Implement custom data tracker

src/main/java/com/minelittlepony/unicopia/Race.java

@@ -11,6 +11,7 @@ import com.minelittlepony.unicopia.ability.Abilities;
 import com.minelittlepony.unicopia.ability.Ability;
 import com.minelittlepony.unicopia.ability.magic.Affine;
 import com.minelittlepony.unicopia.util.RegistryUtils;
+import com.minelittlepony.unicopia.util.serialization.PacketCodec;
 import com.mojang.brigadier.context.CommandContext;
 import com.mojang.brigadier.exceptions.CommandSyntaxException;
 import com.mojang.brigadier.exceptions.DynamicCommandExceptionType;
@@ -44,6 +45,7 @@ public record Race (
     public static final String DEFAULT_ID = "unicopia:unset";
     public static final Registry<Race> REGISTRY = RegistryUtils.createDefaulted(Unicopia.id("race"), DEFAULT_ID);
     public static final Registry<Race> COMMAND_REGISTRY = RegistryUtils.createDefaulted(Unicopia.id("race/grantable"), DEFAULT_ID);
+    public static final PacketCodec<Race> PACKET_CODEC = PacketCodec.ofRegistry(REGISTRY);
     public static final RegistryKey<? extends Registry<Race>> REGISTRY_KEY = REGISTRY.getKey();
     private static final DynamicCommandExceptionType UNKNOWN_RACE_EXCEPTION = new DynamicCommandExceptionType(id -> Text.translatable("commands.race.fail", id));
     private static final Function<Race, Composite> COMPOSITES = Util.memoize(race -> new Composite(race, null, null));

src/main/java/com/minelittlepony/unicopia/ability/magic/SpellPredicate.java

@@ -7,10 +7,10 @@ import com.minelittlepony.unicopia.Affinity;
 import com.minelittlepony.unicopia.ability.magic.spell.*;
 import com.minelittlepony.unicopia.ability.magic.spell.effect.MimicSpell;
 import com.minelittlepony.unicopia.ability.magic.spell.effect.ShieldSpell;
-
 import net.minecraft.entity.Entity;
 
 public interface SpellPredicate<T extends Spell> extends Predicate<Spell> {
+    SpellPredicate<?> ALL = spell -> true;
     SpellPredicate<IllusionarySpell> CAN_SUPPRESS = s -> s instanceof IllusionarySpell;
     SpellPredicate<PlaceableSpell> IS_PLACED = s -> s instanceof PlaceableSpell;
     SpellPredicate<AbstractDisguiseSpell> IS_DISGUISE = s -> s instanceof AbstractDisguiseSpell;

src/main/java/com/minelittlepony/unicopia/client/render/spell/AllSpells.java

@@ -1,8 +0,0 @@
-package com.minelittlepony.unicopia.client.render.spell;
-
-import com.minelittlepony.unicopia.ability.magic.SpellPredicate;
-import com.minelittlepony.unicopia.ability.magic.spell.Spell;
-
-public interface AllSpells extends SpellPredicate<Spell> {
-    AllSpells INSTANCE = spell -> true;
-}

src/main/java/com/minelittlepony/unicopia/client/render/spell/SpellEffectsRenderDispatcher.java

@@ -11,6 +11,7 @@ import org.jetbrains.annotations.Nullable;
 import com.minelittlepony.unicopia.Unicopia;
 import com.minelittlepony.unicopia.ability.magic.Caster;
 import com.minelittlepony.unicopia.ability.magic.SpellContainer.Operation;
+import com.minelittlepony.unicopia.ability.magic.SpellPredicate;
 import com.minelittlepony.unicopia.ability.magic.spell.Spell;
 import com.minelittlepony.unicopia.ability.magic.spell.effect.SpellType;
 import com.minelittlepony.unicopia.entity.Living;
@@ -124,7 +125,7 @@ public class SpellEffectsRenderDispatcher implements SynchronousResourceReloader
                         caster.asEntity().getDisplayName().copy().append(" (" + Registries.ENTITY_TYPE.getId(caster.asEntity().getType()) + ")"),
                         caster.getMaster() != null ? Text.literal("Master: ").append(caster.getMaster().getDisplayName()) : Text.empty()
                 ),
-                caster.getSpellSlot().stream(AllSpells.INSTANCE, false).flatMap(spell ->
+                caster.getSpellSlot().stream(SpellPredicate.ALL, false).flatMap(spell ->
                     Stream.of(
                             Text.literal("UUID: " + spell.getUuid()),
                             Text.literal("|>Type: ").append(Text.literal(spell.getTypeAndTraits().type().getId().toString()).styled(s -> s.withColor(spell.getTypeAndTraits().type().getColor()))),

