private final ProtocolManager pm = ProtocolLibrary.getProtocolManager(); //Hooks into ProtocolLib
private Set<UUID> ghosts = new HashSet<UUID>(); //Keeps track of players who should be semi-transparent
public GhostMaker(Plugin plugin) {
pm.addPacketListener(new PacketAdapter(plugin, PacketType.Play.Server.SPAWN_ENTITY) { //Listen for anytime a player may see another entity
@Override
public void onPacketSending(PacketEvent event) {
Entity entity = event.getPacket().getEntityModifier(event).read(0);
if (entity != null
&& entity instanceof Player
&& ghosts.contains(entity.getUniqueId()) { //Player can potentially see a ghost
showAsGhost(event.getPlayer(), (Player) entity); //Render the ghost as semi-transparent
}
}
});
}
public void addGhost(Player player) {
if (ghosts.add(player.getUniqueId())) {
player.addPotionEffect(new PotionEffect(PotionEffectType.INVISIBILITY, Integer.MAX_VALUE, 2), true); //Apply invisibility to the ghost
showAsGhost(player, player); //Let ghost see themselves as a ghost
for (Player viewer : pm.getEntityTrackers(player)) { //Send a packet to anyone who can "see" the ghost
showAsGhost(viewer, player);
}
}
}
public void removeGhost(Player player) {
if (ghosts.remove(player.getUniqueId())) {
player.removePotionEffect(PotionEffectType.INVISIBILITY); //Remove invisibility
for (Player viewer : Bukkit.getServer().getOnlinePlayers()) { //Send removal packets to every player (some that recv'd the addGhost packet may no longer be in range)
PacketContainer packet = pm.createPacket(PacketType.Play.Server.SCOREBOARD_TEAM, true);
packet.getStrings().write(0, viewer.getEntityId() + "." + player.getEntityId()); //Make the team name unique to both the viewer and the ghost
packet.getIntegers().write(1, 1); //We are removing this team
try {
pm.sendServerPacket(viewer, packet); //Only the viewer needs to be sent the packet
} catch (InvocationTargetException e) {
e.printStackTRace();
}
}
}
}
private void showAsGhost(Player viewer, Player player) {
PacketContainer packet = pm.createPacket(PacketType.Play.Server.SCOREBOARD_TEAM, true);
packet.getStrings().write(0, viewer.getEntityId() + "." + player.getEntityId()); //Make the team name unique to both the viewer and the ghost
packet.getIntegers().write(1, 0); //We are creating a new team
packet.getModifier().write(6, Lists.newArrayList(viewer.getName(), player.getName())); //Team only consists of the ghost and the viewer
packet.getIntegers().write(2, 3); //Ghost can be seen and attacked by the viewer
try {
pm.sendServerPacket(viewer, packet); //Only the viewer needs to be sent the packet
} catch (InvocationTargetException e) {
e.printStackTRace();
}
}
