POV-Ray : Newsgroups : povray.newusers : output control questions Server Time: 26 Jun 2019 19:53:21 GMT
  output control questions (Message 1 to 5 of 5)  
From: Matt Busche
Subject: output control questions
Date: 28 Mar 2016 15:10:00
Message: <web.56f948fb803c6adb61e35a3c0@news.povray.org>
I've downloaded a couple of .pov files and am trying to figure out the right way
to render them, but am having trouble understanding I/O on the command line.
After quite a bit of fumbling, I eventually use these two different command
lines for the two files:

povray +Icube.pov +H750 > cube.png
povray -D +Idice_usage_examples.pov +w384 +h216

For the first file, the rendered png image is sent to standard out, but for the
other it's sent automatically to a file with the same name as the input file
(ending in .png instead of .pov).

  1) Why the difference?  Is there some setting in one of the two .pov source
files that's governing this behavior that I haven't noticed?

For the latter file, some horrid ncurses stuff is instead sent to standard out
that gets my putty xterm session into quite the tizzy.  I eventually discovered
the -D option to disable this output and saving my xterm the death-throes.  But
again,

  2) Why am I geeting ncurses output in one case, but not the other?

I added the +H750 on the first line because the image otherwise seemed
unnaturally vertically squished.  Not sure why.  Perhaps it's just the nature of
the perspective chosen in that environment.  I guess I'm not too concerned with
that oddity right now.

Anyway, I'd like to understand what the heck I'm doing before I start changing
things.

I'd appreciate any light you can cast into the darkened room in which I
currently stumble.

Matt Busche


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From: Stephen
Subject: Re: output control questions
Date: 28 Mar 2016 15:41:19
Message: <56f9509f$1@news.povray.org>
On 3/28/2016 4:08 PM, Matt Busche wrote:
> povray +Icube.pov +H750 > cube.png
> povray -D +Idice_usage_examples.pov +w384 +h216
>
> For the first file, the rendered png image is sent to standard out, but for the
> other it's sent automatically to a file with the same name as the input file
> (ending in .png instead of .pov).
>
>    1) Why the difference?  Is there some setting in one of the two .pov source
> files that's governing this behavior that I haven't noticed?

A quick reply.

The second line uses the default output name. In the first line, you 
specified what name PovRay should output.

-- 

Regards
     Stephen


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From: Jaime Vives Piqueres
Subject: Re: output control questions
Date: 28 Mar 2016 16:19:52
Message: <56f959a8@news.povray.org>
El 28/03/16 a las 17:08, Matt Busche escribió:
> I've downloaded a couple of .pov files and am trying to figure out
> the right way to render them, but am having trouble understanding I/O
> on the command line. After quite a bit of fumbling, I eventually use
> these two different command lines for the two files:
>
> povray +Icube.pov +H750 > cube.png povray -D
> +Idice_usage_examples.pov +w384 +h216
>
> For the first file, the rendered png image is sent to standard out,
> but for the other it's sent automatically to a file with the same
> name as the input file (ending in .png instead of .pov).
>
> 1) Why the difference?  Is there some setting in one of the two .pov
>  source files that's governing this behavior that I haven't noticed?
>

http://wiki.povray.org/content/Reference:File_Output_Options

> For the latter file, some horrid ncurses stuff is instead sent to
> standard out that gets my putty xterm session into quite the tizzy.
> I eventually discovered the -D option to disable this output and
> saving my xterm the death-throes.  But again,
>
> 2) Why am I geeting ncurses output in one case, but not the other?
>

   I'm guessing you have compiled POV-Ray without any display support, so
it's using the "text display" on the console, which outputs some sort of
"ascii art".

> I added the +H750 on the first line because the image otherwise
> seemed unnaturally vertically squished.  Not sure why.  Perhaps it's
>  just the nature of the perspective chosen in that environment.  I
> guess I'm not too concerned with that oddity right now.

