ca_cave.lua

-- Rules:
-- Winit(p) = rand[0,100) < 40
-- Repeat 4: W?(p) = R1(p) >= 5 || R2(p) == 2
-- Repeat 3: W?(p) = R1(p) >= 5

function ca_cave(map)
	
	local R = function (s, p)
		local ret = 0
		local rt = {}
		for y = -s, s do
			for x = -s, s do
				table.insert(rt, {x, y})
			end
		end
		for i, r in pairs(rt) do
			x = (p % map_width) + r[1]
			y = ((p - (p % map_width)) / map_width) - r[2]
			if (x < 0) or (x > map_width) then
				ret = ret + 1
			elseif (y < 0) or (y > map_height) then
				ret = ret + 1
			elseif (y*map_width+x < 0) or (y*map_width+x > table.maxn(map)) then
				ret = ret + 1
			else
				if map[y*map_width+x] then
					ret = ret + 1
				end
			end
		end
		return ret
	end
	
	for q = 1, 1 do
		updated_map = {}
		for p = 1, table.maxn(map) do
			updated_map[p] = (R(1, p) >= 5) or (R(2, p) == 1)
		end
		map = updated_map
	end

	for q = 1, 2 do
		updated_map = {}
		for p = 1, table.maxn(map) do
			updated_map[p] = R(1, p) >= 5
		end
		map = updated_map
	end
	
	return map
end