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Global low resolution textured sphere/mesh earth base

Postby iamzac » Sun Apr 10, 2016 10:19 am

The flight gear issue the bothers me most is that whenever flying at high altitude, with an airliner for example, I am flying above a big square and I see small squares being loaded in front of me while other small squares are removed in the back and this really ruins the immersion.
Even if I greatly increase the LOD (which "kills" my hard drive and makes everything run very slow because even though I have enough ram the hdd is 5400rpm) there is still a straight line at the horizon and then that white sphere.

In x-plane they have a simple solution for this: a global low resolution texture and mesh that is loaded at start for all the planet and the higher resolution textures are loaded on top on that and not on top of some white cloud sphere like flightgear earth looks by default.
Because this low resolution texture is far away and usually covered by clouds and other lights effects it blends very well with the high resolution one and you can't see the difference.
Also, sometimes terrasync stops working and after a long flight you have to abort because you don't have anywhere to land, with a basic low resolution texture you could still land on some green stuff when you arrive there.
A 3d mesh is not absolutely necessary, a 2d sphere with a earth texture would still be better than how things look right now.
A vector image used as a texture would take very little memory if it can be used.
Also users could choose different textures/meshes for this depending on how much memory they have.

Could this be done?
I see that there is already a textured sphere for when you are in space but that is disabled when you are not in space.
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Re: Global low resolution textured sphere/mesh earth base

Postby Thorsten » Sun Apr 10, 2016 10:43 am

That's almost certainly a configuration weirdness on your side, because when run properly, the default FG scenery engine doesn't do that, the missing terrain is represented by the skydome:

Image

Image

Image

Image

You basically only get to see the terrain edge when you ask FG to give you a visibility beyond the set LOD bare range - and if you instruct FG to give you 200 km of visibility and at the same instruct it to show you the terrain only out to 100 km, then you correctly get to see the terrain edge.

Because this low resolution texture is far away and usually covered by clouds and other lights effects it blends very well with the high resolution one and you can't see the difference.


That works from space, but what you can see in the distance from airliner altitude is not texture (that's fogged anyway) but elevation mesh, i.e. you see hazy mountains at the horizon long before you see any textures. Unfortunately a textured sphere doesn't have the elevation data needed, and in a position-differential lighting scheme as we use, any discontinuity in elevation data would show up very prominently indeed.
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Re: Global low resolution textured sphere/mesh earth base

Postby wkitty42 » Sun Apr 10, 2016 3:15 pm

iamzac wrote in Sun Apr 10, 2016 10:19 am:The flight gear issue the bothers me most is that whenever flying at high altitude, with an airliner for example, I am flying above a big square and I see small squares being loaded in front of me while other small squares are removed in the back and this really ruins the immersion.
Even if I greatly increase the LOD (which "kills" my hard drive and makes everything run very slow because even though I have enough ram the hdd is 5400rpm) there is still a straight line at the horizon and then that white sphere.

as thorsten says, the other stuff should be fuzzed out by fog... however, you might want to give these options a try... they are part of what i use in the additional settings box of the launcher...

Code: Select all
--enable-distance-attenuation
--enable-horizon-effect
--enable-specular-highlight

--fog-disable
# the following distance numbers are based on the horizon distance of 369km @ 35000ft altitude
# visibility 370000 takes fgfs up to ~9.5G of RAM usage with these current settings
# visibility 100000 takes fgfs up to ~4G of RAM usage with these current settings
--visibility=100000
--prop:/local-weather/config/ground-haze-factor=370
--prop:/sim/rendering/clouds3d-vis-range=370000
--prop:/sim/rendering/max-paged-lod=300
--prop:double:/sim/rendering/static-lod/detailed=3000
--prop:double:/sim/rendering/static-lod/rough=20000
--prop:double:/sim/rendering/static-lod/bare=370000
"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: Global low resolution textured sphere/mesh earth base

Postby Hooray » Sun Apr 10, 2016 5:40 pm

Could you please post a few screenshots (or even a youtube video link) to clarify what you are referring to ?
Please don't send support requests by PM, instead post your questions on the forum so that all users can contribute and benefit
Thanks & all the best,
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Re: Global low resolution textured sphere/mesh earth base

Postby iamzac » Sun Apr 10, 2016 6:11 pm

Hooray wrote in Sun Apr 10, 2016 5:40 pm:Could you please post a few screenshots (or even a youtube video link) to clarify what you are referring to ?

