On Wed, 16 Jun 2010 21:01:08 +0200, Samuel Benge <stb### [at] hotmailcom>  
wrote:

> "Nekar Xenos" <nek### [at] gmailcom> wrote:
>> Comments welcome.
>
> It looks good! Too bad about the aa problems, though.
>

Do you think luminous bloom will help here? I've never used it before.

-Nekar Xenos-

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Nekar Xenos wrote:
> On Wed, 16 Jun 2010 21:01:08 +0200, Samuel Benge <stb### [at] hotmailcom> 
> wrote:
> 
>> It looks good! Too bad about the aa problems, though.
> 
> Do you think luminous bloom will help here? I've never used it before.

You mean to reduce aliasing or help the scene in general? You can use 
luminous bloom with a small radius to hide the aliasing where bright 
colors cause trouble, but it might blow out the rest of the colors too 
much. A low lb_exponent would be advised here. If you use it lightly 
just to spread the light a bit, it couldn't hurt. When used carefully, 
it could enhance the realism imperceptibly.

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On Sun, 20 Jun 2010 23:57:36 +0200, stbenge <myu### [at] hotmailcom>  
wrote:

> Nekar Xenos wrote:
>> On Wed, 16 Jun 2010 21:01:08 +0200, Samuel Benge <stb### [at] hotmailcom>  
>> wrote:
>>
>>> It looks good! Too bad about the aa problems, though.
>>  Do you think luminous bloom will help here? I've never used it before.
>
> You mean to reduce aliasing or help the scene in general? You can use  
> luminous bloom with a small radius to hide the aliasing where bright  
> colors cause trouble, but it might blow out the rest of the colors too  
> much. A low lb_exponent would be advised here. If you use it lightly  
> just to spread the light a bit, it couldn't hurt. When used carefully,  
> it could enhance the realism imperceptibly.

Yes, both. Thanks for the info on lb_exponent.

I tried putting an hdr render of this scene through the luminous bloom  
code and I got rather strange artifacts. The bricks had a red "wash"  
overlaid with horizontal white stripes. A normal png didn't get those  
artifacts at all.

-Nekar Xenos-

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Nekar Xenos wrote:
> I tried putting an hdr render of this scene through the luminous bloom 
> code and I got rather strange artifacts. The bricks had a red "wash" 
> overlaid with horizontal white stripes. A normal png didn't get those 
> artifacts at all.

Hmm, could you post an example portion of the result? Or an .hdr version 
of your image so I can try it?

How intense are the brightest areas of light in the original image? I 
personally wouldn't use values much higher than rgb <2,2,2> for 
light_sources, fog and such. I know that really small (<.1) lb_exponent 
values will increase the chance of an image developing artifacts. This 
is made worse by values which are too bright. If this the case with your 
scene, you probably don't want to re-render the whole thing simply to 
make some glare. A color-normalizing file shouldn't be too difficult to 
put together; perhaps I should consider making one. Hopefully it works.

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On Mon, 21 Jun 2010 17:40:58 +0200, stbenge <myu### [at] hotmailcom>  
wrote:

> Nekar Xenos wrote:
>> I tried putting an hdr render of this scene through the luminous bloom  
>> code and I got rather strange artifacts. The bricks had a red "wash"  
>> overlaid with horizontal white stripes. A normal png didn't get those  
>> artifacts at all.
>
> Hmm, could you post an example portion of the result? Or an .hdr version  
> of your image so I can try it?
>
> How intense are the brightest areas of light in the original image? I  
> personally wouldn't use values much higher than rgb <2,2,2> for  
> light_sources, fog and such. I know that really small (<.1) lb_exponent  
> values will increase the chance of an image developing artifacts. This  
> is made worse by values which are too bright. If this the case with your  
> scene, you probably don't want to re-render the whole thing simply to  
> make some glare. A color-normalizing file shouldn't be too difficult to  
> put together; perhaps I should consider making one. Hopefully it works.

I've used extremely high rgb (400+) values for my light source - so I  
guess that's the problem.
The first try was on the default settings and many other settings with the  
same results.

I'm quite happy with the current result without hdr.

There is one other problem: I've noticed the edge pixels don't fit in with  
the rest of the scene - but you don't notice it if the image is on a light  
background.

