Optical depth at infinity for 1 GeV photons interacting with non-thermal hard X-rays (10−100 keV). Gamma rays are injected on the axis of the accretion disk at an altitude z (r ≡ 0) and with an inclination ψ = 30°. The corona X-ray density is homogeneous and isotropic in a spherical region of radius R_c = 6 r_g (solid line), 60 r_g (dashed line) and 600 r_g (dotted-dashed line) around the compact object, here a 20 M_⊙ black hole (6 r_g = 1.8 × 10⁷ cm). Outside, the X-ray flux is radial. The total power injected in hard X-rays is L_c = 5 × 10³⁶ erg s^-1. The gamma-ray optical depth from the disk only is shown with the red dashed line for comparison.