Builders no longer keep a real copy of the object they're "programmed" with. Also, add a "creative mode" configuration flag

README.txt

@@ -24,8 +24,6 @@ Several general concepts are important when building more sophisticated diggers.
 
 * Offset - The location at which a periodic module triggers is globally uniform. This is handy if you want to line up the nodes you're building (for example, placing pillars and a crosspiece every 4 nodes in a tunnel, or punching alcoves in a wall to place glass windows). If you wish to change how the pattern lines up, modify the "offset" setting.
 
-Note that offset and period are calculated from the location of the *controller* node, which is shared across the whole array of modules, so it's not necessary to line up all of your builder heads in the same row or column.
-
 * Shift-right-clicking - since most of the nodes of the digging machine have control screens associated with right-clicking, building additional nodes on top of them or rotating them with the screwdriver requires the shift key to be held down when right-clicking on them.
 
 Detailed module guide
@@ -73,7 +71,7 @@ It can also serve as part of a lawnmower or tree-harvester.
 Builder Head
 ------------
 
-A builder head is the most complex component of this system. It has period and offset properties, and also an inventory slot where you "program" it by placing an example of the node type that you want it to build. Only a single item is needed here, any additional items in this inventory stack will be shunted into the digger's general inventory (or ejected from the control node if there's no space for it).
+A builder head is the most complex component of this system. It has period and offset properties, and also an inventory slot where you "program" it by placing an example of the node type that you want it to build. The builder doesn't keep a real copy of the item, it just reads what you drop in here.
 
 When the "Save & Show" button is clicked the properties for period and offset will be saved, and markers will briefly be shown to indicate where the nearest spots corresponding to those values are. The builder will build its output at those locations provided it is moving along the matching axis.
 

init.lua

@@ -1,14 +1,14 @@
 dofile( minetest.get_modpath( "digtron" ) .. "/util.lua" )
 dofile( minetest.get_modpath( "digtron" ) .. "/pointset.lua" )
 dofile( minetest.get_modpath( "digtron" ) .. "/entities.lua" )
-
 dofile( minetest.get_modpath( "digtron" ) .. "/node_misc.lua" ) -- contains inventory and structure nodes
 dofile( minetest.get_modpath( "digtron" ) .. "/node_diggers.lua" ) -- contains all diggers
 dofile( minetest.get_modpath( "digtron" ) .. "/node_builders.lua" ) -- contains all builders (there's just one currently)
 dofile( minetest.get_modpath( "digtron" ) .. "/node_controllers.lua" ) -- controllers
-
 dofile( minetest.get_modpath( "digtron" ) .."/recipes.lua" )
 
+digtron.creative_mode = false
+
 digtron.cycle_time = 1 -- How many seconds a digtron waits between cycles. Auto-controllers can make this wait longer, but cannot make it shorter.
 digtron.traction_factor = 3.0 -- How many digtron nodes can be moved for each adjacent solid node that the digtron has traction against
 

node_builders.lua

@@ -132,6 +132,16 @@ minetest.register_node("digtron:builder", {
 		digtron.remove_builder_item(pos)
 	end,
 
+	allow_metadata_inventory_put = function(pos, listname, index, stack, player)
+		local inv = minetest.get_inventory({type="node", pos=pos})
+		inv:set_stack(listname, index, stack:take_item(1))
+		return 0
+	end,
+	
+	allow_metadata_inventory_take = function(pos, listname, index, stack, player)
+		return 0
+	end,
+	
 	-- "builder at pos, imagine that you're in test_pos. If you're willing and able to build from there, take the item you need from inventory.
 	-- return the item you took and the inventory location you took it from so it can be put back after all the other builders have been tested.
 	-- If you couldn't get the item from inventory, return an error code so we can abort the cycle.
@@ -168,15 +178,7 @@ minetest.register_node("digtron:builder", {
 		
 		local inv = minetest.get_inventory({type="node", pos=pos})
 		local item_stack = inv:get_stack("main", 1)
-		local count = item_stack:get_count()
+		if not item_stack:is_empty() then
-		if count ~= 0 then
-			if count > 1 then
-				-- player has put more than one item in the "program" slot. Wasteful. Move all the rest to the main inventory so it can be used.
-				item_stack:set_count(count - 1)
-				digtron.place_in_inventory(item_stack, inventory_positions, controller_pos)
-				item_stack:set_count(1)
-				inv:set_stack("main", 1, item_stack)
-			end
 			local source_location = digtron.take_from_inventory(item_stack:get_name(), inventory_positions)
 			if source_location ~= nil then
 				return 1, {item=item_stack, location=source_location}
@@ -200,8 +202,17 @@ minetest.register_node("digtron:builder", {
 		if digtron.can_build_to(buildpos, protected_nodes, nodes_dug) then
 			local inv = minetest.get_inventory({type="node", pos=pos})
 			local item_stack = inv:get_stack("main", 1)
-			local count = item_stack:get_count()
 			if not item_stack:is_empty() then
+			
+				if digtron.creative_mode then
+					local returned_stack, success = digtron.item_place_node(item_stack, player, buildpos, tonumber(build_facing))
+					if success == true then
+						nodes_dug:set(buildpos.x, buildpos.y, buildpos.z, false)
+						return true
+					end
+					return nil
+				end
+			
 				local sourcepos = digtron.take_from_inventory(item_stack:get_name(), inventory_positions)
 				if sourcepos == nil then
 					-- item not in inventory! Need to sound the angry buzzer to let the player know, so return false.
@@ -220,10 +231,4 @@ minetest.register_node("digtron:builder", {
 			end
 		end
 	end,
-	
-	can_dig = function(pos,player)
-		local meta = minetest.get_meta(pos)
-		local inv = meta:get_inventory()
-		return inv:is_empty("main")
-	end,
 })

node_controllers.lua

@@ -180,7 +180,7 @@ local execute_cycle = function(pos, clicker)
 				-- So this should never happen. However, "should never happens" happen sometimes. So
 				-- don't interrupt the build cycle as a whole, we've already moved so might as well try to complete as much as possible.
 				strange_failure = true
-			elseif build_return == true then
+			elseif build_return == true and not digtron.creative_mode == true then
 				building_fuel_cost = building_fuel_cost + digtron.build_cost
 			end
 		else

util.lua

@@ -42,6 +42,8 @@ digtron.mark_diggable = function(pos, nodes_dug)
 		if target.name ~= "air" then
 			local in_known_group = false
 			local material_cost = 0
+			
+			if digtron.creative_mode ~= true then
 				if minetest.get_item_group(target.name, "cracky") ~= 0 then
 					in_known_group = true
 					material_cost = math.max(material_cost, digtron.dig_cost_cracky)
@@ -57,6 +59,7 @@ digtron.mark_diggable = function(pos, nodes_dug)
 				if not in_known_group then
 					material_cost = digtron.dig_cost_default
 				end
+			end
 	
 			return material_cost, minetest.get_node_drops(target.name, "")
 		end