Board index FlightGear Development Effects and shaders

Taxiline Flickering Issue

An exciting "new" option in FlightGear, that includes reflections, lightmaps, the particle system etc.. A lot is yet to be discovered/implemented!

Taxiline Flickering Issue

Postby Imran Anees » Sat Apr 16, 2016 11:33 am

This is an issue which is still unsolved. Even though if you'd set the ALS, Anti-aliasing on and Landmass, Transition effect to maximum, it still persists in some perspective angles. It'd be great if we are able to solve this issue, and set non-flickering taxilines without ALS, Anti-aliasing and max. effects. This would allow users with low-powered machines to enjoy flying without this problem. So, is this problem solved or is team trying to terminate the flickering.

P.S. I was able to terminate the issue, but I was asking if this issue could be terminated with the default FG Settings. (BTW, this issue could be solved with graphics card with great anti-aliasing support.) :D :D
FlightGear! Fly Free!
Imran Anees
 
Posts: 69
Joined: Mon Feb 22, 2016 11:14 am
Callsign: IM-RAN
IRC name: IM-RAN
Version: 2016.1
OS: Windows 10

Re: Taxiline Flickering Issue

Postby Thorsten » Sat Apr 16, 2016 11:57 am

A small line feature seen from an arbitrary distance will flicker because the rasterizer doesn't always pick it up - that's not your standard z-fighting issue which can be addressed by z-displacement but a fundamental limit of fragment processsing. The only solution is, as you realized, anti-aliasing, so I suggest to crank up the number of multi-samples being done.

There's no way to conceptually solve this without multi-sampling.
Thorsten
 
Posts: 9154
Joined: Mon Nov 02, 2009 8:33 am

Re: Taxiline Flickering Issue

Postby jaxsin » Sat Apr 16, 2016 12:49 pm

Thorsten, does --texture-filtering effect this well? I am not sure what has more of a derogatory effect on the GPU, but one could mix and match if it did help. Thinking out loud...
jaxsin
 
Posts: 396
Joined: Mon Dec 28, 2015 3:54 pm

Re: Taxiline Flickering Issue

Postby Thorsten » Sat Apr 16, 2016 2:07 pm

The problem would be absent if the taxiline would be a texture, because then it could be mipmapped (sort of pre-computed antialiasing). But in actual fact the line is a vector structure (it's not painted on the runway mesh, it has its own mesh), so texture operations don't help you.
Thorsten
 
Posts: 9154
Joined: Mon Nov 02, 2009 8:33 am

Re: Taxiline Flickering Issue

Postby Imran Anees » Sun Apr 17, 2016 7:56 am

So will the team take step to terminate the issue by coming releases or is it never possible to solve it, cause it'd be a great improvement in the scenery.
FlightGear! Fly Free!
Imran Anees
 
Posts: 69
Joined: Mon Feb 22, 2016 11:14 am
Callsign: IM-RAN
IRC name: IM-RAN
Version: 2016.1
OS: Windows 10

Re: Taxiline Flickering Issue

Postby Thorsten » Sun Apr 17, 2016 9:17 am

If we mean the same issue, the solution is to use multi-sampling. Which is, 'the team' already provides a solution, it's up to you to use it (or not).
Thorsten
 
Posts: 9154
Joined: Mon Nov 02, 2009 8:33 am

Re: Taxiline Flickering Issue

Postby Imran Anees » Sun Apr 17, 2016 9:44 am

Do you mean enabling Anti-aliasing and set to 4setting. I have already done that and although it may seem gone whn looking close at it. It actually isn't at a more posts ider angle of view, especially when users try take a shot from an interesting angle outside the aircraft, the flickering just makesit seem bad.

I have ALS, Anti-aliasing, Transition and Landmass settiilng to high, but I have the problem at an angle of view as I talked about earlier.

Other than that everything else is good. Cheers for that.
FlightGear! Fly Free!
Imran Anees
 
Posts: 69
Joined: Mon Feb 22, 2016 11:14 am
Callsign: IM-RAN
IRC name: IM-RAN
Version: 2016.1
OS: Windows 10

Re: Taxiline Flickering Issue

Postby psadro_gm » Mon Apr 18, 2016 5:32 pm

I may be wrong, but the ALS fix works when the lines are near coplanar. The issue of taxi-lines 10s of cm above the pavement have been reported as well. These can bust your landing gear. I have a fix for this in the terragear toolchain, and will be available in a future scenery release.
8.50 airport parser, textured roads and streams...
psadro_gm
 
Posts: 750
Joined: Thu Aug 25, 2011 2:23 am
Location: Atlanta, GA USA
IRC name: psadro_*
Version: git
OS: Fedora 21

Re: Taxiline Flickering Issue

Postby Thorsten » Mon Apr 18, 2016 5:43 pm

The issue of taxi-lines 10s of cm above the pavement have been reported as well. These can bust your landing gear.


If the mesh is displaced, they don't flicker due to z-fighting. If the mesh is not displaced, the shader can do it, but that's visual only, the ground interaction code never learns of this - what happens on the GPU stays on the GPU...

Actually I have no real idea what the OP is trying to describe, I know just two types of flickering of the lines.
Thorsten
 
Posts: 9154
Joined: Mon Nov 02, 2009 8:33 am


Return to Effects and shaders

Who is online

Users browsing this forum: No registered users and 2 guests