onwall

[Lash]

what is onwall detection and how do u do it?

[FxChiP]

Depends on how you're using it.

[KJS]

if your making a moving npc you would do something like

if(!onwall(x-1,y)&&dir=1){
x--;
}

this basically says if there is no wall to the left of him and he is faced left then he can go left...