[Release] System Features: Rings

[gsagostinho]

All right, good to know!

If anyone else who is affected needs help cleaning their save files, please let me know.

[Cody]

I think removing the oxz may clear that section of the save-file - it probably should.

[gsagostinho]

Thanks Cody, I will test that later.

I think that the only solution would then be to check if the description has the sub-string "This planet has rings." at any position (since another OXP might append something to the end of the description).

So if anyone has a more elegant suggestion than mine, I am all ears!

[gsagostinho]

I uploaded version 2.8.1, it turns out it was quite trivial to implement the substring search and match with JavaScript. Everything seems fine on my side now.

Cody, would you mind updating to 2.8.1 and checking if everything is fine on your side?

[Cody]

Looks good here!

[gsagostinho]

Great, thanks for all the testing, input and bug searching, Cody, really appreciate it.

[spara]

Thanks Cody, I will test that later.

I think that the only solution would then be to check if the description has the sub-string "This planet has rings." at any position (since another OXP might append something to the end of the description).

So if anyone has a more elegant suggestion than mine, I am all ears!

Don't know a thing about elegance, but some oxps use something like oxpName_runOnce missionVariable, whose existence is checked before the code is run and is written the first time the code is run.

[gsagostinho]

some oxps use something like oxpName_runOnce missionVariable, whose existence is checked before the code is run and is written the first time the code is run.

That's nice to know, but I don't think it would fit the purpose here as this OXP has to be constantly running since the shader has to generate the rings in real time. But the solution I found of searching the description for the phrase is quite satisfactory and gets the job done without any performance issues, albeit a bit inelegant. But I can live with that

[RockDoctor]

but I wouldn't use the term "ring system", it would sound confusing since we speak of star systems already.

Talking of a "ring system" is fine. At different time in the study of the Solar system it has had one ring around one planet (Saturn), 3 rings around one planet (still Saturn, but with visible gaps), 4 rings around one planet (about 1950, another gap identified), then IIRC 7 rings around 2 planets (3 on Jupiter, 4 on Saturn, shortly pre-Voyager), then dozens of rings around 3 planets (Uranus has at least 5, detected by star occultations from the ground). The current estimate is a million-plus rings, mostly around Saturn, some around Jupiter, some around Uranus, at least 3 around Charilko (Arxiv a couple of days ago, Arxiv-1706.00207 The structure of Chariklos rings from stellar occultations), and I wouldn't bet a soggy cigarette against there being other ring systems within the Solar system.

Ring systems aren't simple, as soon as you start to look. Quite why you'd want to look closely unless you're running out of volatiles is another question. Flying lumps - bad news - be elsewhere.

[gsagostinho]

@RockDoctor thanks for all the info but I just meant that perhaps the term would sound confusing, but then again I am not a native speaker. Nevertheless "This planet has rings" sounds all right to me

[RockDoctor]

@RockDoctor thanks for all the info

More incoming. It's a firehose.
A paper published yesterday described a ring around the Trans-Neptunian Object Haumea. The abstract is available on Nature's website, and the full paper and data at http://sci-hub.cc/http://www.nature.com ... 24051.html. You'll probably just want the abstract information :

Secondary events observed around the main body of Haumea are consistent with the presence of a ring with an opacity of 0.5, width of 70 kilometres and radius of about 2,287 kilometres. The ring is coplanar with both Haumea’s equator and the orbit of its satellite Hi’iaka. The radius of the ring places it close to the 3:1 mean-motion resonance with Haumea’s spin period ... Haumea’s largest axis (diameter!) is at least 2,322 kilometres

Neglecting the odd shape of Haumea (it's seriously not a sphere, and it's not even an ellipsoid of rotation), that gives you some grounds for your ring opacity figure, and some hints for ring radius - small integer ratios of the 2/3rd power of the radius of the primary (assuming Keplerian dynamics). The presence of close-in satellites does not preclude there being a ring (again, Haumea is really weird - it's satellites are not all in one plane).
I've noticed over the last couple of days flying around that the number of "thin, far out" rings seems to have increased (it may be coincidence though), which from this example and the Uranian example, sounds generally justified.

[gsagostinho]

Yeah, I have read the news about Haumea, really interesting stuff!

I've noticed over the last couple of days flying around that the number of "thin, far out" rings seems to have increased (it may be coincidence though), which from this example and the Uranian example, sounds generally justified.

I think it might be a coincidence. In the last release I did tweak the conditional for the rings a bit so that now there are more planets with rings, but I did not change the formula itself. This means that if a planet had rings before, they will still have them and they will look identically to how they were before. The ratio of thin/thick rings should remain the same as before as well, as the formula behind it and the random distribution were not changed. Now if the question is whether thin rings are more common than thick ones regarding this OXP, I simply wouldn't know: I am not sure how the random distribution is looking after I process it with the ring formulas! I might take a look at this when I get a chance if anyone is curious.

[RockDoctor]

Someone in another thread "suggested" a feature of a "tractor beam" - for use as a weapon, or other uses. That chimes with a SF story idea that was floated some time ago, but never fleshed out. So over in that thread, I've been fleshing it out.
Can I ask - in your conception of rings, is it possible to fly parallel to the ring and scoop material out of them ? It would certainly let you collect mass faster than by asteroid-hunting, though maybe not as fast as sun-diving. Not being a star, it couldn't yield you any (or, not much) Qurium, but the fuel scoop mechanism already takes stellar plasma, filters out the Qurium and throws away the waste, so surely the same mechanism could also filter out the mineral mass, reject the ice from the ring material, and fill your hold with dull, cheap mass?
Or, would this mission concept need to depend on the system in question containing a star (obviously), a generation ship, and an asteroid swarm?

[gsagostinho]

That might not be possible, RockDoctor. The rings themselves are created with some shader magic but as far as Oolite is concerned the rings object is a 2D plane object which is very large. You could in theory detect when a ship is close to this plane, but the problem would be that you would not be able to tell what parts of this plane are having rings 'printed' onto it by the shader and what parts are just transparent space.

[RockDoctor]

That might not be possible, RockDoctor. The rings themselves are created with some shader magic but as far as Oolite is concerned the rings object is a 2D plane object which is very large. You could in theory detect when a ship is close to this plane, but the problem would be that you would not be able to tell what parts of this plane are having rings 'printed' onto it by the shader and what parts are just transparent space.

Yeah, I suspected it would be tricky, being a pretty picture not a part of the "game engine". It's why you can fly through the rings - which is something I approached very carefully after a game save, and later went through with full on injectors. Just to be sure.
So, for my mission idea, I'd probably just make sure the mission only happens in a system with a nice rich asteroid belt - since dumping momentum is one of the problems which a tractor beam could help with.
I tried getting that "gas giant scooper" add on working a while ago, but it didn't want to play. Gas giant's being easier to find than random swarms of asteroids. Ringed planets are also relatively easy to find from a long way away.