POV-Ray : Newsgroups : povray.beta-test.binaries : Fixing longstanding function/pattern issues in v38. New raw_wave keyword. : Re: Fixing longstanding function/pattern issues in v38. New raw_wave keywor= Server Time
15 Jun 2024 09:40:23 EDT (-0400)
  Re: Fixing longstanding function/pattern issues in v38. New raw_wave keywor=  
From: William F Pokorny
Date: 22 Oct 2019 04:57:32
Message: <5daec47c$1@news.povray.org>
On 10/20/19 1:18 PM, Bald Eagle wrote:
> "Bald Eagle" <cre### [at] netscapenet> wrote:
> 
>> Well, I think I found an issue with the way that the angle is calculated for the
>> radial pattern.
> 
> I had it in the back of my mind to mention the effect of phase, but forgot.
> The equations also seem to botch the phase adjustment as well.
> I noticed this when I realized I could probably use phase to rotate the color
> map instead of applying the unmodified pigment to the object and then rotating
> around the origin.
> 
> I _think_ I got to the point where I fixed this as well, but it's all worth a
> thorough double and triple checking.
> 
> FYI.
> 
I think I have a fix in hand. Further that the problem with phase was 
rooted in the base radial problem affecting non-integer frequencies. 
Internally phase is an adder applied after the frequency multiplication.

See attached. Upper left is your f=360/270 as the new code renders the 
breaks in continuity (ramp_wave).

Upper right f=360/270 phase 1/4. Lower left f=4. Lower right f=4 phase 1/4.

Done a fair bit of testing and looking OK to me. It will be a while 
before I get a branch out as busy with real life until the middle of 
next week. First thought about a branch for just this change, but it's 
getting to where I'm carrying too many off master. I'm going to roll 
this change into a branch for a set of changes around functions and 
patterns I want including this update. I plan opening a more general 
github issue covering everything in the set of changes too.

Bill P.


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Attachments:
Download 'radialfix_wphase.png' (197 KB)

Preview of image 'radialfix_wphase.png'
radialfix_wphase.png


 

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