[ZeLpH_MyStiK]

if (playertouchsme) ?
or
loop through every player using distance formula to check if they're within a distance.
Distance formula: D=((x1-x2)^2 + (y1-y2)^2)^(1/2)
where (x1,y1),(x2,y2) are the coordinates of the two objects (this case npc and player)