api.lua

-- You can use light_tool.add_tool(<ItemStack>, range) to define your own torches
-- and you can use light_tool.light_beam(pos, dir, range) to define your own light beam
-- also you can use  light_tool.register_glow_node(name) to make it so the beam travels through that block (e.g. To make it work underwater)

light_tool = {}
light_tool.tools = {}
light_tool.range = {}
light_tool.lightable_nodes = {}
light_tool.lit_nodes = {}
light_tool.light_beam = function(pos, dir, range)
	-- Normalize dir to have longest component == 1.
	local normalized_dir = vector.divide(dir, math.max(math.abs(dir.x), math.abs(dir.y), math.abs(dir.z), 0.01))
	
	for i = 0, math.floor(range / vector.length(normalized_dir)) do
		local new_pos = vector.add(pos, vector.multiply(normalized_dir, i))
		
		local node = minetest.get_node_or_nil(new_pos)
		if not node or not node.name then 
			return 
		end
		local def = minetest.registered_nodes[node.name]
		if not def then return end
		local lightable = light_tool.check(light_tool.lightable_nodes, node.name)
		local lightable_index = light_tool.check_index(light_tool.lightable_nodes, node.name)
		local lit = light_tool.check(light_tool.lit_nodes, node.name)
		if node.name == "air" or node.name == "light_tool:light" then
			minetest.set_node(new_pos, {name = "light_tool:light"})
		elseif lightable or node.name == lit then
			
			local index = light_tool.check_index(light_tool.lightable_nodes, node.name)
			minetest.set_node(new_pos, {name = light_tool.lightable_nodes[index].."_glowing"})
			
		elseif def and def.sunlight_propagates == false and not lightable and not lit then
			break
		end
	end
end

light_tool.add_tool = function(toolname, range)
	table.insert(light_tool.tools, toolname)
	table.insert(light_tool.range, range)
end

light_tool.register_glow_node = function(name)
	-- Thanks to duane from the MT forums for helping me with this function
	if not (name and type(name) == 'string') then
		return
	end
	if not minetest.registered_nodes[name] then
		return
	end
	
	local node = minetest.registered_nodes[name]
	local def = table.copy(node)
	
	def.paramtype = "light"
	def.light_source = 4
	def.on_construct = function(pos)
		minetest.after(0.1, function()
	        minetest.set_node(pos, {name = name})
	    end)
    end
    
	minetest.register_lbm({
		name = ":"..name.."_glowing_removal",
		nodenames = {name.."_glowing"},
		run_at_every_load = true, 
		action = function(pos, node)
			minetest.set_node(pos, {name = name})
		end,
	})
	minetest.register_node(":"..name.."_glowing", def)
	table.insert(light_tool.lightable_nodes, name)
	table.insert(light_tool.lit_nodes, name.."_glowing")
end
light_tool.directional_pos = function(pos, direction, multiplier, addition)
	if addition == nil then
		addition = 0
	end
	return vector.floor({
		x = pos.x + (direction.x * multiplier+addition),
		y = pos.y  + (direction.y * multiplier+addition),
        z = pos.z + (direction.z * multiplier+addition),
	})
end
light_tool.falling_node_check = function(pos, dist)
	--return false --function is currently unstable
	local objects = minetest.get_objects_inside_radius(pos, dist)
	for i, ob in pairs(objects) do
		local en = ob:get_luaentity()
		if en and en.name == "__builtin:falling_node" then
			return true
		end
	end
	return false
	--
end

light_tool.check = function(table, value)
	for i,v in ipairs(table) do
		if v == value then
			return true
		else
			return false
		end
	end
end

light_tool.check_index = function(table, value)
	for i,v in ipairs(table) do
		if v == value then
			return i
		end
	end
end