src/main/java/com/minelittlepony/unicopia/entity/Creature.java

@@ -21,6 +21,9 @@ import com.minelittlepony.unicopia.entity.ai.PrioritizedActiveTargetGoal;
 import com.minelittlepony.unicopia.entity.ai.TargettingUtil;
 import com.minelittlepony.unicopia.entity.ai.WantItTakeItGoal;
 import com.minelittlepony.unicopia.entity.mob.UEntityAttributes;
+import com.minelittlepony.unicopia.network.track.DataTracker;
+import com.minelittlepony.unicopia.network.track.TrackableDataType;
+import com.minelittlepony.unicopia.util.serialization.PacketCodec;
 
 import net.minecraft.entity.EntityType;
 import net.minecraft.entity.LivingEntity;
@@ -28,7 +31,6 @@ import net.minecraft.entity.SpawnGroup;
 import net.minecraft.entity.ai.goal.*;
 import net.minecraft.entity.attribute.DefaultAttributeContainer;
 import net.minecraft.entity.attribute.EntityAttributes;
-import net.minecraft.entity.data.DataTracker;
 import net.minecraft.entity.data.TrackedData;
 import net.minecraft.entity.data.TrackedDataHandlerRegistry;
 import net.minecraft.entity.mob.*;
@@ -39,13 +41,7 @@ import net.minecraft.nbt.NbtElement;
 import net.minecraft.util.math.MathHelper;
 
 public class Creature extends Living<LivingEntity> implements WeaklyOwned.Mutable<LivingEntity> {
-    private static final TrackedData<NbtCompound> EFFECT = DataTracker.registerData(LivingEntity.class, TrackedDataHandlerRegistry.NBT_COMPOUND);
+    static final TrackedData<NbtCompound> EFFECT = net.minecraft.entity.data.DataTracker.registerData(LivingEntity.class, TrackedDataHandlerRegistry.NBT_COMPOUND);
-    private static final TrackedData<NbtCompound> MASTER = DataTracker.registerData(LivingEntity.class, TrackedDataHandlerRegistry.NBT_COMPOUND);
-    public static final TrackedData<Float> GRAVITY = DataTracker.registerData(LivingEntity.class, TrackedDataHandlerRegistry.FLOAT);
-    private static final TrackedData<Integer> EATING = DataTracker.registerData(LivingEntity.class, TrackedDataHandlerRegistry.INTEGER);
-    private static final TrackedData<Boolean> DISCORDED = DataTracker.registerData(LivingEntity.class, TrackedDataHandlerRegistry.BOOLEAN);
-    private static final TrackedData<Boolean> SMITTEN = DataTracker.registerData(LivingEntity.class, TrackedDataHandlerRegistry.BOOLEAN);
-
     public static void boostrap() {}
 
     private final EntityPhysics<LivingEntity> physics;
@@ -69,26 +65,27 @@ public class Creature extends Living<LivingEntity> implements WeaklyOwned.Mutabl
                 .isEmpty();
     });
 
+    protected final DataTracker.Entry<NbtCompound> master;
+    protected final DataTracker.Entry<Integer> eating;
+    protected final DataTracker.Entry<Boolean> discorded;
+    protected final DataTracker.Entry<Boolean> smitten;
+
     public Creature(LivingEntity entity) {
-        super(entity, EFFECT);
+        super(entity);
-        physics = new EntityPhysics<>(entity, GRAVITY);
+        physics = new EntityPhysics<>(entity, tracker);
         addTicker(physics);
         addTicker(this::updateConsumption);
-    }
 
