In my real time ray tracer, I shoot primary rays from the eye, and at hit points, I trace to a single light source to determine if the object is shadowed or lit.
Pretty straightforward stuff so far. However I have recently added perfect mirrors to my scene. The reflections work just fine.
However, the shadow calculation breaks down!
A shadowed point could still be lit by the light source via a mirror.
Is there an easy way to handle shadow rays towards bounced light?
NOTE: I am not talking about the projection visible in the mirror surface: this shows shadowed and lit objects. But the directly visible scene itself, there are more shadowed objects than there should be, as some of the scene is lit via a mirror.