I'm trying to render space scenes with a extremely sun. Rather than
fiddle around with trying to artificially add lens flares via NKFlare,
it occurs to me it ought to be possible to use the new EXR support to
render the image with the sun at its true brightness, and then
post-process the image to add bleeding around the bright pixels to
produce a similar effect. (I won't get a lens flare, but I'll be quite
happy with smearing around the sun to emphasise its brightness.)

Unfortunately I don't know enough magic Google terms to find out whether
such a thing is possible or what tools are available to do it.

What should I be looking for?

-- 
┌─── ｄｇ＠ｃｏｗｌａｒｋ．ｃｏｍ ─────
http://www.cowlark.com ─────
│ "There does not now, nor will there ever, exist a programming
│ language in which it is the least bit hard to write bad programs." ---
│ Flon's Axiom

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Am 04.12.2013 14:34, schrieb David Given:
> I'm trying to render space scenes with a extremely sun. Rather than
> fiddle around with trying to artificially add lens flares via NKFlare,
> it occurs to me it ought to be possible to use the new EXR support to
> render the image with the sun at its true brightness, and then
> post-process the image to add bleeding around the bright pixels to
> produce a similar effect. (I won't get a lens flare, but I'll be quite
> happy with smearing around the sun to emphasise its brightness.)
>
> Unfortunately I don't know enough magic Google terms to find out whether
> such a thing is possible or what tools are available to do it.
>
> What should I be looking for?

"The Gimp" :-)

Any modern image processing software with OpenEXR support will do. All 
you'll need to do is blur the image, and blend it with the original image.

If you want to achieve the effect in a single step, "bloom" is probably 
what you're looking for.

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Am 04.12.2013 15:11, schrieb clipka:
> Am 04.12.2013 14:34, schrieb David Given:
>> I'm trying to render space scenes with a extremely sun. Rather than
>> fiddle around with trying to artificially add lens flares via NKFlare,
>> it occurs to me it ought to be possible to use the new EXR support to
>> render the image with the sun at its true brightness, and then
>> post-process the image to add bleeding around the bright pixels to
>> produce a similar effect. (I won't get a lens flare, but I'll be quite
>> happy with smearing around the sun to emphasise its brightness.)
>>
>> Unfortunately I don't know enough magic Google terms to find out whether
>> such a thing is possible or what tools are available to do it.
>>
>> What should I be looking for?
>
> "The Gimp" :-)

"LILYsoft IC" is also a good search term. It's primarily an image 
viewer/converter (and a very good one at that), but also has some 
post-processing essentials built in, including a bloom effect (as an 
option of the "gaussian blur" filter).

It's also noteworthy for being developed by POV-Ray community member Ive.

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clipka wrote:

>> What should I be looking for?
> 
> "The Gimp" :-)

Does Gimp support high dynamic range? I thought the official
version only supports 8 bit data. I did download 2.9 beta for
some 16 bit image processing but at the time it seemed a bit
shaky stability-wise.

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Am 05.12.2013 20:21, schrieb Christian Froeschlin:
> clipka wrote:
>
>>> What should I be looking for?
>>
>> "The Gimp" :-)
>
> Does Gimp support high dynamic range? I thought the official
> version only supports 8 bit data. I did download 2.9 beta for
> some 16 bit image processing but at the time it seemed a bit
> shaky stability-wise.

I thought it did, but exploring the 'net it seems I was mistaken.

Well, then it's definitely LILYsoft's "IC" to go for.

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[Grr, thought I'd replied to this, but apparently I emailed it instead.
Curse you, Thunderbird.]

On 04/12/13 14:32, clipka wrote:
> Am 04.12.2013 15:11, schrieb clipka:
[...]
>> "The Gimp" :-)
>
> "LILYsoft IC" is also a good search term.

LilySoft is Windows only, I'm afraid. And AFAICT Gimp will *save* HDR,
but it won't *load* HDR --- people seem to be using it to combine
bracketed photos into an HDR image for tone mapping, but I haven't found
a way to load an EXR.

However, now that I know that the magic word is 'bloom' I went and
looked it up, and found that Darktable supports it. After fighting my
way through Darktable's UI I apply it... and it looks terrible. So I'm
going to have to rethink this to a certain extent. But I now know what
to look for, so thanks.

-- ┌─── ｄｇ＠ｃｏｗｌａｒｋ．ｃｏｍ ─────
http://www.cowlark.com ─────
│ "There does not now, nor will there ever, exist a programming
│ language in which it is the least bit hard to write bad programs."
│ --- Flon's Axiom

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Am 05.12.2013 23:05, schrieb David Given:
> LilySoft is Windows only, I'm afraid. And AFAICT Gimp will *save* HDR,
> but it won't *load* HDR --- people seem to be using it to combine
> bracketed photos into an HDR image for tone mapping, but I haven't found
> a way to load an EXR.
>
Yep. Sorry.

> However, now that I know that the magic word is 'bloom' I went and
> looked it up, and found that Darktable supports it. After fighting my
> way through Darktable's UI I apply it... and it looks terrible. So I'm
> going to have to rethink this to a certain extent. But I now know what
> to look for, so thanks.
>

PFSTools is my toolkit of choice when working with linux

http://pfstools.sourceforge.net/

does everything one needs but it's a command line tool so it is helpful 
when you have already an idea what you want to do with HDR images...

-Ive

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