Respect protected areas when spawning remote portals (#27)

* respect protected areas when spawning remote portals

* Use portal_shape to determine area to check for natural/protected

* Log warning on deprecated function call

.luacheckrc

@@ -23,6 +23,7 @@ read_globals = {
 	"PseudoRandom",
 	"stairs",
 	"stairsplus",
+	"string.split",
 	table = { fields = { "copy", "getn" } },
 	"vector",
 	"VoxelArea",

init.lua

@@ -101,7 +101,7 @@ The expedition parties have found no diamonds or gold, and after an experienced
 			return pos.y < nether.DEPTH_CEILING
 		end,
 
-		find_realm_anchorPos = function(surface_anchorPos)
+		find_realm_anchorPos = function(surface_anchorPos, player_name)
 			-- divide x and z by a factor of 8 to implement Nether fast-travel
 			local destination_pos = vector.divide(surface_anchorPos, nether.FASTTRAVEL_FACTOR)
 			destination_pos.x = math.floor(0.5 + destination_pos.x) -- round to int
@@ -116,12 +116,12 @@ The expedition parties have found no diamonds or gold, and after an experienced
 				return existing_portal_location, existing_portal_orientation
 			else
 				local start_y = nether.DEPTH_CEILING - math.random(500, 1500) -- Search starting altitude
-				destination_pos.y = nether.find_nether_ground_y(destination_pos.x, destination_pos.z, start_y)
+				destination_pos.y = nether.find_nether_ground_y(destination_pos.x, destination_pos.z, start_y, player_name)
 				return destination_pos
 			end
 		end,
 
-		find_surface_anchorPos = function(realm_anchorPos)
+		find_surface_anchorPos = function(realm_anchorPos, player_name)
 			-- A portal definition doesn't normally need to provide a find_surface_anchorPos() function,
 			-- since find_surface_target_y() will be used by default, but Nether portals also scale position
 			-- to create fast-travel.
@@ -140,7 +140,7 @@ The expedition parties have found no diamonds or gold, and after an experienced
 			if existing_portal_location ~= nil then
 				return existing_portal_location, existing_portal_orientation
 			else
-				destination_pos.y = nether.find_surface_target_y(destination_pos.x, destination_pos.z, "nether_portal")
+				destination_pos.y = nether.find_surface_target_y(destination_pos.x, destination_pos.z, "nether_portal", player_name)
 				return destination_pos
 			end
 		end,

mapgen.lua

@@ -465,10 +465,15 @@ end
 
 
 -- use knowledge of the nether mapgen algorithm to return a suitable ground level for placing a portal.
-function nether.find_nether_ground_y(target_x, target_z, start_y)
+-- player_name is optional, allowing a player to spawn a remote portal in their own protected areas.
+function nether.find_nether_ground_y(target_x, target_z, start_y, player_name)
 	local nobj_cave_point = minetest.get_perlin(np_cave)
 	local air = 0 -- Consecutive air nodes found
 
+	local minp_schem, maxp_schem = nether.get_schematic_volume({x = target_x, y = 0, z = target_z}, nil, "nether_portal")
+	local minp = {x = minp_schem.x, y = 0, z = minp_schem.z}
+	local maxp = {x = maxp_schem.x, y = 0, z = maxp_schem.z}
+
 	for y = start_y, math_max(NETHER_FLOOR + BLEND, start_y - 4096), -1 do
 		local nval_cave = nobj_cave_point:get3d({x = target_x, y = y, z = target_z})
 
