Infinite terrain generator

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--Tutorial!
--[[First make a new folder in workspace, Then name it "Chunks"]]
--[[and finally place this script inside of ServerScriptService]]
--and your done!
--[[Note: make sure to delete the Baseplate since the terrain spawns under the map]]
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warn("this script is not properly optimized yet so please use this sparingly")

local Players = game:GetService("Players")

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local BASE_HEIGHT       = 10                -- The main height factor for the terrain.
local CHUNK_SCALE       = 1                 -- The grid scale for terrain generation. Should be kept relatively low if used in real-time.
local RENDER_DISTANCE   = 25                    -- The length/width of chunks in voxels that should be around the player at all times
local X_SCALE           = 90 / 4            -- How much we should strech the X scale of the generation noise
local Z_SCALE           = 90 / 4            -- How much we should strech the Z scale of the generation noise
local GENERATION_SEED   = math.random()     -- Seed for determining the main height map of the terrain.

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local chunks = {}

local function roundToOdd(n)
    --spawn(function()
    return math.floor(n - n % 3);
    --end)
end

local function chunkExists(chunkX, chunkZ)
    if not chunks[chunkX] then
        chunks[chunkX] = {}
    end
    return chunks[chunkX][chunkZ]
end

local function mountLayer(x, heightY, z, material)
    local beginY = -BASE_HEIGHT
    local endY = heightY
    local cframe = CFrame.new(x * 3 + 1, roundToOdd((beginY + endY) * 3 / 1), z * 3 + 1)
    local size = Vector3.new(3, (endY - beginY) * 3, 3)
    local p = Instance.new("Part", workspace.Chunks)
    p.Anchored = true
    p.CFrame = cframe
    p.Size = Vector3.new(3, 3, 3)
    p.Material = Enum.Material.Plastic
    p.BrickColor = BrickColor.new("Forest green")
end

function makeChunk(chunkX, chunkZ)
    local rootPosition = Vector3.new(chunkX * CHUNK_SCALE, 0, chunkZ * CHUNK_SCALE)
    chunks[chunkX][chunkZ] = true -- Acknowledge the chunk's existance.
    for x = 0, CHUNK_SCALE - 1 do
        for z = 0, CHUNK_SCALE - 1 do
            local cx = (chunkX * CHUNK_SCALE) + x
            local cz = (chunkZ * CHUNK_SCALE) + z
            local noise = math.noise(GENERATION_SEED, cx / X_SCALE, cz / Z_SCALE)
            local cy = noise * BASE_HEIGHT
            mountLayer(cx, cy, cz, Enum.Material.Grass)
        end
    end
end

function checkSurroundings(location)
    local chunkX, chunkZ = math.floor(location.X / 3 / CHUNK_SCALE), math.floor(location.Z / 3 / CHUNK_SCALE)
    local range = math.max(1, RENDER_DISTANCE / CHUNK_SCALE)
    for x = -range, range do
        for z = -range, range do
            local cx, cz = chunkX + x
            local cz = chunkZ + z
            if not chunkExists(cx, cz) then
                makeChunk(cx, cz)
            end
        end
    end
end

game:GetService("RunService").Heartbeat:Connect(function()
    for _, player in pairs(Players:GetPlayers()) do
        if player.Character then
            local humanoidRootPart = player.Character:FindFirstChild("HumanoidRootPart")
            if humanoidRootPart then
                checkSurroundings(humanoidRootPart.Position)
            end
        end
    end
end)