From 3a4014623eccb0187b355d38af5323654a313d84 Mon Sep 17 00:00:00 2001
From: FlorianMichael <florian.michael07@gmail.com>
Date: Mon, 26 Aug 2024 22:28:12 +0200
Subject: [PATCH] Spawn falling blocks at correct position

---
 .../rewriter/EntityPacketRewriter1_19_4.java  | 80 ++++++++++++++++++-
 .../storage/EntityTracker1_19_4.java          | 32 ++++----
 .../storage/LinkedEntityStorage.java          | 14 +++-
 3 files changed, 105 insertions(+), 21 deletions(-)

diff --git a/common/src/main/java/com/viaversion/viabackwards/protocol/v1_19_4to1_19_3/rewriter/EntityPacketRewriter1_19_4.java b/common/src/main/java/com/viaversion/viabackwards/protocol/v1_19_4to1_19_3/rewriter/EntityPacketRewriter1_19_4.java
index a733899d..9488f6e2 100644
--- a/common/src/main/java/com/viaversion/viabackwards/protocol/v1_19_4to1_19_3/rewriter/EntityPacketRewriter1_19_4.java
+++ b/common/src/main/java/com/viaversion/viabackwards/protocol/v1_19_4to1_19_3/rewriter/EntityPacketRewriter1_19_4.java
@@ -20,22 +20,26 @@ package com.viaversion.viabackwards.protocol.v1_19_4to1_19_3.rewriter;
 import com.viaversion.nbt.tag.CompoundTag;
 import com.viaversion.nbt.tag.ListTag;
 import com.viaversion.nbt.tag.NumberTag;
+import com.viaversion.viabackwards.api.entities.storage.EntityPositionHandler;
 import com.viaversion.viabackwards.api.entities.storage.EntityReplacement;
 import com.viaversion.viabackwards.api.rewriters.EntityRewriter;
 import com.viaversion.viabackwards.protocol.v1_19_4to1_19_3.Protocol1_19_4To1_19_3;
 import com.viaversion.viabackwards.protocol.v1_19_4to1_19_3.storage.LinkedEntityStorage;
 import com.viaversion.viabackwards.protocol.v1_19_4to1_19_3.storage.EntityTracker1_19_4;
+import com.viaversion.viaversion.api.data.entity.StoredEntityData;
 import com.viaversion.viaversion.api.minecraft.entities.EntityType;
 import com.viaversion.viaversion.api.minecraft.entities.EntityTypes1_19_3;
 import com.viaversion.viaversion.api.minecraft.entities.EntityTypes1_19_4;
 import com.viaversion.viaversion.api.minecraft.entitydata.EntityData;
 import com.viaversion.viaversion.api.minecraft.item.Item;
 import com.viaversion.viaversion.api.protocol.packet.PacketWrapper;
+import com.viaversion.viaversion.api.protocol.remapper.PacketHandler;
 import com.viaversion.viaversion.api.protocol.remapper.PacketHandlers;
 import com.viaversion.viaversion.api.type.Types;
 import com.viaversion.viaversion.api.type.types.version.Types1_19_3;
 import com.viaversion.viaversion.api.type.types.version.Types1_19_4;
 import com.viaversion.viaversion.libs.gson.JsonElement;
+import com.viaversion.viaversion.protocols.v1_13_2to1_14.packet.ClientboundPackets1_14;
 import com.viaversion.viaversion.protocols.v1_19_1to1_19_3.packet.ClientboundPackets1_19_3;
 import com.viaversion.viaversion.protocols.v1_19_3to1_19_4.packet.ClientboundPackets1_19_4;
 import com.viaversion.viaversion.util.TagUtil;
@@ -48,10 +52,40 @@ public final class EntityPacketRewriter1_19_4 extends EntityRewriter<Clientbound
 
     @Override
     public void registerPackets() {
-        registerTrackerWithData1_19(ClientboundPackets1_19_4.ADD_ENTITY, EntityTypes1_19_4.FALLING_BLOCK);
         registerRemoveEntities(ClientboundPackets1_19_4.REMOVE_ENTITIES);
         registerSetEntityData(ClientboundPackets1_19_4.SET_ENTITY_DATA, Types1_19_4.ENTITY_DATA_LIST, Types1_19_3.ENTITY_DATA_LIST);
 
