Add a hollowellipsoid command

worldeditadditions/ellipsoid.lua

@@ -1,9 +1,13 @@
 --- Overlap command. Places a specified node on top of 
 -- @module worldeditadditions.overlay
 
-function worldedit.ellipsoid(position, radius, target_node)
+function worldedit.ellipsoid(position, radius, target_node, hollow)
 	-- position = { x, y, z }
-	
+	local hollow_inner_radius = {
+		x = radius.x - 1,
+		y = radius.y - 1,
+		z = radius.z - 1
+	}
 	
 	-- Fetch the nodes in the specified area
 	-- OPTIMIZE: We should be able to calculate a more efficient box-area here
@@ -30,11 +34,24 @@ function worldedit.ellipsoid(position, radius, target_node)
 				
 				-- If we're inside the ellipse, then fill it in
 				local x_comp, y_comp, z_comp = x/radius.x, y/radius.y, z/radius.z
-				if x_comp*x_comp + y_comp*y_comp + z_comp*z_comp <= 1 then
+				local ellipsoid_dist = x_comp*x_comp + y_comp*y_comp + z_comp*z_comp
+				if ellipsoid_dist <= 1 then
+					local place_ok = not hollow;
 					
-					data[i] = node_id
+					if not place_ok then
-					count = count + 1
+						-- It must be hollow! Do some additional calculations.
+						local hx_comp = x/hollow_inner_radius.x
+						local hy_comp = y/hollow_inner_radius.y
+						local hz_comp = z/hollow_inner_radius.z
 						
+						-- It's only ok to place it if it's outside our inner ellipse
+						place_ok = hx_comp*hx_comp + hy_comp*hy_comp + hz_comp*hz_comp >= 1
+					end
+					
+					if place_ok then
+						data[i] = node_id
+						count = count + 1
+					end
 				end
 				
 				

worldeditadditions_commands/init.lua

@@ -117,13 +117,7 @@ local function parse_params_ellipsoid(params_text)
 		z = tonumber(radius_z)
 	}
 	
-	minetest.log("action", "Radius x: " .. radius_x)
-	minetest.log("action", "Radius y: " .. radius_y)
-	minetest.log("action", "Radius z: " .. radius_z)
-	
-	minetest.log("action", "Raw target node: " .. replace_node)
 	replace_node = worldedit.normalize_nodename(replace_node)
-	minetest.log("action", "Normalised target node: " .. replace_node)
 	
 	return replace_node, radius
 end
@@ -145,7 +139,7 @@ minetest.register_chatcommand("/ellipsoid", {
 		end
 		
 		local start_time = os.clock()
-		local replaced = worldedit.ellipsoid(worldedit.pos1[name], radius, target_node)
+		local replaced = worldedit.ellipsoid(worldedit.pos1[name], radius, target_node, false)
 		local time_taken = os.clock() - start_time
 		
 		worldedit.player_notify(name, replaced .. " nodes replaced in " .. time_taken .. "s")
@@ -160,3 +154,37 @@ minetest.register_chatcommand("/ellipsoid", {
 		return math.ceil(4/3 * math.pi * radius.x * radius.y * radius.z)
 	end)
 })
+
+-- TODO: This duplicates a lot of code. Perhaps we can trim it down a bit?
+minetest.register_chatcommand("/hollowellipsoid", {
+	params = "<rx> <ry> <rz> <replace_node>",
+	description = "Creates a 3D hollow ellipsoid with a radius of (rx, ry, rz) at pos1, filled with <replace_node>.",
+	privs = { worldedit = true },
+	func = safe_region(function(name, params_text)
+		local target_node, radius = parse_params_ellipsoid(params_text)
+		
+		if not target_node then
+			worldedit.player_notify(name, "Error: Invalid node name.")
+			return false
+		end
+		if not radius then
+			worldedit.player_notify(name, "Error: Invalid radius(es).")
+			return false
+		end
+		
+		local start_time = os.clock()
+		local replaced = worldedit.ellipsoid(worldedit.pos1[name], radius, target_node, true)
+		local time_taken = os.clock() - start_time
+		
+		worldedit.player_notify(name, replaced .. " nodes replaced in " .. time_taken .. "s")
+		minetest.log("action", name .. " used //hollowellipsoid at " .. worldeditadditions.vector.tostring(worldedit.pos1[name]) .. ", replacing " .. replaced .. " nodes in " .. time_taken .. "s")
+	end, function(name, params_text)
+		local target_node, radius = parse_params_ellipsoid(params_text)
+		if not target_node or not radius then
+			worldedit.player_notify(name, "Error: Invalid input '" .. params_text .. "'. Try '/help /ellipsoid' to learn how to use this command.")
+			return 0
+		end
+		
+		return math.ceil(4/3 * math.pi * radius.x * radius.y * radius.z)
+	end)
+})