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From: AF
Subject: Pixel display - Just curious
Date: 9 Oct 2003 15:40:05
Message: <11ebovccgk1ko4lrc5oejr5fnvjlhkro80@4ax.com>
Not important, I am just curious.

Is the current version of POV displaying each pixel after calculation,
or holding each pixel in a buffer, and then displaying the entire
line?

Thanks gang,

AF


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From: Christoph Hormann
Subject: Re: Pixel display - Just curious
Date: 9 Oct 2003 16:05:53
Message: <njug51-gq.ln1@triton.schunter.etc.tu-bs.de>
AF wrote:
> Not important, I am just curious.
> 
> Is the current version of POV displaying each pixel after calculation,
> or holding each pixel in a buffer, and then displaying the entire
> line?

That depends on the platform.  The Unix version with X-Windows display
updates the image after every line.  You can force an update in between
by pressing any key or the mouse.  I guess the Windows version dows
about the same.

Christoph

-- 
POV-Ray tutorials, include files, Sim-POV,
HCR-Edit and more: http://www.tu-bs.de/~y0013390/
Last updated 2 Sep. 2003 _____./\/^>_*_<^\/\.______


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From: Thorsten Froehlich
Subject: Re: Pixel display - Just curious
Date: 9 Oct 2003 16:26:05
Message: <3f85c45d@news.povray.org>
In article <11ebovccgk1ko4lrc5oejr5fnvjlhkro80@4ax.com> , AF 
<xxa### [at] notvalidxxnetdoorcom>  wrote:

> Is the current version of POV displaying each pixel after calculation,
> or holding each pixel in a buffer, and then displaying the entire
> line?

POV-Ray itself outputs every pixel (also the code supports buffering a
line), but GUI frontends tend to buffer several pixels or a whole line
because it takes a lot of time to draw many individual pixels via the
high-level interfaces used on platforms that support a GUI.

Anyway, it doesn't really matter, and you could actually have checked
yourself really easily ;-)

    Thorsten

____________________________________________________
Thorsten Froehlich
e-mail: mac### [at] povrayorg

I am a member of the POV-Ray Team.
Visit POV-Ray on the web: http://mac.povray.org


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From: Warp
Subject: Re: Pixel display - Just curious
Date: 9 Oct 2003 16:41:13
Message: <3f85c7e9@news.povray.org>
Actually it's better that it doesn't show every pixel immediately
because in long renders it can be truely hypnotical to watch the
render progressing pixel by pixel... You'd better be alone when you get
hypnotized like that or other people will think you are crazy. :P

-- 
#macro M(A,N,D,L)plane{-z,-9pigment{mandel L*9translate N color_map{[0rgb x]
[1rgb 9]}scale<D,D*3D>*1e3}rotate y*A*8}#end M(-3<1.206434.28623>70,7)M(
-1<.7438.1795>1,20)M(1<.77595.13699>30,20)M(3<.75923.07145>80,99)// - Warp -


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From: Jellby
Subject: Re: Pixel display - Just curious
Date: 9 Oct 2003 17:24:16
Message: <3f85d1ff@news.povray.org>
Among other things, Warp wrote:

>   Actually it's better that it doesn't show every pixel immediately
> because in long renders it can be truely hypnotical to watch the
> render progressing pixel by pixel... You'd better be alone when you get
> hypnotized like that or other people will think you are crazy. :P

I remember doing that with Pov 1.0 rendering iortest.pov at maybe 640x480 in 
a 386...

-- 
light_source{9+9*x,1}camera{orthographic look_at(1-y)/4angle 30location
9/4-z*4}light_source{-9*z,1}union{box{.9-z.1+x clipped_by{plane{2+y-4*x
0}}}box{z-y-.1.1+z}box{-.1.1+x}box{.1z-.1}pigment{rgb<.8.2,1>}}//Jellby


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From: Gilles Tran
Subject: Re: Pixel display - Just curious
Date: 9 Oct 2003 18:40:25
Message: <3f85e3d9@news.povray.org>

news:11ebovccgk1ko4lrc5oejr5fnvjlhkro80@4ax.com...
>
> Not important, I am just curious.
>
> Is the current version of POV displaying each pixel after calculation,
> or holding each pixel in a buffer, and then displaying the entire
> line?

In the Windows version, just move the cursor on the slider bar and you'll
see the pixels crawling.
It's quite helpful to see the "difficult" areas but it can become pretty
addictive with slow renders, so I often turn off the display just to avoid
the temptation... It's sort of stupid to shout "go, go, go, you can do it"
to a slow pixel and then "ha, good boy, you made it" once it's rendered.

G.


