FindANgles

local deg = math.deg
local atan = math.atan
local pi = math.pi
local pi2 = pi * 2

function findAngle( x1, y1, x2, y2 )

    if not x1 or not y1 or not x2 or not y2 then
        return
    end

    local distance = { x = x2 - x1, y = y2 - y1 }

    if distance then

        local angleBetween = atan( distance.y / distance.x )

        if ( x1 < x2 ) then
            angleBetween = angleBetween + rad( 90 )
        else
            angleBetween = angleBetween + rad( 270 )
        end

        if angleBetween == pi or angleBetween == pi2 then
            angleBetween = angleBetween - rad( 180 )
        end

        angleBetween = deg( angleBetween )

        return angleBetween

    end

    return nil

end