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My hunting for some bugs on ATI

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My hunting for some bugs on ATI

Postby Bug Bunny » Tue Feb 24, 2015 7:12 pm

I have FG 3.4 on Windows 7 SP1 on ATI Radeon 6870 (ATI Catalyst 14.10 Omega). Sim is great! I've noticed some bugs with graphics in some cases, I will try to explain them below.

Short description:
1) ALS rendering of fog and horizon is strange (biggest impact in winter mode)
2) Black light sources in distance with ALS
3) Urban shader at winter at second level is not working
4) Red random buildings bug
5) Strange tree bug

Console:
Code: Select all
D:\Games\FlightGear\bin\fgfs.exe
  --fg-root=D:\Games\FlightGear\data
  --fg-scenery=C:\Users\Artem\Documents\FlightGear\Custom Scenery;D:\Games\FlightGear\data\Scenery;C:\Users\Artem\Documents\FlightGear\TerraSync
  --terrasync-dir=C:\Users\Artem\Documents\FlightGear\TerraSync
  --fg-aircraft=C:\Users\Artem\Documents\FlightGear\Aircraft
  --airport=UKON
  --aircraft=c172p
  --console
  --enable-random-objects
  --enable-auto-coordination
  --enable-horizon-effect
  --enable-enhanced-lighting
  --enable-ai-models
  --enable-ai-traffic
  --random-wind
  --enable-real-weather-fetch
  --enable-clouds3d
  --enable-fullscreen
  --prop:/sim/frame-rate-throttle-hz=60
  --geometry=1280x1024
  --bpp=32
  --texture-filtering=8
  --prop:/sim/rendering/multi-sample-buffers=1
  --prop:/sim/rendering/multi-samples=2
  --timeofday=morning
  --disable-terrasync
  --disable-fgcom


1) ALS rendering of fog and horizon is strange (biggest impact in winter mode). ALS in summer:

Notice irregular horizon from both sides, I have no mountains, but some bodies of water:
https://i.imgur.com/8f086yl.png
https://i.imgur.com/RikWiMC.png

Now with ALS on/off. Notice sun and horizon.
https://i.imgur.com/VWIdFP1.png
https://i.imgur.com/k8rBafN.png

Now in winter mode (ALS on/off). With ALS on you see horizon with some land near it over the sea. It looks bad. But with ALS off it is much better.
https://i.imgur.com/k6sfJ2L.png
https://i.imgur.com/JqFdFzj.png

2) Black light sources in distance with ALS

Look at horizon, you will notice black points (looks like ground light sources)
https://i.imgur.com/DFBdXVt.png

3) Urban shader at winter at second level is not working (UKLL, look to left)

https://i.imgur.com/zqaSTnD.png
https://i.imgur.com/4WUK4XA.png

4) Red random buildings bug

Enable "random buldings", go to UKOO, take off and turn left, fly above buildings, look left (>90*), you will notice the red colour. By looking right you will not notice this effect. This red effect works only on random ones. First image shows slight red on houses in front of the plane.
https://i.imgur.com/YvGEAbl.jpg
https://i.imgur.com/nOc2zEr.jpg

5) Strange tree bug
At UKLL trees looking somewhat incorrectly:

https://i.imgur.com/qJFh3vN.png
Last edited by Bug Bunny on Thu Feb 26, 2015 11:23 pm, edited 1 time in total.
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Re: My hunting for some bugs on ATI

Postby Thorsten » Wed Feb 25, 2015 6:20 am

Okay, that's a bug report I can start to work with :-)

This

Image


I have seen something similar to this for two causes before. The first one is visibility slightly exceeding LOD bare range. In essence you can tell FG you want to see farther than it is allowed to draw the terrain, thus you get to see the terrain edge.

The second is specific over the sea, there's sometimes a mismatch in fog color between terrain and skydome because there's a real kink in the water (you can fly there with the ufo and literally see a step). The reason is that water across the planet isn't all really at nominal sea level (as weird as this sounds) and so water surrounding landmasses is placed at its actual elevation and generic ocean at nominal sea level, hence the step at the transition.

