I’ve named this Sven’s Bug because I noticed it running his code posted 
in “15 Shapes Taking Forever” in povray.general
And so he gets his name on something. :-P

There is a difference between renders with and without using Render 
Block Size.
The images are with the windows QUICKRES.INI [800x600, AA 0.3] with and 
without +BS8
I compared them in PaintShop Pro (XOR shows it best)

Ver 3.7.0.msvc10.win64
On Win7

-- 

Regards
     Stephen

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Attachments:
Download 'svens.png' (63 KB) Download 'svens_bs.png' (62 KB)

Preview of image 'svens.png'

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Am 18.02.2016 um 20:29 schrieb Stephen:
> I’ve named this Sven’s Bug because I noticed it running his code posted
> in “15 Shapes Taking Forever” in povray.general
> And so he gets his name on something. :-P
> 
> There is a difference between renders with and without using Render
> Block Size.
> The images are with the windows QUICKRES.INI [800x600, AA 0.3] with and
> without +BS8
> I compared them in PaintShop Pro (XOR shows it best)

Nothing in there that would surprise me.

I see some tiny fluctuations in the results, which are normal -- and a
few more pronounced differences at the objects' edges, which are quite
obviously related to anti-aliasing.

POV-Ray 3.7 performs anti-aliasing at the render block level, /before/
assembling the blocks to an entire image. As a consequence, the decision
to supersample any given pixel not only depends on the neighboring
pixels, but also on whether the pixel is at a block boundary.

Consequently, reducing the render block size, and therefore adding more
block boundaries, will change the behaviour of anti-aliasing, and
increase the risk of aliasing artifacts.

So this is not a bug, just a drawback of how things are implemented.


(Hey, what do you expect if you associate Sven's name with it?! :P)

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Yes, this is truly a good idea to use my name as identifier for this
bug, this way CLipka will enjoy much more having to think about it, and
to work with it. Full support from my side. Now we have implanted my
name even in his mind. Cool! :-D



On 18.02.2016 14:29, Stephen wrote:
> I’ve named this Sven’s Bug because I noticed it running his code posted
> in “15 Shapes Taking Forever” in povray.general
> And so he gets his name on something. :-P

Post a reply to this message

On 2/18/2016 8:38 PM, clipka wrote:
> Consequently, reducing the render block size, and therefore adding more
> block boundaries, will change the behaviour of anti-aliasing, and
> increase the risk of aliasing artifacts.
>
> So this is not a bug, just a drawback of how things are implemented.
>

Within tolerances? Fairy Nough. :)

>
> (Hey, what do you expect if you associate Sven's name with it?! :P)

No! I don't want to think. :)

-- 

Regards
     Stephen

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On 2/18/2016 8:40 PM, Sven Littkowski wrote:
> Yes, this is truly a good idea to use my name as identifier for this
> bug, this way CLipka will enjoy much more having to think about it, and
> to work with it. Full support from my side.

Looks like it is just tolerances but you can't say I did not try.


> Now we have implanted my
> name even in his mind. Cool!:-D
>

I think it was already there. ;)

BTW did not someone else say that it is bad Netiquette to top post?

-- 

Regards
     Stephen

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Am 18.02.2016 um 21:40 schrieb Sven Littkowski:
> Yes, this is truly a good idea to use my name as identifier for this
> bug, this way CLipka will enjoy much more having to think about it, and
> to work with it. Full support from my side. Now we have implanted my
> name even in his mind. Cool! :-D

Someone hand me the Brain Bleach, please...

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Am 18.02.2016 um 22:02 schrieb Stephen:

> BTW did not someone else say that it is bad Netiquette to top post?

At least he's now quoting /at all/ ;)

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On 2/18/2016 9:16 PM, clipka wrote:
> Am 18.02.2016 um 22:02 schrieb Stephen:
>
>> BTW did not someone else say that it is bad Netiquette to top post?
>
> At least he's now quoting /at all/ ;)
>

"One day at a time. Sweet..." ;)

-- 

Regards
     Stephen

Post a reply to this message

Le 16-02-18 15:38, clipka a écrit :
> Am 18.02.2016 um 20:29 schrieb Stephen:
>> I’ve named this Sven’s Bug because I noticed it running his code posted
>> in “15 Shapes Taking Forever” in povray.general
>> And so he gets his name on something. :-P
>>
>> There is a difference between renders with and without using Render
>> Block Size.
>> The images are with the windows QUICKRES.INI [800x600, AA 0.3] with and
>> without +BS8
>> I compared them in PaintShop Pro (XOR shows it best)
>
> Nothing in there that would surprise me.
>
> I see some tiny fluctuations in the results, which are normal -- and a
> few more pronounced differences at the objects' edges, which are quite
> obviously related to anti-aliasing.
>
> POV-Ray 3.7 performs anti-aliasing at the render block level, /before/
> assembling the blocks to an entire image. As a consequence, the decision
> to supersample any given pixel not only depends on the neighboring
> pixels, but also on whether the pixel is at a block boundary.
>
> Consequently, reducing the render block size, and therefore adding more
> block boundaries, will change the behaviour of anti-aliasing, and
> increase the risk of aliasing artifacts.
>
> So this is not a bug, just a drawback of how things are implemented.
>
>
> (Hey, what do you expect if you associate Sven's name with it?! :P)
>

Is it possible that using antialiasing method 2 could reduce that kind 
of artefacts?
With method 1, you sample the center of each pixel, and compare that 
with the neibors. With method 2, you start with samples at each corners 
that are then compared.

