gistfile1.lua

map = {}
map.width = 70
map.height = 30

function initMap()
  for i = 1, map.width do
		map[i] = {}
		for j = 1, map.height do
			map[i][j] = "."
		end
	end
end

function showMap()
	for j = 1, map.height do
		for i = 1, map.width do
			io.write( map[i][j] )
		end
		io.write( "\n" )
	end
end

function isLegal( x, y )
	return ( x > 0 and y > 0 and x <= map.width and y <= map.height )
end

function wall( x, y, d, door )
	local cx, cy = x, y
	local wl = {}

	while isLegal( cx, cy ) do
		if map[cx][cy] ~= "." then break end
		map[cx][cy] = "#"
		cx = cx + d.x
		cy = cy + d.y
		table.insert( wl, { x=cx, y=cy } )
	end

	if door and #wl > 1 then
		local i = math.random( 1, #wl-1 )
		map[wl[i].x][wl[i].y] = "+"
	end

	if door and #wl == 1 then
		map[wl[1].x][wl[1].y] = "+"
	end
end

function count( x, y )
	local i, j = 0, 0
	local c = 0

	for i = x-1, x+1 do
		for j = y-1, y+1 do
			if isLegal( i, j ) then
				if map[i][j] ~= "." then
					c = c + 1
				end
			end
		end
	end

	return c
end

function neardoor( x, y )
	local i, j = 0, 0

	for i = x-1, x+1 do
		for j = y-1, y+1 do
			if isLegal( i, j ) then
				if map[i][j] == "+" then
					return true
				end
			end
		end
	end

	return false
end

function bsp( walls )
	local cx, cy = 0, 0
	local i = 0

	while i < walls do
		cx = math.random( 1, map.width )
		cy = math.random( 1, map.height )

		if math.random() < 0.5 then
			while map[cx][cy] == "." do
				cx = cx - 1
			end
			cx = cx + 1

			if count( cx, cy ) < 4 and not neardoor( cx, cy ) then
				wall( cx, cy, { x=1, y=0 }, true )
			end
		else
			while map[cx][cy] == "." do
				cy = cy - 1
			end
			cy = cy + 1

			if count( cx, cy ) < 4 and not neardoor( cx, cy ) then 
				wall( cx, cy, { x=0, y=1 }, true )
			end
		end

		i = i + 1
	end
end

function main()
	math.randomseed( os.time() )

	initMap()
	wall( 1, 1, { x=1, y=0 }, false )
	wall( 1, map.height, { x=1, y=0 }, false )
	wall( 1, 2, { x=0, y=1 }, false )
	wall( map.width, 2, { x=0, y=1 }, false )

	bsp( 20 )

	showMap()
end

main()