Galaxy colors etc.

General discussion about Celestia that doesn't fit into other forums.
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t00fri
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Post #61by t00fri » 17.07.2005, 22:11

selden wrote:Fridger,

There always has been a problem with recompiling under Windows, especially when .h files are updated. It's like nmake isn't finding all the dependencies. I deleted everything in /src/ so that CVS downloaded a fresh copy of all of the source code and thus forced makerelease.bat to recompile everything.

After installing your prototypes and turning the galaxy limiting magnitude way up, I now can see many of your galaxies. As you say, they're an ugly pink :)

However, it's clear that a lot of Windows user-interface code hasn't been written yet. For example, I'm getting no on-screen text display showing the change in limiting magnitude for galaxies when I type either ( or ) I think there ought to be a text display like there is for the change in limiting magnitude of stars.

Much more important to me, however, no Nebula objects are being drawn at all, no matter how long I hold down ( [shift 9]. My understanding is that now they're selected separately from galaxies, but there is no "show Nebula" option in the Render/View Options menu.


Selden,

good to see that at least the previous "mystery" seems solved. I am never using nmake. For CVS updating I use the CYGWIN layer with all standard LINUX tools and scripts. Only after everything is ready, I switch on MS-VC++ .net.

The things you mention will certainly come. They are of the easy kind. Linux-KDE has already separate display options of galaxies, nebulae, clusters...since quite some time. The drawing of nebulae works there. Chris was in quite a hurry when he tried to finish the new 1.4.0pre version before leaving for Mt. Baker.

I have written quite some code for proper magnitude handling and coloration. Toti has just now finished a new octree template class treatment that works both for stars and DSO's. Octree optimization etc is where the real challenges are, since these culling things finally determine the fps rates that people can enjoy! I spent quite a bit of time with the latter...
Chris has not yet implemented these newer things due to his next climb at Mt. Baker before the weekend.

But I am confident: we are getting there!

Bye Fridger

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Post #62by Paolo » 18.07.2005, 14:56

Hi all.

I've compiled the new code. Thank you Fridger for publishing the galaxy models file.
I found a z-sorting problem. It seems that Galaxies are drawn in loading order not accordingly with the distance of the observer. So if you rotate the observer and galaxies superimposes, one of the two remains on top of the other even if you rotate 180 degrees.
The problem appears clearly visible if you set the luminosity at maximum using the "(" key.
I'm using the standard galaxy catalogue in the current Celestia 1.3.2 distribution (8-9) galaxies.
Did anyone experienced the same problem?
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Post #63by Toti » 18.07.2005, 15:18

Paolo wrote:I found a z-sorting problem. It seems that Galaxies are drawn in loading order not accordingly with the distance of the observer. So if you rotate the observer and galaxies superimposes, one of the two remains on top of the other even if you rotate 180 degrees.

The same happens with blobs in each single galaxy: they are sorted by creation order and the result is not good.
In the original code I set the openGl blending mode to avoid these issues without doing per frame sorting, but Chris reverted back to the previous mode.

selden wrote:For example, I'm getting no on-screen text display showing the change in limiting magnitude for galaxies when I type either ( or ) I think there ought to be a text display like there is for the change in limiting magnitude of stars.


When adjusting light gain there was a flash message that showed the value as a percentage (0-100%) It was also removed.

Bye

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Post #64by t00fri » 18.07.2005, 16:03

Selden, et.al.,

I now have found the bug that Chris introduced in a hurry when integrating our galaxy code with his own views...

He forgot to increase FAR_DIST in render.cpp by at least a factor of 10!

With the bug present, only the very closest galaxies from my new deepsky.dsc catalog were rendered.

So just increase FAR_DIST by a factor of 10 and recompile the CVS code. I have done it here with my laptop with VS++.net.

Then, use my latest deepsky.dsc file from CVS and make the following check:

enter
m 65
c
push ( until the three galaxies become nicely visible.



Now you can display the complete revised NGC/IC catalog with an applied Bmag<12 cut (for reasons of space).
I would also advice to interchange the function of the ( and the ) key in celestiacore.cpp.

Bye Fridger

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Post #65by ElChristou » 26.07.2005, 20:49

Hi,

Meanwhile I was browsing the last build from Dirkpitt including the last advances in galaxy topic, I was wondering if it can be possible to have 2 or 3 models for each galaxy type with subttles differences in shape and color positioning to avoid the "d?©j?  vu" effect when exploring those remote areas... the choice for model 1, 2, or 3 could be done randomly at once before writing the final catalogue...
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Post #66by t00fri » 26.07.2005, 21:26

ElChristou wrote:Hi,

Meanwhile I was browsing the last build from Dirkpitt including the last advances in galaxy topic, I was wondering if it can be possible to have 2 or 3 models for each galaxy type with subttles differences in shape and color positioning to avoid the "d?©j?  vu" effect when exploring those remote areas... the choice for model 1, 2, or 3 could be done randomly at once before writing the final catalogue...


