POV-Ray : Newsgroups : povray.advanced-users : Bug in POV3.5???? Server Time
29 Jul 2024 08:20:11 EDT (-0400)
  Bug in POV3.5???? (Message 1 to 9 of 9)  
From: Jaap Frank
Subject: Bug in POV3.5????
Date: 25 Jul 2002 12:35:52
Message: <3d4028e8$1@news.povray.org>
Hi,

I'm designing a system to make a controlled landscape
with a height_field when I stumbled over this strange
behaviour.
I use the Gaussian formula ( exp((-x/sigma)^2) ) to generate
the crude mountain shape and add a fine structure with
'f_hetero_mf()' to get the real mountain view.
In the example (see povray.text.scene-files) I have
removed the fine structure and everything that don't
contribute to the problem.
The problem appears when I rotate the mountain.
The sigma values for the length and width of the mountain
in the X- and Z-direction (translated in the formula to Y)
have to be combined with cos(Rot) and sin(Rot) for the
rotation (see the #switch-section).
When I do that, things go wrong. You can see for yourself
if you change the 'Test-value' in the beginning of the file.
I have checked all the '()' over and over, but that is allwright.
Somehow a multiplication factor is added and I can't
figure out where it is coming from.

Anyone who sees what is going on??

Jaap Frank


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From: Jaap Frank
Subject: Re: Bug in POV3.5????
Date: 25 Jul 2002 13:47:46
Message: <3d4039c2$1@news.povray.org>
"Jaap Frank" <jjf### [at] xs4allnl> wrote in message
news:3d4028e8$1@news.povray.org...
> Hi,
>
> I'm designing a system to make a controlled landscape
> with a height_field when I stumbled over this strange
> behaviour.
> ...
> The problem appears when I rotate the mountain.
> The sigma values for the length and width of the mountain
> in the X- and Z-direction (translated in the formula to Y)
> have to be combined with cos(Rot) and sin(Rot) for the
> rotation (see the #switch-section).

I just figured out that it don't give the rotation I want. There
have to be a X-Z-dependent scaling of sigma, but the effect
of the multiplication is not what you expect.

Jaap Frank

PS. Read allwright without 'w', :-)


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From: Jaap Frank
Subject: Re: Bug in POV3.5????
Date: 25 Jul 2002 17:52:08
Message: <3d407308@news.povray.org>
I've found the cause of this!
It's a problem with brackets.
If you use:

exp(-pow((x-PosX1/LndScpWidth)/(L1/LndScpWidth/4),2))
                                                           ^^
everything is fine, but if you put more brackets in it, for instance with:

exp(-pow((x-PosX1/LndScpWidth)/((L1*4+W1*3)/LndScpWidth/4),2))
                                                           ^^^^^^^^^^^^^^
then something goes wrong.
It has nothing to do with what's inside, for this goes wrong too:

exp(-pow((x-PosX1/LndScpWidth)/((L1)/LndScpWidth/4),2))
                                                           ^^^^
but

exp(-pow((x-PosX1/LndScpWidth)/(((L1)/LndScpWidth)/4),2))
                                                           ^ ^^^
^
is fine again.

The only thing I can think of is the parser. Somehow the brackets
cause something weird.

Jaap Frank.


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From: Warp
Subject: Re: Bug in POV3.5????
Date: 25 Jul 2002 20:32:33
Message: <3d4098a1@news.povray.org>
Jaap Frank <jjf### [at] xs4allnl> wrote:
> exp(-pow((x-PosX1/LndScpWidth)/(L1/LndScpWidth/4),2))
>                                                            ^^

  Why do you suppose that everyone is using the exact same variable-width
font you are?
  If you really want everyone to see what you see, use a fixed-width font.

