Add mirror dir helper function

mods/lzr_laser/blocks.lua

@@ -1,5 +1,48 @@
 local S = minetest.get_translator("lzr_laser")
 
+local mirror_out = {
+	[0] = {1,0,0},
+	[1] = {0,0,-1},
+	[2] = {-1,0,0},
+	[3] = {0,0,1},
+
+	[4] = {1,0,0},
+	[5] = {0,1,0},
+	[6] = {-1,0,0},
+	[7] = {0,-1,0},
+
+	[8] = {1,0,0},
+	[9] = {0,-1,0},
+	[10] = {-1,0,0},
+	[11] = {0,1,0},
+
+	[12] = {0,-1,0},
+	[13] = {0,0,-1},
+	[14] = {0,1,0},
+	[15] = {0,0,1},
+
+	[16] = {0,1,0},
+	[17] = {0,0,-1},
+	[18] = {0,-1,0},
+	[19] = {0,0,1},
+
+	[20] = {-1,0,0},
+	[21] = {0,0,-1},
+	[22] = {1,0,0},
+	[23] = {0,0,1},
+}
+
+lzr_laser.get_mirror_dirs = function(param2)
+	local dir_input = minetest.facedir_to_dir(param2)
+	if not dir_input then
+		return
+	end
+	dir_input = vector.multiply(dir_input, -1)
+	local dir_output = vector.new(unpack(mirror_out[param2]))
+
+	return dir_input, dir_output
+end
+
 minetest.register_node("lzr_laser:mirror", {
 	description = S("Mirror"),
 	paramtype2 = "facedir",