Development Sending dynamic data to the client

pra

Member
Mar 7, 2015
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Overworld
I can't figure out how GalactiCraft sends space station data to the clients when they connect.
It seems to be done in src/main/java/micdoodle8/mods/galacticraft/core/network/ConnectionPacket.java and ConnectionEvents.java, but I can't seem to replicate this.

My ConnectionEvents:
Code:
public class ConnectionEvents {
    private static boolean clientConnected = false;

    @SubscribeEvent
    public void onPlayerLogout(PlayerLoggedOutEvent event) {
        //ChunkLoadingCallback.onPlayerLogout(event.player);
    }

    @SubscribeEvent
    public void onPlayerLogin(PlayerLoggedInEvent event) {

    }

    @SubscribeEvent
    public void onConnectionReceived(ServerConnectionFromClientEvent event) {
 
        NBTTagCompound nbt = new NBTTagCompound ();
        ProceduralGalaxy.instance.getSolarSystemManager().writeToNBT(nbt);
        event.manager.scheduleOutboundPacket(
                ConnectionPacket.createUpdateSystemPacket(nbt)
        );
    
    }

    @SubscribeEvent
    public void onConnectionOpened(ClientConnectedToServerEvent event) {
        if (!event.isLocal) {
            ConnectionEvents.clientConnected = true;
        }
    }

    @SubscribeEvent
    public void onConnectionClosed(ClientDisconnectionFromServerEvent event) {
        if (ConnectionEvents.clientConnected) {
            ConnectionEvents.clientConnected = false;

        }
    }
}


My ConnectionPacket:
Code:
public class ConnectionPacket {
    public static final String CHANNEL = "proceduralgalaxy";
    public static FMLEventChannel bus;
   
   
   
    // I have no idea whenever I have to be unique here or something...
    public static final int PACKET_ID_UPDATE_DYN_SYSTEMS = 91;
   
    public static final int PACKET_SIGNATURE = 5381;
   
    public void handle(ByteBuf payload, EntityPlayer player) {
        int packetId = payload.readByte();
        List<Object> data = new ArrayList<Object>();
        // no idea how this actually works...
       
        Class<?>[] test = {NBTTagCompound.class};
       
        switch (packetId) {
        case PACKET_ID_UPDATE_DYN_SYSTEMS:
            data = NetworkUtil.decodeData(test, payload);
            break;
       

        default:
        }
        if (payload.readInt() != PACKET_SIGNATURE) {
            GCLog.severe("Packet completion problem for connection packet "
                    + packetId
                    + " - maybe the player's Galacticraft version does not match the server version?");
        }
    }

    public static FMLProxyPacket createPacket(byte packetId,
            Collection<Integer> data) {
        ByteBuf payload = Unpooled.buffer();
        payload.writeByte(packetId);
        payload.writeInt(data.size());
        for (Integer i : data) {
            payload.writeInt(i.intValue());
        }
        payload.writeInt(3519); // signature
        return new FMLProxyPacket(payload, CHANNEL);
    }

    public static FMLProxyPacket createUpdateSystemPacket(NBTTagCompound data) {
        List<Object> data1 = new ArrayList<Object>();
        data1.add(data);
        // NBTTagCompound data
        ByteBuf payload = Unpooled.buffer();
        payload.writeByte(PACKET_ID_UPDATE_DYN_SYSTEMS);
        try {
            NetworkUtil.encodeData(payload, data1);
        } catch (IOException e) {
            e.printStackTrace();
        }
        payload.writeInt(PACKET_SIGNATURE); // signature
        return new FMLProxyPacket(payload, CHANNEL);
    }

    @SubscribeEvent
    @SideOnly(Side.CLIENT)
    public void onPacketData(FMLNetworkEvent.ClientCustomPacketEvent event) {
        FMLProxyPacket pkt = event.packet;
        onFMLProxyPacketData(event.manager, pkt,
                Minecraft.getMinecraft().thePlayer);
    }

    @SubscribeEvent
    public void onPacketData(FMLNetworkEvent.ServerCustomPacketEvent event) {
        FMLProxyPacket pkt = event.packet;
        onFMLProxyPacketData(event.manager, pkt,
                ((NetHandlerPlayServer) event.handler).playerEntity);
    }

    public void onFMLProxyPacketData(NetworkManager manager,
            FMLProxyPacket packet, EntityPlayer player) {
        try {
            if ((packet == null) || (packet.payload() == null))
                throw new RuntimeException(
                        "Empty packet sent to channel"+CHANNEL);
            ByteBuf data = packet.payload();
            this.handle(data, player);
        } catch (Exception e) {
            GCLog.severe("GC login packet handler: Failed to read packet");
            GCLog.severe(e.toString());
            e.printStackTrace();
        }
    }
}
Then that in my preInit:
Code:
ConnectionPacket.bus = NetworkRegistry.INSTANCE.newEventDrivenChannel(ConnectionPacket.CHANNEL);

and in my init:
Code:
FMLCommonHandler.instance().bus().register(new ConnectionEvents());
mostly stolen from GC, but anyway.

What happens is this:
Code:
14:04:28] [Client thread/ERROR] [FML/]: FMLIndexedMessageCodec exception caught
io.netty.handler.codec.DecoderException: java.lang.NullPointerException: Undefined message for discriminator 91 in channel proceduralgalaxy
    at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:99) ~[MessageToMessageDecoder.class:?]
<etc...>
So it seems like I need to define/register the discriminator/packet ID somewhere, but where/how? GC doesn't seem to do it, or at least I couldn't find it anywhere? Or is it this part?
Code:
 static
{
EnumConnectionState.field_150761_f.put(PacketSimple.class, EnumConnectionState.PLAY);
EnumConnectionState.PLAY.field_150770_i.put(2515, PacketSimple.class);
}
from the ConnectionEvents? But how does this even work? Field field_150761_f is private, how can you put anything into it? And what does 2515 mean?
 

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