pico8 - random dungeon

random-dungeon.lua

-- Copyright(c) Matt McFarland - 2017
-- MIT LICENSE
-- This will create rooms using the BSP method

rooms = {}

function _init() 
 local main_container = container(0, 6, 127, 121)
 local max_depth = 6
 local container_tree = split_container(main_container, max_depth)
 cls()
 square = 1
 --add a function to room
 --which updates the map
 foreach(rooms, function (room)
  room:paint()
 end)
 --use paths for map
 paths(container_tree)
 container_tree:paint()
end

function tree(leaf)
 return {
  leaf=leaf,
  lchild=nil,
  rchild=nil,
  paint=function(self)
   self.leaf:paint()
   if (self.lchild ~= nil) then
    self.lchild:paint()
   end
   if (self.rchild ~= nil) then
    self.rchild:paint()
   end
  end
 }
end

function paths(t)
 if (nil == t.lchild or nil == t.rchild) return
 t.lchild.leaf:path(t.rchild.leaf)
 paths(t.lchild)
 paths(t.rchild)
end

function container(x, y, w, h)
 -- create a container cell
 -- it may be discarded
 local c = {
  x=flr(x), y=flr(y),
  w=flr(w), h=flr(h),
 }
 c.cx=c.x+flr(c.w/2) 
 c.cy=c.y+flr(c.h/2) 
 function c:paint()
	  rect(
	   self.x,  self.y,
	   self.x + self.w,
	   self.y + self.h,
	   7
	  )
 end
 function c:path(o)
  line(
   self.cx,
   self.cy,
   o.cx,
   o.cy,
   5
  )
 end
 return c
end

function make_room(c)
 if (nil == c) return
 -- create and add room from
 -- the given container's info
 local r = {}
 local padding = 3
 r.x=c.x + padding
 r.y=c.y + padding
 r.w=c.w - padding * 2
 r.h=c.h - padding * 2
 function r:paint()
  rectfill(
	  self.x,  self.y,
	  self.x + self.w,
	  self.y + self.h,
	  3
  )
 end
 add(rooms, r) 
end

-- "random split" a container
function r_split(cont)
 local r1 = nil
 local r2 = nil
 if (rint(0,1) == 1) then
  r1 = container(
   cont.x, cont.y,
   rint(1, cont.w), cont.h
  )
  r2 = container(
   cont.x + r1.w, cont.y,
   cont.w - r1.w, cont.h
  )
  if (r1.w / r1.h < 0.45 or r2.w / r2.h < 0.45) then
   return r_split(cont)  
  end
 else
  r1 = container(
   cont.x, cont.y,
   cont.w, rint(1, cont.h)
  )	
  r2 = container(
   cont.x, cont.y + r1.h,
   cont.w, cont.h - r1.h
  )
  if (r1.h / r1.w < 0.45 or r2.h / r2.w < 0.45) then
   return r_split(cont)  
  end
 end
 return r1, r2
end

function split_container(c, iter)
 local root = tree(c)
 if (iter ~= 0) then
  local sr1, sr2 = r_split(c)
  root.lchild = split_container(sr1, iter-1)
  root.rchild = split_container(sr2, iter-1)
  -- when we reach the end,
  -- add rooms to the containers
  if (iter == 1) then
   make_room(sr1)
   make_room(sr2)  
  end 
 end
 return root
end

function rint(a, b) 
 return flr(rnd(b+1) + a)
end