I am using deferred rendering so my pointlights are modeled by sphere geometry. Suppose I place my pointlight so that it is tangent to a wall. Of course the wall is not lit. Now say I move the point light a little closer to the wall. A section of the pointlight sphere intersects the wall, and that region is lit. The problem to me is that this creates an unnatural lighting discontinuity between the region that intersects the sphere (and is lit), and the region that does not.
Is there a way people go about fixing this? The obvious way would be to make my sphere pointlights cover the whole screen, but that isn't practical. So I'm wondering if there are some tricks people do for this.