Hide sign/frame entity from player

I'm (hopefully) going to make a flag plugin for WorldGuard that will disable showing signs/item frames for a region, unless a player is inside that region.

I know it's possible to hide players from players, but how would hide signs and item frames from players?

 

Look into packet blocking with ProtocolLib

 

So I'm looking at PacketLib now... I'm honestly not sure how I'd stop signs etc from being viewed... A little more help?

 

You can use player.sendBlockChange and set the material as air for all the signs.

 

What about paintings and frames? They're entities, not blocks, so...

 

Right. It's possible to use BlockPatcher to prevent the sign block from ever being sent, though it's probably overkill.

Instead, you can use sendBlockChange() to simply reset all the sign blocks as their written content is sent to the player. You can also block the painting and the item frame from being spawned as well (download):

Code:java

public class ExampleMod extends JavaPlugin {
    @Override
    public void onEnable() {
        final ProtocolManager manager = ProtocolLibrary.getProtocolManager();
 
        manager.addPacketListener(
            new PacketAdapter(this, ConnectionSide.SERVER_SIDE, 
                    Packets.Server.VEHICLE_SPAWN, 
                    Packets.Server.ENTITY_METADATA) {
                @Override
                public void onPacketSending(PacketEvent event) {
                    if (!event.getPlayer().hasPermission("cansee.itemframe")) {
                        // Handle the spawn packet and the metadata packet
                        if (event.getPacketID() == Packets.Server.VEHICLE_SPAWN) {
                            Packet17SpawnObjectVehicle spawnFrame = new Packet17SpawnObjectVehicle(event.getPacket());
 
                            // Use getX(), getY() and getZ() to get the coordinates.
                            if (spawnFrame.getType() == Packet17SpawnObjectVehicle.ObjectTypes.ITEM_FRAME) {
                                // Excellent - disable it
                                event.setCancelled(true);
                            }
 
                        // The packet that updates the content of the item frame
                        } else {
                            Packet28EntityMetadata metadata = new Packet28EntityMetadata(event.getPacket());
 
                            if (metadata.getEntity(event) instanceof ItemFrame) {
                                event.setCancelled(true);
                            }
                        }
                    }
                }
            });
 
        manager.addPacketListener(
            new PacketAdapter(this, ConnectionSide.SERVER_SIDE, 
                        Packets.Server.ENTITY_PAINTING) {
                    @Override
                    public void onPacketSending(PacketEvent event) {
                        if (!event.getPlayer().hasPermission("cansee.painting")) {
                            //Packet19SpawnPainting spawnPainting = new Packet19SpawnPainting(event.getPacket());
 
                            // We'll just cancel it all - but you can get the coordindates of the painting
                            event.setCancelled(true);
                        }
                    }
                }
            );
 
        manager.addPacketListener(
            new PacketAdapter(this, ConnectionSide.SERVER_SIDE, 
                        Packets.Server.UPDATE_SIGN) {
                    @Override
                    public void onPacketSending(PacketEvent event) {
                        if (!event.getPlayer().hasPermission("cansee.sign")) {
                            Packet82UpdateSign spawnPainting = new Packet82UpdateSign(event.getPacket());
                            Location loc = new Location(
                                            event.getPlayer().getWorld(), 
                                            spawnPainting.getX(), spawnPainting.getY(), spawnPainting.getZ());
 
                            // Don't update the sign
                            event.setCancelled(true);
 
                            // Send a fake block update
                            event.getPlayer().sendBlockChange(loc, Material.AIR, (byte)0);
                        }
                    }
                }
            );
    }
}

Note, you'll need to add in a few classes from PacketWrapper to get the code above working.

The biggest problem is probably how to update players that have suddenly received permission to see the signs or paintings. A simple hack is to teleport them to a different spot, and then back again.

 

Holy shit, thanks! That looks like it'll do everything I want! I'll take a look at it, see if I can fit it to the example I want. Again, thanks!