@@ -476,13 +481,14 @@ function nether.find_nether_ground_y(target_x, target_z, start_y)
 			air = air + 1
 		else -- Not cavern, check if 4 nodes of space above
 			if air >= 4 then
+				local portal_y = y + 1
 				-- Check volume for non-natural nodes
-				local minp = {x = target_x - 1, y = y    , z = target_z - 2}
+				minp.y = minp_schem.y + portal_y
-				local maxp = {x = target_x + 2, y = y + 4, z = target_z + 2}
+				maxp.y = maxp_schem.y + portal_y
-				if nether.volume_is_natural(minp, maxp) then
+				if nether.volume_is_natural_and_unprotected(minp, maxp, player_name) then
-					return y + 1
+					return portal_y
 				else -- Restart search a little lower
-					nether.find_nether_ground_y(target_x, target_z, y - 16)
+					nether.find_nether_ground_y(target_x, target_z, y - 16, player_name)
 				end
 			else -- Not enough space, reset air to zero
 				air = 0

mapgen_nobiomes.lua

@@ -201,24 +201,30 @@ end)
 
 
 -- use knowledge of the nether mapgen algorithm to return a suitable ground level for placing a portal.
-function nether.find_nether_ground_y(target_x, target_z, start_y)
+-- player_name is optional, allowing a player to spawn a remote portal in their own protected areas.
+function nether.find_nether_ground_y(target_x, target_z, start_y, player_name)
 	local nobj_cave_point = minetest.get_perlin(np_cave)
 	local air = 0 -- Consecutive air nodes found
 
-	for y = start_y, start_y - 4096, -1 do
+	local minp_schem, maxp_schem = nether.get_schematic_volume({x = target_x, y = 0, z = target_z}, nil, "nether_portal")
+	local minp = {x = minp_schem.x, y = 0, z = minp_schem.z}
+	local maxp = {x = maxp_schem.x, y = 0, z = maxp_schem.z}
+
+	for y = start_y, math.max(NETHER_FLOOR + BLEND, start_y - 4096), -1 do
 		local nval_cave = nobj_cave_point:get3d({x = target_x, y = y, z = target_z})
 
 		if nval_cave > TCAVE then -- Cavern
 			air = air + 1
 		else -- Not cavern, check if 4 nodes of space above
 			if air >= 4 then
+				local portal_y = y + 1
 				-- Check volume for non-natural nodes
-				local minp = {x = target_x - 1, y = y    , z = target_z - 2}
+				minp.y = minp_schem.y + portal_y
-				local maxp = {x = target_x + 2, y = y + 4, z = target_z + 2}
+				maxp.y = maxp_schem.y + portal_y
-				if nether.volume_is_natural(minp, maxp) then
+				if nether.volume_is_natural_and_unprotected(minp, maxp, player_name) then
-					return y + 1
+					return portal_y
 				else -- Restart search a little lower
-					nether.find_nether_ground_y(target_x, target_z, y - 16)
+					nether.find_nether_ground_y(target_x, target_z, y - 16, player_name)
 				end
 			else -- Not enough space, reset air to zero
 				air = 0
@@ -226,5 +232,5 @@ function nether.find_nether_ground_y(target_x, target_z, start_y)
 		end
 	end
 
-	return start_y -- Fallback
+	return math.max(start_y, NETHER_FLOOR + BLEND) -- Fallback
 end

portal_api.lua

@@ -1303,8 +1303,9 @@ end
 
 
 -- invoked when a player attempts to turn obsidian nodes into an open portal
+-- player_name is optional, allowing a player to spawn a remote portal in their own protected area
 -- ignition_node_name is optional
-local function ignite_portal(ignition_pos, ignition_node_name)
+local function ignite_portal(ignition_pos, player_name, ignition_node_name)
 
 	if ignition_node_name == nil then ignition_node_name = minetest.get_node(ignition_pos).name end
 	if DEBUG then minetest.chat_send_all("IGNITE the " .. ignition_node_name .. " at " .. minetest.pos_to_string(ignition_pos)) end
@@ -1354,9 +1355,9 @@ local function ignite_portal(ignition_pos, ignition_node_name)
 
