Re: pfDrawBin and pfDraw

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Mario Veraart (rioj7++at++fel.tno.nl)
Tue, 19 May 1998 20:06:27 +0200 (MET DST)

Remi Arnaud wrote:
> Mario Veraart wrote:
> >
> > I would like to implement a multipass algorithm and for this I have to
> > draw the geometry in a certain order. For this I want to use the bins
> > of a pfChannel. As an experiment I replaced the call of pfDraw with
> > the following two lines
> >
> > pfDrawBin(PFSORT_OPAQUE_BIN);
> > pfDrawBin(PFSORT_TRANSP_BIN);
> >
> > The result is that nothing gets drawn, only the sky and ground are
> > drawn. If I set the bin number explicitly then only the geometry in
> > the transparent bin is visible.
> >
> > My questions
> >
> > 1: What is pfDraw() doing besides calling pfDrawBin() in the order
> > specified with setBinOrder()?
>
> pfDraw() draws everything that do not fall in a Bin, and then draw
> the bins.

But how can it be explained that if I set the bin number explicitly
and call pfDrawBin for every bin I see only the geometry of the
transparent bin? Is this not equivalent to a call to pfDraw()?

> Since 2.2 you can use pfDrawBin(-1) to draw the objects that are
> not in a bin. Note, you have to use CULL separated from DRAW or
> CULL_DL_DRAW for the object not to be rendered immediately.
>
> > 2: The programmers guide tells that it is possible to add more bins
> > but does not tell you how. Is a call to setBinOrder() with an unkown
> > bin number enough to create a new bin for this pfChannel?
>
> pfGeoSet::setDrawBin(b) will tell Performer to draw the geoset in
> the bin b. setBinOrder(b,order) will create the bin b and tell pfDraw
> in wich order to draw the bins.
> Note that each geoset has to have its own geostate for the bin mechanism
> to work. See 2.2 pfChannel man pages.

Is this also true for Performer 2.0? In the test program I used a few
simple flight models. So it could be that they share the geostate.

> > 3: If I have to rely on pfDraw() to draw the geometry how can I set up
> > the right GL calls to implement the wanted multipass algorithm?
> Since 2.2 you can use pfDrawScene(). pfDraw() may call an internal
> multipass (for pfLightSource).

> > Any help to solve this problem is appreciated.
> > I use Performer 2.0 on a REII. If Performer 2.2 is better on the point
> > of using bins I will have to upgrade.
>
> A lot better, please upgrade.

Mario Veraart
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