What's the difference between 0 and (1 << 0)?// I use this ISceneNode ID to indicate a scene node that is
// not pickable by getSceneNodeAndCollisionPointFromRay()
ID_IsNotPickable = 0,
// I use this flag in ISceneNode IDs to indicate that the
// scene node can be picked by ray selection.
IDFlag_IsPickable = 1 << 0,
(I read from MSDN Document that the value of a left-shift expression x << y is x * 2y.
So 1 << 0 is 1 * 2(0) = 1 * 0 = 0. Did I misunderstand?)