Post a reply to this message

Well, we can always hunt for more bugs and show them to CLipka. Never
give up. His thanks are certain. :-)

On 18.02.2016 16:02, Stephen wrote:
> Looks like it is just tolerances but you can't say I did not try.

Post a reply to this message

Am 18.02.2016 um 23:55 schrieb Alain:
> Is it possible that using antialiasing method 2 could reduce that kind
> of artefacts?
> With method 1, you sample the center of each pixel, and compare that
> with the neibors. With method 2, you start with samples at each corners
> that are then compared.

That may well be.

Note that even anti-aliasing mode 1 already does some extra work to try
to prevent such aliasing artifacts, by silently rendering the pixels
immediately to the top and left of each block again to check if
oversampling is necessary. This way, the same comparisons normally done
for pixels in the bulk of the block can also be applied to the pixels at
the boundary. But in the bulk the neighboring pixels would also have
been subject to potential oversampling already, while the extra pixels
at the boundary will never be oversampled. This /can/ lead to aliasing
artefacts at the boundaries that wouldn't be there in the bulk.

In mode 2, this difference can't happen because the oversampling
decision is based on original trace results, not on oversampled pixels.

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Le 18/02/2016 22:15, clipka a écrit :
> Am 18.02.2016 um 21:40 schrieb Sven Littkowski:
>> Yes, this is truly a good idea to use my name as identifier for this
>> bug, this way CLipka will enjoy much more having to think about it, and
>> to work with it. Full support from my side. Now we have implanted my
>> name even in his mind. Cool! :-D
>
> Someone hand me the Brain Bleach, please...
>

Hi, please look at my raised hand, with the metal rod  and its tiny red 
light at the end of it.

*** Flash ***

You are a good programmer coding days and nights to make povray better. 
you aim at releasing a major version soon and won't let you disturbed by 
small hindrance like hunger or need of sleep.

Have a good day.

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On 19-2-2016 8:30, Le_Forgeron wrote:
> Le 18/02/2016 22:15, clipka a écrit :
>> Am 18.02.2016 um 21:40 schrieb Sven Littkowski:
>>> Yes, this is truly a good idea to use my name as identifier for this
>>> bug, this way CLipka will enjoy much more having to think about it, and
>>> to work with it. Full support from my side. Now we have implanted my
>>> name even in his mind. Cool! :-D
>>
>> Someone hand me the Brain Bleach, please...
>>
>
> Hi, please look at my raised hand, with the metal rod  and its tiny red
> light at the end of it.
>
> *** Flash ***
>
> You are a good programmer coding days and nights to make povray better.
> you aim at releasing a major version soon and won't let you disturbed by
> small hindrance like hunger or need of sleep.
>
> Have a good day.
>
>

[at least he can have sex]

-- 
Thomas

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On 2/19/2016 7:30 AM, Le_Forgeron wrote:
>
> Hi, please look at my raised hand, with the metal rod  and its tiny red
> light at the end of it.
>
> *** Flash ***
>
> You are a good programmer


Nah. It didn't work. :)

-- 

Regards
     Stephen

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Am 19.02.2016 um 08:30 schrieb Le_Forgeron:

>> Someone hand me the Brain Bleach, please...
>>
> 
> Hi, please look at my raised hand, with the metal rod  and its tiny red
> light at the end of it.
> 
> *** Flash ***
> 
> You are a good programmer coding days and nights to make povray better.
> you aim at releasing a major version soon and won't let you disturbed by
> small hindrance like hunger or need of sleep.
> 
> Have a good day.

In other words: Back to normal mode of operation.

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Can he..? POV-Ray's more important.

On 19.02.2016 02:53, Thomas de Groot wrote:

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And we all are waiting now like the vultures for the new major bugs of
the new major release...

But seriously, I wished I could assist in programming. I have so many
ideas about editor and other things, and little improvements (-e2), that
it is sad I use a different programming language than C++.

Yes, indeed, CLipka is doing some kinda good job. Big thanks to him and
all the other developers of this magnificent software!!!!!!!



On 19.02.2016 02:53, Thomas de Groot wrote:
>> You are a good programmer coding days and nights to make povray better.
>> you aim at releasing a major version soon and won't let you disturbed by
>> small hindrance like hunger or need of sleep.

Post a reply to this message

Le 16-02-18 14:29, Stephen a écrit :
> I’ve named this Sven’s Bug because I noticed it running his code posted
> in “15 Shapes Taking Forever” in povray.general
> And so he gets his name on something. :-P
>
> There is a difference between renders with and without using Render
> Block Size.
> The images are with the windows QUICKRES.INI [800x600, AA 0.3] with and
> without +BS8
> I compared them in PaintShop Pro (XOR shows it best)
>
> Ver 3.7.0.msvc10.win64
> On Win7
>

After Clipka's answer to my comment, I'd recomend using antialiasing 
method 2, +am2, to reduce or elliminate those artefacts.

