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17 Sep 2021 21:00:12 EDT (-0400)
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From: Dick Balaska
Subject: Re: Hello darkness (was Re: 3.8 and text {})
Date: 14 Nov 2019 15:49:32
Message: <5dcdbddc@news.povray.org>
On 11/14/19 7:26 AM, William F Pokorny wrote:
> On 11/14/19 2:27 AM, Dick Balaska wrote:
>>
>> Changing my SDL from #version 3.7 to 3.8 causes the image to be much 
>> darker.
>>
> 
> One of the changes 3.7 to 3.8 was to take the default ambient to 0.0. 
> It's a funky color adder disconnected from gamma handling, and at 0.1, 
> it tends to brink near blacks way up in intensity with AG 1.0 - washing 
> out the contrast in the images. Your 1.7 AG is already compensating for 
> this effect to a large degree.
> 
> Have you tried changing the default ambient back to 0.1 when changing 
> your version to 3.8?
> 
> Bill P.

I'm trying to explore/understand this.
This,
https://www.povray.org/documentation/3.7.0/r3_4.html#r3_4_1
says the default ambient is <1,1,1>, not 0.1.  Am I looking at the wrong 
thing?

-- 
dik
Rendered 23,657,702,400 of 40,928,716,800 pixels (57%)


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From: Bald Eagle
Subject: Re: Hello darkness (was Re: 3.8 and text {})
Date: 14 Nov 2019 16:20:00
Message: <web.5dcdc498bf609be64eec112d0@news.povray.org>
Dick Balaska <dic### [at] buckosoftcom> wrote:

> I'm trying to explore/understand this.
> This,
> https://www.povray.org/documentation/3.7.0/r3_4.html#r3_4_1
> says the default ambient is <1,1,1>, not 0.1.  Am I looking at the wrong
> thing?

This is why I hate "documentation" compared to direct access to the values and
parameters that something uses.

I think, after 25 years, there ought to be access through SDL, or at least a
text-stream command that regurgitates things that are hidden "under the hood".

And, you probably _are_ looking at the wrong thing, since we're on
3.8.something.

http://wiki.povray.org/content/Reference:Finish#Ambient

"In version 3.8 there has been a Change to the ambient default setting. The
default setting is now ambient 0 as opposed to the ambient 0.1 value used in
previous versions. Requires #version 3.8; or equivalent INI setting or
command-line option. See also: Version Directive."


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From: Dick Balaska
Subject: Re: Hello darkness (was Re: 3.8 and text {})
Date: 14 Nov 2019 23:58:33
Message: <5dce3079$1@news.povray.org>
On 11/14/19 7:26 AM, William F Pokorny wrote:

> 
> Have you tried changing the default ambient back to 0.1 when changing 
> your version to 3.8?

The global ambient_light is silently ignored if the #version is 3.8

I used the Basic Scene 01 - Checkered Plane template
and added a Wire_Box.  Then at the top changed these 3 lines:

#version 3.8;
global_settings{ assumed_gamma 1.7 ambient_light 5.0}
//#default{ finish{ ambient 0.1 diffuse 0.9 }}

If the version is 3.7, then that ambient_light 5.0 washes everything 
right out.  If the version is 3.8, it matters not what I set that number to.

So I tried

global_settings{ assumed_gamma 1.7 }
#default{ finish{ ambient 0.1 }}

This does look a lot like the effect I want, after a couple of tests on 
my movie.  However, I am greeted with a plethora of:

Parse Warning: Scene language version changed after a 'default' 
statement. The changes in defaults normally associated with the language 
version change are not applied.

because the standard includes push the version, change to 3.5, pop the 
version.

sigh.