So, my follow-up questions would be:

Is this effect characteristic for dawn/dusk? Do LOD settings match visibility? Does it occur over land as well?

Image


This one is a bit stranger... So the same scene does work using the summer materials? What's the landclass (ctrl + alt + click with the ufo on the white terrain).

It doesn't look like land, it looks like part of the sea /not/ rendering in ALS at all (if you compare color values, it looks pretty much like what the default renderer does). So it's probably a bad materials declaration which somehow by-passes the ALS effects which nobody ever notices because the winter set is considered a bit obsolete (since we can render dynamical snow, no need to bake it into textures any more).

I'll check on that.

Image


Nearby lights render fine though - look at the road. Does this change in any way with time? If it's really light sources, they'd go away as the day starts, if it's something else they'd persist.

3) Urban shader at winter at second level is not working (UKLL, look to left)


The first pic has the European regional city texture - that doesn't have urban effect. The second has the urban effect seen under a very shallow angle - that never worked, a heightmap can't deliver real heights, you have to view it from somewhat higher up.

Enable "random buldings", go to UKOO, take off and turn left, fly above buildings, look left (>90*), you will notice the red colour. By looking right you will not notice this effect. This red effect works only on random ones. First image shows slight red on houses in front of the plane.


ALS or default renderer or both? Does this depend on daytime (i.e. could this be a specular channel going haywire)?

At UKLL trees looking somewhat incorrectly:


That'd be because they are. Try rendering them with FGs antialiasing function on (on Windows, you can find the option on the launcher) - looks much nicer for trees.
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Re: My hunting for some bugs on ATI

Postby Thorsten » Wed Feb 25, 2015 6:30 am

Edit: Try adding the block

Code: Select all
  <material include="Materials/base/water.xml">
    <name>Ocean</name>
    <effect>Effects/water</effect>
    <texture>Terrain/water.png</texture>
  </material>


into /Materials/regions/global-winter.xml - that indeed seems to be missing.
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Re: My hunting for some bugs on ATI

Postby wlbragg » Wed Feb 25, 2015 6:54 am

At UKLL trees looking somewhat incorrectly:

The extra little spikes sticking up (that all look the same), I saw those when I was editing the tree texture sheet for some custom terrain. It is caused by the trees not being positioned properly or exactly where they belong in the texture sheet. We need a real artist to make us some new tree texture sheets.

LATE EDIT:
Oops, that sounded bad, the trees are wonderful, it would be nice it we could improve on the great start we already have.
Last edited by wlbragg on Thu Feb 26, 2015 7:05 pm, edited 1 time in total.
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Re: My hunting for some bugs on ATI

Postby Bug Bunny » Wed Feb 25, 2015 5:18 pm

Is this effect characteristic for dawn/dusk? Do LOD settings match visibility? Does it occur over land as well?


Looks like only for dawn/dusk. Max visibility is 25km, LOD is 30km (default). I think it does, but in some angles it looks good.

Screenshots:
https://i.imgur.com/P3Y7s97.png
https://i.imgur.com/KdJa4jl.png

This one is a bit stranger... So the same scene does work using the summer materials? What's the landclass (ctrl + alt + click with the ufo on the white terrain).


This effect is fixed by your code below, water looks much better (as in summer), there is no huge contrast sharp edges. Interestingly there is a place on a screenshot, lake pond (?) - it has no reflection, I wonder if it is correct (it is winter).

https://i.imgur.com/7Lck4HP.jpg

Nearby lights render fine though - look at the road. Does this change in any way with time?


I was not able to reproduce it again :S

The first pic has the European regional city texture - that doesn't have urban effect. The second has the urban effect seen under a very shallow angle - that never worked, a heightmap can't deliver real heights, you have to view it from somewhat higher up.


Yeah, it just looks bad near the ground, at UP there it is good. Is it possible to smooth it somehow in cases near the ground?

ALS or default renderer or both? Does this depend on daytime (i.e. could this be a specular channel going haywire)?


both, depends on shader settings (look at screenshots). Reddish part of the house is illuminated by the Sun (and depends on the sun location).
Look at my screenshots with settings that have effect on a issue.

