key shortcuts (CTRL Y). Again, I have coded it and it does work.

Whoever is interested to find out what commands are implemented and how their arguments are used, is advised to have a look at the routine src/celengine/cmdparser.cpp in the sources. In the CVS archive this single file can easily be inspected.

Even non-programmers should be able to find their way (I hope;-)).

Bye Fridger

Ok... I thought that the automag was enabled by default...

For the FOV I have seen that it wasn't in the cmdparser.cpp but since It was written in the changelog I thought it was elsewhere in the code ;o)

This evening I will start to add an opposition finder for Celestia...

Kendrix wrote:Ok... I thought that the automag was enabled by default...

For the FOV I have seen that it wasn't in the cmdparser.cpp but since It was written in the changelog I thought it was elsewhere in the code ;o)

This evening I will start to add an opposition finder for Celestia...

In the Linux gtk version I have enabled AutoMag by default. In the new KDE version your preferences are saved automatically, so once you switch it on by means of CTRL Y it will always be on...

In Windows it is off by default (well I have no Windows compiler;-))

setfaintestautomag45deg{} is important as to the FOV dependent characteristics of the AutoMag feature. That's why I made it resettable via a script.

Bye Fridger

Fridger,
I've noticed you use the "chase" function. Could you please explain what it is ? (it looks similar to the lock function).

Kendrix wrote:The set FOV command doesn't work in Celestia 1.2.5...

Unless I mistyped it ! -> set { FOV 35.0 }

I have also tried set { "FOV" 35 } and some others tries...

Nothing works...

As well as the Autofaintestmag feature (changing with the FOV) that doesn't work too !

The set command should work for FOV . . . Celestia's script syntax is a bit peculiar, however, so you need to write:



--Chris

chris wrote:The set command should work for FOV . . . Celestia's script syntax is a bit peculiar, however, so you need to write:

Code: Select all

set { name "FOV" value 35.0 }


--Chris

Yes, indeed, it works and after looking into the code, it's obvious. Coded before my time...;-)

Bye Fridger

thanx !

I have polished the jovian.cel script a bit to add the row -3 command. I also have added another script: tutorial.cel to the web page. The idea being to demo and teach a new user the basics in one script.

If any one has a document about the 'undocumented' features of the scripting language - please post it!

http://explorer.arc.nasa.gov/Celestia

Alan,

A cryptic summary of the scripting commands available in Celestia v1.2.5 is included in my "notes" page at http://www.lns.cornell.edu/~seb/celestia/celestia_notes.html#4.0

I say "cryptic" because it doesn't include the units that Celestia assumes are being provided: they aren't mentioned in the source files I looked at. I hope this helps a little, though.

Alan,

I'd suggest using significantly longer pauses in your tutorial script:
2 or 3 x as much, at least.

For one thing, you need to allow for the "dead time" while textures are being loaded, especially if they're high resolution. Although Celestia seems to "freeze" while it's loading a texture, the realtime clock keeps ticking, and that's what controls what gets shown. If it takes a long time to load a texture, all of the events that might have been seen during that time are discarded. I missed several of the introductory messages while the earth textures loaded.

This also can be compensated for by preloading the appropriate textures, assuming you know what they are, of course. I'd suggest assuming the standard set and leave it to the "Celestia system manager" to make appropriate changes if others have been installed.

Also, a novice needs some time to read the information and then relate it to what's on the screen.

Related suggestion: instead of completely replacing the previous text,
you might want to consider "scrolling" the messages: reetyping several previous lines a row higher each time a new line is written. This ensures that the user hasn't missed anything while admiring the view.

That kept happening to me. I was watching what was happening and missing what was being "said".

I hope these suggestions help a little.

[quote="selden"]
Alan,

I'd suggest using significantly longer pauses in your tutorial script:
2 or 3 x as much, at least.



Thanks for the hint - hard to know how fast/slow things run 'out there' I try the script on a couple of different machines of different speeds to get a feel for it - but I don't want to bore anyone with long waits.
I also will check out the new scripting commands.

Do you think making the Tutorial a script would be a good thing for newbies?

Any suggestions on how to improve text display in scripts are appreciated. For one, the "scrolling" behavior mentioned by selden sounds like something that should be built in.

--Chris