POV-Ray : Newsgroups : povray.programming : 3.5 src questions : Re: 3.5 src questions Server Time
28 Jul 2024 06:11:07 EDT (-0400)
  Re: 3.5 src questions  
From: Christopher James Huff
Date: 2 Oct 2002 16:06:44
Message: <chrishuff-0E3E58.16040302102002@netplex.aussie.org>
In article <3D9A9B12.70DC2D1E@nospam_zip.to>,
 Pabs <pab### [at] nospam_zipto> wrote:

> It just seems logical that the base of a cylinder from the SDL should be
> stored in a variable called base. Of course mathematically it probably
> makes little difference. There is similar problem in Parse_Cone.

It makes no difference, but I am surprised...it would seem more 
"natural" to specify the base first.


> How have other ppl satisfied the POV licence wrt not enabling new
> features unless #version unofficial is in the file?
> 
> My matrix math is a little rusty, so can anyone tell if MTransNormal
> alters the length of a normal eg through a scale/translate/skew
> transform?

I would say "yes". If MTransNormal were used several times on a normal, 
all but the last normalization would be redundant and wasteful of CPU. 
And I don't remember seeing a normalization in the code. The act of 
transforming a normal can change its length, scaling and probably 
shearing will do so. Translation has no effect on normals.


> This one for someone who is familiar with the hf code: how do I get the
> height and normal (possibly smoothed) at a particular **noninteger** x,
> z position? Yes I'm stupid.

Hmm...can't really help there, but I'd look at intersect_pixel(). There 
could be a better way to do what you want, more information would help.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: chr### [at] tagpovrayorg
http://tag.povray.org/


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