vm_lighting_wand/core/pointed_node.lua

local MT = minetest
local vMod = vm_lighting_wand

-- returns a noderef only if its still registered (uninstalled mod)
local get_registered_node = function(pos)
	local node = MT.get_node_or_nil(pos)
	return MT.registered_nodes[node.name] ~= nil and MT.registered_nodes[node.name] or nil
end

local check_groups = function(groups)
	if groups == nil then
		return true
	end
	for group, _ in pairs(groups) do
		if vMod.is_ignored_group(group) ~= nil then
			return false
		end
	end
	return true
end

-- given a player will return where ever the crosshair is pointing upto range limit
vMod.get_pointed_node = function(player, objects, sneak, range)
	local result
	local eye_height = player:get_properties().eye_height or 1.625
	local eye_offset = player:get_eye_offset()
	local eye_pos = {
		x = eye_offset.x * 0.1,
		y = eye_height + eye_offset.y,
		z = eye_offset.z * 0.1
	}
	local pos = vector.add(player:get_pos(), eye_pos)
	local dir = player:get_look_dir()
	sneak = sneak and player:get_player_control().sneak or false
	objects = objects or false
	local ray = MT.raycast(pos, vector.add(pos, vector.multiply(dir, range)), objects, sneak)
	for pointed_thing in ray do
		local node_under = get_registered_node(pointed_thing.under)
		-- we found a node, check its not ignored
		if node_under ~= nil then
			if not vMod.is_ignored_drawtype(node_under.drawtype) and not vMod.is_ignored_name(node_under.name) then
				if check_groups(node_under.groups) then
					result = {
						pos_under = pointed_thing.under,
						pos_above = pointed_thing.above,
						node_under = node_under,
						node_above = get_registered_node(pointed_thing.above)
					}
					break
				end
			end
		else
			-- looks like we found a unknown node - uninstalled mod
			result = {
				pos_under = pointed_thing.under,
				pos_above = pointed_thing.above,
				node_under = nil,
				node_above = get_registered_node(pointed_thing.above)
			}
			break
		end
	end
	return result
end