From Frederic Bouvier, "here is my proposal. It is supposed to be used like this :

osg::Camera* c = createCamera();
   c->attach( osg::Camera::COLOR_BUFFER0, texture3d, 0,
osg::Camera::FACE_CONTROLLED_BY_GEOMETRY_SHADER );

it works also for cubemap textures and 2d texture arrays
"

src/osg/Camera.cpp

@@ -16,6 +16,8 @@
 
 using namespace osg;
 
+const unsigned int Camera::FACE_CONTROLLED_BY_GEOMETRY_SHADER = 0xffffffff;
+
 Camera::Camera():
     _view(0),
     _allowEventFocus(true),