Material sciences could bring a solution: Transparent material that becomes opaque to bright light (something like gamma < 1, gain < 1) in the direction of the

Material sciences could bring a solution: Transparent material that becomes opaque to bright light (something like gamma < 1, gain < 1) in the direction of the light. So each point of the material is transparent or opaque depending on the viewing angle and respective directed light flow through it. I think such a material could be engineered.