Fix for plugins that use display entities as nametag (#5157)

* Fix for display entity nametags

* Added check

* Moved lines count to TextDisplayEntity class
Removed useless offset

* Reset lines when text is null

* Conversation changes

* Changed y offset formula
Removed space

* Played around with the yOffset a bit

---------

Co-authored-by: Tim203 <mctim203@gmail.com>

core/src/main/java/org/geysermc/geyser/entity/type/TextDisplayEntity.java

@@ -25,18 +25,25 @@
 
 package org.geysermc.geyser.entity.type;
 
+import lombok.Getter;
 import net.kyori.adventure.text.Component;
+import net.kyori.adventure.text.serializer.plain.PlainTextComponentSerializer;
 import org.cloudburstmc.math.vector.Vector3f;
 import org.cloudburstmc.protocol.bedrock.data.entity.EntityDataTypes;
 import org.geysermc.geyser.entity.EntityDefinition;
 import org.geysermc.geyser.session.GeyserSession;
 import org.geysermc.geyser.translator.text.MessageTranslator;
 import org.geysermc.mcprotocollib.protocol.data.game.entity.metadata.EntityMetadata;
+import org.jetbrains.annotations.Nullable;
 
 import java.util.UUID;
 
 // Note: 1.19.4 requires that the billboard is set to something in order to show, on Java Edition
+@Getter
 public class TextDisplayEntity extends DisplayBaseEntity {
+
+    private int lineCount;
+
     public TextDisplayEntity(GeyserSession session, int entityId, long geyserId, UUID uuid, EntityDefinition<?> definition, Vector3f position, Vector3f motion, float yaw, float pitch, float headYaw) {
         super(session, entityId, geyserId, uuid, definition, position.add(0, definition.offset(), 0), motion, yaw, pitch, headYaw);
     }
@@ -61,5 +68,14 @@ public class TextDisplayEntity extends DisplayBaseEntity {
 
     public void setText(EntityMetadata<Component, ?> entityMetadata) {
         this.dirtyMetadata.put(EntityDataTypes.NAME, MessageTranslator.convertMessage(entityMetadata.getValue()));
+        calculateLineCount(entityMetadata.getValue());
+    }
+
+    private void calculateLineCount(@Nullable Component text) {
+        if (text == null) {
+            lineCount = 0;
+            return;
+        }
+        lineCount = PlainTextComponentSerializer.plainText().serialize(text).split("\n").length;
     }
 }

core/src/main/java/org/geysermc/geyser/util/EntityUtils.java

@@ -209,6 +209,18 @@ public final class EntityUtils {
                         zOffset = displayTranslation.getZ();
                     }
                 }
+                case PLAYER -> {
+                    if (passenger instanceof TextDisplayEntity textDisplay) {
+                        Vector3f displayTranslation = textDisplay.getTranslation();
+                        int lines = textDisplay.getLineCount();
+                        if (displayTranslation != null && lines != 0) {
+                            float multiplier = .1414f;
+                            xOffset = displayTranslation.getX();
+                            yOffset += displayTranslation.getY() + multiplier * lines;
+                            zOffset = displayTranslation.getZ();
+                        }
+                    }
+                }
             }
             if (mount instanceof ChestBoatEntity) {
                 xOffset = 0.15F;