Something wrong with constellation labels

[Boux]

Hi there...
There may be a nasty bug with the placement of the constellation labels.

Here is a view with the correct labelling:



When the view is rotated by more than 90 degrees here is what is happening (180 degrees rotation in this case):



The bug shows up when the view is rotated more than 90 degrees.

[Cham]

I don't have this problem at all. Must be something on your system...

[Vincent]

I can confirm that there's a bug with constellation labels on Windows.
It only concerns the main truck SVN version. The 1.6.1 branch version looks OK.

Constellation labels are displayed on and off when one rotates the view.
Here's a video that shows this issue: http://vincent.giangiulio.perso.sfr.fr/ ... on_bug.avi

[Cham]

Then this is a HUGE bug !

I never experienced it on a Mac yet.

[Hungry4info]

I am unable to reproduce this on 1.6.0 on Windows Vista SP1.

[Boux]

Forgot to specify that this is with a fresh build of svn trunk.
Standard 1.6 is OK though.
Really a very nasty bug.
Last night we had a really very clear sky here.
I brought a laptop and large marine binoculars out in the garden to show off relatives how Celestia was accurate.
Went to Earth surface, rotated the view and bang! Constellation labels all messed up
--->insert sarcasms from the assistance here <---
By chance I had Stellarium too on that laptop.
What was intended to be a brilliant demo of Celestia turned into a convincing demo of Stellarium.
Bad luck

[piellepi]

Hi Celestians!
I can confirm that I found this bug only in a compiled SVN version, NOT the official 1.6.0 version!
Perhaps there's something wrong in the new code in the SVN...
Ciao
Pierluigi

[Cham]

--->insert sarcasms from the assistance here <---
By chance I had Stellarium too on that laptop.
What was intended to be a brilliant demo of Celestia turned into a convincing demo of Stellarium.
Bad luck

This happens to me very frequently in the classroom ! I often need to show students something they are asking. I then try to show them some phenomenon with Celestia, ... and need to apologize because Celestia is doing something very wrong, or uncomplete, or too crudely, or too approximate, or simply because the computer (video card, memory management, OS version, etc) can't stand the graphical weight. My students are then responding some sarcasms about Celestia being a piece of crap !

Demonstrations with Celestia may easily turn into a badly negative publicity against it. In some sense, Celestia is very "weak" and "fragile" on its educational side!

Celestia's interactivity in the classroom is really VERY different than at home. Especially since time is not managed the same way in a classroom than on a personal basis at home...

[t00fri]

Clearly LATEST SVN builds are unsuited for doing classroom demonstrations!

As to the above constellation bug, for example, it was NOT present in the 1.6.0 release version... SVN code is REALLY raw development stuff.

Fridger

[chris]

Some serious UI work is definitely necessary to make Celestia better suited for the classroom. But, as Fridger pointed out, the SVN version is not recommended for classroom demonstrations.

Here's the fix for constellations. Change this line in labelConstellations:

Code: Select all

                if ((observer.getOrientationf().conjugate() * rpos).z() < 0)


to:

Code: Select all

                if ((observer.getOrientationf() * rpos).z() < 0)


This bug appeared during the conversion to Eigen--Celestia's custom vector library used row vectors, while Eigen uses column vectors, so a lot of products had to be reordered. Looks like I missed this case... I'm traveling right now, so I'm not sure when I can commit the fix. Vincent or Fridger: would you be able to take care of this?

--Chris

[Cham]

But, as Fridger pointed out, the SVN version is not recommended for classroom demonstrations.

Well, obviously, I NEVER use a development version in the classroom (too risky). I was talking about 1.6.0...

[t00fri]

But, as Fridger pointed out, the SVN version is not recommended for classroom demonstrations.

Well, obviously, I NEVER use a development version in the classroom (too risky). I was talking about 1.6.0...

Yes, Boux used latest SVN, but you described a behaviour of the 1.6.0 released version that at least I cannot confirm at all:

...need to apologize because Celestia is doing something very wrong, or uncomplete, or too crudely, or too approximate,

My students are then responding some sarcasms about Celestia being a piece of crap !

Celestia 1.6.0 is certainly accurate enough for class-room standards and certainly NOT a fragile piece of crap! Some limitations are natural or unavoidable and spotting them actually represents a good (astro)physics exercise for your students.

Fridger

[Cham]

you described a behaviour of the 1.6.0 released version that at least I cannot confirtm at all:

This is because, obviousy, you DON'T teach with Celestia in a classroom. Or else, you'll know what I'm talking about.

[t00fri]

you described a behaviour of the 1.6.0 released version that at least I cannot confirtm at all:

This is because, obviousy, you DON'T teach with Celestia in a classroom. Or else, you'll know what I'm talking about.

Yet, I think you were vastly exaggerating. The accuracy, stability etc of software is not a matter of using it in a classroom or outside of it...

Fridger

[Cham]

stability etc of software is not a matter of using it in a classroom or outside of it...

Of course it is ! The uses aren't exactly the same. Especially on a network of computers in a computer lab, where the students can do all sorts of "stupid" things while the teacher is elsewhere in the classroom. Unfortunately, Celestia isn't "idiot proof" yet.

Anyway, nevermind...

[Boux]

Some serious UI work is definitely necessary to make Celestia better suited for the classroom. But, as Fridger pointed out, the SVN version is not recommended for classroom demonstrations.

Here's the fix for constellations. Change this line in labelConstellations:

Code: Select all

                if ((observer.getOrientationf().conjugate() * rpos).z() < 0)


to:

Code: Select all

                if ((observer.getOrientationf() * rpos).z() < 0)


This bug appeared during the conversion to Eigen--Celestia's custom vector library used row vectors, while Eigen uses column vectors, so a lot of products had to be reordered. Looks like I missed this case... I'm traveling right now, so I'm not sure when I can commit the fix. Vincent or Fridger: would you be able to take care of this?

--Chris

Thanks Chris, just rebuilt and the bug is gone.
Now I will be able to make a really brilliant demo of Celestia.
... which is vastly superior to a mere "convincing" presentation

[Vincent]

Some serious UI work is definitely necessary to make Celestia better suited for the classroom. But, as Fridger pointed out, the SVN version is not recommended for classroom demonstrations.

Here's the fix for constellations. Change this line in labelConstellations:

Code: Select all

                if ((observer.getOrientationf().conjugate() * rpos).z() < 0)


to:

Code: Select all

                if ((observer.getOrientationf() * rpos).z() < 0)


This bug appeared during the conversion to Eigen--Celestia's custom vector library used row vectors, while Eigen uses column vectors, so a lot of products had to be reordered. Looks like I missed this case... I'm traveling right now, so I'm not sure when I can commit the fix. Vincent or Fridger: would you be able to take care of this?

Chris,

I've checked your fix in SVN [revision 4887].
Constellation labels look good on my system now.
Thanks.

[selden]

Cham,

If you want either Celestia or its ED version to be more "idiot proof", you'll have to provide specific examples of things that don't work well in your classroom.

It might be appropriate to start a new thread in the "Celestia in Education" forum for these issues.