Thanks Carsten,
i've tried it with points now (OSG::Pnt3f)
but something is still strange.... values are still negatives and too big...
any other suggestion?
heres the code im using...
OSG::Matrix m;
getCamera()->getWorldToScreen( m, *(_viewport) ); // get the world to
screen matrix to matrix 'm'
OSG::Pnt3f spoint; // destination point
m.multMatrixPnt( _start3d, spoint ); // transform world point (_start3d)
to screen point
printf( "POINT = ( %f %f %f )\n", _start3d.x(), _start3d.y(),
_start3d.z() ); // print world point
printf( "NEW MATRIXPNT (COLUMN) MAPPED POINT = ( %f %f %f )\n",
spoint.x(), spoint.y(), spoint.z() ); // print result
m.multPntMatrix( _start3d, spoint ); // try with a row-format point
printf( "NEW PNTMATRIX (ROW) MAPPED POINT = ( %f %f %f )\n", spoint.x(),
spoint.y(), spoint.z() );
Thanks!!!!
On Tue, Jun 3, 2008 at 5:35 PM, Carsten Neumann <[EMAIL PROTECTED]>
wrote:
> Hello Pablo,
>
> Pablo Carneiro Elias wrote:
> > Hi all.. I have some trouble trying to map points from world to
> > screen... I've found a function within the camera matrix that should
> > give me the world to screen matrix...
> >
> > virtual void getWorldToScreen (Matrix &result, const Viewport&
> port);
> >
> > So I took my camera from SimpleSceneManager (which is a
> > PerspectiveCamera), and called the getWorldToScreen acquiring a matrix...
> >
> > then I tried to multiply a world point in order to get a screen point
> > like this:
> >
> > OSG::Matrix m;
> >
> > getCamera()->getWorldToScreen( m, *(_viewport.getCPtr()) ); // _viewport
> > is a ViewportPtr
> >
> > OSG::Vec3f result;
> > m.multMatrixVec( _start3d, result ); // _start3d is my 3d world point
>
> OpenSG makes a distinction between points (locations in space) and
> vectors (basically directions), therefore you need to use Pnt3f and
> multMatrixPnt.
> The (3 element) vectors are translation invariant as they are considered
> to have w = 0 in homogeneous coordinates, while 3 element points are
> treated as if w = 1.
> See also Source/Base/Base/Base.dox \section BaseVectors for more
> information on the distinction between points and vectors.
>
> Hope it helps,
> Carsten
>
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