From: DAVE HOATSON (HOATSO++at++aaicorp.com)
Date: 05/09/2000 06:50:22
The textures used on the billboards can be rendered offline, so they can be made highly realistic, with high tesselation, complex lighting, phong shading, bump-mapping, etc., so the final appearance could be very good.
Subject: 15000 spheres
> Vieri Di Paola wrote:
> >
> > anywhere on the Internet that explains an algorithm for efficient >15000
> > spheres drawing. I suppose "hidden" spheres (according to a
> > certain view angle) shouldn't be drawn, etc... Does IRIS-performer provide
> > an efficient algorithm for the "spatial" model representation of
> > molecules?
> > Can anybody tell me exactly where to look at in the "performer" source
> > code examples?
> > Or can anybody tell me where (if) I can find a simple, to-the-point
> > tutorial that handles this rendering problem?
> >
>
> I happen to be working with PDB files and molecular models at
> the moment.
>
> Displaying 15,000 or more spheres at the same time is too much
> for an O2 and a bit sluggish (couple of seconds redraw time)
> even for our mighty Onyx.
>
> If you only want to look at a few thousand atoms at a time,
> you'll need to add some hierarchy to the scene graph so that
> Performer can clip the spheres more efficiently. I think that
> PDB files have pretty good spatial coherence, in that atoms
> are listed next to the atoms they bond with, so you can cluster
> them together into groups that can be culled.
>
> The solution I used was to draw antialiased points. Set the
> point size to 8, enable antialiasing in your graphics state,
> and you get nice little circles. Obviously they are not lit,
> so I added fog to the gstate for a depth cueing effect. Looks
> good, especially in stereo.
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