-- 
-Nekar Xenos-

"The spoon is not real"

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On Mon, 21 Jun 2010 17:40:58 +0200, stbenge <myu### [at] hotmailcom>  
wrote:

> Nekar Xenos wrote:
>> I tried putting an hdr render of this scene through the luminous bloom  
>> code and I got rather strange artifacts. The bricks had a red "wash"  
>> overlaid with horizontal white stripes. A normal png didn't get those  
>> artifacts at all.
>
> Hmm, could you post an example portion of the result? Or an .hdr version  
> of your image so I can try it?
>
> How intense are the brightest areas of light in the original image? I  
> personally wouldn't use values much higher than rgb <2,2,2> for  
> light_sources, fog and such. I know that really small (<.1) lb_exponent  
> values will increase the chance of an image developing artifacts. This  
> is made worse by values which are too bright. If this the case with your  
> scene, you probably don't want to re-render the whole thing simply to  
> make some glare. A color-normalizing file shouldn't be too difficult to  
> put together; perhaps I should consider making one. Hopefully it works.

I posted an hdr image on povray.binaries.misc for you to test on.

-Nekar Xenos-

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Nekar Xenos wrote:
> stbenge wrote:
>>
>> How intense are the brightest areas of light in the original image?
> 
> I've used extremely high rgb (400+) values for my light source - so I 
> guess that's the problem.
> The first try was on the default settings and many other settings with 
> the same results.

Wow, that's a bright light_source.


> I'm quite happy with the current result without hdr.

Cool :)


> There is one other problem: I've noticed the edge pixels don't fit in 
> with the rest of the scene - but you don't notice it if the image is on 
> a light background.

I think this might be an internal problem with POV-Ray itself. It's a 
bad line of pixels around the edge and arises when warp{repeat n flip n} 
is used on an image_map. Heck, it's probably an image_map problem, and I 
wouldn't be surprised if it was somehow related to the interpolation 
shifting problems clipka was exploring.


> I posted an hdr image on povray.binaries.misc for you to test on.

OK, I'll grab it.

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stbenge wrote:
> Nekar Xenos wrote:
>> I posted an hdr image on povray.binaries.misc for you to test on.
> 
> OK, I'll grab it.

The preliminary results don't look very promising. I tried remapping the 
color values to create a new range of intensity. When the colors are 
remapped 0 - 1, the result in luminous bloom is exactly the same as if a 
.png or .tga image had been used. When remapped 0 - 2 or greater, the 
shadows become too light, changing the light level for the entire image.

I think your best bet, if you plan to use luminous bloom, would be to 
render your scenes with reasonably low light_source intensities, or just 
use pngs or tgas.

Now, about that bad line of pixels around the edge. It's definitely a 
problem with POV-Ray. It exists whether the "once" keyword was used or 
not, and always when repeat/flip warps are used. To alter my code to fix 
the problem is not really a good solution, as there is a possibility 
that the render times will rise significantly. I'll try posting a bug 
report, and hopefully it will be fixed soon. For now, maybe you can just 
remove the outer layer of pixels?

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stbenge wrote:
> Now, about that bad line of pixels around the edge. It's definitely a 
> problem with POV-Ray. It exists whether the "once" keyword was used or 
> not, and always when repeat/flip warps are used.

New update. I tried adding "once" to the image_map, and now the problem 
/appears/ to be gone. I could swear I had tried this before without 
success. It only happens when an image is interpolated and given a 
repeat/flip warp so it's definitely an interpolation issue, but probably 
not a real bug.

I'll do some more testing, and when I am satisfied with the result, an 
updated version of luminous bloom will be issued.

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On Tue, 22 Jun 2010 22:26:08 +0200, stbenge <myu### [at] hotmailcom>  
wrote:

> stbenge wrote:
>> Nekar Xenos wrote:
>>> I posted an hdr image on povray.binaries.misc for you to test on.
>>  OK, I'll grab it.
>
> The preliminary results don't look very promising. I tried remapping the  
> color values to create a new range of intensity. When the colors are  
> remapped 0 - 1, the result in luminous bloom is exactly the same as if a  
> .png or .tga image had been used. When remapped 0 - 2 or greater, the  
> shadows become too light, changing the light level for the entire image.
>
> I think your best bet, if you plan to use luminous bloom, would be to  
> render your scenes with reasonably low light_source intensities, or just  
> use pngs or tgas.
>

I'll stick to png. I onlys used hdr because you docs said it would be  
better :)

Thanks,

-Nekar Xenos-

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