-- 
dik
Rendered 23,792,486,400 of 40,928,716,800 pixels (58%)


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From: William F Pokorny
Subject: Re: Hello darkness (was Re: 3.8 and text {})
Date: 15 Nov 2019 09:02:11
Message: <5dceafe3$1@news.povray.org>
On 11/14/19 11:58 PM, Dick Balaska wrote:
> On 11/14/19 7:26 AM, William F Pokorny wrote:
> 
>>
>> Have you tried changing the default ambient back to 0.1 when changing 
>> your version to 3.8?
> 
> The global ambient_light is silently ignored if the #version is 3.8
> 
> I used the Basic Scene 01 - Checkered Plane template
> and added a Wire_Box.  Then at the top changed these 3 lines:
> 
> #version 3.8;
> global_settings{ assumed_gamma 1.7 ambient_light 5.0}
> //#default{ finish{ ambient 0.1 diffuse 0.9 }}
> 
> If the version is 3.7, then that ambient_light 5.0 washes everything 
> right out.  If the version is 3.8, it matters not what I set that number 
> to.
> 
> So I tried
> 
> global_settings{ assumed_gamma 1.7 }
> #default{ finish{ ambient 0.1 }}
> 
> This does look a lot like the effect I want, after a couple of tests on 
> my movie.  However, I am greeted with a plethora of:
> 
> Parse Warning: Scene language version changed after a 'default' 
> statement. The changes in defaults normally associated with the language 
> version change are not applied.
> 
> because the standard includes push the version, change to 3.5, pop the 
> version.
> 
> sigh.
> 

Hey. Sorry, I should've written out 'default{ finish{ ambient 0.1 }}' 
(1) to make clear what's needed if using #version 3.8 and wanting to 
match the 3.7 finish ambient behavior.

The ambient_light color has an effect only when a texture's ambient 
setting is > 0.0 and so has no effect anywhere the v3.8 default ambient 
0 finish is used.

Those parse warnings showed up in one of the last updates and I join you 
in not being a fan of the warning in it's current form. It's very noisy 
in typical use. I worked recently a little in v3.8 with Norbert's 
assumed_gamma scene which included stdinc.inc - and yuck. If the warning 
could not warn when an alternate version is detected but the original 
restored before exiting an include file - or the main file - it would be 
better(2).

Bill P.

(1) - Christoph recommends using default {} over #default {}.

(2) - I recall no discussion around the addition of this parser check 
and warning before its introduction. Perhaps Christoph was thinking all 
the shipped includes would be updated to version 3.8 before any v3.8 
release so those wouldn't be an issue for this warning. I don't know.


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From: Alain Martel
Subject: Re: Hello darkness (was Re: 3.8 and text {})
Date: 15 Nov 2019 11:52:07
Message: <5dced7b7$1@news.povray.org>
Le 2019-11-14 à 15:49, Dick Balaska a écrit :
> On 11/14/19 7:26 AM, William F Pokorny wrote:
>> On 11/14/19 2:27 AM, Dick Balaska wrote:
>>>
>>> Changing my SDL from #version 3.7 to 3.8 causes the image to be much 
>>> darker.
>>>
>>
>> One of the changes 3.7 to 3.8 was to take the default ambient to 0.0. 
>> It's a funky color adder disconnected from gamma handling, and at 0.1, 
>> it tends to brink near blacks way up in intensity with AG 1.0 - 
>> washing out the contrast in the images. Your 1.7 AG is already 
>> compensating for this effect to a large degree.
>>
>> Have you tried changing the default ambient back to 0.1 when changing 
>> your version to 3.8?
>>
>> Bill P.
> 
> I'm trying to explore/understand this.
> This,
> https://www.povray.org/documentation/3.7.0/r3_4.html#r3_4_1
> says the default ambient is <1,1,1>, not 0.1.  Am I looking at the wrong 
> thing?
> 

Yes, you are looking at the wrong thing.

This refers to ambient_light in the global_settings. This is not the 
default ambient value but a multiplicator that is applied to every 
ambient values in the whole scene.

