Implement Hologram

nPaper-API/src/main/java/io/noks/Hologram.java

@@ -0,0 +1,17 @@
+public interface Hologram {	
+	void delete();
+
+	String getMessage();
+
+	void setMessage(String paramString);
+
+	Location getLocation();
+
+	void setMessageHandler(MessageHandler paramMessageHandler);
+
+	Hologram addLineBelow(String text);
+
+	public static interface MessageHandler {
+		String getMessage(Player param1Player, String param1String);
+	}
+}

nPaper-API/src/main/java/org/bukkit/Server.java

@@ -904,4 +904,11 @@ public double[] getTPS()
     }
 
     Spigot spigot();
+
+    /**
+     * Spawn a new hologram.
+     *
+     * @return Created Hologram
+     */
+    public Hologram newHologram(Location location, String text);
 }

nPaper-Server/src/main/java/io/noks/cb/CraftHologram.java

@@ -0,0 +1,237 @@
+package io.noks.cb;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Set;
+import java.util.UUID;
+import java.util.WeakHashMap;
+
+import org.bukkit.Bukkit;
+import org.bukkit.Location;
+import org.bukkit.craftbukkit.CraftWorld;
+import org.bukkit.entity.Player;
+
+import com.avaje.ebean.validation.NotNull;
+
+import io.noks.Hologram;
+import net.minecraft.server.Chunk;
+import net.minecraft.server.DataWatcher;
+import net.minecraft.server.Entity;
+import net.minecraft.server.EntityPlayer;
+import net.minecraft.server.MathHelper;
+import net.minecraft.server.PacketPlayOutAttachEntity;
+import net.minecraft.server.PacketPlayOutEntityDestroy;
+import net.minecraft.server.PacketPlayOutEntityTeleport;
+import net.minecraft.server.PacketPlayOutSpawnEntity;
+import net.minecraft.server.PacketPlayOutSpawnEntityLiving;
+import net.minecraft.server.WorldServer;
+
+public class CraftHologram implements Hologram {
+	private static final List<CraftHologram> holograms = new ArrayList<CraftHologram>();
+	private String text;
+	private Location location;
+	private final int entityId;
+	private @NotNull final UUID uuid;
+	private Set<EntityPlayer> viewers = Collections.newSetFromMap(new WeakHashMap<>());
+	private final int viewDistance = 32;
+	private Hologram.MessageHandler messageHandler;
+	private int playerSearchTick = 0;
+
+	public CraftHologram(Location location, String text) {
+		this.text = text;
+		this.location = location;
+		this.entityId = Entity.entityCount;
+		Entity.entityCount += 2;
+		this.uuid = UUID.randomUUID();
+		holograms.add(this);
+	}
+
+	public static void tickAll() {
+		final Iterator<CraftHologram> iter = holograms.iterator();
+		while (iter.hasNext()) {
+			CraftHologram hologram = iter.next();
+			if (hologram.location == null) {
+				iter.remove();
+				continue;
+			}
+			hologram.tick();
+		}
+	}
+
+	private void tick() {
+		if (--this.playerSearchTick < 0) {
+	        this.playerSearchTick = 10;
+	        final double viewDistanceSq = this.viewDistance * this.viewDistance;
+	        final Iterator<EntityPlayer> iter = this.viewers.iterator();
+		    while (iter.hasNext()) {
+		        EntityPlayer player = iter.next();
+		        if (shouldRemovePlayer(player, this.location, viewDistanceSq)) {
+		            iter.remove();
+		            sendDestroyPacket(player);
+		        }
+	        }
+	        WorldServer world = ((CraftWorld) this.location.getWorld()).getHandle();
+	        int chunkX = this.location.getBlockX() >> 4;
+	        int chunkZ = this.location.getBlockZ() >> 4;
+	        for (int x = chunkX - 1; x <= chunkX + 1; x++) {
+	            for (int z = chunkZ - 1; z <= chunkZ + 1; z++) {
+	                Chunk chunk = world.getChunkIfLoaded(x, z);