-    @Override
+        master = tracker.startTracking(TrackableDataType.of(PacketCodec.NBT), owner.toNBT());
-    public void initDataTracker() {
+        eating = tracker.startTracking(TrackableDataType.of(PacketCodec.INT), 0);
-        super.initDataTracker();
+        discorded = tracker.startTracking(TrackableDataType.of(PacketCodec.BOOLEAN), false);
-        entity.getDataTracker().startTracking(MASTER, owner.toNBT());
+        smitten = tracker.startTracking(TrackableDataType.of(PacketCodec.BOOLEAN), false);
-        entity.getDataTracker().startTracking(EATING, 0);
-        entity.getDataTracker().startTracking(DISCORDED, false);
-        entity.getDataTracker().startTracking(SMITTEN, false);
     }
 
     @Override
     public void setMaster(LivingEntity owner) {
         this.owner.set(owner);
-        entity.getDataTracker().set(MASTER, this.owner.toNBT());
+        tracker.set(master, this.owner.toNBT());
         if (owner != null) {
             targets.ifPresent(this::initMinionAi);
         }
@@ -99,20 +96,20 @@ public class Creature extends Living<LivingEntity> implements WeaklyOwned.Mutabl
     }
 
     public boolean isDiscorded() {
-        return entity.getDataTracker().get(DISCORDED);
+        return tracker.get(this.discorded);
     }
 
     public boolean isSmitten() {
-        return entity.getDataTracker().get(SMITTEN);
+        return tracker.get(this.smitten);
     }
 
     public void setSmitten(boolean smitten) {
         smittenTicks = smitten ? 20 : 0;
-        entity.getDataTracker().set(SMITTEN, smitten);
+        tracker.set(this.smitten, smitten);
     }
 
     public void setDiscorded(boolean discorded) {
-        entity.getDataTracker().set(DISCORDED, discorded);
+        tracker.set(this.discorded, discorded);
         discordedChanged = true;
     }
 
@@ -124,9 +121,8 @@ public class Creature extends Living<LivingEntity> implements WeaklyOwned.Mutabl
 
     @Override
     public EntityReference<LivingEntity> getMasterReference() {
-        if (entity.getDataTracker().containsKey(MASTER)) {
+        if (master != null) {
-            NbtCompound data = entity.getDataTracker().get(MASTER);
+            owner.fromNBT(tracker.get(master));
-            owner.fromNBT(data);
         }
         return owner;
     }
@@ -239,10 +235,10 @@ public class Creature extends Living<LivingEntity> implements WeaklyOwned.Mutabl
 
     private void updateConsumption() {
         if (isClient()) {
-            eatTimer = entity.getDataTracker().get(EATING);
+            eatTimer = tracker.get(eating);
         } else if (eatMuffinGoal != null) {
             eatTimer = eatMuffinGoal.getTimer();
-            entity.getDataTracker().set(EATING, eatTimer);
+            tracker.set(eating, eatTimer);
         }
     }
 
@@ -331,8 +327,8 @@ public class Creature extends Living<LivingEntity> implements WeaklyOwned.Mutabl
         }
         if (compound.contains("master", NbtElement.COMPOUND_TYPE)) {
             owner.fromNBT(compound.getCompound("master"));
-            if (entity.getDataTracker().containsKey(MASTER)) {
+            if (master != null) {
-                entity.getDataTracker().set(MASTER, owner.toNBT());
+                tracker.set(master, owner.toNBT());
             }
             if (owner.isSet()) {
                 targets.ifPresent(this::initMinionAi);

src/main/java/com/minelittlepony/unicopia/entity/EntityPhysics.java

@@ -1,14 +1,16 @@
 package com.minelittlepony.unicopia.entity;
 
