local chunks = {}
local player = game.Players.LocalPlayer
local char = player.Character
local torso = char:WaitForChild("Torso")

local baseHeight = 10 -- The main height factor for the terrain.
local chunkScale = 40 -- The grid scale for terrain generation. Should be kept relatively low if used in real-time.
local renderDist = 1000 -- The length/width of chunks in voxels that should be around the player at all times
local xScale = 50 -- How much we should strech the X scale of the generation noise
local zScale = 50 -- How much we should strech the Z scale of the generation noise

local generationSeed = math.random() -- Seed for determining the main height map of the terrain.
local mountainSeed = math.random() -- Seed for determining if we should make mountains.

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

function mountLayer(x,heightY,z,material)
    local x = math.floor(x/4)
    local z = math.floor(z/4)
    for y = -baseHeight,heightY do
        workspace.Terrain:SetCell(x,y,z,material,0,0)
    end
end

function makeChunk(chunkX,chunkZ)
    local rootPos = Vector3.new(chunkX*chunkScale,0,chunkZ*chunkScale)
    chunks[chunkX][chunkZ] = true -- Acknowledge the chunk's existance.
    for x = 0,chunkScale-1 do
        for z = 0,chunkScale-1 do
            local cx = (chunkX*chunkScale) + x
            local cz = (chunkZ*chunkScale) + z
            local noise = math.noise(generationSeed,cx/xScale,cz/zScale)
            local material = noise < 0 and 1 or 4
            local cy = noise*baseHeight*material
            mountLayer(cx,cy,cz,material)
        end
    end
end

while true do
    local chunkX,chunkZ = math.floor(torso.Position.X/chunkScale),math.floor(torso.Position.Z/chunkScale)
    local range = math.max(1,renderDist/chunkScale)
    for x = -range,range do
        for z = -range,range do
            if not (x == 0 and z == 0) then
                local cx,cz = chunkX + x,chunkZ + z
                if not chunkExists(cx,cz) then
                    makeChunk(cx,cz)
                end
            end
        end
    end
    wait()
end