CellurarCaves (better)

local CHANCE_TO_START_ALIVE = 450
local BIRTH_LIMIT = 5
local DEATH_LIMIT = 5
local STEPS = 6

local distance = 40
local pointSize = 16

function generateCave()
    if MapFeatureSize then distance = MapFeatureSize*2 end

  x = GetRandom(4096)
  y = GetRandom(2048)

  local world = {}

  initializeWord(world)

  for i=1, STEPS do
    world = simulationStep(world)
  end

  local x = 1
  local y = 1

  while x <= 4096/distance do
    while y <= 2048/distance do
      if world[x][y] then
        AddPoint((x-1) * distance + distance/2, (y-1) * distance + distance/2, pointSize)
      end

      y = y+1
    end

    x = x+1
    y = 1
  end

  local distance2 = distance*2

  x = 1
  y = 1

  while x <= 4096/distance2 do
    while y <= 2048/distance2 do
      local average = 0
      if world[x*2][y*2] then average = average+1 end
      if world[x*2+1][y*2] then average = average+1 end
      if world[x*2+1][y*2+1] then average = average+1 end
      if world[x*2+1][y*2] then average = average+1 end

      if average >= 2 then
        AddPoint((x*2-2) * distance + distance/2, (y*2-1) * distance + distance/2, pointSize/2)
        AddPoint((x*2-2) * distance + distance/2, (y*2-2) * distance + distance/2, pointSize/2)
        AddPoint((x*2-1) * distance + distance/2, (y*2-2) * distance + distance/2, pointSize/2)
        AddPoint((x*2-1) * distance + distance/2, (y*2-1) * distance + distance/2, pointSize/2)
      end

      y = y+1
    end

    x = x+1
    y = 1
  end

    FlushPoints()
end

function initializeWord(world)
  local x = 1
  local y = 1

  while x <= 4096/distance do
    table.insert(world, {})

    while y <= 2048/distance do
      if GetRandom(1000) < CHANCE_TO_START_ALIVE then
        table.insert(world[x], true)
      else
        table.insert(world[x], false)
      end

      y = y+1
    end

    x = x+1
    y = 1
  end
end

function simulationStep(world)
  local x = 1
  local y = 1
  world2 = {}

  while x <= 4096/distance do
    table.insert(world2, {})

    while y <= 2048/distance do
      local count = countNeigbours(world, x, y)

      if world[x][y] then
        if count < DEATH_LIMIT then
          table.insert(world2[x], false)
        else
          table.insert(world2[x], true)
        end
      else
        if count > BIRTH_LIMIT then
          table.insert(world2[x], true)
        else
          table.insert(world2[x], false)
        end
      end

      y = y+1
    end

    x = x+1
    y = 1
  end

  return world2
end

function countNeigbours(world, x, y)
  count = 0

  for dx=1, 3 do
    for dy=1, 3 do
      local x2 = x+dx-2
      local y2 = y+dy-2

      if x2 == 0 or x2 > 4096/distance or y2 == 0 or y2 > 2048/distance or world[x2][y2] then
        count = count + 1
      end
    end
  end

  return count
end

function onGameInit()
    MapGen = mgDrawn
    TemplateFilter = 0
    generateCave()
end

function onPreviewInit()
    onGameInit()
end