function math.sign(x)
	if x<0 then
		return -1
	elseif x>0 then
		return 1
	else
		return 0
	end
end

function math.round(x)
	return math.floor(x+0.5)
end

function vector(x, y)
	return {x = x, y = y}
end

function getVectorValue(vector)
	return math.sqrt(vector.x ^ 2 + vector.y ^ 2)
end

function getAngleFromVector(vector)
	local reduce = 0
	if vector.x < 0 then
		reduce = math.rad(180)
	end
	return math.atan(vector.y/vector.x) - reduce
end