ALS off, shader settings:
https://i.imgur.com/UaYVfGX.jpg
https://i.imgur.com/XZPQE6F.jpg
https://i.imgur.com/SBLU4vv.jpg

ALS on:
https://i.imgur.com/K9EETfn.jpg
https://i.imgur.com/l4MY2H6.jpg

Dawn vs Dusk (red part is changing with illumination):
https://i.imgur.com/ytqhoaF.jpg
https://i.imgur.com/5QUeCG9.jpg

That'd be because they are. Try rendering them with FGs antialiasing function on (on Windows, you can find the option on the launcher) - looks much nicer for trees.


It is already enabled at AA 2x.

Another small observations:
1) Not sure if a bug, when i do F3 (screenshot), mouse cursor hides itself, but I'm not sure how to bring it back easily.
2) New Canvas map is not working properly (I guess), You cannot move inside it, and there is lacking text data that is in simple map). I've tried to zoom in but no text info like in simple map. Screenshot:
https://i.imgur.com/n6XNDUO.png
3) BTW I've noticed that on pause sky sometimes changes to more bluish colour (in ALS)
4) Also, at UKKE there's a thing on a runway (another one is below and behind), I was very surprised when I 'crashed' into it doing night landing :S. Not sure if it needs seperate thread. Screenshot:
https://i.imgur.com/Ld2CKyP.png
Last edited by Bug Bunny on Thu Feb 26, 2015 11:24 pm, edited 1 time in total.
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Re: My hunting for some bugs on ATI

Postby Thorsten » Thu Feb 26, 2015 6:24 pm

Please make your screenshots smaller before posting, I have a GSM connection at home, and it takes forever to load this thread.

Looks like only for dawn/dusk. Max visibility is 25km, LOD is 30km (default). I think it does, but in some angles it looks good.


That sort of looks like a color curve mismatch in some shader. There's a gazillion of corrections for light colors at low sun, so the problem might occur under specific conditions only (say, no clear skies,...). And it may be a particular shader, so it might affect a particular landclass and quality level only.

So I'd need to know your quality settings (in the detailed dialog if possible) and whether it occurs over land as well as water, and if the same thing happens in clear skies or not. That'll give me some idea what to look for (otherwise it's literally dozens of combiantions to check...)

Is it possible to smooth it somehow in cases near the ground?


I would assume that yes, since we know the view angle, we can simply quench it. I'll keep this in mind, but it's not a particularly high priority.


The red buildings are the specular light channel. For some reason the random building have a really strong specular response coded in, so they light up when the sun is on them. I think I fixed that for the ALS model shader at high quality - can you test whether this persists? At low quality, the model shader simply uses the default specular light (because the ALS computation is pretty expensive and performance hungry), and that works mostly (with the exception of the buildings largely...)

It is already enabled at AA 2x.


Strange - your trees don't show the alpha to coverage technique...
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Re: My hunting for some bugs on ATI

Postby Hooray » Thu Feb 26, 2015 6:57 pm

Bug Bunny wrote in Wed Feb 25, 2015 5:18 pm:New Canvas map is not working properly (I guess), You cannot move inside it, and there is lacking text data that is in simple map). I've tried to zoom in but no text info like in simple map. Screenshot:
Image


  • mouse panning isn't implemented
  • equally, certain labels are not implemented

For a summary, see: http://wiki.flightgear.org/Canvas_MapSt ... map_dialog
Feel free to make feature requests (via the tracker or the wiki) or simply get involved directly (it's just Nasal coding after all)

People already familiar with a simple programming language like JavaScript can easily add both features in 45-90 minutes, by using at existing examples and docs.
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: My hunting for some bugs on ATI

Postby Thorsten » Fri Feb 27, 2015 7:29 am

I've given both the red buildings thing and the horizon thing a try on my box. I could get red buildings as you show in default with low sun, but not in ALS, no matter what time, settings and light I tried.

