Oolite Bulletins

Hoopy wrote:

Anybody got somewhere I can upload an image or two to show the sort of thing it spits out?

Try imageshack!

And while I'm posting: what about this texture for a tech planet?

@ Kaks: pretty snazzy!

@ Hoopy, CaptKev and others: I am continually amazed at the way people on this forum can just sit down and make this kind of stuff happen. I like to think of myself as computer-literate because I can use one without (usually) hurting myself or starting a fire, but you guys...

the secret is finding it fun playing with stuff. that way you can spend hours without realising and eventually you work it out!

I'm constantly amazed by people who can draw / design / create stuff. i'm just plugging together a few commands and a bit of maths...

Kaks wrote:

Are these any good?

Great stuff Kaks, I'll give them a test this morning and report back to you.

Disembodied wrote:

Hmm... an interesting site here. Permission would be required to use the textures but it should be free of charge, at least! (Edit: just noticed LittleBear beat me to this one by some considerable margin...)

And some of the planetary maps here might be useable... Callisto and Ganymede have a sort of scarred industrial look to them.

I must admit I did discover planetpixelemporium before they started charging for there bigger texture maps.

I have most of the solar system textures from other sources without any copyright restrictions.

Great stuff guys, keep 'em coming!

Hoopy wrote:

right. i have a procedural texture generator working now.

It needs a GUI (instead of rebuilding the code each time) to get allow easy adjustment of the parameters

It needs a a better 2D interpolation than simple linear between the nearest 4 points. Although adding extra smoothing on the later passes does stop all the peaks looking too much like pyramids.

It possibly needs some sort of palette generating tool as well, it took me a while fiddling about with polynomials to generate a mars like palette... Otherwise it can always be tweaked in photoshop etc.

I'd forgotten how fiddly all this stuff is from first principles!

And how much fun it is once you get it working!

Anybody got somewhere I can upload an image or two to show the sort of thing it spits out?

http://www.flickr.com/photos/24657513@N04/

@ Hoopy: In the long run I would prefer a procedural approach in-game, so I think you're on the right track finding out believable parameters for procedures.

However, the textures on the link don't yet do it for me. They still look rather artificial. The other two problems with them, as they are now, is the wrong ratio (a planetary texture should be twice as wide as it is high), and that they are actually tiles, which also means they lack polar areas.

Anyway, please keep fiddling. You're not yet quite there, but I'm sure you will.

*****

Myself I have done two textures for two planets for ghosts-from-the-past.oxp, one Earth-like and one gas giant, for which I butchered pictures from Nasa's planetary photojournal, namely a false-colour of Venus and one of Neptune.

I post them here as samples and perhaps for inspiration, but I'd rather reserve them for their special purpose (and Oolite's normal planets are not supposed to be gas giants, anyway).

And then there is another Moon-like texture from the same OXP, for which I again butchered a tiny fraction of a moon picture from the same site. I wanted to give it a certain artificial look, because it's supposed to be the texture of an artificial interstellar moon.

Both the earth-like and the interstellar moon texture suffer from the same pole-projection problem, when wrapped around a sphere, so they are not ideal. And the textures are not very big (the planets 256x128, the moon 512x256). For my purpose I found them detailed enough this way, and at the end of the day one has to make a compromise between detail and file-size.

Anyway, I thought you might like to see them:

Planet A (Earth-like):


Planet B (gas giant):


artificial moon:

Here they are Kaks, in all there glory.



I really like the first one, but I'm not so sure about the other two.

Those are the first textures that 'worked' then i spent a couple of minutes tweaking a few parameters. So yes, they are a way of being 'ready' for use.

For a start it's set at 256x256 so is too low res. I hadn't thought about aspect ratio so I guess 1024x512 would be better?

I hadn't even though about polar regions. I guess I can stick in a post generation parameter that will artifically make the top and bottom higher, and therefore whiter with the palette that those have. That should be quite easy actually.

Once I add a user inteface to the app that generates them it'll be easy to tweak the parameters and some one more creative than me will have an easier time looking for some good sets of values.

I think better colouring will help a lot as well. I should perhaps create a pure 'sea' texture (ie flat blue with a bit of random noise) and then display that in all the sea regions. At present it just makes deep sea black and shallow sea mid blue. In reality all the sea looks the same (apart from the very shallow regions)

@Hoopy, this could be a very useful tool, have you had a look to see how the textured planet branch generates it's images?

I've not looked at the oolite code at all (although I've got a link to the SVN repository somewhere).

It's actually something I've been meaning to play with for just over 10 years so this was just the impetous to get me started

I'm thinking that once I have a good tool for finding suitable parameters etc then it may be worth handing over to an Objective C expert (it's written in C# but Oolite is Obj C) who could then try plugging it into the game.

If that doesn't happy then the textures can simply be used alongside downloaded earth images by anyone who wants to use them in an OXP.

And if no one uses them for that then no worries, I've still had my fun

How is the (square) texture wrapped to the sphere? does it automatically progressively blur the more polar regions to stop them looking all squashed up?

The problem with the poles is not so much that they should be white (there doesn't need to be snow on a pole), but the "pinching" effect at the poles, because the whole length of the texture has to be squeezed into very few pixels (exactly at the pole it's only one).

Ahruman posted a link to a website which deals with this problem somewhere, but of course polar caps with an area of reasonable uniform colour are a good workaround.

Another small issue is that the way in which Oolite wraps a texture around a planet is not as sophisticated as e.g. Celestia does. If you use just a pattern from a graphics software as a texture, you will see what I mean. It's like Oolite treats the planet a little like a polyedron and glues small pieces of the texture to its faces, rather than a smooth transition from the equator to the poles. (EDIT: I think you can recognize a little bit of this in the lower left quadrant of the left example in Captn Kev's post.)

I think the textures still look reasonably well in the game, so it's not really a big issue. (Probably this slightly sub-optimal way is more processor-efficient than the optimal way would be.)

that's sort of what i thought.

The height scaling things I suggested will help then by making it more uniform in colour at the poles.

I may try adding some progressive smoothing at higher latitudes as well. That way when it gets scrunched up the level of detail will look fairly uniform throughout. I think that'll be much easier than trying to work out how much complexity to add when generating it in the first place.

Skyscraper planet anyone?

Look Industrial enough?