   It depends on the aspect ratio of the camera on the scene. You should
always first look for the camera for this information, as not all people
uses the default 4/3.

http://wiki.povray.org/content/Reference:Camera#Aspect_Ratio

--
jaime


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From: Matt Busche
Subject: Re: output control questions
Date: 28 Mar 2016 17:50:01
Message: <web.56f96de4128bf5c561e35a3c0@news.povray.org>
Stephen <mca### [at] aolcom> wrote:
> On 3/28/2016 4:08 PM, Matt Busche wrote:
> > povray +Icube.pov +H750 > cube.png
> > povray -D +Idice_usage_examples.pov +w384 +h216
> >
> > For the first file, the rendered png image is sent to standard out, but for the
> > other it's sent automatically to a file with the same name as the input file
> > (ending in .png instead of .pov).
> >
> >    1) Why the difference?  Is there some setting in one of the two .pov source
> > files that's governing this behavior that I haven't noticed?
>
> A quick reply.
>
> The second line uses the default output name. In the first line, you
> specified what name PovRay should output.
>
> --
>
> Regards
>      Stephen

After fiddling around a bit more, I think I've discovered what's actually
happening.

I think in the first case, ncurses output, which is consistently being sent to
stdout in both cases, is indeed being written to cube.png (which is obiously not
what I want); and then at the end of rendering, the in-core png image is then
written to cube.png overwriting the previously written ncurses content of the
file making it disappear into the magician's hat.

Thanks to everyone for taking the time to respond.

Matt


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From: Alain
Subject: Re: output control questions
Date: 28 Mar 2016 21:29:50
Message: <56f9a24e$1@news.povray.org>
Le 16-03-28 11:08, Matt Busche a écrit :
> I've downloaded a couple of .pov files and am trying to figure out the right way
> to render them, but am having trouble understanding I/O on the command line.
> After quite a bit of fumbling, I eventually use these two different command
> lines for the two files:
>
> povray +Icube.pov +H750 > cube.png

With this command, the image gets displayed as it is rendered and saved 
with the name that you have provided.
If your compile did not include the libraries to actualy display the 
image, then, you essentialy get garbage to display. Use the -D switch, 
or add it to the master ini file.
You set the hight of the image and use the "default" width.
In my opinion, it's beter to provide both hight (+hxxx) and width 
(+wxxx). It reduce the chances of bad surprises.

> povray -D +Idice_usage_examples.pov +w384 +h216

With this command line, you disable the display of the image and use the 
default naming whitch is the name of the .POV file with the extention .PNG.
It also set the dimention of the image to 384 pixels whide and 216 
pixeld high. This override the dimention from the master ini file.

>
> For the first file, the rendered png image is sent to standard out, but for the
> other it's sent automatically to a file with the same name as the input file
> (ending in .png instead of .pov).
>
>    1) Why the difference?  Is there some setting in one of the two .pov source
> files that's governing this behavior that I haven't noticed?
>
> For the latter file, some horrid ncurses stuff is instead sent to standard out
> that gets my putty xterm session into quite the tizzy.  I eventually discovered
> the -D option to disable this output and saving my xterm the death-throes.  But
> again,
>
>    2) Why am I geeting ncurses output in one case, but not the other?
>
> I added the +H750 on the first line because the image otherwise seemed
> unnaturally vertically squished.  Not sure why.  Perhaps it's just the nature of
> the perspective chosen in that environment.  I guess I'm not too concerned with
> that oddity right now.

By default, the aspect ratio is assumed to be 4:3. If you look at 
icube.pov, you'll find a camera that use a different aspect ratio and 
setting the hight to 750 pixels gives you the correct, or almost 
correct, aspect ratio.
The key calues are up and right. Usualy, up = <0,1,0> and right = <4/3, 
0, 0>, but the author choose a different value.
Take a look at the camera{} statement of that file.

>
> Anyway, I'd like to understand what the heck I'm doing before I start changing
> things.
>
> I'd appreciate any light you can cast into the darkened room in which I
> currently stumble.
>
> Matt Busche
>
>

Welcome Matt.


Alain


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