Add support for sticky blocks for pistons and a a sample sticky block

mesecons_mvps/init.lua

@@ -19,7 +19,6 @@ function mesecon.is_mvps_stopper(node, pushdir, stack, stackid)
 	if type (get_stopper) == "function" then
 		get_stopper = get_stopper(node, pushdir, stack, stackid)
 	end
-	if (get_stopper) then print(node.name) end
 	return get_stopper
 end
 
@@ -48,27 +47,76 @@ function mesecon.mvps_process_stack(stack)
 	end
 end
 
-function mesecon.mvps_get_stack(pos, dir, maximum)
+function mesecon.mvps_get_stack(pos, dir, maximum, all_pull_sticky)
 	-- determine the number of nodes to be pushed
-	local np = {x = pos.x, y = pos.y, z = pos.z}
 	local nodes = {}
-	while true do
-		local nn = minetest.get_node_or_nil(np)
-		if not nn or #nodes > maximum then
-			-- don't push at all, something is in the way (unloaded map or too many nodes)
-			return nil
+	local frontiers = {pos}
+
+	while #frontiers > 0 do
+		local np = frontiers[1]
+		local nn = minetest.get_node(np)
+
+		if nn.name ~= "air"
+		and minetest.registered_nodes[nn.name]
+		and minetest.registered_nodes[nn.name].liquidtype == "none" then
+			table.insert(nodes, {node = nn, pos = np})
+			if #nodes > maximum then return nil end
+
+			-- add connected nodes to frontiers, connected is a vector list
+			-- the vectors must be absolute positions
+			local connected = {}
+			if minetest.registered_nodes[nn.name]
+			and minetest.registered_nodes[nn.name].mvps_sticky then
+				connected = minetest.registered_nodes[nn.name].mvps_sticky(np, nn)
+			end
+
+			table.insert(connected, vector.add(np, dir))
+
+			-- If adjacent node is sticky block and connects add that
+			-- position to the connected table
+			for _, r in ipairs(mesecon.rules.alldirs) do
+				local adjpos = vector.add(np, r)
+				local adjnode = minetest.get_node(adjpos)
+				if minetest.registered_nodes[adjnode.name]
+				and minetest.registered_nodes[adjnode.name].mvps_sticky then
+					local sticksto = minetest.registered_nodes[adjnode.name]
+						.mvps_sticky(adjpos, adjnode)
+
+					-- connects to this position?
+					for _, link in ipairs(sticksto) do
+						if vector.equals(link, np) then
+							table.insert(connected, adjpos)
+						end
+					end
+				end
+			end
+
+			if all_pull_sticky then
+				table.insert(connected, vector.subtract(np, dir))
+			end
+
+			-- Make sure there are no duplicates in frontiers / nodes before
+			-- adding nodes in "connected" to frontiers
+			for _, cp in ipairs(connected) do
+				local duplicate = false
+				for _, rp in ipairs(nodes) do
+					if vector.equals(cp, rp.pos) then
+						duplicate = true
+					end
+				end
+				for _, fp in ipairs(frontiers) do
+					if vector.equals(cp, fp) then
+						duplicate = true
+					end
+				end
+				if not duplicate then
+					table.insert(frontiers, cp)
+				end
+			end
 		end
-
-		if nn.name == "air"
-		or (minetest.registered_nodes[nn.name]
-		and minetest.registered_nodes[nn.name].liquidtype ~= "none") then --is liquid
-			break
-		end
-
-		table.insert (nodes, {node = nn, pos = np})
-
-		np = mesecon.addPosRule(np, dir)
+		table.remove(frontiers, 1)
 	end
+
 	return nodes
 end
 
@@ -77,11 +125,19 @@ function mesecon.mvps_push(pos, dir, maximum)
 end
 
 function mesecon.mvps_pull_all(pos, dir, maximum)
+	return mesecon.mvps_push_or_pull(pos, vector.multiply(dir, -1), dir, maximum, true)
+end
+
+function mesecon.mvps_pull_single(pos, dir, maximum)
 	return mesecon.mvps_push_or_pull(pos, vector.multiply(dir, -1), dir, maximum)
 end
 
-function mesecon.mvps_push_or_pull(pos, stackdir, movedir, maximum) -- pos: pos of mvps; stackdir: direction of building the stack; movedir: direction of actual movement; maximum: maximum nodes to be pushed
-	local nodes = mesecon.mvps_get_stack(pos, stackdir, maximum)
+-- pos: pos of mvps; stackdir: direction of building the stack
+-- movedir: direction of actual movement
+-- maximum: maximum nodes to be pushed
+-- all_pull_sticky: All nodes are sticky in the direction that they are pulled from
+function mesecon.mvps_push_or_pull(pos, stackdir, movedir, maximum, all_pull_sticky)
+	local nodes = mesecon.mvps_get_stack(pos, movedir, maximum, all_pull_sticky)
 
 	if not nodes then return end
 	-- determine if one of the nodes blocks the push / pull
@@ -133,27 +189,6 @@ mesecon.register_on_mvps_move(function(moved_nodes)
 	end
 end)
 
-function mesecon.mvps_pull_single(pos, dir) -- pos: pos of mvps; direction: direction of pull (matches push direction for sticky pistons)
-	local np = mesecon.addPosRule(pos, dir)
-	local nn = minetest.get_node(np)
-
-	if ((not minetest.registered_nodes[nn.name]) --unregistered node
-	or minetest.registered_nodes[nn.name].liquidtype == "none") --non-liquid node
-	and not mesecon.is_mvps_stopper(nn, dir, {{pos = np, node = nn}}, 1) then --non-stopper node
-		local meta = minetest.get_meta(np):to_table()
-		minetest.remove_node(np)
-		minetest.add_node(pos, nn)
-		minetest.get_meta(pos):from_table(meta)
-
-		nodeupdate(np)
-		nodeupdate(pos)
-		mesecon.on_dignode(np, nn)
-		mesecon.update_autoconnect(np)
-		on_mvps_move({{pos = pos, oldpos = np, node = nn, meta = meta}})
-	end
-	return {{pos = np, node = {param2 = 0, name = "air"}}, {pos = pos, node = nn}}
-end
-
 function mesecon.mvps_move_objects(pos, dir, nodestack)
 	local objects_to_move = {}