+	                if (chunk == null) continue;
+
+	                for (EntityPlayer player : chunk.playersInChunk) {
+	                    if (!this.viewers.contains(player) && shouldAddPlayer(player, this.location, viewDistanceSq)) {
+	                        this.viewers.add(player);
+	                        sendSpawnPackets(player);
+	                    }
+	                }
+	            }
+	        }
+	    }
+	}
+
+	private boolean shouldRemovePlayer(EntityPlayer player, Location hologramLocation, double viewDistanceSq) {
+	    return player.dead || player.world.getWorld() != hologramLocation.getWorld() || player.getBukkitEntity().getLocation().distanceSquared(hologramLocation) > viewDistanceSq;
+	}
+
+	private boolean shouldAddPlayer(EntityPlayer player, Location hologramLocation, double viewDistanceSq) {
+	    return player.getBukkitEntity().getLocation().distanceSquared(hologramLocation) < viewDistanceSq;
+	}
+
+	public void delete() {
+		this.location = null;
+		this.text = null;
+		for (EntityPlayer player : this.viewers) {
+			sendDestroyPacket(player);
+		}
+		this.viewers = null;
+	}
+
+	public String getMessage() {
+		return this.text;
+	}
+
+	public void setMessage(String msg) {
+		this.text = msg;
+		for (EntityPlayer player : this.viewers) {
+			sendMessagePacket(player);
+		}
+	}
+
+	public Location getLocation() {
+		return this.location;
+	}
+
+	public void setMessageHandler(Hologram.MessageHandler messageHandler) {
+		this.messageHandler = messageHandler;
+	}
+
+	private void sendSpawnPackets(EntityPlayer player) {
+		if (player.playerConnection.networkManager.getVersion() < 47) {
+			final PacketPlayOutSpawnEntity skullPacket = new PacketPlayOutSpawnEntity();
+		    skullPacket.a = this.entityId + 1;
+		    skullPacket.b = MathHelper.floor(this.location.getX() * 32.0D);
+		    skullPacket.c = MathHelper.floor((this.location.getY() + 54.55D) * 32.0D);
+		    skullPacket.d = MathHelper.floor(this.location.getZ() * 32.0D);
+		    skullPacket.j = 64;
+		    final PacketPlayOutAttachEntity attachEntityPacket = new PacketPlayOutAttachEntity();
+		    attachEntityPacket.leash = 0;
+		    attachEntityPacket.entityId = this.entityId;
+		    attachEntityPacket.vehicleEntityId = this.entityId + 1;
+		    final PacketPlayOutSpawnEntityLiving horsePacket = new PacketPlayOutSpawnEntityLiving();
+		    horsePacket.a = this.entityId;
+		    horsePacket.b = 100; 
+		    horsePacket.c = MathHelper.floor(location.getX() * 32.0D);
+		    horsePacket.d = MathHelper.floor(location.getY() * 32.0D);
+		    horsePacket.e = MathHelper.floor(location.getZ() * 32.0D);
+		    horsePacket.l = new DataWatcher(null);
+
+		    horsePacket.l.a(10, getMessageForPlayer(player));
+		    horsePacket.l.a(11, (byte) 1);
+		    horsePacket.l.a(12, -1700000);
+
+		    player.playerConnection.sendPacket(horsePacket);
+		    player.playerConnection.sendPacket(skullPacket);
+		    player.playerConnection.sendPacket(attachEntityPacket);
+		    return;
+		}
+		final PacketPlayOutEntityTeleport packetPlayOutEntityTeleport = new PacketPlayOutEntityTeleport();
+	    packetPlayOutEntityTeleport.a = this.entityId;
+	    packetPlayOutEntityTeleport.b = MathHelper.floor(this.location.getX() * 32.0D);
+	    packetPlayOutEntityTeleport.c = MathHelper.floor((this.location.getY() - 0.25) * 32.0D);
+	    packetPlayOutEntityTeleport.d = MathHelper.floor(this.location.getZ() * 32.0D);
+	    packetPlayOutEntityTeleport.onGround = true;
+	    final PacketPlayOutSpawnEntityLiving armorStandPacket = new PacketPlayOutSpawnEntityLiving();
