[osg-users] Calculating Up Vector

[Cysneros, Nelson SPAWAR]

I'm having a problem trying to calculate the UP vector of a node as it
makes a 360 roll. 


I'm setting the camera viewpoint like this:

//Update View
osg::Vec3 eye( cameraX, cameraY, cameraZ);
osg::Vec3 center(nodeX,nodeY,nodeZ);
osg::Vec3 up(nodeX,nodeY,nodeZ); 
viewer->getCamera()->setViewMatrixAsLookAt(eye,center,up); 

Which works great in a geoCentric system. I can place a node anywhere on
the earth and it will be right side up.

Now the node wants to make a 360 roll and we want the camera to roll
with it.  Not sure how to calculate the UP vector in this case.

I tried something like this:

osg::Matrix rotX, rotY, rotZ, transXYZ;
rotX.makeRotate(myNode->getXRotation(), osg::Vec3(1,0,0));
rotY.makeRotate(myNode->getYRotation(), osg::Vec3(0,1,0));
rotZ.makeRotate(myNode->getZRotation(), osg::Vec3(0,0,1));
up = eye ^ center;//cross product
osg::Vec3 up2; 
up2   = up * rotZ * rotY * rotX;
viewer->getCamera()->setViewMatrixAsLookAt(eye,center,up2); 


Does not work...  Any suggestions?

Thanks