Right now I am waiting for terramaster to finish downloading the whole scenery which might take a few days but I think that what Thorsten said about decreasing the visible range below LOD range might work to hide this problem if the LOD is big enough.
I did search on google for several flightgear screenshots right now and I can't see the square thing in any so maybe my settings were wrong.
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Re: Global low resolution textured sphere/mesh earth base

Postby f-ojac » Sun Apr 10, 2016 6:59 pm

I'm not sure downloading the whole scenery is a good solution for the poor Terrasync server...
If you want to support my server, hosting Terrasync + World Scenery + TGWeb + osm2city data mirror, hosted on a private server, you can donate here: http://ns334561.ip-5-196-65.eu/WS2.0/WS ... 2.0.1.html
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Re: Global low resolution textured sphere/mesh earth base

Postby wkitty42 » Sun Apr 10, 2016 8:20 pm

@f-ojac: is there any clue if/when other terrasync servers will be coming online to share the load? is there any indication that fgfs will switch between terrasync servers as it pulls additional tiles so as to spread the load around?
"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: Global low resolution textured sphere/mesh earth base

Postby rominet » Mon Apr 11, 2016 9:00 am

Not implying that downloading the whole world scenery is necessarily a great idea (cf. my post in the Support section), but:

If bandwidth of the TerraSync servers is a real problem... remember the FlightGear Development Push thread?

/hides away :wink:
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Re: Global low resolution textured sphere/mesh earth base

Postby psadro_gm » Mon Apr 11, 2016 6:00 pm

I'm making slow but steady progress on the scenery LOD project. My hope is to have some test scenery on dropbox by the end of April. This scenery will only work with fgviewer, but hopefully, we can get the other renderers reading the .SPT hierarchy as well.
8.50 airport parser, textured roads and streams...
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Re: Global low resolution textured sphere/mesh earth base

Postby f-ojac » Tue Apr 12, 2016 8:37 am

@rominet, @wkitty42 : the bandwidth must of course be something of attention, I currently own/pay a dedicated server for Terrasync. 100 Mbps bandwidth, hosted in a quite professional way, and the result is this:
Image
So, yes, there's quite a high demand on bandwidth, with peaks up to 100 Mbps nearly every day. And we're not hosting movies, so I let you imagine the number of clients... Those are people using Terrasync, of course, but also Terramaster, or even grabbing the whole scenery via httrack and the like.
The RAM is 4Go, full to 10/20% most of the time.
The CPU is another problem, it's most of the time over 50%, reaching sometimes 100%. Due to the amount of bullshit intercepted via fail2ban and others, and also due to the fact that the Apache libsvn is core-ing a lot due to the way Terrasync sends some requests. James is aware of that and working on it, with a full http solution. Still, this module is crashing tens of time per second (yeah) and therefore causing a lot of logs, which themselves are digested by fail2ban and using RAM.
Well, that's not a big problem, the whole thing is working, no problem yet, but I think this is something everyone should have in attention. And, when in the logs I see people harvesting the whole WS2.0, I'm just wondering why. I haven't put more restrictions right now, but if the situation gets worse, maybe I'll do.
@rominet, I've never felt easy with asking for contribution to me hosting the TS server. Until now, despite a lot of discussion, we've never found a proper way to financially contribute FG-wide (and wise) for projects which need money (I mean apart buying the DVD stuff or advertising). Yes, I pay to host the TS server on a dedicated server every month. So if you feel like helping, please do. The link is at the bottom of the page ( http://ns334561.ip-5-196-65.eu/WS2.0/WS ... 2.0.1.html ). If someone sees a better solution, please say. Yes, I could host this server at home, I have a decent bandwidth, but it's not sufficient.
And, who knows, maybe we'll be able to make it the scenery server for future scenery builds (the server also hosts the TGWeb service for now, so the basics are there).
PS : sorry for nearly hijacking the thread, but I feel it's important for everyone to know what's behind. The Terrasync data is not send to users "out of the blue".
If you want to support my server, hosting Terrasync + World Scenery + TGWeb + osm2city data mirror, hosted on a private server, you can donate here: http://ns334561.ip-5-196-65.eu/WS2.0/WS ... 2.0.1.html
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Re: Global low resolution textured sphere/mesh earth base

