Re: [Celestia-developers] Label depth sorting patch

[vincent <vin...@fr...>]

Chris,

I've just tested your patch, and noticed that sometimes label are
partially masked. This seems to happen mainly when the object they
refer to is not centered on screen.

Here's a shot showing this "bug":
http://vincent.gian.club.fr/celestia/labelbug.jpg

This shot was taken using the following celURL:
cel://Follow/Sol:Earth/2007-11-21T12:22:25.17416?x=QOMEYLzAtB4I&y=jxipmFmLnP///////////w&z=+L3Mgua5kpLy/////////w&ow=0.283268&ox=-0.008081&oy=0.958996&oz=0.004468&select=Sol:Earth&fov=26.859941&ts=1.000000&ltd=0&p=0&rf=837511&lm=358&ver=2

@+
Vincent


Selon Chris Laurel <cl...@gm...>:

> I've made a fix for bug 18833728, "Labels are not properly depth
> sorted":
>
http://sourceforge.net/tracker/index.php?func=detail&aid=1833728&group_id=21302&atid=121302
>
> The patch is here:
> http://www.shatters.net/~claurel/celestia/files/patches/labeldepth/
>
> You can either replace render.cpp and render.h with the files in
> that
> directory, or use the patch file labeldepth.patch. I'd just check
> in the
> fix, but I would like to hear whether people think it's an
> improvement. The
> patched render.cpp does indeed correctly compute label correctly
> (the first
> time it's ever really been right in Celestia) by mimicking the
> OpenGL
> perspective projection that converts from eye coordinates to
> normalized
> device coordinates.
>
> But now that labels get the correct depth value, they can partially
> disappear into other objects. The effect is most noticeable for
> objects that
> orbit close to the surface of a planet or moon. I've moved object
> labels to
> be centered above the object position to somewhat mitigate the
> effect. A
> complete fix for partial obscuring of labels is complex, and much
> too large
> a project to complete for Celestia 1.5.0 (unless there's some
> simple
> shortcut I haven't thought of.) I personally find the new code
> gives results
> that are much less distracting than labels showing through objects
> that
> should completely obscure them. Other opinions?
>
> --Chris