Low sun in default has very red specular light channel (see also on the hills in the background):

Image

ALS has the colors for similar light somewhat less saturated - buildings are sticking out, but I don't get the same red color:

Image

Same with the horizon thing - I tried LOD setting of 30 with 25 km visibility in hazy weather as in your screenshot and couldn't get the light mismatch for any time, quality setting or weather change I tried.

So I fear I'm going to need more systematic tests from you.
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Re: My hunting for some bugs on ATI

Postby Bug Bunny » Fri Feb 27, 2015 5:17 pm

So I'd need to know your quality settings (in the detailed dialog if possible) and whether it occurs over land as well as water, and if the same thing happens in clear skies or not. That'll give me some idea what to look for (otherwise it's literally dozens of combiantions to check...)


My experiments with UFO at dawn (not a good catch but anyway, warm sector):
https://i.imgur.com/iNe2lNx.png - 240 deg over land and ocean
https://i.imgur.com/pYfyA01.png - 240 deg over land
https://i.imgur.com/GRaAhd9.png - 180deg over ocean
https://i.imgur.com/Kgd0G31.png - view from the sea at the land near horizon (~North or NW)

Clear sky (Fair weather), much harder to catch, looks good?
https://i.imgur.com/frWqUws.png
https://i.imgur.com/oXVjxiq.png
https://i.imgur.com/IWwobJv.png

A buuug with ocean with different depth (i guess):
https://i.imgur.com/u4NJJxC.png - notice horizon and ocean...
https://i.imgur.com/HOlEuE6.png

Another interesting case: 60deg bearing, 3000ft, fog, ground, sun (dusk) is behind to left, too bad I was in Cessna and didn't record it, you can see strange line on the left (only in that place), could be some kind of land... https://i.imgur.com/adw4J1s.png

Thorsten wrote in Fri Feb 27, 2015 7:29 am:So I fear I'm going to need more systematic tests from you.


Try to unpause it and move mouse a bit to catch red again in ALS.
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Re: My hunting for some bugs on ATI

Postby Thorsten » Fri Feb 27, 2015 6:20 pm

My experiments with UFO at dawn (not a good catch but anyway, warm sector):


So, at low sun, chiefly over the sea, with a hazy weather like the Warm Sector, for all quality levels. And it's not something which appears readily in a pronounced way (this series looks much less spectacular than your initial post)?

I have a suspicion that this might be a high haze light curve correction... this would occur just for very specific weather situations. I'll check that tomorrow.

The red building thing might be an ATI specific thing - Emilian informed me that he's tracing something similar, so I'll wait for the outcome of that one.

A buuug with ocean with different depth (i guess):


Sure looks like it.
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Re: My hunting for some bugs on ATI

Postby Bug Bunny » Sat Feb 28, 2015 5:09 pm

Thorsten wrote in Thu Feb 26, 2015 6:24 pm:I think I fixed that for the ALS model shader at high quality - can you test whether this persists? At low quality, the model shader simply uses the default specular light (because the ALS computation is pretty expensive and performance hungry), and that works mostly (with the exception of the buildings largely...)


Do I need to compile or update FG for this?
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Re: My hunting for some bugs on ATI

Postby Thorsten » Sat Feb 28, 2015 5:23 pm

My bad - you tested this already (it's just a menu item).
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Re: My hunting for some bugs on ATI

Postby Bug Bunny » Sun Mar 01, 2015 1:21 pm

Thorsten wrote in Sat Feb 28, 2015 5:23 pm:My bad - you tested this already (it's just a menu item).


Btw, Environment -> Environment Settings has "Snow line" setting and checkbox to "set maximum level according to METAR". I'm using winter scenery with ALS, that box is unticked and snow line is set to minimum (ground with snow), however, after flights it resets itself to over >3km.
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Re: My hunting for some bugs on ATI

Postby Thorsten » Sun Mar 01, 2015 2:41 pm

That's the intended behaviour.
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Re: My hunting for some bugs on ATI

Postby Bug Bunny » Thu Aug 06, 2015 5:02 pm

Red buildings bug is still present in 3.6.0 RC, just tested.
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