[fluxus] (build-polygons) and normals

[Dave Griffiths]

> Hi all,
>
> I've been playing around with (build-polygons) this afternoon, and have
> made a nice tetrahedron (attached), practice for making more
> interestingahedra.
>
> But, it is about 1/4 the brightness of a cube of the same nominal
> colour, and activating (hint-normals) shows that it has 1 normal per
> vertex, whereas the cube has 3, and the tetrahedron's normal is rather
> short.
>
> I am using (recalc-normals) to create the normals, because I don't know
> any other way.  How would I specify the normals properly?

couple of things here, one the recalc normals generates the geometric
normals, then goes ahead and automatically smoothes them - so you're
seeing three coincident normals there. the other thing is that it appears
the normal isn't renormalised after smoothing, which is a dave-bug :)

I'll add a switch to recalc-normals to disable the smoothing, and fix the
renomalisation bug.

cheers!

dave