[osg-users] Polytope from view frustum

Trajce Nikolov NICK trajce.nikolov.nick at gmail.com
Wed Nov 2 03:04:07 PDT 2016

Thanks Robert

On Wed, Nov 2, 2016 at 9:43 AM, Robert Osfield <robert.osfield at gmail.com>

> On 1 November 2016 at 21:45, Trajce Nikolov NICK
> <trajce.nikolov.nick at gmail.com> wrote:
> > Hi Community,
> >
> > anyone knowing how to achieve this and with will to share?
> >
> > Thanks a bunch as always !!
> Have a look at the API's...
> First one to look at is osg::Polytope, create one of these with a unit
> frustum.  This will be in clip space.
> Next step transform this Polytope by the projection matrix using the
> transformProvidingInverse() method (to transform a plane you multiple
> it by the inverse of that matrix), so in our case the projection
> matrix transform from eye space into clip space which is the inverse
> of the transform we intend, but thanks to the way that planes are
> transformed we can just use the projection matrix directly as long as
> we use the transformProvidingInverse().  See the src/osg/CullStack.cpp
> to see this in action.
> Then transform into object coordinates using the same method by
> providing the view and model matrices.
> Robert.
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trajce nikolov nick
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