Re: pfLightpoint alpha
John Rohlf (jrohlf++at++tubes)
Fri, 10 Mar 95 17:38:50 PST
>
> On Thu, 9 Mar 1995, Simon Bennett wrote:
>
> > 2000 - Performer doesn't do anything clever with lightpoint nodes. The
> > only way that I can see to do what you want is to create/destroy new
> > lightpoint nodes on the fly.
>
> I don't think that 1000 extra (invisible) light points are worth the expense
> of checking every light point to see if its alpha value is close to 0. (Via
> some PF_ALMOST_EQUAL function with a certain tolerance threshold). It takes
> about 4-5ms on an Indigo2 Extreme to display 5000 light points (all same size,
> but varying colors & alpha values). I was thinking about making each light
> point (a star in my case) be a different size, but I haven't gotten around to
> it yet. It would require a different light point node for every size, or for
> every point, which might be a serious drain on memory and cause performance
> loss. Any comment on how (or if it is worth it) to make varying or random
> sizes for about 5000 light points?
>
Changing pointsize often is expensive so pfGeoSets
discourage you from doing this by not providing a pointsize array.
However, I imagine you can get pretty decent-looking stars with
only a few different (<= 10) sizes so I would go ahead and use multiple
pfGeoSets. I don't think you need the extra functionality (and bugs 8-)
provided by pfLightPoints.
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on Mon Aug 10 1998 - 17:51:03 PDT