-- | Helper to convert a 'CameraShift' to 'Vertex3' parametrised
-- by 'GLdouble'.
ctvf :: CameraShift -> Vertex3 GLdouble
ctvf (CameraShift x y z) = Vertex3 x y z
ctvf :: CameraShift -> Vertex3 GLdouble
ctvf (CameraShift x y z) = Vertex3 x y z
ctvf (CameraShift x y z) = Vertex3 x y z