Re: smooth globe clarification

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Shuxxx!! (engp7534++at++leonis.nus.sg)
Tue, 14 Oct 1997 09:41:38 +0800 (SST)

On Mon, 13 Oct 1997, Julie Cardosi wrote:

> Let me clarify my previous message:
>
> > I have what's probably a fairly simple problem.
> >
> > I'm rendering a globe in a Performer application and it looks faceted
> > (like Epcot at Disney). If I view the same globe using perfly, it looks
> > smooth (as it should). Does anyone know what I'm missing??
>
>
> This globe was generated with MultiGen and Gouraud shadding is being applied
> when rendering with Performer. The problem is that the normals for the
> triangles (of the globe) are being used instead of the normals for the vertices
> of the triangles. Any ideas??
>

Just a query: Do you have the individual vertex normals? If you have,
you can set the normals on a per-vertex basis (using gset->setAttributes
(PFGS_PER_VERTEX, ...)) . As you said, your Performer application is
probably using PFGS_PER_PRIM (I'm assuming that MultiGen creates a
list of indept triangles here) -- hence the Epcot look for the globe.

If you don't have the list of individual vertex normals, you may either
calculate it out bruteforce (yuck) or extract it from perfly. Have a look
at the source code of the database loading for MultiGen files.

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