Andy Cocker wrote:
> 
> "Tor Olav Kristensen" <tor### [at] hotmailcom> wrote in message
> news:3A907A86.DFDD441D@hotmail.com...
> >
> > Ahh... So it's about a game; Riven. Those images are great !
> > (I guess they are raytraced with radiosity =)
> >
> 
> I'm not sure which software they used on this.. maybe their own 'in-house'
> code. I think they used Strata for Riven's predecessor.. 'Myst'.
> 
> > Is the game equally great ?
> 
> You either love it or hate it, I think. Personally I really liked it.. very
> atmospheric.. it's a puzzle-solving game really. My favourite aspect was
> that although the game is mainly still images, occasionally parts of these
> images are animated.. fireflies buzz around in dark caves etc.

Now you made me hope I that get the chance to try
these games one day.


-- 
Best regards,

Tor Olav

mailto:tor### [at] hotmailcom
http://www.crosswinds.net/~tok

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Tor Olav Kristensen wrote:
> 
> Thank you very much everyone !
> 
> Sorry for not replying earlier.
> (I've been out in the real world doing a lot of ray-catching
> with my macro lens today.)
> 
> I guess I'll use radiosity a lot in the future. I love it !
> 
> To Christoph:
> I have now had a look at your radiosity pages and I find
> them very informative. Thanks for making them.
> 

Thanks, i'm already planning to add some new things, but don't know when i
have time to make them.

> To Kari:
> Can you give any clues on what differences we might see
> if POV-Ray becomes able to output 48 bit images ?
> 

You have more possibilities to adjust contrast etc. after rendering
without too much loss of quality.  For example your picture whould still
contain enough diversity in the areas totally white in the 24 bit output.
Although most graphic output devices do not have those capabilities, this
would mean a much higher contrast ratio in the actual data.

What I don't understand is the problem itself, AFAIK Povray can generate
48 bit png files.

Christoph

-- 
Christoph Hormann <chr### [at] gmxde>
IsoWood include, radiosity tutorial, TransSkin and other 
things on: http://www.schunter.etc.tu-bs.de/~chris/

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Tor Olav Kristensen wrote:
>
> Can you give any clues on what differences we might see
> if POV-Ray becomes able to output 48 bit images ?

I plan to experiment with different post processing algorithms,
dynamic range compression etc., which take images with high dynamic
range and optimise them for monitor viewing. This requires the 48 bits.
The images should look more like photographs than CG. That's the short
version.


______________________________________________________________________
Kari Kivisalo                                  http://www.kivisalo.net

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Christoph Hormann wrote:
>
> What I don't understand is the problem itself, AFAIK Povray can generate
> 48 bit png files.

I haven't found a single program that can read those pngs and convert
them to raw or 48bit tiff for Photoshop and Matlab. Even some converter
program from the png group reported them as invalid.


______________________________________________________________________
Kari Kivisalo                                  http://www.kivisalo.net

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Kari Kivisalo wrote:
> 
> I haven't found a single program that can read those pngs and convert
> them to raw or 48bit tiff for Photoshop and Matlab. Even some converter
> program from the png group reported them as invalid.
> 

But libpng obviously supports them (otherwise Povray could not write
them).  As the Delphi component i use for reading and writing png's works
fine with grayscale 16 bit i suppose it also works with 48 bit:

http://www.geocities.com/SiliconValley/Network/2114/

It should not be very difficult to write a conversion program, but it
would be better to directly write it with Povray, IIRC Povray 3.5 will add
tiff output.  

Christoph

-- 
Christoph Hormann <chr### [at] gmxde>
IsoWood include, radiosity tutorial, TransSkin and other 
things on: http://www.schunter.etc.tu-bs.de/~chris/

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In article <3A9220F5.F5E3D687@kivisalo.net>, Kari Kivisalo 
<kar### [at] kivisalonet> wrote:

> > Can you give any clues on what differences we might see
> > if POV-Ray becomes able to output 48 bit images ?
> 
> I plan to experiment with different post processing algorithms,
> dynamic range compression etc., which take images with high dynamic
> range and optimise them for monitor viewing. This requires the 48 bits.
> The images should look more like photographs than CG. That's the short
> version.

I don't think 48 bit output will do what you want...it doesn't affect 
the dynamic range of the image, just the number of levels in each color 
channel. You will probably need to use the post_process patch, which has 
access to the unclipped, full precision values.

-- 
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/

<><

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Chris Huff wrote:
> 
> In article <3A9220F5.F5E3D687@kivisalo.net>, Kari Kivisalo
> <kar### [at] kivisalonet> wrote:
>
> > I plan to experiment with different post processing algorithms,
> > dynamic range compression etc., which take images with high dynamic
> > range and optimise them for monitor viewing. This requires the 48 bits.
> > The images should look more like photographs than CG. That's the short
> > version.
> 
> I don't think 48 bit output will do what you want...it doesn't affect
> the dynamic range of the image, just the number of levels in each color
> channel.

Dynamic range/contrast ratio is directly proportional to number of levels,
when talking about linear samples.

Think about audio analogy, 8bit samples have a dynamic range of 48 dB
and 16 bit samples have 96 dB. ( dB=20*log(max_sample/min_sample) )

I know what I'm doing. Trust me :) I also know what you mean but for
hands on quick testing I have to get the images to Matlab and Photoshop.


______________________________________________________________________
Kari Kivisalo                                  http://www.kivisalo.net

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Kari Kivisalo wrote:
> 
> Tor Olav Kristensen wrote:
> >
> > Can you give any clues on what differences we might see
> > if POV-Ray becomes able to output 48 bit images ?
> 
> I plan to experiment with different post processing algorithms,
> dynamic range compression etc., which take images with high dynamic
> range and optimise them for monitor viewing. This requires the 48 bits.
> The images should look more like photographs than CG. That's the short
> version.

I see.

Thank you for explaining.

I also wonder if there are any non-linear properties 
related to the monitor's "presentations" of the binary 
coded light intensities (in images) that needs to be 
corrected.

Do you have any thoughts regarding this ?


-- 
Best regards,

Tor Olav

mailto:tor### [at] hotmailcom
http://www.crosswinds.net/~tok

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I like the over-exposed bits - this makes it seem more real to me (in a
similar way to my comments on lens flare elsewhere). I know that this isn't
a real object (although it would be an interesting challenge for a sculptor)
but I enjoy seeing bits of the real world creeping in.

"Christoph Hormann" <chr### [at] gmxde> very nearly wrote in message
news:3A8F0261.3859B799@gmx.de...
>
> It looks good, the bright parts are a bit overexposed.  The radiosity
> settings seem quite good, I suppose you used the same values Gilles used
> in his picture.
>

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Tor Olav Kristensen wrote:
>
> I also wonder if there are any non-linear properties
> related to the monitor's "presentations" of the binary
> coded light intensities (in images) that needs to be
> corrected.

I'm just trying to find a way to present images on a limited contrast
ratio medium. Display device properties and viewing conditions are
a separate problem. 

______________________________________________________________________
Kari Kivisalo                                  http://www.kivisalo.net

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