 			local destination_anchorPos, destination_orientation
 			if portal_definition.is_within_realm(ignition_pos) then
-				destination_anchorPos, destination_orientation = portal_definition.find_surface_anchorPos(anchorPos)
+				destination_anchorPos, destination_orientation = portal_definition.find_surface_anchorPos(anchorPos, player_name or "")
 			else
-				destination_anchorPos, destination_orientation = portal_definition.find_realm_anchorPos(anchorPos)
+				destination_anchorPos, destination_orientation = portal_definition.find_realm_anchorPos(anchorPos, player_name or "")
 			end
 			if DEBUG and destination_orientation == nil then minetest.chat_send_all("No destination_orientation given") end
 			if destination_orientation == nil then destination_orientation = orientation end
@@ -1825,7 +1826,7 @@ function register_frame_node(frame_node_name)
 	extended_node_def.mesecons = {effector = {
 		action_on = function (pos, node)
 			if DEBUG then minetest.chat_send_all("portal frame material: mesecons action ON") end
-			ignite_portal(pos, node.name)
+			ignite_portal(pos, nil, node.name)
 		end,
 		action_off = function (pos, node)
 			if DEBUG then minetest.chat_send_all("portal frame material: mesecons action OFF") end
@@ -2081,7 +2082,7 @@ function nether.register_portal(name, portaldef)
 	end
 
 	if portaldef.find_surface_anchorPos == nil then	-- default to using find_surface_target_y()
-		portaldef.find_surface_anchorPos = function(pos)
+		portaldef.find_surface_anchorPos = function(pos, player_name)
 
 			local destination_pos = {x = pos.x, y = 0, z = pos.z}
 			local existing_portal_location, existing_portal_orientation =
@@ -2089,7 +2090,7 @@ function nether.register_portal(name, portaldef)
 			if existing_portal_location ~= nil then
 				return existing_portal_location, existing_portal_orientation
 			else
-				destination_pos.y = nether.find_surface_target_y(destination_pos.x, destination_pos.z, name)
+				destination_pos.y = nether.find_surface_target_y(destination_pos.x, destination_pos.z, name, player_name)
 				return destination_pos
 			end
 		end
@@ -2153,10 +2154,10 @@ end
 function nether.register_portal_ignition_item(item_name, ignition_failure_sound)
 
 	minetest.override_item(item_name, {
-		on_place = function(stack, _, pt)
+		on_place = function(stack, placer, pt)
 			local done = false
 			if pt.under and nether.is_frame_node[minetest.get_node(pt.under).name] then
-				done = ignite_portal(pt.under)
+				done = ignite_portal(pt.under, placer:get_player_name())
 				if done and not minetest.settings:get_bool("creative_mode") then
 					stack:take_item()
 				end
@@ -2175,22 +2176,22 @@ end
 
 -- use this when determining where to spawn a portal, to avoid overwriting player builds
 -- It checks the area for any nodes that aren't ground or trees.
+-- player_name is optional, allowing a player to spawn a remote portal in their own protected areas.
 -- (Water also fails this test, unless it is unemerged)
-function nether.volume_is_natural(minp, maxp)
+function nether.volume_is_natural_and_unprotected(minp, maxp, player_name)
+
 	local c_air = minetest.get_content_id("air")
 	local c_ignore = minetest.get_content_id("ignore")
 
 	local vm = minetest.get_voxel_manip()
-	local pos1 = {x = minp.x, y = minp.y, z = minp.z}
+	local emin, emax = vm:read_from_map(minp, maxp)
-	local pos2 = {x = maxp.x, y = maxp.y, z = maxp.z}
-	local emin, emax = vm:read_from_map(pos1, pos2)
 	local area = VoxelArea:new({MinEdge = emin, MaxEdge = emax})
 	local data = vm:get_data()
 
