Re: Updated volumetric clouds on next

Stuart Buchanan <[email protected]> Tue, 23 Jun 2026 09:34:48 +0100
Newsgroups gmane.games.flightgear.devel
Message-ID <CAP3ntysJ-PX+sGwACU35dDiYVVhYHrm+P2Ru8TbeO_5v=Pzhjw@mail.gmail.com>
Hi Chris,

On Tue, Jun 23, 2026 at 8:53 AM Chris Boylan wrote:

> Agreed, very nice work and thanks for posting your progress.
>

When I came to upload the photos I was pleasantly surprised at how much
better they were than the screenshots that I posted in January.  Being
heads down and improving things incrementally meant I really hadn't noticed
the progress in the last couple of months.

One thing that's perhaps not very obvious from the screenshots I shared is
that the clouds shadow each other.  So if you have a low layer of stratus
with a layer above you get lovely shadows of the upper clouds against the
lower.  I'm hoping to extend this to shadowing the rest of the scene as
well.  Because this is all within the HDR pipeline  I can just apply the
shadowing to the right stage and it will automatically apply to the entire
scene.  Even better, the light balance exposure etc will be adjusted
automatically.

An observation: In the images at this development stage, I see see
> duplicate cloud shapes and some banding artifacts,
> and I'm assuming you're aware while you work on the oversll effect rather
> than scaling across larger areas with some sort of random seed.
>

Yes, these are known issues.

The individual cloud shapes are defined as 3D textures of density and
wispiness/billowiness (see
https://wiki.flightgear.org/3D_clouds#Voxel-based_clouds_(post_2024) ).
Right now there aren't many cloud definitions, and there are some
particularly "blocky" ones that need to be changed.

There's also a bit or mirroring of the cloud field itself under "basic"
weather.  The cloud field is approximately 100km across and then is
mirrored.  When Advanced Weather is supported that problem should go away.

The banding is an ongoing issue I've still to resolve.  It's proving quite
stubborn to diagnose!

-Stuart

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