+		armorStandPacket.a = this.entityId;
+		armorStandPacket.b = 30;
+		armorStandPacket.c = packetPlayOutEntityTeleport.b;
+		armorStandPacket.d = packetPlayOutEntityTeleport.c;
+		armorStandPacket.e = packetPlayOutEntityTeleport.d;
+		armorStandPacket.l = new DataWatcher(null);
+
+		armorStandPacket.l.a(0, (byte) 0x20);
+		armorStandPacket.l.a(2, getMessageForPlayer(player));
+		armorStandPacket.l.a(3, (byte) 1);
+		armorStandPacket.l.a(10, (byte) 0x16);
+
+		player.playerConnection.sendPacket(armorStandPacket);
+		player.playerConnection.sendPacket(packetPlayOutEntityTeleport);
+	}
+
+	// TODO: ONLY REFRESH WHEN UNTRACKING AND TRACKING BACK WHEN USING THE NON RETRACK METHOD
+	private void sendMessagePacket(EntityPlayer player) {
+		this.retrack(player);
+		/*
+		final DataWatcher dataWatcher = new DataWatcher(null);
+        dataWatcher.a((player.playerConnection.networkManager.getVersion() < 47 ? 10 : 2), getMessageForPlayer(player));
+        final PacketPlayOutEntityMetadata metadataPacket = new PacketPlayOutEntityMetadata();
+        metadataPacket.a = this.entityId;
+        metadataPacket.b = dataWatcher.b();
+        player.playerConnection.sendPacket(metadataPacket);*/
+
+	}
+
+	/*private void sendMessagePacket(EntityPlayer player) {
+	    PacketPlayOutEntityMetadata metadataPacket = new PacketPlayOutEntityMetadata();
+	    metadataPacket.a = Entity.entityCount;
+	    metadataPacket.b = new DataWatcher(null).b(); // Initialize an empty DataWatcher and get list of WatchableObjects
+	    metadataPacket.b.add(new WatchableObject(10, 0, getMessageForPlayer(player))); // Add custom name for the hologram
+	    metadataPacket.b.add(new WatchableObject(11, 1, (byte) 1)); // Add flag for custom name
+	    player.playerConnection.sendPacket(metadataPacket);
+	}*/
+
+	private void sendDestroyPacket(EntityPlayer player) {
+		player.playerConnection.sendPacket(new PacketPlayOutEntityDestroy(new int[] { this.entityId, this.entityId + 1 }));
+	}
+
+	private String getMessageForPlayer(EntityPlayer player) {
+		String message = this.text;
+		if (message.contains("{player}"))
+			message = message.replace("{player}", player.getName());
+		if (message.contains("{displayname}"))
+			message = message.replace("{displayname}", player.getBukkitEntity().getDisplayName());
+		if (this.messageHandler != null)
+			try {
+				message = this.messageHandler.getMessage((Player) player.getBukkitEntity(), message);
+			} catch (Exception ex) {
+				Bukkit.getLogger().severe("Exception in CraftHologram.messageHandler:");
+				ex.printStackTrace();
+			}
+		if (message.length() > 64)
+			message = message.substring(0, 64);
+		return message;
+	}
+
+	@Override
+	public Hologram addLineBelow(String text) {
+		final Hologram holow = new CraftHologram(location.clone().subtract(0, 0.25, 0), text);
+		return holow;
+	}
+
+	// TEMP FIX
+	private void retrack(EntityPlayer player) {
+		this.sendDestroyPacket(player);
+		this.sendSpawnPackets(player);
+	}
+}

nPaper-Server/src/main/java/net/minecraft/server/MinecraftServer.java

@@ -812,6 +812,7 @@ public void v() {
         SpigotTimings.tickablesTimer.stopTiming(); // Spigot
 
         this.methodProfiler.b();
+        CraftHologram.tickAll();
     }
 
     private boolean needDayUpdate() {

nPaper-Server/src/main/java/org/bukkit/craftbukkit/CraftServer.java

@@ -1813,4 +1813,8 @@ public Spigot spigot()
     {
         return spigot;
     }
+
+    public Hologram newHologram(Location location, String text) {
+		return new CraftHologram(location.clone(), text);
+	}
 }