Quote - Jon,

Absolutely - you could probably fix a lot of scenes by putting fresnel on the lights.

Since we've discovered that the diffuse light is inverse fresnel (i.e. it gets brighter towards the camera and darker away) then fresnel on that would improve things.

And so if you want fresnel on the diffuse (to cancel the inverse fresnel that isn't supposed to be there) and also fresnel on the specular (because its missing) then just stick it on the light intensity.

Of course, if you want to control the fresnel and anti-inverse fresnel separately, then you should put one edge blend on the diffuse and another on the specular.

Either way, I bet this would give you a lot more control that could be put to good use.

However, a word of caution. If you are using materials that already properly include fresnel on their specular response (like any of my shiny materials or my new skin shader) then the addition of fresnel on the light itself will accidentally square the effect and produce undesirable results.

 

So much info...  Fresnel cancels inverse fresnel, does it have to be increased then I wonder...