fixes

src/main/java/io/github/retrooper/packetevents/packettype/PacketTypeClasses.java

@@ -180,14 +180,14 @@ public class PacketTypeClasses {
                         GROUND = SubclassUtil.getSubClass(FLYING, 0);
                     }
                     if (POSITION == null) {
-                        GROUND = SubclassUtil.getSubClass(FLYING, 2);
+                        POSITION = SubclassUtil.getSubClass(FLYING, 2);
                     }
                     if (POSITION_LOOK == null) {
-                        GROUND = SubclassUtil.getSubClass(FLYING, 3);
+                        POSITION_LOOK = SubclassUtil.getSubClass(FLYING, 3);
                     }
 
                     if (LOOK == null) {
-                        GROUND = SubclassUtil.getSubClass(FLYING, 1);
+                        LOOK = SubclassUtil.getSubClass(FLYING, 1);
                     }
                 }
                 else {

src/main/java/io/github/retrooper/packetevents/packetwrappers/WrappedPacket.java

@@ -416,9 +416,17 @@ public class WrappedPacket implements WrapperPacketReader, WrapperPacketWriter {
     public Vector3i readBlockPosition(int index) {
         Object blockPosObj = readObject(index, NMSUtils.blockPosClass);
         try {
-            int x = (Integer) NMSUtils.getBlockPosX.invoke(blockPosObj);
-            int y = (Integer) NMSUtils.getBlockPosY.invoke(blockPosObj);
-            int z = (Integer) NMSUtils.getBlockPosZ.invoke(blockPosObj);
+            int x, y, z;
+            if (version.isNewerThanOrEquals(ServerVersion.v_1_20_5)) {
+                x = (int) NMSUtils.getBaseBlockPosX.get(blockPosObj);
+                y = (int) NMSUtils.getBaseBlockPosY.get(blockPosObj);
+                z = (int) NMSUtils.getBaseBlockPosZ.get(blockPosObj);
+            }
+            else {
+                x = (int) NMSUtils.getBlockPosX.invoke(blockPosObj);
+                y = (int) NMSUtils.getBlockPosY.invoke(blockPosObj);
+                z = (int) NMSUtils.getBlockPosZ.invoke(blockPosObj);
+            }
             return new Vector3i(x, y, z);
         } catch (IllegalAccessException | InvocationTargetException e) {
             e.printStackTrace();

src/main/java/io/github/retrooper/packetevents/utils/nms/NMSUtils.java

@@ -59,6 +59,7 @@ public final class NMSUtils {
             asNMSCopy, getMessageMethod, chatFromStringMethod, getMaterialFromNMSBlock, getNMSBlockFromMaterial,
             getMobEffectListId, getMobEffectListById, getItemId, getItemById, getBukkitEntity;
     private static Field entityPlayerPingField, entityBoundingBoxField, mobEffectsRegistryField;
+    public static Field  getBaseBlockPosX, getBaseBlockPosY, getBaseBlockPosZ;
     private static Object minecraftServer;
     private static Object minecraftServerConnection;
 
@@ -258,6 +259,15 @@ public final class NMSUtils {
             }
         }
 
+        Class<?> baseBlockPosClass = NMSUtils.getNMSClassWithoutException("BaseBlockPosition");
+        if (baseBlockPosClass == null) {
+            baseBlockPosClass = getNMClassWithoutException("core.BaseBlockPosition");
+        }
+        if (baseBlockPosClass != null) {
+            getBaseBlockPosX = Reflection.getField(baseBlockPosClass, int.class, 0);
+            getBaseBlockPosY = Reflection.getField(baseBlockPosClass, int.class, 1);
+            getBaseBlockPosZ = Reflection.getField(baseBlockPosClass, int.class, 2);
+        }
         vec3DClass = NMSUtils.getNMSClassWithoutException("Vec3D");
         if (vec3DClass == null) {
             vec3DClass = getNMClassWithoutException("world.phys.Vec3D");
@@ -379,6 +389,9 @@ public final class NMSUtils {
             // Mappings changed with 1.18
             if (getBlockPosX == null) {
                 getBlockPosX = Reflection.getMethod(NMSUtils.blockPosClass, "u", int.class);
+                if (getBlockPosX == null) {
+
+                }
             }
             if (getBlockPosY == null) {
                 getBlockPosY = Reflection.getMethod(NMSUtils.blockPosClass, "v", int.class);