-- 
**********************
http://www.oyonale.com
**********************
- Graphic experiments
- POV-Ray and Poser computer images
- Posters


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From: AF
Subject: Re: Pixel display - Just curious
Date: 9 Oct 2003 19:03:15
Message: <eupbov4h7jufaee50b6ipuig6if1e0jar8@4ax.com>
On 9 Oct 2003 16:41:13 -0400, Warp <war### [at] tagpovrayorg> wrote:

>  Actually it's better that it doesn't show every pixel immediately
>because in long renders it can be truely hypnotical to watch the
>render progressing pixel by pixel... You'd better be alone when you get
>hypnotized like that or other people will think you are crazy. :P

Other people will think I'm crazy?  A thousand years ago on a 386-33 I
remember watching pixels on slow renders until I realized that I was
crazy.  POV rehab saved me.  Sort of.

One of the reasons I asked this question was to settle an argument.
POV docs are clear that the video card is not a part of the rendering
speed equation.  From the responses here, depending on the GUI, a few
milli-seconds or in a few cases perhaps a few seconds might be saved
with a really fast video card.   Not for me.  I can wait a few
milli-seconds and save big bucks.  :-)

Thanks guys,

AF


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From: Marc Champagne
Subject: Re: Pixel display - Just curious
Date: 9 Oct 2003 21:18:00
Message: <Xns940FD829FD911POVMIKA@204.213.191.226>
"Gilles Tran" <git### [at] wanadoofr> wrote in
news:3f85e3d9@news.povray.org: 

> 

> message de 
> news:11ebovccgk1ko4lrc5oejr5fnvjlhkro80@4ax.com... 
>>
>> Not important, I am just curious.
>>
>> Is the current version of POV displaying each pixel after
>> calculation, or holding each pixel in a buffer, and then
>> displaying the entire line?
> 
> In the Windows version, just move the cursor on the slider
> bar and you'll see the pixels crawling.
> It's quite helpful to see the "difficult" areas but it can
> become pretty addictive with slow renders, so I often turn
> off the display just to avoid the temptation... It's sort
> of stupid to shout "go, go, go, you can do it" to a slow
> pixel and then "ha, good boy, you made it" once it's
> rendered. 

That disease seems pretty common then, I can vouch that I do 
have the antibodies for it :) 

-- 
Marc Champagne
marcch.AT.videotron.DOT.ca
Montreal, Canada


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From: Warp
Subject: Re: Pixel display - Just curious
Date: 10 Oct 2003 04:03:56
Message: <3f8667eb@news.povray.org>
AF <xxa### [at] notvalidxxnetdoorcom> wrote:
> POV docs are clear that the video card is not a part of the rendering
> speed equation.  From the responses here, depending on the GUI, a few
> milli-seconds or in a few cases perhaps a few seconds might be saved
> with a really fast video card.

  I'm not sure if that's so.
  POV-Ray for Windows will render to a pixel buffer in memory and then
this buffer is copied to the display, that is the video card. This copying
process is a really tiny amount compared to the rendering time, but it still
is something (even though it might be 0.0001% of the rendering time). However,
I don't think it's the speed of the video card which affects this copying
speed, but the speed of the AGP bus (or PCI bus if you happen to have such
an old video card).
  A superfast videocard is superfast when rendering triangles (which
coordinates and other info are *already* in the card's memory). This is
the so-called fill-rate. However, the video card can't affect the speed of
reading data from memory to the video card because it's the AGP bus speed
which limits it.

  (Btw, AFAIK the fastest way of copying data from memory to the screen
is using a frame buffer eg. using DirectDraw. OTOH I don't think POV-Ray
would benefit from DirectDraw support at all.)

-- 
#macro M(A,N,D,L)plane{-z,-9pigment{mandel L*9translate N color_map{[0rgb x]
[1rgb 9]}scale<D,D*3D>*1e3}rotate y*A*8}#end M(-3<1.206434.28623>70,7)M(
-1<.7438.1795>1,20)M(1<.77595.13699>30,20)M(3<.75923.07145>80,99)// - Warp -


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From: Thorsten Froehlich
Subject: Re: Pixel display - Just curious
Date: 10 Oct 2003 08:23:42
Message: <3f86a4ce$1@news.povray.org>
In article <eupbov4h7jufaee50b6ipuig6if1e0jar8@4ax.com> , AF 
<xxa### [at] notvalidxxnetdoorcom>  wrote:

> One of the reasons I asked this question was to settle an argument.
> POV docs are clear that the video card is not a part of the rendering
> speed equation.  From the responses here, depending on the GUI, a few
> milli-seconds or in a few cases perhaps a few seconds might be saved
> with a really fast video card.

No, it much more depends on the operating system and how much it abstracts
drawing.  I.e. the most extreme case, the drawing could take place not even
on your system but a remote system.

In any case, the video card will not matter at all. The operating system
will do much more than just draw that little pixel. It has to factor in that
the section the pixel is drawn in for example isn't visible at all, among
many other things.

    Thorsten

____________________________________________________
Thorsten Froehlich, Duisburg, Germany
e-mail: tho### [at] trfde

Visit POV-Ray on the web: http://mac.povray.org


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