-	for z = pos1.z, pos2.z do
+	for z = minp.z, maxp.z do
-	for y = pos1.y, pos2.y do
+	for y = minp.y, maxp.y do
-		local vi = area:index(pos1.x, y, z)
+		local vi = area:index(minp.x, y, z)
-		for x = pos1.x, pos2.x do
+		for x = minp.x, maxp.x do
 			local id = data[vi] -- Existing node
 			if DEBUG and id == nil then minetest.chat_send_all("nil block at index " .. vi) end
 			if id ~= c_air and id ~= c_ignore and id ~= nil then -- checked for common natural or not emerged
@@ -2200,7 +2201,7 @@ function nether.volume_is_natural(minp, maxp)
 					-- trees are natural but not "ground content"
 					local node_groups = nodedef.groups
 					if node_groups == nil or (node_groups.tree == nil and node_groups.leaves == nil and node_groups.leafdecay == nil) then
-						if DEBUG then minetest.chat_send_all("volume_is_natural() found unnatural node " .. name) end
+						if DEBUG then minetest.chat_send_all("volume_is_natural_and_unprotected() found unnatural node " .. name) end
 						return false
 					end
 				end
@@ -2210,13 +2211,73 @@ function nether.volume_is_natural(minp, maxp)
 	end
 	end
 
-	if DEBUG then minetest.chat_send_all("Volume is natural") end
+	if minetest.is_area_protected(minp, maxp, player_name or "") then
+		if DEBUG then minetest.chat_send_all("Volume is protected " .. minetest.pos_to_string(minp) .. "-" .. minetest.pos_to_string(maxp)) end
+		return false;
+	end
+
+	if DEBUG then minetest.chat_send_all("Volume is natural and unprotected for player '" .. (player_name or "") .. "', " .. minetest.pos_to_string(minp) .. "-" .. minetest.pos_to_string(maxp)) end
 	return true
 end
 
+-- Deprecated, use nether.volume_is_natural_and_unprotected() instead.
+function nether.volume_is_natural(minp, maxp)
+
+	if nether.deprecation_warning_volume_is_natural == nil then
+		local stack = debug.traceback("", 2);
+		local calling_func = (string.split(stack, "\n", false, 2, false)[2] or ""):trim()
+		minetest.log("warning",
+			"Deprecated function \"nether.volume_is_natural()\" invoked. Use \"nether.volume_is_natural_and_unprotected()\" instead. " ..
+			calling_func)
+		nether.deprecation_warning_volume_is_natural = true;
+	end
+
+	return nether.volume_is_natural_and_unprotected(minp, maxp)
+end
+
+-- Gets the volume that may be altered if a portal is placed at the anchor_pos
+-- orientation is optional, but specifying it will reduce the volume returned
+-- portal_name is optional, but specifying it will reduce the volume returned
+-- returns minp, maxp
+function nether.get_schematic_volume(anchor_pos, orientation, portal_name)
+
+	if orientation == nil then
+		-- Return a volume large enough for any orientation
+		local minp0, maxp0 = nether.get_schematic_volume(anchor_pos, 0, portal_name)
+		local minp1, maxp1 = nether.get_schematic_volume(anchor_pos, 1, portal_name)
+
+		-- ToDo: If an asymmetric portal is used with an anchor not at the center of the
+		-- schematic then we will also need to check orientations 3 and 4.
+		-- (The currently existing portal-shapes are not affected)
+		return
+			{x = math.min(minp0.x, minp1.x), y = math.min(minp0.y, minp1.y), z = math.min(minp0.z, minp1.z)},
+			{x = math.max(maxp0.x, maxp1.x), y = math.max(maxp0.y, maxp1.y), z = math.max(maxp0.z, maxp1.z)}
+	end
+
+	-- Assume the largest possible portal shape unless we know it's a smaller one.
+	local shape_defintion = nether.PortalShape_Circular
+	if portal_name ~= nil and nether.registered_portals[portal_name] ~= nil then
+		shape_defintion = nether.registered_portals[portal_name].shape
+	end
+
+	local size = shape_defintion.schematic.size
+	local minp = shape_defintion.get_schematicPos_from_anchorPos(anchor_pos, orientation);
+	local maxp
+
+	if (orientation % 2) == 0 then
+		maxp = {x = minp.x + size.x - 1, y = minp.y + size.y - 1, z = minp.z + size.z - 1}
+	else
+		maxp = {x = minp.x + size.z - 1, y = minp.y + size.y - 1, z = minp.z + size.x - 1}
+	end
+	return minp, maxp
+end
+
+
 -- Can be used when implementing custom find_surface_anchorPos() functions
--- portal_name is optional, providing it allows existing portals on the surface to be reused.
+-- portal_name is optional, providing it allows existing portals on the surface to be reused, and
-function nether.find_surface_target_y(target_x, target_z, portal_name)
+-- a potentially smaller volume to be checked by volume_is_natural_and_unprotected().
+-- player_name is optional, allowing a player to spawn a remote portal in their own protected areas.
+function nether.find_surface_target_y(target_x, target_z, portal_name, player_name)
 
