ROBLOX DesiredAngle points with mouse

-- Expects character to already be there (does not check for nil or wait for character)
-- Needs Animate script removed
local p = Game.Players.LocalPlayer
local m = p:GetMouse()
local joint = p.Character.Torso['Right Shoulder'];

function AngleBetween(v1, v2)
    local d = v1:Dot(v2);
    local angle = d/(v1.magnitude * v2.magnitude)
    return math.acos(angle);
end

m.Move:connect(function()
    local Omega = (m.hit.p - p.Character.Torso.Position).unit;
    local Omega_c = Vector3.new(Omega.X, Omega.Y,0);
    local Theta = AngleBetween(Vector3.new(0,-1,0), Omega_c);
    joint.DesiredAngle = Theta;
    print(math.deg(Theta));
end)