fix spiral

README.md

@@ -125,13 +125,13 @@ Add cylinder at WorldEdit position 1 along the x/y/z/? axis with length <length>
     //cylinder z -12 3 mesecons:mesecon
     //cylinder ? 2 4 stone
     
-### //spiral <size> <node>
+### //spiral <width> <height> <spacer> <node>
 
-Add spiral at WorldEdit position 1 with size <size>, composed of <node>.
+Add spiral at WorldEdit position 1 with width <width>, height <height>, space between walls <spacer>, composed of <node>.
 
-    //spiral 8 dirt
-    //spiral 5 default:glass
-    //spiral 2 stone
+    //spiral 20 5 3 dirt
+    //spiral 5 2 1 default:glass
+    //spiral 7 1 5 stone
 
 
 ### //copy x/y/z/? <amount>

functions.lua

@@ -238,21 +238,67 @@ worldedit.cylinder = function(pos, axis, length, radius, nodename)
 	return count
 end
 
---adds a spiral at `pos` with size `size`, composed of `nodename`, returning the number of nodes changed
-worldedit.spiral = function(pos, size, nodename)
-	local shift_x, shift_y
-	sa = spiralt(size)
-	shift_y = #sa -- "Height" of the Array
-	local fe = sa[1]
-	shift_x = #fe -- "Width" of the Array
-	fe = nil
-
+--adds a spiral at `pos` with width `width`, height `height`, space between walls `spacer`, composed of `nodename`, returning the number of nodes changed
+worldedit.spiral = function(pos, width, height, spacer, nodename)
+	-- spiral matrix - http://rosettacode.org/wiki/Spiral_matrix#Lua
+	av, sn = math.abs, function(s) return s~=0 and s/av(s) or 0 end
+	local function sindex(z, x) -- returns the value at (x, z) in a spiral that starts at 1 and goes outwards
+		if z == -x and z >= x then return (2*z+1)^2 end
+		local l = math.max(av(z), av(x))
+		return (2*l-1)^2+4*l+2*l*sn(x+z)+sn(z^2-x^2)*(l-(av(z)==l and sn(z)*x or sn(x)*z)) -- OH GOD WHAT
+	end
+	local function spiralt(side)
+		local ret, id, start, stop = {}, 0, math.floor((-side+1)/2), math.floor((side-1)/2)
+		for i = 1, side do
+			for j = 1, side do
+				local id = side^2 - sindex(stop - i + 1,start + j - 1)
+				ret[id] = {x=i,z=j}
+			end
+		end
+		return ret
+	end
+	-- connect the joined parts
+	local spiral = spiralt(width)
+	height = tonumber(height)
+	if height < 1 then height = 1 end
+	spacer = tonumber(spacer)-1
+	if spacer < 1 then spacer = 1 end
 	local count = 0
 	local node = {name=nodename}
-	for x, v in ipairs(sa) do
-		for y, z in ipairs(v) do
-			minetest.env:add_node({x=pos.x - shift_x + x,y=pos.y - shift_y + y,z=pos.z + z}, node)
-			count = count + 1
+	local np,lp
+	for y=0,height do
+		lp = nil
+		for _,v in ipairs(spiral) do
+			np = {x=pos.x+v.x*spacer, y=pos.y+y, z=pos.z+v.z*spacer}
+			if lp~=nil then
+				if lp.x~=np.x then 
+					if lp.x<np.x then 
+						for i=lp.x+1,np.x do
+							minetest.env:add_node({x=i, y=np.y, z=np.z}, node)
+							count = count + 1
+						end
+					else
+						for i=np.x,lp.x-1 do
+							minetest.env:add_node({x=i, y=np.y, z=np.z}, node)
+							count = count + 1
+						end
+					end
+				end
+				if lp.z~=np.z then 
+					if lp.z<np.z then 
+						for i=lp.z+1,np.z do
+							minetest.env:add_node({x=np.x, y=np.y, z=i}, node)
+							count = count + 1
+						end
+					else
+						for i=np.z,lp.z-1 do
+							minetest.env:add_node({x=np.x, y=np.y, z=i}, node)
+							count = count + 1
+						end
+					end
+				end
+			end
+			lp = np
 		end
 	end
 	return count

init.lua

@@ -272,8 +272,8 @@ minetest.register_chatcommand("/hollowcylinder", {
 })
 
 minetest.register_chatcommand("/spiral", {
-	params = "<size> <node>",
-	description = "Add spiral at WorldEdit position 1 with size <size>, composed of <node>",
+	params = "<width> <height> <space> <node>",
+	description = "Add spiral at WorldEdit position 1 with width <width>, height <height>, space between walls <space>, composed of <node>",
 	privs = {worldedit=true},
 	func = function(name, param)
 		local pos = worldedit.pos1[name]
@@ -282,7 +282,7 @@ minetest.register_chatcommand("/spiral", {
 			return
 		end
 
-		local found, _, size, nodename = param:find("(%d+)%s+([^%s]+)$")
+		local found, _, width, height, space, nodename = param:find("(%d+)%s+(%d+)%s+(%d+)%s+([^%s]+)$")
 		if found == nil then
 			minetest.chat_send_player(name, "Invalid usage: " .. param)
 			return
@@ -292,7 +292,7 @@ minetest.register_chatcommand("/spiral", {
 			return
 		end
 
-		local count = worldedit.spiral(pos, tonumber(size), nodename)
+		local count = worldedit.spiral(pos, tonumber(width), tonumber(height), tonumber(space), nodename)
 		minetest.chat_send_player(name, count .. " nodes changed")
 	end,
 })