.gif files and such...

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Hungry4info
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.gif files and such...

Post #1by Hungry4info » 19.07.2007, 22:05

Somebody mentioned this in the "Lightning!" topic in the "Celestia Users" forum. I thought the topic deserved some attention, but didn't want to divert from the topic of that discussion, so I'll bring it up here.

Is it possible that future releases of Celestia could use .gif files? It would be great for evolving clouds, seasonal changes of the planets, perhaps stellar variability, solar flares, sunspots, and such.

There could perhaps be a command line in the .ssc file that declares how long each "Animation" should run (i.e. 1 year for seasonal changes in Earth, ~50 hours for cloud evolution, and so on...).

On the downside, from what I understand, .gif files can't achieve very good resolution.
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selden
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Post #2by selden » 19.07.2007, 22:47

Hungry,

By ".gif files" I assume you mean "gif animations". Unfortunately, GIF is a patented technology and, although the patent has run out, I suspect that opensource programs like Celestia are unlikely to use it.

Chris has mentioned that he'd like to incorporate animated textures in some future version of Celestia, but it doesn't seem to have gotten onto the roadmap. That suggests to me that it won't happen soon.

There have been several different proposals to extend the PNG format to include animation, but none of them have received wide-spread acceptance.

A movie format that uses JPEG (M-JPEG) has been in use for quite some time. It just consists of concatenated JPEG images, so that would be relatively easy to adopt, I think.

A quick search didn't locate any equivalent movie/animation formats that use DDS/DXT texture files. :(

Celestia depends on external codecs to create movie files from individual screen frames. I don't know how hard it would be to use an external decoder to produce the individual frames that Celestia would need in order to display animated textures. It'd have to be compatible with multiple platforms, of course.

Most modern graphics cards include hardware acceleration for the features of the various video formats (mpeg decompression, bob, weave, etc). I don't know how easily that functionality could be used by Celestia, though.
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Fenerit M
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Re: .gif files and such...

Post #3by Fenerit » 20.07.2007, 13:16

Hungry4info wrote:
Is it possible that future releases of Celestia could use .gif files? It would be great for evolving clouds, seasonal changes of the planets, perhaps stellar variability, solar flares, sunspots, and such.



Having the animated textures would be very interesting; e.a (for my purpose) the animate lava volcano who rise from deep. My question is: do someone has tried to map something with a small uncompressed (which allow the transparency, nor the black blackground, although for lava it would be not a problem) .AVI?
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Post #4by duds26 » 15.08.2007, 11:35

Movies in flash would be better for this purpose, because they are vector and object based.
Also mng could be a good format, the ogg formats could also be a good candidate for this.

(mng is the official animated png, it stands for multiple network graphics)
Last edited by duds26 on 15.04.2018, 21:33, edited 3 times in total.

Larre
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Re: .gif files and such...

Post #5by Larre » 07.07.2008, 03:49

I did note that there is an animated form of the .png format now. They tend to call it apng. Firefox 3.0 supports apng now, and has an animation editor.

This is a very promising future for the .png format of image files. If you can, or if I finally come up with the code, let's add animated .png support to celestia. It would be really good for the celestians out there. It is a brand new concept, so the code might not be developed right away, because it has to be learned...

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John Van Vliet
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Re: .gif files and such...

Post #6by John Van Vliet » 15.07.2008, 00:08

it is called mng
http://www.libmng.com/MNGsuite/
and the download (one Microsoft package from 2002)
http://www.libmng.com/download.html?cat=4

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Re: .gif files and such...

Post #7by Brendan » 15.07.2008, 05:22

MNG and APNG are two formats. There are some examples of APNG images at http://en.wikipedia.org/wiki/APNG. It works in the new Firefox and Opera browsers and displays the first frame in IE and Safari.

duds26
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Re: .gif files and such...

Post #8by duds26 » 25.07.2008, 14:49

Fenerit wrote:
Hungry4info wrote:
Is it possible that future releases of Celestia could use .gif files? It would be great for evolving clouds, seasonal changes of the planets, perhaps stellar variability, solar flares, sunspots, and such.


Having the animated textures would be very interesting; e.a (for my purpose) the animate lava volcano who rise from deep. My question is: do someone has tried to map something with a small uncompressed (which allow the transparency, nor the black blackground, although for lava it would be not a problem) .AVI?

It will be heavy for the processor, so to have a decent framerate Chris would have to learn how to use OpenML (standard for having the graphic card doing rendering work for video's, foto's and other multimedia) and apply it for video files.
Think of a planet: cloud, normal, light, reflection maps and some static maps. And addons already give the CPU's their hands full.

And again, mng and apng are two different formats. Actualy mng wouldn't be such a bad idea to implement on the short term for small animations.


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