Celestia Forums

I just downloaded and installed Celestia yesterday and I think it's brilliant.

My problem is that I'm having trouble installing addons.

I've searched the forum for hours, and read the FAQs and 'A (not so) Brief Introduction to Celestia Addons (3rd edition)'. I've found documentation that tells how to install new objects, but nothing that details how to replace default stuff. I've seen references to 'alternate texture' code in ssc files, but the authors seem to be assuming prior knowledge that I don't have.

For example: I thought I'd try a small addon to start with, particularly as I'm on dialup, so I downloaded the 'Moon-4K' surface map textures by Hermes to replace the built-in ones, but the zip file doesn't contain any documentation, just the files 'moon-4k.dds' and 'moon-4k.png'.

I have put these in their own '/moon-4k/textures/medres' folder in the 'extras' folder - is that correct for replacement textures?

I expect there will be some configuration changes I will have to make in Celestia to make the program use the new textures, but I haven't been able to find what those changes are.

Is there a document that details how to install replacement textures like this, or is it an idiosyncratic process that varies for each addon?

Phil,

If you're only adding one new high resolution surface texture for each body, the easiest way to add a hires surface texture is to put it in the directory Celestia/textures/hires/ (not in extras) and rename it to have the same name as the corresponding texture files in textures/lores and textrures/medres. Its filetype extension should *not* be changed, though. You don't need both the dds and the png versions of the file: dds versions are smaller and faster, png images have somewhat better resolution.

e.g.

put moon-4k.dds in textures/hires
and rename it to be moon.dds

then you can use the r and R keyboard commands to switch among the three resolutions.

If you haven't already, you might take a look at the Web page
http://www.lepp.cornell.edu/~seb/celestia/textures.html
It tries to explain the hows and whyfores of the various surface texture images. For example, if you have both dds and png files with the same name in the same directory, Celestia will display the png file.

Does this help?

Selden,

Thanks, that was fast. About 2 minutes from posting my question to getting a reply.

It does help for this particular example, but I expect I will be adding more complex replacement textures in the future.

Your reply referred to this as the solution for adding only one texture, so I'm curious to know what the procedure is if multiple replacement textures were added.

I expect that this is where the 'alternate texture' code will be required, and that is where I have been unable to find any detailed instructions.

Thanks again,

Phil

Phil,

Yes, you're right: AltSurface declarations can be used to provide access to many different surface textures on the same object.

I've included a discussion of that SSC directive at
http://www.lepp.cornell.edu/~seb/celest ... s.html#2.4

Please let me know how it can be improved.

Selden,

Thanks again for your prompt reply.

I have seen a reference to the document you mentioned but it seemed to be recommended only for people wanting to create textures, so I didn't follow it up.

Looking through the document, it looks like section 2.3 'Substituting Surface Textures' would be most appropriate for replacing the Moon texture with the new one.

So the steps for the moon-4k example would be:

1. create a file 'moon-4k.ssc' in the folder '\extras\moon-4k\'
2. in that file put the lines 'Modify "Moon" "Sol/Earth" { Texture "moon-4k.*" }'
3. extract the file 'moon-4k.dds' into the folder '\extras\moon-4k\textures\hires'

Is that correct?

I don't think the document needs to be improved, it's just that I was expecting to find some 'baby-steps' documentation for beginners, whereas most of what I've found is more like being hit in the head with a brick full of information.

Phil

Philstix wrote:Selden,

Thanks again for your prompt reply.

I have seen a reference to the document you mentioned but it seemed to be recommended only for people wanting to create textures, so I didn't follow it up.

It's intended for people who want to understand how Celestia's texturing works, whether they're creating an Addon or trying to get an Addon to work, as you are. I probably need to change some of the introductory phrases.

Looking through the document, it looks like section 2.3 'Substituting Surface Textures' would be most appropriate for replacing the Moon texture with the new one.

So the steps for the moon-4k example would be:

1. create a file 'moon-4k.ssc' in the folder '\extras\moon-4k\'
2. in that file put the lines 'Modify "Moon" "Sol/Earth" { Texture "moon-4k.*" }'
3. extract the file 'moon-4k.dds' into the folder '\extras\moon-4k\textures\hires'

Is that correct?

That's what you should do if you want to "permanently" replace the Moon's default surface texture image by surface texture images named moon-4k.whatever. To change them later, you'd have to edit the SSC file or entirely replace this Addon you've created by a different one. In contrast, an AltSurface SSC will let you change the surface texture while Celestia is running.

(I've realized that the AltSurface section doesn't mention extras/ at all. It probably needs to include that as part of its example.)

I don't think the document needs to be improved, it's just that I was expecting to find some 'baby-steps' documentation for beginners, whereas most of what I've found is more like being hit in the head with a brick full of information.

Unfortunately, there's a brick-load of information that's relevant. The Addons and Textures documents both were much simpler when I started working on them. Then one detail after another had to be added. I think I'm much too close to the problem: it is not at all obvious to me what should be left out in order to create a simpler introductory version.

selden wrote:I think I'm much too close to the problem: it is not at all obvious to me what should be left out in order to create a simpler introductory version.

I agree with this part completely. As I'm reading the document, it's all making sense to me. But then again, I've been fiddling around with Celestia for a little over a year now.

I think I learned how to do Alt Textures with a little help from this document, but mostly it was from using other Add-ons' Alt-texture files and applying them to my own use.

From a beginner's perspective, I think it would be helpful if documentation detailed exactly where files should go within the folder structure, and specified exactly what changes have to be made to which files and the location of those files.

I understand that this stuff is obvious to experienced users, and once learnt it seems trivial, but to a complete novice there are baffling gaps in some of the documentation and on some of the forum posts, where the writer has assumed a basic understanding that I lack.

Phil