 import com.minelittlepony.unicopia.entity.mob.UEntityAttributes;
+import com.minelittlepony.unicopia.network.track.DataTracker;
+import com.minelittlepony.unicopia.network.track.TrackableDataType;
 import com.minelittlepony.unicopia.util.Copyable;
 import com.minelittlepony.unicopia.util.Tickable;
+import com.minelittlepony.unicopia.util.serialization.PacketCodec;
 
 import net.minecraft.block.BlockState;
 import net.minecraft.block.FenceGateBlock;
 import net.minecraft.entity.Entity;
 import net.minecraft.entity.LivingEntity;
-import net.minecraft.entity.data.TrackedData;
 import net.minecraft.entity.mob.MobEntity;
 import net.minecraft.nbt.NbtCompound;
 import net.minecraft.registry.tag.BlockTags;
@@ -18,15 +20,18 @@ import net.minecraft.util.math.Vec3d;
 
 public class EntityPhysics<T extends Entity> implements Physics, Copyable<EntityPhysics<T>>, Tickable {
 
-    private final TrackedData<Float> gravity;
-
     protected final T entity;
 
     private float lastGravity = 1;
 
-    public EntityPhysics(T entity, TrackedData<Float> gravity) {
+    private final DataTracker tracker;
+    protected final DataTracker.Entry<Float> gravity;
+
+    public EntityPhysics(T entity, DataTracker tracker) {
         this.entity = entity;
-        this.gravity = gravity;
+        this.tracker = tracker;
+        //this.gravity = gravity;
+        gravity = tracker.startTracking(TrackableDataType.of(PacketCodec.FLOAT), 1F);
     }
 
     @Override
@@ -91,12 +96,12 @@ public class EntityPhysics<T extends Entity> implements Physics, Copyable<Entity
 
     @Override
     public void setBaseGravityModifier(float constant) {
-        entity.getDataTracker().set(gravity, constant);
+        tracker.set(gravity, constant);
     }
 
     @Override
     public float getBaseGravityModifier() {
-        return entity.getDataTracker().get(gravity);
+        return tracker.get(gravity);
     }
 
     @Override

src/main/java/com/minelittlepony/unicopia/entity/ItemImpl.java

@@ -5,16 +5,16 @@ import java.util.List;
 import com.minelittlepony.unicopia.*;
 import com.minelittlepony.unicopia.item.enchantment.UEnchantments;
 import com.minelittlepony.unicopia.item.enchantment.WantItNeedItEnchantment;
+import com.minelittlepony.unicopia.network.track.DataTracker;
+import com.minelittlepony.unicopia.network.track.DataTrackerManager;
+import com.minelittlepony.unicopia.network.track.Trackable;
+import com.minelittlepony.unicopia.network.track.TrackableDataType;
 import com.minelittlepony.unicopia.particle.FollowingParticleEffect;
 import com.minelittlepony.unicopia.particle.ParticleUtils;
 import com.minelittlepony.unicopia.particle.UParticles;
 import com.minelittlepony.unicopia.util.VecHelper;
-
 import net.minecraft.enchantment.EnchantmentHelper;
 import net.minecraft.entity.*;
-import net.minecraft.entity.data.DataTracker;
-import net.minecraft.entity.data.TrackedData;
-import net.minecraft.entity.data.TrackedDataHandlerRegistry;
 import net.minecraft.entity.decoration.ItemFrameEntity;
 import net.minecraft.entity.player.PlayerEntity;
 import net.minecraft.entity.projectile.ProjectileEntity;
@@ -29,24 +29,26 @@ import net.minecraft.util.math.Vec3d;
 import net.minecraft.util.math.random.Random;
 
 public class ItemImpl implements Equine<ItemEntity> {
-    private static final TrackedData<String> ITEM_RACE = DataTracker.registerData(ItemEntity.class, TrackedDataHandlerRegistry.STRING);
-    static final TrackedData<Float> ITEM_GRAVITY = DataTracker.registerData(ItemEntity.class, TrackedDataHandlerRegistry.FLOAT);
-
     private final ItemEntity entity;
 
     private final ItemPhysics physics;
 