+        protocol.registerClientbound(ClientboundPackets1_19_4.ADD_ENTITY, new PacketHandlers() {
+            @Override
+            public void register() {
+                map(Types.VAR_INT); // Entity id
+                map(Types.UUID); // Entity UUID
+                map(Types.VAR_INT); // Entity type
+                map(Types.DOUBLE); // X
+                map(Types.DOUBLE); // Y
+                map(Types.DOUBLE); // Z
+                map(Types.BYTE); // Pitch
+                map(Types.BYTE); // Yaw
+                map(Types.BYTE); // Head yaw
+                map(Types.VAR_INT); // Data
+                handler(wrapper -> {
+                    final int entityId = wrapper.get(Types.VAR_INT, 0);
+                    final int entityType = wrapper.get(Types.VAR_INT, 1);
+
+                    // First track (and remap) entity, then put storage for block display entity
+                    getSpawnTrackerWithDataHandler1_19(EntityTypes1_19_4.FALLING_BLOCK).handle(wrapper);
+                    if (entityType != EntityTypes1_19_4.BLOCK_DISPLAY.getId()) {
+                        return;
+                    }
+
+                    final StoredEntityData data = tracker(wrapper.user()).entityData(entityId);
+                    if (data != null) {
+                        data.put(new LinkedEntityStorage());
+                    }
+                });
+            }
+        });
+
         protocol.registerClientbound(ClientboundPackets1_19_4.LOGIN, new PacketHandlers() {
             @Override
             public void register() {
@@ -142,6 +176,40 @@ public final class EntityPacketRewriter1_19_4 extends EntityRewriter<Clientbound
             final int duration = wrapper.read(Types.VAR_INT);
             wrapper.write(Types.VAR_INT, duration == -1 ? 999999 : duration);
         });
+
+        // Track the position of block display entities to later spawn the linked entities, we will put them
+        // as passengers but the spawn position needs to be in the players view distance
+
+        protocol.registerClientbound(ClientboundPackets1_19_4.TELEPORT_ENTITY, wrapper -> {
+            final int entityId = wrapper.passthrough(Types.VAR_INT);
+            final double x = wrapper.passthrough(Types.DOUBLE);
+            final double y = wrapper.passthrough(Types.DOUBLE);
+            final double z = wrapper.passthrough(Types.DOUBLE);
+
+            final EntityTracker1_19_4 tracker = tracker(wrapper.user());
+            final LinkedEntityStorage storage = tracker.linkedEntityStorage(entityId);
+            if (storage == null) {
+                return;
+            }
+            storage.setCoordinates(x, y, z, false);
+        });
+
+        final PacketHandler entityPositionHandler = wrapper -> {
+            final int entityId = wrapper.passthrough(Types.VAR_INT);
+            final double x = wrapper.passthrough(Types.SHORT) / EntityPositionHandler.RELATIVE_MOVE_FACTOR;
+            final double y = wrapper.passthrough(Types.SHORT) / EntityPositionHandler.RELATIVE_MOVE_FACTOR;
+            final double z = wrapper.passthrough(Types.SHORT) / EntityPositionHandler.RELATIVE_MOVE_FACTOR;
+
+            final EntityTracker1_19_4 tracker = tracker(wrapper.user());
+            final LinkedEntityStorage storage = tracker.linkedEntityStorage(entityId);
+            if (storage == null) {
+                return;
+            }
+            storage.setCoordinates(x, y, z, true);
+        };
+
+        protocol.registerClientbound(ClientboundPackets1_19_4.MOVE_ENTITY_POS, entityPositionHandler);
+        protocol.registerClientbound(ClientboundPackets1_19_4.MOVE_ENTITY_POS_ROT, entityPositionHandler);
     }
 
     @Override
@@ -180,10 +248,14 @@ public final class EntityPacketRewriter1_19_4 extends EntityRewriter<Clientbound
             final int value = data.value();
 
             final EntityTracker1_19_4 tracker = tracker(event.user());
-            tracker.clearLinkedEntityStorage(event.entityId());
+            tracker.clearLinkedEntities(event.entityId());
 
-            final int linkedEntity = tracker.spawnEntity(EntityTypes1_19_3.FALLING_BLOCK, value);
-            tracker.entityData(event.entityId()).put(new LinkedEntityStorage(linkedEntity));
+            final LinkedEntityStorage storage = tracker.linkedEntityStorage(event.entityId());
+            if (storage == null) {
+                return;
+            }
+            final int linkedEntity = tracker.spawnEntity(EntityTypes1_19_3.FALLING_BLOCK, storage.x(), storage.y(), storage.z(), value);
+            storage.setEntities(linkedEntity);
 
             final PacketWrapper wrapper = PacketWrapper.create(ClientboundPackets1_19_3.SET_PASSENGERS, event.user());
             wrapper.write(Types.VAR_INT, event.entityId()); // Entity id
diff --git a/common/src/main/java/com/viaversion/viabackwards/protocol/v1_19_4to1_19_3/storage/EntityTracker1_19_4.java b/common/src/main/java/com/viaversion/viabackwards/protocol/v1_19_4to1_19_3/storage/EntityTracker1_19_4.java
index b398d60d..8449eacc 100644
--- a/common/src/main/java/com/viaversion/viabackwards/protocol/v1_19_4to1_19_3/storage/EntityTracker1_19_4.java
+++ b/common/src/main/java/com/viaversion/viabackwards/protocol/v1_19_4to1_19_3/storage/EntityTracker1_19_4.java
@@ -39,16 +39,16 @@ public final class EntityTracker1_19_4 extends EntityTrackerBase {
         super(connection, EntityTypes1_19_4.PLAYER);
     }
 
