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Earthview - an orbital terrain rendering engine [v2.0]

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Re: Earthview - an orbital terrain rendering engine [v2.0]

Postby GinGin » Fri Jan 31, 2020 8:39 pm

chris_blues wrote in Fri Jan 31, 2020 5:41 pm:
GinGin wrote in Fri Jan 31, 2020 5:25 pm:What kind of cloud textures would you need ?

I don't understand. What cloud textures and why?




The cloud textures have 3 empty channels available for 3 new maps or textures or whatever.
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Re: Earthview - an orbital terrain rendering engine [v2.0]

Postby chris_blues » Fri Jan 31, 2020 10:16 pm

chris_blues wrote in Fri Jan 31, 2020 1:43 pm:Plus, I seem to remember some talk about missing space for more textures (couldn't find it at a glance).

This is actually the thing, I meant by that. But this space is actually not usable, as Thorsten explained.
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Re: Earthview - an orbital terrain rendering engine [v2.0]

Postby GinGin » Fri Jan 31, 2020 10:34 pm

I see, thanks
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Re: Earthview - an orbital terrain rendering engine [v2.0]

Postby eatdirt » Sat Feb 01, 2020 12:14 am

@Thorsten, I have a working version of the spherical tiles loading in earthview.nas. I am trying to crash it now, and that seems to work fine to my surprise. At some point, I'll be brave enough to share it, but for the time being I would appreciate of bit of help to understand these:

Code: Select all
var R1 = 5800000.0;
var R2 = 58000.0;

var altitude1 = getprop("/position/altitude-ft");
var altitude2 = R2/R1 * altitude1;
var model_alt = altitude1 - altitude2 - R2 * m_to_ft;


I have added some new method in geo.nas, and from the very beginning, as one of the inputs, I need the altitude of the Shuttle above a spherical Earth and I don't know what to take here? I can see 3 spheres in the code, in addition to geo.ERAD:

R1=5800km
R2=58km
and the one in earth.xml (rendered?) which has a radius of 58030km!

Would you mind to explain, as far as you can, the magic tricks here? :)

Thanks!!
Cheers,
chris.
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Re: Earthview - an orbital terrain rendering engine [v2.0]

Postby Thorsten » Sat Feb 01, 2020 7:15 am

but for the time being I would appreciate of bit of help to understand these


Ray optics basically - the renderer doesn't work with an object 7000 km distant (and the numerical accuracy of a graphics card would simply kill you off at that distance anyway), so we give it an object 70 km distant at 1/100 the size - that gets processed fine and looks the same.

If you don't move too much from the reference point... 8)

which has a radius of 58030km!


You'll find that the numbers are all meters...
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Re: Earthview - an orbital terrain rendering engine [v2.0]

Postby eatdirt » Sat Feb 01, 2020 9:35 am

Wow!
So, you get the real altitude with respect to the real surface (altitude1?) and then we scale the real altitude by 1/100 and put a perfect sphere under it with radius 58.3km. But because Earth is not a sphere, the rendered sphere is then shifted compared to the origin to get the same angle of sight of, say, the horizon. And it's shifted by at most something corresponding to the real 30km (equator - pole radius)?

If I got it fine, I've just understood a minor issue with the Moon. With respect to the stars, when you travel around Earth in Earthview, it's having sinusoidal oscillations.

Ok, I need to do some maths... :)
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Re: Earthview - an orbital terrain rendering engine [v2.0]

Postby Thorsten » Sat Feb 01, 2020 12:55 pm

With respect to the stars, when you travel around Earth in Earthview, it's having sinusoidal oscillations.


Neither Moon nor stars nor your actual orbit have anything to do with Earthview, so I don't think an oscillation of the Moon with respect to the stars can be explained that way.
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Re: Earthview - an orbital terrain rendering engine [v2.0]

Postby eatdirt » Sat Feb 01, 2020 3:54 pm

Ok, got the maths right now for model_alt. What I don't get is the choice of R2, which is not geo.ERAD/100 (but geo.ERAD/110), so you voluntary induce distortion for objects getting close to the horizon, why?
Or, equivalently, the horizon in earthview is slightly larger than in a geo.ERAD sphere, which I need to take into account, but that's easy!

thanks!
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Re: Earthview - an orbital terrain rendering engine [v2.0]

Postby wkitty42 » Sat Feb 01, 2020 4:50 pm

would that induced distortion be atmospheric distortion?
"You get more air close to the ground," said Angalo. "I read that in a book. You get lots of air low down, and not much when you go up."
"Why not?" said Gurder.
"Dunno. It's frightened of heights, I guess."
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Re: Earthview - an orbital terrain rendering engine [v2.0]

Postby eatdirt » Sun Feb 02, 2020 2:43 pm

@Chris (and others) the 16K textures are there, I'll let them for a while, but a long term solution is indeed torrent.

fg/output/

cheers,
Chris.
Last edited by eatdirt on Fri Feb 14, 2020 2:10 pm, edited 1 time in total.
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Re: Earthview - an orbital terrain rendering engine [v2.0]

Postby chris_blues » Sun Feb 02, 2020 5:24 pm

Nice, got them. But they are smaller than I expected! Very nice!

Are there any testers/voluntaries around, willing to check if the textures are alright?

Here's the latest magnet link (torrent):
magnet:?xt=urn:btih:892a73c3bf3adcf30ca338b3be47c1a8dd67d2f2&dn=EarthView%20-%20Complete%202020-02

Happy testing!
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Re: Earthview - an orbital terrain rendering engine [v2.0]

Postby wlbragg » Sun Feb 02, 2020 6:27 pm

I'm attempting but I get no incoming from the torrent. Looks like no seed/peers/tracker?
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Re: Earthview - an orbital terrain rendering engine [v2.0]

Postby chris_blues » Sun Feb 02, 2020 6:30 pm

I'm online with the torrent. Sometimes it can take a while to connect to a trackerless torrent.
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Re: Earthview - an orbital terrain rendering engine [v2.0]

Postby wlbragg » Sun Feb 02, 2020 6:45 pm

OK, I'll let it sit there and do its thing. It did finally update files/size and whatnot.
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Re: Earthview - an orbital terrain rendering engine [v2.0]

Postby chris_blues » Sun Feb 02, 2020 6:51 pm

Yes, mine shows 1 connected peer. Probably you. So it only needs to start loading...

Edit: I'll add some more peers...

Edit2: I have 2 more peers now online. Should work pretty well now.
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