Fresnel specular?

Mr Whippy

When rendering with energy conservation and spec/gloss maps is it sensible to apply a falloff to the specular elements?

I've just been tinkering with some shaders for asphalt/road type surfaces and no matter what combination of spec/gloss values I use, as soon as I change the time of day so the sun angle changes vs the camera of the driver on the road, the realism of the material seems to suffer...


I'm attributing this to a lack of falloff but I'm not sure.

I know the renderer in question isn't using any falloff on specular (legacy thing).


Is it common to see falloff on the specular in modern game engines?
Is it considered generally important to operate on ALL specular responding materials, or too subtle to be bothered with except for specific shaders?


Any advice on this would be really useful so I can make sure I make my shader properly hehe.


Cheers

Dave

Ace-Angel

The general rule is; Everything has Fresnel: http://filmicgames.com/archives/557

Mr Whippy

Ah, great reference as usual from Filmic Games, thanks!

So I assume in HDR, energy conserving, real value renderers these days then people are providing IOR/fresnel parameters for all materials, or using a reasonable default across the board? Especially on materials where you are likely to see them from many angles.


I know technically ambient lighting is an approximation of all the point lights from all around the object, so fresnel must still have an impact on how the ambient light calculation is conducted too?
I'll have to check up now to see how ambient lighting should be done while using energy conserving spec/diffuse and fresnel parameters!



Thanks

Dave