 	assert(target_x ~= nil and target_z ~= nil, "Arguments `target_x` and `target_z` cannot be nil when calling find_surface_target_y()")
 
@@ -2246,18 +2307,22 @@ function nether.find_surface_target_y(target_x, target_z, portal_name)
 		end
 	end
 
+	local minp_schem, maxp_schem = nether.get_schematic_volume({x = target_x, y = 0, z = target_z}, nil, portal_name)
+	local minp = {x = minp_schem.x, y = 0, z = minp_schem.z}
+	local maxp = {x = maxp_schem.x, y = 0, z = maxp_schem.z}
+
 	for y = start_y, start_y - 256, -16 do
 		-- Check volume for non-natural nodes
-		local minp = {x = target_x - 1, y = y - 1, z = target_z - 2}
+		minp.y = minp_schem.y + y
-		local maxp = {x = target_x + 2, y = y + 3, z = target_z + 2}
+		maxp.y = maxp_schem.y + y
-		if nether.volume_is_natural(minp, maxp) then
+		if nether.volume_is_natural_and_unprotected(minp, maxp, player_name) then
 			return y
 		elseif portal_name ~= nil and nether.registered_portals[portal_name] ~= nil then
 			-- players have built here - don't grief.
 			-- but reigniting existing portals in portal rooms is fine - desirable even.
 			local anchorPos, orientation, is_ignited = is_within_portal_frame(nether.registered_portals[portal_name], {x = target_x, y = y, z = target_z})
 			if anchorPos ~= nil then
-				if DEBUG then minetest.chat_send_all("Volume_is_natural check failed, but a portal frame is here " .. minetest.pos_to_string(anchorPos) .. ", so this is still a good target y level") end
+				if DEBUG then minetest.chat_send_all("volume_is_natural_and_unprotected check failed, but a portal frame is here " .. minetest.pos_to_string(anchorPos) .. ", so this is still a good target y level") end
 				return y
 			end
 		end

portal_api.txt

@@ -49,17 +49,22 @@ surface.
 Helper functions
 ----------------
 
-* `nether.volume_is_natural(minp, maxp)`: returns a boolean
+* `nether.volume_is_natural_and_unprotected(minp, maxp, player_name)`: returns
+  a boolean.
     * use this when determining where to spawn a portal, to avoid overwriting
       player builds. It checks the area for any nodes that aren't ground or
       trees.
       Water will fail this test, unless it is unemerged.
+    * player_name is optional, providing it allows the player's own protected
+      areas to be treated as unprotected.
 
-* `nether.find_surface_target_y(target_x, target_z, portal_name)`: returns a
+* `nether.find_surface_target_y(target_x, target_z, portal_name, player_name)`:
-  suitable anchorPos
+  returns a suitable anchorPos
     * Can be used when implementing custom find_surface_anchorPos() functions
     * portal_name is optional, providing it allows existing portals on the
       surface to be reused.
+    * player_name is optional, providing it prevents the exclusion of surface
+      target areas which are protected by the player.
 
