POV-Ray : Newsgroups : povray.advanced-users : render differences between 3.63 and 3.7 Server Time
31 Oct 2024 21:22:19 EDT (-0400)
  render differences between 3.63 and 3.7 (Message 1 to 3 of 3)  
From: Woody
Subject: render differences between 3.63 and 3.7
Date: 18 May 2011 23:40:00
Message: <web.4dd4908b840c6af1bfd9b30a0@news.povray.org>
I'm noticing a difference in how renders are being displayed between version
3.63 and 3.7.

In 3.63 each pixel in a line was rendered before moving onto the next line.

In 3.7, squares of pixels are rendered, then moving onto the next square in a
line.

How do I change in version 3.7 the way it was done in 3.63? Is there a setting
or command line option that I can change, or is this just a difference in
versions?

What keyword / topic should I be looking for in the online help / documentation
that explains this?

Thanks
-Jeff


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From: Jim Holsenback
Subject: Re: render differences between 3.63 and 3.7
Date: 19 May 2011 06:37:51
Message: <4dd4f2ff$1@news.povray.org>
On 05/19/2011 12:37 AM, Woody wrote:
> I'm noticing a difference in how renders are being displayed between version
> 3.63 and 3.7.
>
> In 3.63 each pixel in a line was rendered before moving onto the next line.
>
> In 3.7, squares of pixels are rendered, then moving onto the next square in a
> line.
>
> How do I change in version 3.7 the way it was done in 3.63? Is there a setting
> or command line option that I can change, or is this just a difference in
> versions?
>
> What keyword / topic should I be looking for in the online help / documentation
> that explains this?
>
> Thanks
> -Jeff
>
>
start here:
http://wiki.povray.org/content/Documentation:Reference_Section_1.3#Tracing_Options

block size and pattern


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From: clipka
Subject: Re: render differences between 3.63 and 3.7
Date: 19 May 2011 11:10:44
Message: <4dd532f4$1@news.povray.org>
Am 19.05.2011 05:37, schrieb Woody:
> I'm noticing a difference in how renders are being displayed between version
> 3.63 and 3.7.

(I guess you mean 3.62, not 3.63; the latter version doesn't exist ;-))

> In 3.63 each pixel in a line was rendered before moving onto the next line.
>
> In 3.7, squares of pixels are rendered, then moving onto the next square in a
> line.
>
> How do I change in version 3.7 the way it was done in 3.63? Is there a setting
> or command line option that I can change, or is this just a difference in
> versions?

It's just the way it is. The change was introduced to better suit 
multithreading support: The image is subdivided into squares of equal 
size, and each square is rendered by a separate thread (well, not 
exactly, but it reflects the basic idea).

This is a more or less arbitrary choice; for instance, subdivision could 
have been done on a pixel line basis, so that each thread would work on 
a pixel line instead of a pixel block. However, the block approach gets 
more benefit out of certain caching mechanisms; in layman's terms, a 
thread working exclusively on the top left corner of the image can 
"specialize" on the objects that actually affect that corner.


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