kingdoms_game/mods/utils/nodeutil.lua

--[[
Copyright (c) 2014, Robert 'Bobby' Zenz
All rights reserved.

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* Redistributions of source code must retain the above copyright notice, this
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--]]


--- Various functions related to nodes.
nodeutil = {}


--- Gets the content id of the given node.
--
-- @param node The node, can either be an id, a name or a table with the name.
-- @return The content id of the given node.
function nodeutil.get_id(node)
	if type(node) == "string" then
		return minetest.get_content_id(node)
	elseif type(node) == "table" then
		return minetest.get_content_id(node.name)
	end
	
	return node
end

--- Gets the name of given node.
--
-- @param node The node, can either be an id, a name or a table with the name.
-- @return The name of the given node.
function nodeutil.get_name(node)
	if type(node) == "number" then
		return minetest.get_name_from_content_id(node)
	elseif type(node) == "table" then
		return node.name
	end
	
	return node
end

--- Checks if the given node has the given group.
--
-- @param node The node to check.
-- @param group_name The name of the group.
-- @return true if the node has the given group.
function nodeutil.has_group(node, group_name)
	local node_name = nodeutil.get_name(node)
	
	return minetest.get_item_group(node_name, group_name) > 0
end

--- Checks if the given node is walkable.
--
-- @param node The node to check, can either be an id, a name or a table with
--             the name.
-- @return true if the given node is walkable.
function nodeutil.is_walkable(node)
	local node_name = nodeutil.get_name(node)
	local node_definition = minetest.registered_nodes[node_name]
	
	if node_definition ~= nil then
		-- Test against false needed in case that walkable is not set,
		-- as it defaults to true.
		return node_definition.walkable ~= false
	end
	
	-- The node does not exist, sad.
	return false
end

--- Iterates over the surroundings of the given position and invokes
-- the callback for every node in the surroundings.
--
-- For example if you want to iterate over the direct neighbourse in all
-- dimensions, you'd do the following:
--
--    nodeutil.surroundings(pos, -1, 1, -1, 1, -1, 1, callback)
--
-- @param pos The position that is the center.
-- @param x_begin The modifier for the beginning in the x dimension.
-- @param x_end The modifier for the end in the x dimension.
-- @param z_begin The modifier for the beginning in the z dimension.
-- @param z_end The modifier for the end in the z dimension.
-- @param y_begin The modifier for the beginning in the y dimension.
-- @param y_end The modifier for the end in the y dimension.
-- @param callback The callback to invoke for every surrounding node. can
--                 return true if iterating over the surroundings should be
--                 stopped.
-- @return true if the iterating over the surroundings has been stopped by
--         a callback.
function nodeutil.surroundings(pos, x_begin, x_end, z_begin, z_end, y_begin, y_end, callback)
	for x = pos.x + x_begin, pos.x + x_end, 1 do
		for z = pos.z + z_begin, pos.z + z_end, 1 do
			for y = pos.y + y_begin, pos.y + y_end, 1 do
				if x ~= pos.x or z ~= pos.z or y ~= pos.y then
					local current_pos = {
						x = x,
						y = y,
						z = z
					}
					
					if callback(current_pos, minetest.get_node(current_pos)) then
						return true
					end
				end
			end
		end
	end
	
	return false
end