As concerns myself, I am still dissatisfied with most Hubble type templates that exist so far. Once we have a good algorithm of producing those templates, we can certainly try to incorporate more subtypes. Actually there are quite a few more types in use professionally. So far we have just reduced them to the "good old" Hubble ones.


The quality of the whole galaxy display hinges crucially on the quality of the templates! I am continuously experimenting with possible improvements.

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Post #67by ElChristou » 26.07.2005, 21:37

hmm...
...also, what about the process of colors? it's still a work in progress or is it almostdone? For now I found the limit between the inner/outer zone a bit too strict...
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Post #68by Toti » 26.07.2005, 22:57

ElChristou wrote:Meanwhile I was browsing the last build from Dirkpitt including the last advances in galaxy topic, I was wondering if it can be possible to have 2 or 3 models for each galaxy type with subttles differences in shape and color positioning to avoid the "d?©j?  vu" effect when exploring those remote areas... the choice for model 1, 2, or 3 could be done randomly at once before writing the final catalogue...


Even better would be the possibility to override the 6-7 basic point cloud templates with your own ones (built from real imagery)
I'll take a look at this after the incoming prerelease.

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Post #69by ElChristou » 27.07.2005, 00:10

Toti wrote:Even better would be the possibility to override the 6-7 basic point cloud templates with your own ones (built from real imagery)
I'll take a look at this after the incoming prerelease...


Sounds very interesting...
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Post #70by t00fri » 27.07.2005, 07:37

ElChristou wrote:hmm...
...also, what about the process of colors? it's still a work in progress or is it almostdone? For now I found the limit between the inner/outer zone a bit too strict...


It's almost done, but there are apparently sync problems with Chris. Since more than a month he said that he was working on elliptical galaxies. The present CVS has some early code on that but it's not activated and not functioning as he wrote to me. So I have asked for his latest patch which he did not send.

As to my actual method: I have taken the Hue distribution directly from true-color photographic imaging and fitted it to some math function. The Hue distribution turned out rather universal for spirals. All one might have to consider eventually is a global shift of the hue.

The missing part is Chris elliptical code: elliptical galaxies are redder than spirals, since they are much older. When I do galaxy colors, I obviously don't want to restrict that work on spirals...

Similar issue with the absolute magnitude stuff. Everything related to /non-ellipticals/ is done and works nicely. I am waiting for Chris ellipticals to to properly normalize the brightness.

Bye Fridger

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Post #71by Sky Pilot » 01.08.2005, 19:51

This is just a very tiny-brained interruption into a very interesting thread...

You brainiacs are providing a TON of value to Celestia, and you're to be commended. We simpletons are humbled and delighted by your hard work!!

However, this thread -- seems to me -- probably belongs over in the Celestia Development forum. Us users who don't know how to compile code from CVS, and don't know how to adjust a "simple" perl script, are at a complete loss at how to benefit from your INGENIOUS work.

I'm requesting the simplest of explanations: when and how will we "non-computer-programmer users" of celestia get to benefit from these beautiful galaxy renderings?

Many many many thanks to you all!!

Sky Pilot
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Post #72by ElChristou » 01.08.2005, 20:17

Sky Pilot wrote:...I'm requesting the simplest of explanations: when and how will we "non-computer-programmer users" of celestia get to benefit from these beautiful galaxy renderings?...


I'm exactly in your position (not a coder at all) and like you I wait with anxiety the final release of this topic... The people who are working hard on this nice piece of the soft are more than busy, so by respect I think the only thing we (us) can do is wait without disturbing too much :wink:...
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Post #73by t00fri » 01.08.2005, 21:16

I have actually worked quite hard on a vastly improved version of my 'deepsky.dsc' galaxy data. I shall make it available for testing by others very soon and then commit it to CVs.

I have heard NOTHING from Chris recently.

Bye Fridger

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Post #74by jgrillo2002 » 27.08.2005, 03:25

selden wrote:The new galaxy database requires the new Celestia code. You have to download it all and compile from scratch. But, despite it working for Fridger, it still doesn't work for me, so don't waste your time on it just yet.
where can I find the new Celestia 1.4.0 Pre 7 like what symaski62 said?

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Post #75by selden » 27.08.2005, 11:20

The official release of v1.4.0 pre7 for Windows is not yet available. Several features of Celestia are in the middle of being changed right now. When their coding has been finished, but perhaps not quite fully debugged, Chris will announce where you can get it.

You can build Celestia from its current source code if you want, however. See the thread at http://216.231.48.101/forum/viewtopic.php?t=6255 for instructions.

Alternatively, an "Extended Celestia" is available from Brendan. See the thread at http://216.231.48.101/forum/viewtopic.php?t=7864.
Selden


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