Rotations around world and local coordinate system

[mokopa]

Hi there

I hope someone can help me with this little prob.

I need to rotate my viewplatform (henceforth referred to as camera) around the world Y-axis, and at the same time, around the camera's own local X-axis. The camera should only have pitch and yaw capabilities, but the way I'm doing it now it also rolls because it rotates around the world x-axis. Here's a snippet:

           xgrpVP is a TransformGroup
           x3dVPcurrXform is a Transform3D
           translate is a Vector3D
           origin is a Vector3D
           x3dVPTemp... are Transform3D's
           incElev and incAzim are doubles

            xgrpVP.getTransform(x3dVPcurrXform);
            x3dVPcurrXform.get(mxVP);
            translate.set(mxVP.m03, mxVP.m13, mxVP.m23);
            x3dVPcurrXform.setTranslation(origin);
            x3dVPTemp2.rotX(0.0);
            x3dVPTemp1.rotY(0.0);
            x3dVPcurrXform.mul(x3dVPTemp1, x3dVPcurrXform);
            x3dVPcurrXform.mul(x3dVPTemp2, x3dVPcurrXform);
            x3dVPcurrXform.normalize();
            x3dVPTemp2.rotX(incElev);
            x3dVPTemp1.rotY(incAzim);
            x3dVPcurrXform.mul(x3dVPTemp1, x3dVPcurrXform);
            x3dVPcurrXform.mul(x3dVPTemp2, x3dVPcurrXform);
            x3dVPcurrXform.normalize();
            x3dVPcurrXform.setTranslation(translate);
            xgrpVP.setTransform(x3dVPcurrXform );

Q: How do I rotate my camera around the world's Y-axis, and at the same time, around the camera's own local X-axis?

Q: How do I obtain the lookat vector from the camera? I need it for picking purposes.

Thanks in advance

mokopa