Add //spiral and worldedit.spiral API function

README.md

@@ -108,6 +108,15 @@ Add cylinder at WorldEdit position 1 along the x/y/z/? axis with length <length>
     //cylinder y 28 10 default:glass
     //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>
 
@@ -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.
@@ -286,4 +301,4 @@ This mod is licensed under the [GNU Affero General Public License](http://www.gn
 
 Basically, this means everyone is free to use, modify, and distribute the files, as long as these modifications are also licensed the same way.
 
-Most importantly, the Affero variant of the GPL requires you to publish your modifications in source form, even if the mod is run only on the server, and not distributed.
+Most importantly, the Affero variant of the GPL requires you to publish your modifications in source form, even if the mod is run only on the server, and not distributed.

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)
@@ -476,4 +497,4 @@ worldedit.deserialize_old = function(originpos, value)
 		count = count + 1
 	end
 	return count
-end
+end

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>",
@@ -486,4 +516,4 @@ minetest.register_chatcommand("/load", {
 
 		minetest.chat_send_player(name, count .. " nodes loaded")
 	end,
-})
+})

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