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Re: Runway lighting

Postby wkitty42 » Tue Jan 05, 2016 6:50 pm

i expect that at 50nm out, he was probably also at a decent altitude... if my math is correct, at 5000ft (1524m) altitude, the horizon is about 86.6mi (75.2nm or 139.4km) away so it is feasible that one might see an airport at 50nm with dark adapted eyes and excellent seeing conditions...
"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: Runway lighting

Postby abcaster » Tue Jan 05, 2016 7:50 pm

Yeah probably FL80-150ish.
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Re: Runway lighting

Postby wkitty42 » Wed Jan 06, 2016 12:46 am

be careful when using altitude and flight level... they are not the same thing and they mean different things in different places... http://aviation.stackexchange.com/questions/13204/what-is-the-difference-between-flight-level-and-altitude

assuming that you mean 8000ft up to 15000ft, the horizon is then 109.6sm up to 150.1sm out... "sm" meaning "statute miles"... conversion between sm and nm may or may not be accurate depending on which formula you use...
"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: Runway lighting

Postby hamzaalloush » Wed Jan 06, 2016 4:28 am

I love the fact that FG is more about realistic perception, then it is about artificial situation awareness, someone otoh can make use of this, in a dim and dark dedicated sim environment. And it would be "orders of magnitude" then FSX let say....

If I want to have training, I'd rather prepare for meteorological conditions where i might have limited perception over things, locked zoom with realistic FOV(no cheating), searching for a runway to land is a skill, that's why you should come prepared for a landing with the most possible info that you gather for the area, this what makes you a navigator.

/off-topic(?) rant/personal opinion, please continue this good discussion.
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Re: Runway lighting

Postby abcaster » Wed Jan 06, 2016 8:32 am

wkitty42 wrote in Wed Jan 06, 2016 12:46 am:be careful when using altitude and flight level... they are not the same thing and they mean different things in different places... http://aviation.stackexchange.com/questions/13204/what-is-the-difference-between-flight-level-and-altitude

assuming that you mean 8000ft up to 15000ft, the horizon is then 109.6sm up to 150.1sm out... "sm" meaning "statute miles"... conversion between sm and nm may or may not be accurate depending on which formula you use...


The transition altitude in my area (EKDK) is 5000, hence my usage of FL.
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Re: Runway lighting

Postby wkitty42 » Thu Jan 07, 2016 2:02 am

@abcaster: understood and valid reasoning... as long at it is understood about the variances to other locales... ;) yeah, i know... sometimes it means adding more detailed info that may or may not make any sense to noobs or others unfamiliar with your locale's procedures... but it's all good! :)
"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: Runway lighting

Postby vnts » Mon Jan 11, 2016 1:54 am

Isn't there two regimes for lights?

a). When the large 'lit surface' of the light, which can be lit by a single small emitting element, can be resolved i.e. when it is much larger than the best angular resolution of the eye (This ultimately is limited by the density of receptors in the most sensitive part of retina)
Scattering, including mie scattering by fog/smog, will contribute to any visible halo around the light.

b). When the lit surface of the light starts to approach the best angular resolution of the eye.
The halo surrounding the light should involve visible spikes, -if I recall correctly- they are the diffraction patterns caused by the structures where fibers that make up the lens meet.

(The eye is also subject to optical aberrations, scattering, and various effects which can vary depending on frequency which vary from person to person and with age.)

2 regimes would need a transition (blending between textures or something).

Come to think of it, stars in FG are done also without any spikes/halo.

I wonder how the way mipmaps are generated in FG would play with textured lights with halos at distance..perhaps they get dimmer much quicker than they otherwise would be because the bright parts get 'averaged out' as the texture is shrunk - because the variation in brightness in a texture (256 levels) is far more limited than in reality (even distant lights too small for the eye to resolve are quite visible). This might also apply to night textures showing small brightly lit areas.

Kind regards,
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Re: Runway lighting

Postby gsagostinho » Wed Feb 03, 2016 10:57 pm

@Thorsten I noticed that recently the desaturation effect in the lights has been quite reduced. I know a lot of people complained that they couldn't see the colour of the PAPI lights due to the desaturation effect, but I really think the lights looked so much better before (and I was one of those who could identify easily the colours for some reason). So I'd like to ask you: would you be willing to leave this desaturation parameter as a property in the property tree?
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Re: Runway lighting

Postby Thorsten » Thu Feb 04, 2016 6:51 am

Isn't there two regimes for lights?


