Re: My own billboard?
Mario Veraart (rioj7++at++fel.tno.nl)
Thu, 15 Jan 1998 12:50:59 +0100 (MET)
Brad Colbert wrote:
>
> On Jan 14, 1:50pm, Mario Veraart wrote:
> > Subject: Re: My own billboard?
> > >
> > > Hey folks,
> > >
> > > I need to implement my own "Billboard" so that I may articulate the
> > > geometry that I am "Billboarding".
> > >
> > > This geometry will be attached below a couple pfDCS's so it's coordinate
> > > system will be a bit different than the world coordinate system.
> > >
> > > O (pfScene)
> > > / \
> > > / \
> > > / O-----(pfDCS:myBillboard)
> > > / (pfDCS)
> > > /
> > > (eye)
> > >
> > > My problem is how do I come up with the angles in myBillboard
> coordinates
> > > that will make it face my eye?
> > >
> > > Any examples would be great.
> >
> > You dont need to know this. Performer will calculate the angle needed
> > for an axis billboard or a point billboard. You just model that the
> > geometry of the billboard is visible looking from a point on the
> > positive y-axis towards the origin.
> >
>
> Are you referring to the pfBillboard? If so I am unable to use this since
> the model you give it is contained in a pfGeode. I need something more
> complex so that I may manipulate pfDCS's contained in the billboarded
> geometry.
What you then need is to enable/disable a pfSprite in the draw callbacks of the
base node of the geometry. You have point and axis pfSprites.
A point about pfSprites I have found out in performer 2.0 is that if a
geoset contains more than the PFSPRITE_MATRIX_THRESHOLD the geometry
disappears. Is this a bug? Because if I let performer transform the
geometry it all goes well.
Mario
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on Mon Aug 10 1998 - 17:56:33 PDT