POV-Ray : Newsgroups : povray.bugreports : polygon with overlap : Re: polygon with overlap Server Time
29 Apr 2024 10:53:52 EDT (-0400)
  Re: polygon with overlap  
From: clipka
Date: 4 Jan 2011 15:36:26
Message: <4d2384ca$1@news.povray.org>
Am 04.01.2011 21:21, schrieb Le_Forgeron:
> Greetings,
>
> Can someone check if I made any error on the following script:
> It should render [step] nested polygons of [num] sides.
> But the rendered picture is bogus for me (both 3.6&  3.7).
> I searched the bugs site, but found no match for polygon.

Apparently the polygon code requires start and end points to /exactly/ 
match in order to recognize the end of a "sub-polygon"; you can work 
around this with the following change:

> #default { texture { pigment { rgb 1 }finish { ambient 1.0} } }
>
> camera { orthographic
> 	up 3.5*y
>    right 3.5*x*image_width/image_height
>    location<0,0,-4>
>    look_at<0,0,0>
> }
>
> #declare num=5;
> #declare step=5;
> #macro aa(xx,yy,a)
>
> polygon { (num+1)*step,
> #local j=0.70;
> #while(j>0.01)
> #local i=0;
> #while(i<num+1)
>    j*<  cos(i*2*pi/num),sin(i*2*pi/num),0>

replace this with

      j*<  cos(mod(i,num)*2*pi/num),sin(mod(i,num)*2*pi/num),0>

> #local i=i+1;
> #end
> #local j=j-0.7/step;
> #end
> translate<xx-0.0,yy,0>
>   }
> #end
>
> aa(0,0,0)

I'd consider it a bug nonetheless.


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