local verlet = {}
verlet.step_time = 1 / 50
verlet.gravity = Vector3.new(0, -10, 0)

local char = game.Players.LocalPlayer.Character
local torso = char:WaitForChild("Torso")
local parts = {}
local render = game:GetService("RunService").RenderStepped

wait(2)

local point = {}
local link = {}
local rope = {}

local function ccw(A,B,C)
    return (C.y-A.y) * (B.x-A.x) > (B.y-A.y) * (C.x-A.x)
end

local function intersect(A,B,C,D)
    return ccw(A,C,D) ~= ccw(B,C,D) and ccw(A,B,C) ~= ccw(A,B,D)
end

local function vec2(v)
	return Vector2.new(v.x, v.z)
end

function point:step()
	if not self.fixed then
		local derivative = (self.position - self.last_position) * 0.95
		self.last_position = self.position
		self.position = self.position + derivative + (self.velocity * verlet.step_time ^ 2)
		--[[local torsoP = torso.CFrame * CFrame.new(-1, 0, 0.5)
		local torsoE = torso.CFrame * CFrame.new(1, 0, 0.5)
		local pointE = self.position + torso.CFrame.lookVector * 100
		local doIntersect = intersect(vec2(torsoP.p), vec2(torsoE.p), vec2(self.position), vec2(pointE))
		if not doIntersect then
			self.postition = self.position - torso.CFrame.lookVector * 10
		end]]
	end
end

function link:step()
	for i = 1, 1 do
		local distance = self.point1.position - self.point2.position
		local magnitude = distance.magnitude
		local differance = (self.length - magnitude) / magnitude
		local translation = ((self.point1.fixed or self.point2.fixed) and 1 or 0.6) * distance * differance
		if not self.point1.fixed then
			self.point1.position = self.point1.position + translation
		end
		if not self.point2.fixed then
			self.point2.position = self.point2.position - translation
		end
	end
end

function verlet.new(class, a, b, c)
	if class == "Point" then
		local new = {}
		setmetatable(new, {__index = point})
		new.class = class
		new.position = a or Vector3.new()
		new.last_position = new.position
		new.velocity = verlet.gravity
		new.fixed = false
		return new
	elseif class == "Link" then
		local new = {}
		setmetatable(new, {__index = link})
		new.class = class
		new.point1 = a
		new.point2 = b
		new.length = c or (a.position - b.position).magnitude
		return new
	elseif class == "Rope" then
		local new = {}
		setmetatable(new, {__index = link})
		new.class = class
		new.start_point = a
		new.finish_point = b
		new.points = {}
		new.links = {}
		local inc = (b - a) / 10
		for i = 0, 10 do
			table.insert(new.points, verlet.new("Point", a + (i * inc)))
		end
		for i = 2, #new.points do
			table.insert(new.links, verlet.new("Link", new.points[i - 1], new.points[i]))
		end
		return new
	end
end

local tris = {}
local triParts = {}

local function GetDiscoColor(hue)
 local section = hue % 1 * 3
 local secondary = 0.5 * math.pi * (section % 1)
 if section < 1 then
  return Color3.new(1, 1 - math.cos(secondary), 1 - math.sin(secondary))
 elseif section < 2 then
  return Color3.new(1 - math.sin(secondary), 1, 1 - math.cos(secondary))
 else
  return Color3.new(1 - math.cos(secondary), 1 - math.sin(secondary), 1)
 end
end

local function setupPart(part)
	part.Anchored = true
	part.FormFactor = 3
	part.CanCollide = false
	part.TopSurface = 10
	part.BottomSurface = 10
	part.LeftSurface = 10
	part.RightSurface = 10
	part.FrontSurface = 10
	part.BackSurface = 10
	part.Material = "Neon"
	local m = Instance.new("SpecialMesh", part)
	m.MeshType = "Wedge"
	m.Scale = Vector3.new(0.2, 1, 1)
	return part
end

local function CFrameFromTopBack(at, top, back)
	local right = top:Cross(back)
	return CFrame.new(at.x, at.y, at.z, right.x, top.x, back.x,  right.y, top.y, back.y, right.z, top.z, back.z)
end

local function drawTri(parent, a, b, c)
	local this = {}
	local mPart1 = table.remove(triParts, 1) or setupPart(Instance.new("Part"))
	local mPart2 = table.remove(triParts, 1) or setupPart(Instance.new("Part"))
	function this:Set(a, b, c)
		local ab, bc, ca = b-a, c-b, a-c
		local abm, bcm, cam = ab.magnitude, bc.magnitude, ca.magnitude
		local edg1 = math.abs(0.5 + ca:Dot(ab)/(abm*abm))
		local edg2 = math.abs(0.5 + ab:Dot(bc)/(bcm*bcm))
		local edg3 = math.abs(0.5 + bc:Dot(ca)/(cam*cam))
		if edg1 < edg2 then
			if edg1 >= edg3 then
				a, b, c = c, a, b
				ab, bc, ca = ca, ab, bc
				abm = cam
			end
		else
			if edg2 < edg3 then
				a, b, c = b, c, a
				ab, bc, ca = bc, ca, ab
				abm = bcm
			else
				a, b, c = c, a, b
				ab, bc, ca = ca, ab, bc
				abm = cam
			end
		end

