I've noticed that when driving at night, when the road surface is dry, my headlights appear to illuminate much further than when the road surface is wet. I presume that this is due to the differences in how my headlights is being reflected under wet and dry conditions.
In dry conditions, my headlight will reflect in a diffuse way, producing producing enough scatter to allow me to see the texture of the road for quite a long distance. In the wet however, the thin layer of water over the road surface, combined with the shallow angle of incidence, causes the light from my headlights to be reflected in a specular way and not back scattered to me.
Thinking about this, I realised that I can't remember ever having seen this effect being reproduced in a game.
Has this wet/dry effect been implemented in any game?
- If so, what is the name of the technique used to produce the effect?
- If not, could this effect be produced without ray-tracing?