Hello Stephane,
Stephane Routelous wrote:
> Hi,
>
> I'm trying to implement a "window select" (meaning that the 3d objects
> are selected when the user drag a rectangle in the window).
> for that, I'm projecting my object to the screen with multFullMatrixPnt
> and check if the projected object (in screencoord) intersect the
> selection rectangle.
quick question:
> <pseudo-code>
> void WindowSelect(int x1,int y1,int x2.int y2)
> {
> //x1,y1 and x2,y2 are the 2d mouse position on the select
> rectangle in screen coordinates
> ViewportPtr vp = getWindow()->getPort(0);
> OSG::Matrix wtos;
> getCamera()->getWorldToScreen(wtos,*vp);
> int w = vp->getWidth();
> int h = vp->getHeight();
> foreach ( obj3d o in objList )
> {
> SphereVolume sph = o->GetSphereVolume();
^^^^^^^^^^^^^^^^^^^^^^
is this volume in world coordinates ? If not you are missing the local
to world coordinate transformation. You can get the matrix for that from
a Node with getToWorld.
> Pnt3f center = sph.GetCenter(); //the center of the
> sphere is on the center of the screen
> Pnt3f projectedCenter ;
> wtos.multFullMatrixPnt( center, projectedCenter );
> //map the center to screen coordinates
> //as the sphere center in in the middle of the screen, I
> expect projectedCenter[0] = 0 and projectedCenter[1] = 0
> //but I got [0,1.66,0.93]
> //as explained in
> http://www.mail-archive.com/[email protected]/msg02156.html
>
>
> float curXC = w*(projectedCenter [0]+1)/2.0f;
> float curYC = h*(projectedCenter [1]+1)/2.0f;
> if ( IsIn(curXC,curYC,x1,y1,x2,y2) )
> {
> obj3d->Select();
> }
> }
> }
>
> </pseudocode>
Hope it helps,
Carsten
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