points = nil

function getPoints()
	return points
end

function init(points_)
	points = points_
	pointDistances = {}
	local distAd2Sum = 0
	local lastP = nil
	for pointIdx, p in ipairs(points) do
		if lastP ~= nil then
			local distAd2 = lastP:distAd2(p)
			pointDistances[pointIdx-1] = distAd2
			distAd2Sum = distAd2Sum + distAd2
		end
		lastP = p
	end
	for pointIdx, distAd2 in ipairs(pointDistances) do
		pointDistances[pointIdx] = distAd2 / distAd2Sum
	end
end

function eval(t)
	if points == nil or #points == 0 then
		return nil
	end

	-- find the closest points for the given t parameter
	local pointIdx = 1
	while pointIdx <= #pointDistances and t - pointDistances[pointIdx] >= 0 do
		t = t - pointDistances[pointIdx]
		pointIdx = pointIdx + 1
	end
	if pointIdx == #pointDistances + 1 then
		return points[pointIdx]
	end
	
	-- normalize the t parameter to only mean the distance between the two closest points
	t = t / pointDistances[pointIdx]
	return points[pointIdx]:interpolate(points[pointIdx+1], t)
end