 * `nether.find_nearest_working_portal(portal_name, anchorPos, distance_limit, y_factor)`: returns
   (anchorPos, orientation), or nil if no portal was found within the
@@ -208,7 +213,7 @@ Used by `nether.register_portal`.
         -- Ideally implementations are fast, as this function can be used to
         -- sift through a list of portals.
 
-        find_realm_anchorPos = function(surface_anchorPos),
+        find_realm_anchorPos = function(surface_anchorPos, player_name),
         -- Required. Return a position in the realm that a portal created at
         -- surface_anchorPos will link to.
         -- Return an anchorPos or (anchorPos, orientation)
@@ -218,8 +223,10 @@ Used by `nether.register_portal`.
         -- orientation, otherwise the existing portal could be overwritten by
         -- a new one with the orientation of the surface portal.
         -- Return nil to prevent the portal from igniting.
+        -- player_name may be "", e.g. if the portal was ignited by a mesecon,
+        -- and is provided for use with volume_is_natural_and_unprotected() etc.
 
-        find_surface_anchorPos = function(realm_anchorPos),
+        find_surface_anchorPos = function(realm_anchorPos, player_name),
         -- Optional. If you don't implement this then a position near the
         -- surface will be picked.
         -- Return an anchorPos or (anchorPos, orientation)
@@ -233,6 +240,8 @@ Used by `nether.register_portal`.
         -- orientation, otherwise the existing portal could be overwritten by
         -- a new one with the orientation of the realm portal.
         -- Return nil to prevent the portal from igniting.
+        -- player_name may be "", e.g. if the portal was ignited by a mesecon,
+        -- and is provided for use with volume_is_natural_and_unprotected() etc.
 
         on_run_wormhole      = function(portalDef, anochorPos, orientation),
         -- invoked once per second per portal

portal_examples.lua

@@ -85,7 +85,7 @@ This portal is different to the others, rather than acting akin to a doorway it
 			return pos.y > FLOATLAND_LEVEL - 200
 		end,
 
-		find_realm_anchorPos = function(surface_anchorPos)
+		find_realm_anchorPos = function(surface_anchorPos, player_name)
 			-- TODO: Once paramat finishes adjusting the floatlands, implement a surface algorithm that finds land
 			local destination_pos = {x = surface_anchorPos.x ,y = FLOATLAND_LEVEL + 2, z = surface_anchorPos.z}
 
@@ -131,13 +131,13 @@ Due to such difficulties, we never learned what determines the direction and dis
 			return true
 		end,
 
-		find_realm_anchorPos = function(surface_anchorPos)
+		find_realm_anchorPos = function(surface_anchorPos, player_name)
 			-- This function isn't needed, since this type of portal always goes to the surface
 			minetest.log("error" , "find_realm_anchorPos called for surface portal")
 			return {x=0, y=0, z=0}
 		end,
 
-		find_surface_anchorPos = function(realm_anchorPos)
+		find_surface_anchorPos = function(realm_anchorPos, player_name)
 			-- A portal definition doesn't normally need to provide a find_surface_anchorPos() function,
 			-- since find_surface_target_y() will be used by default, but these portals travel around the
 			-- surface (following a Moore curve) so will be calculating a different x and z to realm_anchorPos.
@@ -192,7 +192,7 @@ Due to such difficulties, we never learned what determines the direction and dis
 				end
 
 				local destination_pos = {x = target_x + adj_x, y = 0, z = target_z + adj_z}
-				destination_pos.y = nether.find_surface_target_y(destination_pos.x, destination_pos.z, "surface_portal")
+				destination_pos.y = nether.find_surface_target_y(destination_pos.x, destination_pos.z, "surface_portal", player_name)
 
 				return destination_pos
 			end