[Fluxus] avoiding glitches and sphere normals

[gabor papp]

> parts. I suspect it's due to the sphere being a single primitive. I also had
> that issue on the flat plane and there it was solved by chopping up the
> plane into separate planes. Clearly for a sphere doing that would be a lot
> harder to do. One of the things I fear there is lighting. A single sphere
it's not that difficult. you just copy the points and normals and build 
your triangles from the data. something like this:

(clear)

(define s (build-sphere 10 10))

; rebuild the sphere from triangles
(with-primitive s
     (poly-for-each-triangle
         (lambda (indices)
             (let ([tri (build-polygons 3 'triangle-list)]
                   [points (for/list ([i '(2 1 0)])
                                (pdata-ref "p" (list-ref indices i)))]
                   [normals (for/list ([i '(2 1 0)])
                                (pdata-ref "n" (list-ref indices i)))])
                 (with-primitive tri
                   (pdata-index-map!
                     (lambda (i p)
                         (list-ref points i))
                     "p")
                   (pdata-index-map!
                     (lambda (i n)
                         (list-ref normals i))
                     "n"))))))

; destroy original
(destroy s)


and congrats for your village project. it evolved very nicely in the 
last months.

best,
gabor