Add //overlay, and start filling out README

README.md

@@ -1,2 +1,26 @@
 # Minetest-WorldEditAdditions
-Extra tools and commands to extend WorldEdit for Minetest
+> Extra tools and commands to extend WorldEdit for Minetest
+
+## Current commands:
+
+### `//floodfill [<replace_node> [<radius>]]`
+Floods all connected nodes of the same type starting at _pos1_ with <replace_node> (which defaults to `water_source`), in a sphere with a radius of <radius> (which defaults to 50).
+
+```
+//floodfill
+//floodfill water_source 50
+//floodfill glass 25
+```
+
+### `//overlay <node_name>`
+Places <replace_node> in the last contiguous air space encountered above the first non-air node. In other words, overlays all top-most nodes in the specified area with <replace_node>.
+
+Will also work in caves, as it scans columns of nodes from top to bottom, skipping every non-air node until it finds one - and only then will it start searching for a node to place the target node on top of.
+
+Note that all-air columns are skipped - so if you experience issues with it not overlaying correctly, try `//expand down 1` to add an extra node's space to your defined region.
+
+```
+//overlay grass
+//overlay glass
+//overlay grass_with_dirt
+```

worldeditadditions/floodfill.lua

@@ -47,7 +47,9 @@ function worldedit.floodfill(start_pos, radius, replace_node)
 	-- Calculate the area we want to modify
 	local pos1 = vector.add(start_pos, { x = radius, y = 0, z = radius })
 	local pos2 = vector.subtract(start_pos, { x = radius, y = radius, z = radius })
-	pos1, pos2 = worldedit.sort_pos(pos1, pos2) -- Just in case
+	pos1, pos2 = worldedit.sort_pos(pos1, pos2)
+	-- pos2 will always have the highest co-ordinates now
+	
 	
 	-- Fetch the nodes in the specified area
 	local manip, area = worldedit.manip_helpers.init(pos1, pos2)

worldeditadditions/init.lua

@@ -9,3 +9,4 @@ worldeditadditions = {}
 
 dofile(minetest.get_modpath("worldeditadditions") .. "/utils.lua")
 dofile(minetest.get_modpath("worldeditadditions") .. "/floodfill.lua")
+dofile(minetest.get_modpath("worldeditadditions") .. "/overlay.lua")

worldeditadditions/overlay.lua

@@ -0,0 +1,52 @@
+--- Overlap command. Places a specified node on top of 
+-- @module worldeditadditions.overlay
+
+function worldedit.overlay(pos1, pos2, target_node)
+	pos1, pos2 = worldedit.sort_pos(pos1, pos2)
+	-- pos2 will always have the highest co-ordinates now
+	
+	-- Fetch the nodes in the specified area
+	local manip, area = worldedit.manip_helpers.init(pos1, pos2)
+	local data = manip:get_data()
+	
+	local node_id_air = minetest.get_content_id("air")
+	local node_id_target = minetest.get_content_id(target_node)
+	
+	minetest.log("action", "pos1: " .. worldeditadditions.vector.tostring(pos1))
+	minetest.log("action", "pos2: " .. worldeditadditions.vector.tostring(pos2))
+	
+	-- z y x is the preferred loop order, but that isn't really possible here
+	
+	local changes = { updated = 0, skipped_columns = 0 }
+	for z = pos2.z, pos1.z, -1 do
+		for x = pos2.x, pos1.x, -1 do
+			local found_air = false
+			local placed_node = false
+			
+			for y = pos2.y, pos1.y, -1 do
+				if data[area:index(x, y, z)] ~= node_id_air then
+					if found_air then
+						-- We've found an air block previously, so it must be above us
+						-- Replace the node above us with the target block
+						data[area:index(x, y + 1, z)] = node_id_target
+						changes.updated = changes.updated + 1
+						placed_node = true
+						break -- Move on to the next column
+					end
+				else
+					found_air = true
+				end
+			end
+			
+			if not placed_node then
+				changes.skipped_columns = changes.skipped_columns + 1
+			end
+		end
+	end
+	
+	
+	-- Save the modified nodes back to disk & return
+	worldedit.manip_helpers.finish(manip, data)
+	
+	return changes
+end

worldeditadditions_commands/init.lua

@@ -25,8 +25,8 @@ local function parse_params_floodfill(params_text)
 end
 
 minetest.register_chatcommand("/floodfill", {
-	params = "<replace_node> [<radius>]",
-	description = "Floods all connected nodes of the same type starting at pos1 with <replace_node>, in a box-shape with a radius of <radius>, which defaults to 50.",
+	params = "[<replace_node> [<radius>]]",
+	description = "Floods all connected nodes of the same type starting at pos1 with <replace_node> (which defaults to `water_source`), in a sphere with a radius of <radius> (which defaults to 50).",
 	privs = { worldedit = true },
 	func = safe_region(function(name, params_text)
 		local replace_node, radius = parse_params_floodfill(params_text)
@@ -44,7 +44,41 @@ minetest.register_chatcommand("/floodfill", {
 		minetest.log("action", name .. " used floodfill at " .. worldeditadditions.vector.tostring(worldedit.pos1[name]) .. ", replacing " .. nodes_replaced .. " nodes in " .. time_taken .. "s")
 	end, function(name, params_text)
 		local replace_node, radius = parse_params_floodfill(params_text)
-		
-		return math.ceil(((4 * math.pi * (tonumber(radius) ^ 3)) / 3) / 2) -- Volume of a hemisphere
+		-- Volume of a hemisphere
+		return math.ceil(((4 * math.pi * (tonumber(radius) ^ 3)) / 3) / 2)
+	end)
+})
+
+
+minetest.register_chatcommand("/overlay", {
+	params = "<replace_node>",
+	description = "Places <replace_node> in the last contiguous air space encountered above the first non-air node. In other words, overlays all top-most nodes in the specified area with <replace_node>.",
+	privs = { worldedit = true },
+	func = safe_region(function(name, params_text)
+		local target_node = worldedit.normalize_nodename(params_text)
+		
+		if not target_node then
+			worldedit.player_notify(name, "Error: Invalid node name.")
+			return false
+		end
+		
+		local start_time = os.clock()
+		local changes = worldedit.overlay(worldedit.pos1[name], worldedit.pos2[name], target_node)
+		local time_taken = os.clock() - start_time
+		
+		worldedit.player_notify(name, changes.updated .. " nodes replaced and " .. changes.skipped_columns .. " columns skipped in " .. time_taken .. "s")
+		minetest.log("action", name .. " used overlay at " .. worldeditadditions.vector.tostring(worldedit.pos1[name]) .. ", replacing " .. changes.updated .. " nodes and skipping " .. changes.skipped_columns .. " columns in " .. time_taken .. "s")
+	end, function(name, params_text)
+		if not worldedit.normalize_nodename(params_text) then
+			worldedit.player_notify(name, "Error: Invalid node name '" .. params_text .. "'.")
+		end
+		
+		local pos1 = worldedit.pos1[name]
+		local pos2 = worldedit.pos2[name]
+		pos1, pos2 = worldedit.sort_pos(pos1, pos2)
+		
+		local vol = vector.subtract(pos2, pos1)
+		
+		return vol.x*vol.z
 	end)
 })