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Corona texture not adjusted for refraction

Open Atque opened this issue 3 years ago • 4 comments

Viewing solar eclipses close to the horizon, we see that the corona texture is not affected by atmospheric refraction. See the screenshot below.

stellarium-117

Note how the Moon is squeezed while the corona texture is not, creating an ugly artifact.

Atque avatar Feb 11 '22 12:02 Atque

I'm not sure this can be considered as a fix or not. I just try to make it better by editing the images (not sure this is allowed for image's owner) and adjust the size of corona.

corona

The process make it looks like this for 1957-10-23 total solar eclipse.

1957-10-23-tse-fix

worachate001 avatar Feb 16 '22 02:02 worachate001

No, please don't paint the corona. It is pixel-perfect from the 2008 Mongolian eclipse. What we need to do is adding refraction to the corona texture. Currently it is drawn as simple image that only can be rotated, but not squeezed by-vertex. (I.e. use VertexArray for it.)

gzotti avatar Feb 16 '22 09:02 gzotti

I just noted that the texture is not aligned with the ecliptic, at least if the eclipse is high in the sky. Look at the July 5 2168 eclipse (from the location of maximal eclipse), and note how the texture rotates as you pan around. It should be fixed.

Atque avatar Feb 16 '22 20:02 Atque

Yes, when somebody will implement it in a technically fully different way than it is done right now (DSO-like vertex array, not rotated image), this will likewise be fixed.

gzotti avatar Feb 16 '22 21:02 gzotti