Re: [Flightgear-devel] png textures

[Melchior F. <mf...@ao...>]

* Curtis Olson -- Monday 13 October 2008:
> Just real quickly, ".rgba" signifies to our .rgb loader
> than the texture contains an alpha channel.

That would be a rather bad idea, but it doesn't look at
the extension at all, and neither do the loaders of
plib/osg/gimp/blender/kde. All SGI loaders/writers that
I know (or wrote -- KDE's :-) use the ZSIZE in the
header to determine the number of layers. The file name
extension is only an informal and not even standardized
hint for humans.

To switch the sky textures to PNG one will have to change
the source code, as the file names are hardcoded:

cloud.cxx:        state = SGMakeState(texture_path, "broken.rgba", "broken_n.rgb");
cloud.cxx:        state = SGMakeState(texture_path, "scattered.rgba", "scattered_n.rgb");
cloud.cxx:        state = SGMakeState(texture_path, "few.rgba", "few_n.rgb");
cloud.cxx:        state = SGMakeState(texture_path, "cirrus.rgba", "cirrus_n.rgb");
moon.cxx:    osg::Texture2D* texture = SGLoadTexture2D("moon.rgba", options.get());
oursun.cxx:    osg::Texture2D* texture = SGLoadTexture2D("sun.rgba", options.get());
oursun.cxx:    texture = SGLoadTexture2D("inner_halo.rgba", options.get());
oursun.cxx:    texture = SGLoadTexture2D("outer_halo.rgba", options.get());

Putting these texture names into materials.xml might
be a good idea.

m.