![Big Grin :D](./images/smilies/biggrin.png)
I have tried to work this out myself, but just MASSIVELY confused myself in the process. I want to calculate the angle of incidence upon a player shooting a wall. I am not worried whether this is a 2D or 3D angle, however must be calculated from the wall.
Picture below to explain a bit better.
![Image](http://i.gyazo.com/59fdb000da368e91a5c3c852801b104a.png)