If you set that value to <1,0,0>, then, ALL ambient, default and 
explicit, will become red. Then, if you have an ambient value set to 
something like rgb<0, 0.02, 0.1>, it will result in black.

You need to look in the finish section :
https://www.povray.org/documentation/3.7.0/r3_4.html#r3_4_6_3_1



Alain


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From: Alain Martel
Subject: Re: Hello darkness (was Re: 3.8 and text {})
Date: 15 Nov 2019 11:55:08
Message: <5dced86c$1@news.povray.org>
Le 2019-11-14 à 23:58, Dick Balaska a écrit :

> This does look a lot like the effect I want, after a couple of tests on 
> my movie.  However, I am greeted with a plethora of:
> 
> Parse Warning: Scene language version changed after a 'default' 
> statement. The changes in defaults normally associated with the language 
> version change are not applied.
> 
> because the standard includes push the version, change to 3.5, pop the 
> version.
> 
> sigh.
> 

You can get rid of those warnings simply by moving the #default 
statement after your includes.


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From: Dick Balaska
Subject: Re: Hello darkness (was Re: 3.8 and text {})
Date: 16 Nov 2019 16:42:53
Message: <5dd06d5d$1@news.povray.org>
On 11/15/19 11:55 AM, Alain Martel wrote:
> Le 2019-11-14 à 23:58, Dick Balaska a écrit :
> 
>> This does look a lot like the effect I want, after a couple of tests 
>> on my movie.  However, I am greeted with a plethora of:
>>
>> Parse Warning: Scene language version changed after a 'default' 
>> statement. The changes in defaults normally associated with the 
>> language version change are not applied.
>>
>> because the standard includes push the version, change to 3.5, pop the 
>> version.
>>
>> sigh.
>>
> 
> You can get rid of those warnings simply by moving the #default 
> statement after your includes.


Yeah, but that's a hacky hacking hack.

I think really my only way out is to bite the bullet, surrender to 
clipka, and rework the whole shebang to gamma 1.0.

It's only 90,984 lines of lovingly handcrafted SDL.  (And 17,047 lines 
of Java and 9,799 lines of c++ giving 68,245 separate images.)

How hard can it be?

[insert maniacal laughter here]

-- 
dik
Rendered 24,043,392,000 of 40,928,716,800 pixels (58%)


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From: clipka
Subject: Re: Hello darkness (was Re: 3.8 and text {})
Date: 29 May 2021 16:20:00
Message: <web.60b2a119bf609be6860b50e9afff112@news.povray.org>
Dick Balaska <dic### [at] buckosoftcom> wrote:

> I think really my only way out is to bite the bullet, surrender to
> clipka, and rework the whole shebang to gamma 1.0.

All that, only to suppress some parser warnings about `text`?

There had been some attempts to clean up character encoding related stuff (you
know, ASCII vs. Latin-1 vs. Windows-1252 vs. Windows-1251 vs. Mac OS Roman vs.
UTF-8 vs. UCS-2 vs. UTF-16 vs. Whatever-Have-You) that turned out to stretch its
dirty tentacles deep into the heart of the `text` code, revealing that the
POV-Ray default fonts are totally borked, etc etc...

The 2019 status of POV-Ray was right smack-bang in the middle of trying to get
to grips with all that madness. Unless I run away screaming again, the current
state of affairs with overzealous text-related warnings will settle down a bit.
For starters, I guess I could spare you a few warnings as long as you promise to
stick to ASCII characters only...

> It's only 90,984 lines of lovingly handcrafted SDL.  (And 17,047 lines
> of Java and 9,799 lines of c++ giving 68,245 separate images.)
>
> How hard can it be?
>
> [insert maniacal laughter here]

Not too shabby. That's actually in a similar ballbark as the POV-Ray back-end
(22k Base, 48k Core, 23k Parser, 5k POVMS, 7k miscellaneous Backend, last time
someone counted; for a total of about 105k lines of code).

Indeed, how hard can it possibly be...


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