		local len1 = -ca:Dot(ab)/abm
		local len2 = abm - len1
		local width = (ca + ab.unit*len1).magnitude

		local maincf = CFrameFromTopBack(a, ab:Cross(bc).unit, -ab.unit)

		if len1 > 0.2 then
			mPart1.Parent = parent
			mPart1.Size = Vector3.new(0.2, width, len1)
			mPart1.CFrame = maincf*CFrame.Angles(math.pi,0,math.pi/2)*CFrame.new(0,width/2,len1/2)
		else
			mPart1.Parent = nil
		end

		if len2 > 0.2 then
			mPart2.Parent = parent
			mPart2.Size = Vector3.new(0.2, width, len2)
			mPart2.CFrame = maincf*CFrame.Angles(math.pi,math.pi,-math.pi/2)*CFrame.new(0,width/2,-len1 - len2/2)
		else
			mPart2.Parent = nil
		end
	end
	function this:SetProperty(prop, value)
		mPart1[prop] = value
		mPart2[prop] = value
	end
	this:Set(a, b, c)
	function this:Destroy()
		mPart1:Destroy()
		mPart2:Destroy()
	end
	this.p1 = mPart1
	this.p2 = mPart2
	this.p1.BrickColor = BrickColor.new(GetDiscoColor(math.noise(0.5, 0.5, this.p1.CFrame.Y * 0.5 + time())))
	this.p2.BrickColor = BrickColor.new(GetDiscoColor(math.noise(0.5, 0.5, this.p2.CFrame.Y * 0.5 + time())))
	return this
end

function verlet.draw(object, id)
	if object.class == "Point" then
		local part = parts[id]
		part.BrickColor = BrickColor.new(1, 1, 1)
		part.Transparency = 0
		part.formFactor = 3
		part.Anchored = true
		part.CanCollide = false
		part.TopSurface = 0
		part.BottomSurface = 0
		part.Size = Vector3.new(0.35, 0.35, 0.35)
		part.Material = "Neon"
		part.CFrame = CFrame.new(object.position)
		part.Parent = torso
		return part
	elseif object.class == "Link" then
		local part = parts[id]
		local dist = (object.point1.position - object.point2.position).magnitude
		part.Size = Vector3.new(0.2, 0.2, dist)
		part.CFrame = CFrame.new(object.point1.position, object.point2.position) * CFrame.new(0, 0, dist * -0.5)
		part.Parent = torso
		return part
	end
end

function verlet.clear()
	for _, v in pairs(workspace:GetChildren()) do
		if v.Name == "Part" then
			v:Destroy()
		end
	end
end

local points = {}
local links = {}

for x = 0, 2 do
	points[x] = {}
	for y = 0, 3 do
		points[x][y] = verlet.new("Point", torso.Position + Vector3.new(x * 0.8 - 2, 2 - y * 0.8, 5 + y * 0.4))
		points[x][y].fixed = y == 0
	end
end

for x = 1, 2 do
	for y = 0, 3 do
		links[#links + 1] = verlet.new("Link", points[x][y], points[x - 1][y], 1 + y * 0.08)
	end
end

for x = 0, 2 do
	for y = 1, 3 do
		links[#links + 1] = verlet.new("Link", points[x][y], points[x][y - 1], 1.2 + y * 0.03)
	end
end

render:connect(function()
	for x = 0, 2 do
		for y = 0, 3 do
			if y == 0 then
				points[x][y].position = (torso.CFrame * CFrame.new(x * 1 - 1, 1, 0.5)).p
			else
				points[x][y]:step()
			end
		end
	end
	for i = 1, #links do
		links[i]:step()
	end
	for i = 1, #tris do
		triParts[#triParts + 1] = tris[i].p1
		triParts[#triParts + 1] = tris[i].p2
	end
	tris = {}
	for x = 1, 2 do
		for y = 1, 3 do
			tris[#tris + 1] = drawTri(torso, points[x - 1][y - 1].position, points[x - 1][y].position, points[x][y - 1].position)
			tris[#tris + 1] = drawTri(torso, points[x][y].position, points[x - 1][y].position, points[x][y - 1].position)
		end
	end
end)