-    private Race serverRace;
+    private final DataTrackerManager trackers;
+    protected final DataTracker tracker;
+
+    private final DataTracker.Entry<Race> race;
 
     public ItemImpl(ItemEntity owner) {
         this.entity = owner;
-        this.physics = new ItemPhysics(owner);
+        this.trackers = Trackable.of(entity).getDataTrackers();
+        this.tracker = trackers.getPrimaryTracker();
+        this.physics = new ItemPhysics(owner, tracker);
+
+        race = tracker.startTracking(TrackableDataType.of(Race.PACKET_CODEC), Race.HUMAN);
     }
 
     @Override
     public void initDataTracker() {
-        entity.getDataTracker().startTracking(ITEM_GRAVITY, 1F);
-        entity.getDataTracker().startTracking(ITEM_RACE, Race.REGISTRY.getId(Race.HUMAN).toString());
     }
 
     @Override
@@ -58,13 +60,6 @@ public class ItemImpl implements Equine<ItemEntity> {
     public boolean beforeUpdate() {
 
         if (!entity.getWorld().isClient) {
-            Race race = getSpecies();
-            if (race != serverRace) {
-                serverRace = race;
-                setSpecies(Race.HUMAN);
-                setSpecies(race);
-            }
-
             if (WantItNeedItEnchantment.getLevel(entity) > 0) {
                 var random = entity.getWorld().random;
 
@@ -150,12 +145,12 @@ public class ItemImpl implements Equine<ItemEntity> {
 
     @Override
     public Race getSpecies() {
-        return Race.fromName(entity.getDataTracker().get(ITEM_RACE), Race.HUMAN);
+        return tracker.get(race);
     }
 
     @Override
     public void setSpecies(Race race) {
-        entity.getDataTracker().set(ITEM_RACE, Race.REGISTRY.getId(race).toString());
+        tracker.set(this.race, race);
     }
 
     @Override
@@ -165,7 +160,7 @@ public class ItemImpl implements Equine<ItemEntity> {
 
     @Override
     public void toNBT(NbtCompound compound) {
-        compound.putString("owner_race", Race.REGISTRY.getId(getSpecies()).toString());
+        compound.putString("owner_race", getSpecies().getId().toString());
         physics.toNBT(compound);
     }
 

src/main/java/com/minelittlepony/unicopia/entity/ItemPhysics.java

@@ -1,10 +1,12 @@
 package com.minelittlepony.unicopia.entity;
 
+import com.minelittlepony.unicopia.network.track.DataTracker;
+
 import net.minecraft.entity.ItemEntity;
 
 class ItemPhysics extends EntityPhysics<ItemEntity> {
-    public ItemPhysics(ItemEntity entity) {
+    public ItemPhysics(ItemEntity entity, DataTracker tracker) {
-        super(entity, ItemImpl.ITEM_GRAVITY);
+        super(entity, tracker);
     }
 
     @Override

src/main/java/com/minelittlepony/unicopia/entity/Living.java

@@ -32,10 +32,15 @@ import com.minelittlepony.unicopia.item.UItems;
 import com.minelittlepony.unicopia.item.enchantment.UEnchantments;
 import com.minelittlepony.unicopia.network.datasync.EffectSync;
 import com.minelittlepony.unicopia.network.datasync.Transmittable;
+import com.minelittlepony.unicopia.network.track.DataTracker;
+import com.minelittlepony.unicopia.network.track.DataTrackerManager;
+import com.minelittlepony.unicopia.network.track.Trackable;
+import com.minelittlepony.unicopia.network.track.TrackableDataType;
 import com.minelittlepony.unicopia.particle.ParticleUtils;
 import com.minelittlepony.unicopia.projectile.ProjectileImpactListener;
 import com.minelittlepony.unicopia.server.world.DragonBreathStore;
 import com.minelittlepony.unicopia.util.*;
+import com.minelittlepony.unicopia.util.serialization.PacketCodec;
 
