Re: [Flightgear-devel] PNG compression causes black terrain in WS3.0

[Stuart B. <stu...@gm...>]

Hi Folks,

Coming back to this after over a month away...

On Thu, May 11, 2023 at 11:37 AM Erik Hofman wrote:

> On 5/10/23 00:11, Stuart Buchanan wrote:
> > have a plan that will work for WS3.0.  One option would be to mandate
> > that only RGB textures are used for WS3.0, but I'd need to review the
> > shader code to check we don't rely on the alpha channel anywhere.
>
> I can't see any reason to have an alpha layer for ground textures. So
> I'd say remove them.
>

I had a check, and unfortunately we do currently use the alpha layer for
a number of things in the advanced terrain shaders, including as a mask for
 autumnal coloring, and some aspects of the dot and grain textures.

So unfortunately I think we need to keep the alpha channels for any texture
that
might end up in the WS3.0 texture atlas.  That effectively means any
texture referenced
by materials.xml plus a couple of others that are hardcoded in some terrain
effects.

-Stuart