RE: [openvrml-develop] getting coordinates from ViewPoint- and Sound-Nodes

[S. K. B. <bo...@pa...>]

> -----Original Message-----
> From: ope...@li...
> [mailto:ope...@li...]On Behalf Of -oli-
> Sent: Wednesday, April 10, 2002 8:46 PM
> To: ope...@li...
> Subject: [openvrml-develop] getting coordinates from ViewPoint- and
> Sound-Nodes

> (1) How can I get the coordinates of the actual ViewPoint, i.e. including
> the user navigation transformations, in the VRML-world coordinate system
> (_not_ the OpenGL coordinate system)?
> I have found some code concerning this in VrmlScene.render(). But
> how can I
> get the position out of the modelview-matrices used here? After a
> MV.getTransform(pos,...) the values in pos don't change even if I
> turn the
> scene around the viewer (or the viewer around the scene, which
> probably is
> more correctly). I also need some information (e.g. view-up-vector) about
> the ViewPoint's orientation.

You go through the code "NodeBillboard::billboard_to_matrix(...)" or
"NodeLOD::render(..)". Here you will find how to get viewer position w.r.t.
local coordinate system. For your case don't inverse it.

>
> (2) How can I get the coordinates of a Sound node in the VRML-world
> coordinate system?
> It seems to have something to do with the rc.getMatrix() method,
> but how do
> I get the position out of the matrix? Can I multiply the matrix with the
> position field of the Sound node?

Definitely yes.

Thanks,

Bose