Add //spiral and worldedit.spiral API function

README.md

@@ -109,6 +109,15 @@ 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>
+
+Add Spiral at WorldEdit position 1 with size <size>, composed of <node>.
+
+    //spiral 8 dirt
+    //spiral 5 default:glass
+    //spiral 2 stone
+
+
 ### //copy x/y/z/? <amount>
 
 Copy the current WorldEdit region along the x/y/z/? axis by <amount> nodes.
@@ -216,6 +225,12 @@ Adds a cylinder at `pos` along the `axis` axis ("x" or "y" or "z") with length `
 
 Returns the number of nodes added.
 
+### worldedit.spiral(pos, size, nodename)
+
+Adds a Spiral at `pos` with size `size`.
+
+Returns the number of nodes changed.
+
 ### worldedit.copy(pos1, pos2, axis, amount)
 
 Copies the region defined by positions `pos1` and `pos2` along the `axis` axis ("x" or "y" or "z") by `amount` nodes.

functions.lua

@@ -1,3 +1,4 @@
+dofile(minetest.get_modpath("worldedit") .. "/spirals.lua")
 --modifies positions `pos1` and `pos2` so that each component of `pos1` is less than or equal to its corresponding conent of `pos2`, returning two new positions
 worldedit.sort_pos = function(pos1, pos2)
 	pos1 = {x=pos1.x, y=pos1.y, z=pos1.z}
@@ -182,6 +183,26 @@ worldedit.cylinder = function(pos, axis, length, radius, nodename)
 	return count
 end
 
+--adds a spiral at `pos` with size `size`, 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
+    
+    local count = 0
+    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}, {name=nodename})
+            count = count + 1
+        end
+    end
+	
+	return count
+end
+
 --copies the region defined by positions `pos1` and `pos2` along the `axis` axis ("x" or "y" or "z") by `amount` nodes, returning the number of nodes copied
 worldedit.copy = function(pos1, pos2, axis, amount)
 	local pos1, pos2 = worldedit.sort_pos(pos1, pos2)

init.lua

@@ -216,6 +216,36 @@ minetest.register_chatcommand("/hollowcylinder", {
 	end,
 })
 
+
+minetest.register_chatcommand("/spiral", {
+	params = "<size> <node>",
+	description = "Add Spiral at WorldEdit position 1 with size <size>, composed of <node>",
+	privs = {worldedit=true},
+	func = function(name, param)
+		local pos = worldedit.pos1[name]
+		if pos == nil then
+			minetest.chat_send_player(name, "No WorldEdit region selected")
+			return
+		end
+
+		local found, _, size, nodename = param:find("(%d+)%s+([^%s]+)$")
+		if found == nil then
+			minetest.chat_send_player(name, "Invalid usage: " .. param)
+			return
+		end
+		if axis == "?" then
+			axis = worldedit.player_axis(name)
+		end
+		if not worldedit.node_is_valid(pos, nodename) then
+			minetest.chat_send_player(name, "Invalid node name: " .. param)
+			return
+		end
+
+		local count = worldedit.spiral(pos, tonumber(size), nodename)
+		minetest.chat_send_player(name, count .. " nodes changed")
+	end,
+})
+
 minetest.register_chatcommand("/cylinder", {
 	params = "x/y/z/? <length> <radius> <node>",
 	description = "Add cylinder at WorldEdit position 1 along the x/y/z/? axis with length <length> and radius <radius>, composed of <node>",

spirals.lua

@@ -0,0 +1,17 @@
+av, sn = math.abs, function(s) return s~=0 and s/av(s) or 0 end
+function sindex(y, x) -- returns the value at (x, y) in a spiral that starts at 1 and goes outwards
+  if y == -x and y >= x then return (2*y+1)^2 end
+  local l = math.max(av(y), av(x))
+  return (2*l-1)^2+4*l+2*l*sn(x+y)+sn(y^2-x^2)*(l-(av(y)==l and sn(y)*x or sn(x)*y)) -- OH GOD WHAT
+end
+ 
+function spiralt(side)
+  local ret, start, stop = {}, math.floor((-side+1)/2), math.floor((side-1)/2)
+  for i = 1, side do
+    ret[i] = {}
+    for j = 1, side do
+      ret[i][j] = side^2 - sindex(stop - i + 1,start + j - 1) --moves the coordinates so (0,0) is at the center of the spiral
+    end
+  end
+  return ret
+end