vector math as a lua object

vector.lua

local vector = {x,y,z}
vector.__index = vector
vector.__add = function(lhs, rhs)
	if rhs == nil then return lhs end
	local _n = vector(0,0,0)
	if type(rhs) == "number" then rhs = vector(rhs,rhs,rhs) end
	_n.x = lhs.x + rhs.x
	_n.y = lhs.y + rhs.y
	_n.z = lhs.z + rhs.z
	return _n
end
vector.__sub = function(lhs, rhs)
	if rhs == nil then return lhs end
	local _n = vector(0,0,0)
	if type(rhs) == "number" then rhs = vector(rhs,rhs,rhs) end
	_n.x = lhs.x - rhs.x
	_n.y = lhs.y - rhs.y
	_n.z = lhs.z - rhs.z
	return _n
end
vector.__mul = function(lhs, rhs)
	if rhs == nil then return lhs end
	local _n = vector(0,0,0)
	if type(rhs) == "number" then rhs = vector(rhs,rhs,rhs) end
	_n.x = lhs.x * rhs.x
	_n.y = lhs.y * rhs.y
	_n.z = lhs.z * rhs.z
	return _n
end
vector.__div = function(lhs, rhs)
	if rhs == nil then return lhs end
	local _n = vector(0,0,0)
	if type(rhs) == "number" then rhs = vector(rhs,rhs,rhs) end
	_n.x = lhs.x / rhs.x
	_n.y = lhs.y / rhs.y
	_n.z = lhs.z / rhs.z
	return _n
end

setmetatable(vector, {
	__call = function(cls, ...)
		return cls.new(...)
	end
})
function vector.new(x,y,z)
	self = setmetatable({}, vector)
	self.x = x or 0
	self.y = y or 0
	self.z = z or 0
	return self
end

function vector:dist(target)
	return math.sqrt(math.pow(self.x-target.x,2) + math.pow(self.y-target.y,2))
end

function vector:copy()
	return vector(self.x, self.y, self.z)
end

function vector:length()
	return math.sqrt(self.x*self.x + self.y*self.y + self.z*self.z)
end

function vector:normalize()
	local len = self:length()
	self.x = self.x/len
	self.y = self.y/len
	self.z = self.z/len
end

function rvec()
	local angle = math.rad(math.random(360))
	local vec = vector(math.cos(angle), math.sin(angle), 0)
	return vec
end


--- port of the processing map function
function map(v, a1, a2, b1, b2)
	return b1 + (b2-b1) * ((v-a1) / (a2 - a1))
end

return vector