Don't allow placement of vines on ceiling

mods/ITEMS/mcl_core/nodes.lua

@@ -1334,6 +1334,50 @@ minetest.register_node("mcl_core:vine", {
 			minetest.add_item(pos, oldnode.name)
 		end
 	end,
+	node_placement_prediction = "",
+	-- Restrict placement of vines
+	on_place = function(itemstack, placer, pointed_thing)
+		if pointed_thing.type ~= "node" then
+			-- no interaction possible with entities
+			return itemstack
+		end
+
+		local under = pointed_thing.under
+		local node = minetest.get_node(under)
+		local def = minetest.registered_nodes[node.name]
+		local groups = def.groups
+
+		-- Check special rightclick action of pointed node
+		if def and def.on_rightclick then
+			if not placer:get_player_control().sneak then
+				return def.on_rightclick(under, node, placer, itemstack,
+					pointed_thing) or itemstack, false
+			end
+		end
+
+		-- Only allow placement on solid nodes
+		if (not groups) or (not groups.solid) then
+			return itemstack
+		end
+
+		local above = pointed_thing.above
+
+		-- Vines may not be placed on the ceiling
+		if under.y > above.y then
+			return itemstack
+		end
+		local idef = itemstack:get_definition()
+		local success = minetest.item_place_node(itemstack, placer, pointed_thing)
+
+		if success then
+			if idef.sounds and idef.sounds.place then
+				minetest.sound_play(idef.sounds.place, {pos=above, gain=1})
+			end
+		end
+		return itemstack
+	end,
+
+
 	_mcl_blast_resistance = 1,
 	_mcl_hardness = 0.2,
 })