In article <web.3f9927d7a022f3b88062416c0@news.povray.org>, 
dma### [at] wrmnwestmnscuedu says...
> Mike Williams wrote:
> >Wasn't it Patrick Elliott who wrote:
> >
> >> I would love to actually know how they got that StarrRose. :(
> >
> >If you feel strongly enough about it to go out and buy the book that
> >they got the equation from, then perhaps you could let us know.
> >
> >Mike Williams
> >Gentleman of Leisure
> >
> No need, someone already has the book.
> 
> What's going on here is a simple parametric curve, "doctored up" to look 3D.
>  But we can do something similar in PovRay.
> 
> The radius varies according to a set function:  2 + sin(At)/2, creating an
> "opened-up" rose.
> 
> The twist is that the angle, rather than simply proceeding counter-clockwise
> around the circle, backs up on itself, NewT = t + Sin(Bt)/C, so that we
> have the modified parametric equations:
> 
> x = r(t)cos(NewT), y = r(t)sin(NewT).
> 
> All of the shading is done by connecting the origin to the edge of the
> curve, then shrinking and superimposing repeated copies of the image on
> itself.
> 
> We can get one version of this by letting the vertical (y) component vary
> according to r(t).
> 
> //Starr Rose For PovRay
> 
> #version 3.5;
> 
> #global_settings { assumed_gamma 1.0 }
> 
> camera {        angle 50
>                 right x*image_width/image_height
>                 location <0, 50, 0>
>                 look_at <0, 0, 0>
>         }
> 
> light_source { <800, 1200, -500> color rgb <1, 1, 1> }
> 
> #macro Starr_Rose(A, B, C, N)
> 
>   #local Radius= function(Theta) {2 + sin(A*Theta)/2}
>   #local AngleShift = function(Theta) {sin(B*Theta)/C}
> 
>   #local Angle = 0;
> 
>   #local Cycle = 2*pi;
>   union {
>   #while (Angle <= Cycle)
>        #local X = Radius(Angle)*cos(Angle + AngleShift(Angle));
>        #local Z = Radius(Angle)*sin(Angle + AngleShift(Angle));
>        #local Y = 2 - Radius(Angle) ;
>        cylinder { <0, 0, 0>, <X, Y, Z>, 0.05 }
> 
>     #local Angle = Angle + Cycle/N;
> 
>   #end
>     }
> #end
> 
> 
> 
> object { Starr_Rose(6, 18, 18, 500) texture { pigment { color rgb <1, 0, 0>
> } }
>                                     scale 5}
> 
> /////////////////End of Code
> 
> I'm guessing that one of you with more experience at POVRay can do up a
> better version, but this gives the idea.
> 
Oooh! Nice! Now if someone could find a way to tweak it so it makes the 
petals more petal like. But that is way more than I could have ever 
managed. lol

-- 
void main () {

    call functional_code()
  else
    call crash_windows();
}

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