With method 1, the already rendered pixels on the top and left may, or 
may not, already be supersampled compared to the retraced ones from the 
current block.

With method 2, that start with the NON supersampled corners, you always 
start with fresh samples that are in a known, consistant, state. It 
don't mather if the current pixel is at the edge of the block or not, 
all pixels are treated the same with original data obtained the same way.

If using method 3, you are possibly in a similar situation as with 
method 2. Given the inherent random noise associated with method 3, it 
may not mather at all.



Alain

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Am 20.02.2016 um 02:15 schrieb Sven Littkowski:
> Can he..? POV-Ray's more important.

A good and healthy sex life is... well, good and healthy ;)

Scientific studies have shown that frequent -- shall we say, exercise?
-- reduces the risk of prostate cancer and cardiovascular issues.

And you surely want POV-Ray development to continue for a while, don't
you? ;)

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Am 20.02.2016 um 02:21 schrieb Sven Littkowski:
> Yes, indeed, CLipka is doing some kinda good job. Big thanks to him and
> all the other developers of this magnificent software!!!!!!!

"Kinda" good, huh?
I'll remember that next time you want something fixed ;)

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On 21-2-2016 8:24, clipka wrote:
> Am 20.02.2016 um 02:21 schrieb Sven Littkowski:
>> Yes, indeed, CLipka is doing some kinda good job. Big thanks to him and
>> all the other developers of this magnificent software!!!!!!!
>
> "Kinda" good, huh?
> I'll remember that next time you want something fixed ;)
>

[dreaming] new version of POV-Ray accessible to all, except Sven [/dreaming]

-- 
Thomas

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Am 21.02.2016 um 08:43 schrieb Thomas de Groot:
> On 21-2-2016 8:24, clipka wrote:
>> Am 20.02.2016 um 02:21 schrieb Sven Littkowski:
>>> Yes, indeed, CLipka is doing some kinda good job. Big thanks to him and
>>> all the other developers of this magnificent software!!!!!!!
>>
>> "Kinda" good, huh?
>> I'll remember that next time you want something fixed ;)
>>
> 
> [dreaming] new version of POV-Ray accessible to all, except Sven
> [/dreaming]

I was thinking more along the lines of giving Sven his very own personal
bug to complain about }:->

    if (username.isLike("sven littkowski"))
        FailInSomeRandomManner();

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ha ha ha ha ha! Good answer. You are excused. :-)






On 21.02.2016 02:22, clipka wrote:
> A good and healthy sex life is... well, good and healthy ;)
> 
> Scientific studies have shown that frequent -- shall we say, exercise?
> -- reduces the risk of prostate cancer and cardiovascular issues.
> 
> And you surely want POV-Ray development to continue for a while, don't
> you? ;)
>

Post a reply to this message

We ALL will see, how fast you'll fix the errors your faulty programming
has caused. He he he!




On 21.02.2016 02:24, clipka wrote:
> Am 20.02.2016 um 02:21 schrieb Sven Littkowski:
>> Yes, indeed, CLipka is doing some kinda good job. Big thanks to him and
>> all the other developers of this magnificent software!!!!!!!
> 
> "Kinda" good, huh?
> I'll remember that next time you want something fixed ;)
>

Post a reply to this message

:-D


So, CLipka is the name that flies from mouth to mouth, who will be
named, when the world has to find out, that POV-Ray has finally changed
from a great render software to some tricky malfunctioning trojan horse
malware under the corrupt, pizza-dirted hands of CLipka and his
coca-cola-covered keyboard from 1987...




On 21.02.2016 03:06, clipka wrote:
> Am 21.02.2016 um 08:43 schrieb Thomas de Groot:
>> On 21-2-2016 8:24, clipka wrote:
>>> Am 20.02.2016 um 02:21 schrieb Sven Littkowski:
>>>> Yes, indeed, CLipka is doing some kinda good job. Big thanks to him and
>>>> all the other developers of this magnificent software!!!!!!!
>>>
>>> "Kinda" good, huh?
>>> I'll remember that next time you want something fixed ;)
>>>
>>
>> [dreaming] new version of POV-Ray accessible to all, except Sven
>> [/dreaming]
> 
> I was thinking more along the lines of giving Sven his very own personal
> bug to complain about }:->
> 
>     if (username.isLike("sven littkowski"))
>         FailInSomeRandomManner();
>

Post a reply to this message

Am 27.02.2016 um 07:32 schrieb Sven Littkowski:

> So, CLipka is the name that flies from mouth to mouth, who will be
> named, when the world has to find out, that POV-Ray has finally changed
> from a great render software to some tricky malfunctioning trojan horse
> malware under the corrupt, pizza-dirted hands of CLipka and his
> coca-cola-covered keyboard from 1987...

No, no, no - you're getting this all wrong.

You see, the keyboard I covered in coke just a month ago was the good
Logitech G19 from 2012, not the old 1987 one (which would have been the
entire Schneider CPC 464; I never owned a PC prior to the early '90s).

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