  In this paper, we investigate the photometric variability of magnetic O-type
stars. Such stars possess oblique, predominantly dipolar magnetic fields that
confine their winds roughly axisymmetrically about the magnetic equator, thus
forming a magnetosphere. We interpret their photometric variability as
phase-dependent magnetospheric occultations. For massive star winds dominated
by electron scattering opacity in the optical and NIR, we can compute synthetic
light curves from simply knowing the magnetosphere's mass density distribution.
We exploit the newly-developed Analytical Dynamical Magnetosphere model (ADM)
in order to obtain the predicted circumstellar density structures of magnetic
O-type stars. The simplicity in our light curve synthesis model allows us to
readily conduct a parameter space study. For validation purposes, we first
apply our algorithm to HD 191612, the prototypical Of?p star. Next, we attempt
to model the photometric variability of the Of?p-type stars identified in the
Magellanic Clouds using OGLE photometry. We evaluate the compatibility of the
ADM predictions with the observed photometric variations, and discuss the
magnetic field properties that are implied by our modelling.
