function GetBackFacing takes unit Hero , unit Target , real xAng returns boolean
local real dx = GetUnitX(Target) - GetUnitX(Hero)
local real dy = GetUnitY(Target) - GetUnitY(Hero)
local real cAng = 57.29583*Atan2(dy,dx) - GetUnitFacing(Hero)
local real fAng = GetUnitFacing(Hero) - GetUnitFacing(Target)
set cAng = SquareRoot(cAng*cAng)
set fAng = SquareRoot(fAng*fAng)
return cAng<xAng and fAng<xAng
endfunction

local unit u = GetTriggerUni()
    local unit ut = GetEnumUnit()
    local real x1 = GetWidgetX(u)
    local real y1 = GetWidgetY(u)
    local real x2 = GetWidgetX(ut)
    local real y2 = GetWidgetY(ut)
    local real a = 57.295827 * Atan2(y2-y1,x2-x1) 
    if a>= 20 and a <= -20 then
    // твои действия
    endif
    u =null
    ut = null