Postby wkitty42 » Tue Apr 12, 2016 8:30 pm

@f-ojac: thanks for the information... it helps a lot... now if only things like this could be made aware to those who don't visit other (sub)forums...
"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: Global low resolution textured sphere/mesh earth base

Postby iamzac » Tue Apr 12, 2016 9:28 pm

I have been asked for screenshots to explain what I mean so after finally getting all the scenery here they are:

X-plane (from their dev blog post at http://developer.x-plane.com/2015/03/extended-dsfs-in-x-plane-10-40/) at KSEA with reduced LOD range for low memory:

Image

X-plane (from their dev blog post at http://developer.x-plane.com/2015/03/extended-dsfs-in-x-plane-10-40/) at KSEA with extended LOD range:

Image

Flightgear, current git version, at KSEA with 60000m LOD range, fair weather, high visiblity:
Image

Flightgear, current git version, at KSEA with 60000m LOD range, fair weather, visiblity below LOD as Thorsten sugested:
Image

And as you can see 4fps with the UFO with the latest build after with the previous one I had 60fps with the same settings... or maybe something broke in my PC again...
The square is more obvious if you are looking around and rotating the camera around, in the screenshots it's less obvious but the straight edge in front is one of it's sides and you can see the left and right corners .
I am really curious what flight sim Thorsten is using, I would really like to use that, it looks better than x-plane :)
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Re: Global low resolution textured sphere/mesh earth base

Postby PINTO » Tue Apr 12, 2016 11:48 pm

In that gui box you are showing in your pictures, set your Scenery Bare LOD range to something higher than 60000. I have mine set to 200000, and don't notice the square ever, even flying the SR-71 at 85,000 feet. I usually crank up my visibility with the Z key to 200000-250000 as well.

Also, those pics are using advanced weather (your pics are using basic weather) and ALS, so be sure to set those too.

Also, pro-tip: for prettier scenery, don't fly at noon. Fly at morning/evening.
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Re: Global low resolution textured sphere/mesh earth base

Postby Thorsten » Wed Apr 13, 2016 5:03 am

FG doesn't come with a LOD system for the scenery mesh - which means asking visibilities of more than 150 km in detailed scenery tends to be crippling even for high-end systems. If you have the graphics card and the memory, they render fine nevertheless.

Again, if you set LOD bare to 60 km, you won't see any terrain beyond 60 km - not because FG is inferior to X-plane in any way, but because you asked FG not to show any terrain beyond 60 km.

Setting visibility in the ALS renderer is not trivial, because it's a three component model (wet haze ground layer, wet haze aloft layer, dry haze), which is why using the z-key for visibiity is probably not doing what you expect it, because you only have control over one component - it's a legacy fallback for the old renderers (indeed, I've suggested to remove the binding more than once...)

The solution is really simple:

* set LOD bare to the visibility your computer can handle (memory and GPU speed)
* use AW and set the max. allowed visibility to the same value
-> see FG adjust everything automatically to your needs without seams

Alternatively you can adjust all settings by hand, but there's no safeguards to avoid visual mismatches (for instance, you'll discover that there's also a far camera clipping plane at 120 km which needs to be adjusted if you need more visibility.

I am really curious what flight sim Thorsten is using, I would really like to use that, it looks better than x-plane


If you look through the screenshots posted elsewhere, it's not that magically I managed to get the square to vanish - pretty much everyone did. You're for some reason trying to adjust a lot of things by hand without understanding what the different parameters really do, and that can lead to mismatches. That's all.
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Re: Global low resolution textured sphere/mesh earth base

Postby rominet » Wed Apr 13, 2016 6:10 am

f-ojac wrote in Tue Apr 12, 2016 8:37 am:@rominet, @wkitty42 : the bandwidth must of course be something of attention, I currently own/pay a dedicated server for Terrasync. 100 Mbps bandwidth, hosted in a quite professional way

Thanks for these informations and for generously providing this service to us, f-ojac! I understand your reluctancy of making a lot of publicity for the PayPal link, but IMHO this hosting would probably be one of the least controversial things that FG as a project could officially financially help (paying for hosting as opposed to development). But probably no one is much motivated by/has time for the paperwork that this would entail...

(and yes, sorry for the thread hijacking too, but we more or less all depend on the TerraSync servers in some way, so...)
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