Russell Towle napsal(a):
> "alphaQuad" <alp### [at] earthlinknet> wrote:
> 
>> just do all the calcs in pov script?
>>
>> would love to see the method,
> 
> Well I've been thinking, why not implement the GDM in POV?
> 
> Right now I've got it in Mathematica's language, and I ported it from PostScript
> of all things. Could it live in POV SDL? Maybe. Maybe yes!
> 
> It involves taking a set of lines which could be of the form {x,y,d} where {x,y}
> is a unit vector and d is the distance of the line perpendicular to this vector
> from the origin. Typically d will run through integers -k to k for any given
> {x,y} and typically the various {x,y}'s will run through the vertices of a
> regular polygon. An n-gon, say. So there will be something like n*((2*k)+1)
> lines altogether.
> 
> Then follows a sort of complicated business of taking the signs of determinants
> of 3X3 subsets of the lines. Sign vectors are formed which encode how to make
> the tiling: take a step along this vector, then along that, and so on, until
> you reach a certain point: then make the polygon which is rooted at that point
> from some other subset of the original vectors.
> 
> Along the way various degenerate polygons arise with zero area and so there is
> some parsing to discard any of these.
> 
> It seems daunting to me because it was by an agony of effort I ever ported it
> from PostScript to Mathematica. Does POV even have determinants? I guess that's
> the easiest part, they could be programmed in if they're not there already in
> the SDL.
> 
the determinant is a mixed product of its row vectors (AxB).C . POV does 
have vcross() and vdot().
> If it was done right one would have a macro which accepted as input a list of
> lines of the form {x,y,d}. A different macro could make this list of lines I
> suppose. Just thinking about it makes me feel faint.
> 
> 
> 


-- 
the ultimate time-killer:
+a0.0 +am2 +r9

Johnny D

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