"fls13" <fls### [at] netzeronet> wrote:
> Here's an Earth shot I did recently. I did a lot of color correction on the
> texture map to make the features match up better with actual photos taken from
> space. For this pic, I placed a sphere within a sphere and subdivided both
> pretty heavily, then applied a displacement map for the cloud level and the
> Earth level to add some ruddiness. Not perfect, but not obviously CGI either.

I guess the clouds would be less blueish.

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"clipka" <nomail@nomail> wrote:
> "fls13" <fls### [at] netzeronet> wrote:
> > Here's an Earth shot I did recently. I did a lot of color correction on the
> > texture map to make the features match up better with actual photos taken from
> > space. For this pic, I placed a sphere within a sphere and subdivided both
> > pretty heavily, then applied a displacement map for the cloud level and the
> > Earth level to add some ruddiness. Not perfect, but not obviously CGI either.
>
> I guess the clouds would be less blueish.

Heh, good eye, bad light. Clouds can look bluish because you can see through
them just a bit and see ocean of course. The light was the problem, fixed now.
Thanks. :O)

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"fls13" <fls### [at] netzeronet> wrote:
> Heh, good eye, bad light. Clouds can look bluish because you can see through
> them just a bit and see ocean of course. The light was the problem, fixed now.
> Thanks. :O)

Wanna see--- plz! :)

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"clipka" <nomail@nomail> wrote:
> Wanna see--- plz! :)

Subtle difference, definitely an improvement, otherwise the same. Sometimes when
you have a goal in mind, like making the displacement maps work, which they do,
you forget other fundamentals.

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"fls13" <fls### [at] netzeronet> wrote:
> Subtle difference, definitely an improvement, otherwise the same. Sometimes when
> you have a goal in mind, like making the displacement maps work, which they do,
> you forget other fundamentals.

Hm... displacement maps? So you're using isosurfaces?

(BTW, still not happy: Now I think the clouds look a bit too greenish - and the
Andes a bit too redish...)

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"clipka" <nomail@nomail> wrote:
> "fls13" <fls### [at] netzeronet> wrote:
> > Subtle difference, definitely an improvement, otherwise the same. Sometimes when
> > you have a goal in mind, like making the displacement maps work, which they do,
> > you forget other fundamentals.
>
> Hm... displacement maps? So you're using isosurfaces?
>
> (BTW, still not happy: Now I think the clouds look a bit too greenish - and the
> Andes a bit too redish...)

The clouds are OK, I've done color readings on them and they're straight on the
RGB scale. I don't use CSG at all. Those are imported .obj models. The
displacement I did in Poseray. If you think the Andes look bad, I won't show
you Sahara/Africa. That correction still needs work. It looks orangeish from
space, but the texture maps are more yellowish.

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"fls13" <fls### [at] netzeronet> wrote:
> The clouds are OK, I've done color readings on them and they're straight on the
> RGB scale.

Define "color readings".

If you're saying that you picked those colors from Photoshop or the like,
chances are they're wrong for POV-Ray, as they'll usually be
gamma-precorrected, while POV-Ray needs linear color values.

Try raising all colors to the power of 2.2, as in:

    color rgb <pow(R,2.2),pow(G,2.2),pow(B,2.2)>

or to the power of 1/2.2 (I never can seem to remember which way round is
needed).


> If you think the Andes look bad, I won't show
> you Sahara/Africa. That correction still needs work. It looks orangeish from
> space, but the texture maps are more yellowish.

Again, I suspect gamma issues to be at least partially responsible. Solving
these with texture maps is not so easy though, as you need external tools to
"gamma-un-correct" the images.

There was a thread on povray.tutorials (IIRC) recently about gamma handling, in
which some methods were described to achieve proper gamma adjustment.


(Note that if gamma is wrong, there's no way you can properly fix it with
anything other than gamma (un-)correction.)

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"clipka" <nomail@nomail> wrote:

> Try raising all colors to the power of 2.2, as in:

That;s my standard assumed gamma, 2.2,  and I've got the color and greyscale
bars and they read fine. ;O)

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"fls13" <fls### [at] netzeronet> wrote:
> > Try raising all colors to the power of 2.2, as in:
>
> That;s my standard assumed gamma, 2.2,  and I've got the color and greyscale
> bars and they read fine. ;O)

Note that assumed_gamma doesn't change how POV-Ray handles colors specified
directly in the source file: They're always expected to be linear.

Similarly, I'm not sure about assumed_gamma and input images.

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