-    public int spawnEntity(final EntityTypes1_19_3 entityType, final int data) {
+    public int spawnEntity(final EntityTypes1_19_3 entityType, final double x, final double y, final double z, final int data) {
         final int entityId = nextEntityId();
 
         final PacketWrapper addEntity = PacketWrapper.create(ClientboundPackets1_19_3.ADD_ENTITY, user());
         addEntity.write(Types.VAR_INT, entityId); // Entity id
         addEntity.write(Types.UUID, UUID.randomUUID()); // Entity UUID
         addEntity.write(Types.VAR_INT, entityType.getId()); // Entity type
-        addEntity.write(Types.DOUBLE, 0.0); // X
-        addEntity.write(Types.DOUBLE, 0.0); // Y
-        addEntity.write(Types.DOUBLE, 0.0); // Z
+        addEntity.write(Types.DOUBLE, x); // X
+        addEntity.write(Types.DOUBLE, y); // Y
+        addEntity.write(Types.DOUBLE, z); // Z
         addEntity.write(Types.BYTE, (byte) 0); // Pitch
         addEntity.write(Types.BYTE, (byte) 0); // Yaw
         addEntity.write(Types.BYTE, (byte) 0); // Head yaw
@@ -63,34 +63,36 @@ public final class EntityTracker1_19_4 extends EntityTrackerBase {
         return entityId;
     }
 
-
     @Override
     public void clearEntities() {
         for (final int id : entities.keySet()) {
-            clearLinkedEntityStorage(id);
+            clearLinkedEntities(id);
         }
         super.clearEntities();
     }
 
     @Override
     public void removeEntity(final int id) {
-        clearLinkedEntityStorage(id);
+        clearLinkedEntities(id);
         super.removeEntity(id);
     }
 
-    public void clearLinkedEntityStorage(final int id) {
-        final TrackedEntity entity = entity(id);
-        if (entity == null || !entity.hasData()) {
-            return;
-        }
-
-        final LinkedEntityStorage storage = entity.data().get(LinkedEntityStorage.class);
-        if (storage != null) {
+    public void clearLinkedEntities(final int id) {
+        final LinkedEntityStorage storage = linkedEntityStorage(id);
+        if (storage != null && storage.entities() != null) {
             storage.remove(user());
             generatedEntities.remove(id);
         }
     }
 
+    public LinkedEntityStorage linkedEntityStorage(final int id) {
+        final TrackedEntity entity = entity(id);
+        if (entity != null && entity.hasData()) {
+            return entity.data().get(LinkedEntityStorage.class);
+        }
+        return null;
+    }
+
     private int nextEntityId() {
         final int entityId = -ThreadLocalRandom.current().nextInt(10_000);
         if (generatedEntities.contains(entityId)) {
diff --git a/common/src/main/java/com/viaversion/viabackwards/protocol/v1_19_4to1_19_3/storage/LinkedEntityStorage.java b/common/src/main/java/com/viaversion/viabackwards/protocol/v1_19_4to1_19_3/storage/LinkedEntityStorage.java
index 231410c0..5e34b51b 100644
--- a/common/src/main/java/com/viaversion/viabackwards/protocol/v1_19_4to1_19_3/storage/LinkedEntityStorage.java
+++ b/common/src/main/java/com/viaversion/viabackwards/protocol/v1_19_4to1_19_3/storage/LinkedEntityStorage.java
@@ -17,6 +17,7 @@
  */
 package com.viaversion.viabackwards.protocol.v1_19_4to1_19_3.storage;
 
+import com.viaversion.viabackwards.api.entities.storage.EntityPositionStorage;
 import com.viaversion.viabackwards.protocol.v1_19_4to1_19_3.Protocol1_19_4To1_19_3;
 import com.viaversion.viaversion.api.connection.StorableObject;
 import com.viaversion.viaversion.api.connection.UserConnection;
@@ -24,7 +25,17 @@ import com.viaversion.viaversion.api.protocol.packet.PacketWrapper;
 import com.viaversion.viaversion.api.type.Types;
 import com.viaversion.viaversion.protocols.v1_19_1to1_19_3.packet.ClientboundPackets1_19_3;
 
-public record LinkedEntityStorage(int... entities) implements StorableObject {
+public class LinkedEntityStorage extends EntityPositionStorage implements StorableObject {
+
+    private int[] entities;
+
+    public int[] entities() {
+        return entities;
+    }
+
+    public void setEntities(final int... entities) {
+        this.entities = entities;
+    }
 
     public void remove(final UserConnection connection) {
         final PacketWrapper wrapper = PacketWrapper.create(ClientboundPackets1_19_3.REMOVE_ENTITIES, connection);
@@ -32,5 +43,4 @@ public record LinkedEntityStorage(int... entities) implements StorableObject {
 
         wrapper.send(Protocol1_19_4To1_19_3.class);
     }
-
 }