-- 
#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: Rick [Kitty5]
Subject: Re: Bug in POV3.5????
Date: 26 Jul 2002 03:50:50
Message: <3d40ff5a@news.povray.org>
"Warp" <war### [at] tagpovrayorg> wrote in message
news:3d4098a1@news.povray.org...
>   Why do you suppose that everyone is using the exact same variable-width
> font you are?
>   If you really want everyone to see what you see, use a fixed-width font.

he is posting in plain text, you use a fixed width font


--
Rick

Kitty5 WebDesign - http://Kitty5.com
POV-Ray News & Resources - http://Povray.co.uk
TEL : +44 (01270) 501101 - FAX : +44 (01270) 251105 - ICQ : 15776037

PGP Public Key
http://pgpkeys.mit.edu:11371/pks/lookup?op=get&search=0x231E1CEA


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From: Philippe Lhoste
Subject: Re: Bug in POV3.5????
Date: 26 Jul 2002 04:30:20
Message: <3d41089c$1@news.povray.org>

3d40ff5a@news.povray.org...
>
> "Warp" <war### [at] tagpovrayorg> wrote in message
> news:3d4098a1@news.povray.org...
> >   Why do you suppose that everyone is using the exact same
variable-width
> > font you are?
> >   If you really want everyone to see what you see, use a fixed-width
font.
>
> he is posting in plain text, you use a fixed width font

"Plain text" doesn't make sense, it just means this is not HTML nor RTF nor
Flash, etc.

If he used Times New Roman to compose his text, since I use Arial to read
the messages (but I can use Wide Latin or Haettenschweiler), the ^^^ symbols
are all off, not under the position the author intended to highlight.

-- #=--=#=--=#=--=#=--=#=--=#=--=#=--=#=--=# --
Philippe Lhoste (Paris -- France)
Professional programmer and amateur artist
http://jove.prohosting.com/~philho/


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From: Rafal 'Raf256' Maj
Subject: Re: Bug in POV3.5????
Date: 26 Jul 2002 05:39:53
Message: <Xns92577613B25DEraf256com@204.213.191.226>
"Rick [Kitty5]" <ric### [at] kitty5com> wrote in news:3d40ff5a@news.povray.org

> he is posting in plain text, you use a fixed width font

plain text != fixed width !

I use a fixed-width font (Courier New) and ^^ is in invalis position - so 
it's wrong.
Do You see below lines as same width ?
wwwwwwwwwwwww|
iiiiiiiiiiiii|
.............|

if not - then You should use fixed-width and now You are using variable-
width


-- 
#macro g(U,V)(.4*abs(sin(9*sqrt(pow(x-U,2)+pow(y-V,2))))*pow(1-min(1,(sqrt(
pow(x-U,2)+pow(y-V,2))*.3)),2)+.9)#end#macro p(c)#if(c>1)#local l=mod(c,100
);g(2*div(l,10)-8,2*mod(l,10)-8)*p(div(c,100))#else 1#end#end light_source{
y 2}sphere{z*20 9pigment{function{p(26252423)*p(36455644)*p(66656463)}}}//M


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From: Jaap Frank
Subject: Re: Bug in POV3.5????
Date: 26 Jul 2002 07:56:46
Message: <3d4138fe@news.povray.org>
"Warp" <war### [at] tagpovrayorg> wrote in message news:3d4098a1@news.povray.org...
> Jaap Frank <jjf### [at] xs4allnl> wrote:
> > exp(-pow((x-PosX1/LndScpWidth)/(L1/LndScpWidth/4),2))
> >                                                            ^^
>
>   Why do you suppose that everyone is using the exact same variable-width
> font you are?
>   If you really want everyone to see what you see, use a fixed-width font.
>

I'm using Outlook Express 6. I've searched where I can change the fonts.
All I can find is the send mail section where you can choose the font
to 'compose'. I've set that to Courier 10pt, but that's not the font I'm seeing.
Can anyone tell me where I can change the font of the program so I can
see what is send away?

Jaap Frank

PS
 Test:
=========1=========2=========3
         ^         ^         ^
The carets should be under the numbers now.


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From: KalleK
Subject: Re: Bug in POV3.5????
Date: 26 Jul 2002 15:11:46
Message: <3d419ef2$2@news.povray.org>
> I use a fixed-width font (Courier New) and ^^ is in invalis position - so
> it's wrong.
> Do You see below lines as same width ?
> wwwwwwwwwwwww|
> iiiiiiiiiiiii|
> .............|
>
hmm. That's strange. I told my OE to use Lucida Console (a
fixed-width-font...) for displaying news. But posts from you and Wlodzimierz
ABX Skiba are sometimes not fixed with - like this one. The I's are in fact
much smaller than the W's...

I think, OE is "confused" by your charset ISO-8859-2 (East Europe) somehow.
Not your fault, for sure...

follow-ups set to p.o-t

cukk


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