Quite - that's why I said elsewhere On the other hand, there are larger and smaller emissive sources, and large lights wouldn't cause such spikes.

2 regimes would need a transition (blending between textures or something).


It's complicated by the effect that angular size of a light is distance dependent, but so is intensity - and the intensity of the spikes must be large enough to see them (which is why stars in my opinion correctly don't show any, because the pattern would be too faint to see without trying really hard.

It's further complicated by the technical effect that we have to have something to paint the light on, and the angular size of that quad also usually shrinks with distance, whereas the rays happen in the eyes, so they don't really. But with point sprites, we can partially compensate - see below.

Since the lights are generated procedurally, it's no problem to smoothly vary the generating function - that's the main advantage of functions over textures. The main holdup is that I don't have a good scheme how to map both physical size and intensity into a disc size consistently, because visually disc size encodes both.

I wonder how the way mipmaps are generated in FG would play with textured lights with halos at distance.


Wrong thread really - these are procedural lights, they don't have mipmaps.

perhaps they get dimmer much quicker than they otherwise would be because the bright parts get 'averaged out' as the texture is shrunk - because the variation in brightness in a texture (256 levels) is far more limited than in reality (even distant lights too small for the eye to resolve are quite visible).


Normal textured models do that indeed, but we're talking point sprites for the auto-generated lights, and point sprites can be made not to get arbitrarily small. Basically we're always keeping the disc size at least one pixel so that the rasterizer finds a light and then just dial the alpha channel down to represent its intensity - that way you can render very faint apparent lights far away without being averaged away by the rasterizer.
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Re: Runway lighting

Postby Thorsten » Thu Feb 04, 2016 7:04 am

but I really think the lights looked so much better before (and I was one of those who could identify easily the colours for some reason). So I'd like to ask you: would you be willing to leave this desaturation parameter as a property in the property tree?


I don't see so much sense in making this runtime configurable but not exposed to the menu. You can easily change it back - in Shaders/surface-light-ALS.frag find the line

Code: Select all
  light_color = mix(light_color, vec3 (1.0, 1.0, 1.0), 0.5 * intensity * intensity);


and change the 0.5 to a higher number of your choice (used to be 1 I think).
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Re: Runway lighting

Postby gsagostinho » Thu Feb 04, 2016 1:04 pm

Thanks, Thorsten!
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Re: Runway lighting

Postby ErikGroen » Tue Feb 09, 2016 1:57 pm

i have the same problem i cant see any runway lights
how to toggle oint stripes?
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Re: Runway lighting

Postby legoboyvdlp » Tue Feb 09, 2016 1:59 pm

Hello Erik. Just go to View > Rendering, and disable them there!
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Re: Runway lighting

Postby ErikGroen » Tue Feb 09, 2016 2:01 pm

it works now thank you so much
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Re: Runway lighting

Postby legoboyvdlp » Tue Feb 09, 2016 3:31 pm

Dear sirs --- here is a series of photographs, all from KSFO 28R final.
FGDATA is latest, latest TerraSync terrain, and the build is 2179. Time is the same in all cases.
Code: Select all
gl-vendor:Intel
gl-version:3.1.0 - Build 9.17.10.4101
gl-renderer:Intel(R) HD Graphics
gl-shading-language-version:1.40 - Intel Build 9.17.10.4101

OSG is 3.21; FG + SG are 2016.1.


I will be editing to include screenshots shortly
THE SCREENSHOT'S CAPTION IS ALWAYS BELOW THE SCREENSHOT

Image
2 nm, 1000, ALS on, shaders full, point sprites off
Image
2 nm, 1000, ALS on, shaders full, point sprites on
Image
2 nm, 1000, ALS on, shaders off, point sprites off
Image
2 nm, 1000, ALS on, shaders off, point sprites on
Image
2 nm, 1000, ALS off, shaders off, point sprites off
Image
2 nm, 1000, ALS off, shaders off, point sprites on
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