 import it.unimi.dsi.fastutil.floats.Float2ObjectFunction;
 import net.fabricmc.fabric.api.util.TriState;
@@ -48,7 +53,6 @@ import net.minecraft.entity.attribute.EntityAttributeInstance;
 import net.minecraft.entity.attribute.EntityAttributeModifier;
 import net.minecraft.entity.damage.DamageSource;
 import net.minecraft.entity.damage.DamageTypes;
-import net.minecraft.entity.data.*;
 import net.minecraft.entity.mob.HostileEntity;
 import net.minecraft.entity.player.PlayerEntity;
 import net.minecraft.entity.projectile.ProjectileEntity;
@@ -64,6 +68,7 @@ import net.minecraft.server.world.ServerWorld;
 import net.minecraft.sound.BlockSoundGroup;
 import net.minecraft.sound.SoundCategory;
 import net.minecraft.util.Hand;
+import net.minecraft.util.Util;
 import net.minecraft.util.hit.BlockHitResult;
 import net.minecraft.util.math.BlockPos;
 import net.minecraft.util.math.Direction;
@@ -71,7 +76,7 @@ import net.minecraft.util.math.MathHelper;
 import net.minecraft.util.math.Vec3d;
 
 public abstract class Living<T extends LivingEntity> implements Equine<T>, Caster<T>, Transmittable {
-    private static final TrackedData<Optional<UUID>> CARRIER_ID = DataTracker.registerData(LivingEntity.class, TrackedDataHandlerRegistry.OPTIONAL_UUID);
+    //private static final TrackedData<Optional<UUID>> CARRIER_ID = DataTracker.registerData(LivingEntity.class, TrackedDataHandlerRegistry.OPTIONAL_UUID);
 
     protected final T entity;
 
@@ -99,19 +104,26 @@ public abstract class Living<T extends LivingEntity> implements Equine<T>, Caste
     private final ItemTracker armour = addTicker(new ItemTracker(this));
     private final Transportation<T> transportation = new Transportation<>(this);
 
-    protected Living(T entity, TrackedData<NbtCompound> effect) {
+    private final DataTrackerManager trackers;
+    protected final DataTracker tracker;
+
+    protected final DataTracker.Entry<UUID> carrierId;
+
+    protected Living(T entity) {
         this.entity = entity;
-        this.effectDelegate = new EffectSync(this, effect);
+        this.trackers = Trackable.of(entity).getDataTrackers();
+        this.tracker = trackers.getPrimaryTracker();
+        this.effectDelegate = new EffectSync(this, Creature.EFFECT);
         this.sneakingHeuristic = addTicker(new Interactable(entity::isSneaking));
         this.landedHeuristic = addTicker(new Interactable(entity::isOnGround));
         this.jumpingHeuristic = addTicker(new Interactable(((LivingEntityDuck)entity)::isJumping));
+
+        carrierId = tracker.startTracking(TrackableDataType.of(PacketCodec.UUID), Util.NIL_UUID);
     }
 
     @Override
     public void initDataTracker() {
-        effectDelegate.initDataTracker();
+        entity.getDataTracker().startTracking(Creature.EFFECT, new NbtCompound());
-        entity.getDataTracker().startTracking(Creature.GRAVITY, 1F);
-        entity.getDataTracker().startTracking(CARRIER_ID, Optional.empty());
     }
 
     public <Q extends Tickable> Q addTicker(Q tickable) {
@@ -166,15 +178,16 @@ public abstract class Living<T extends LivingEntity> implements Equine<T>, Caste
     }
 
     public Optional<UUID> getCarrierId() {
-        return entity.getDataTracker().get(CARRIER_ID);
+        UUID carrierId = tracker.get(this.carrierId);
+        return carrierId == Util.NIL_UUID ? Optional.empty() : Optional.of(carrierId);
     }
 
     public void setCarrier(UUID carrier) {
-        entity.getDataTracker().set(CARRIER_ID, Optional.ofNullable(carrier));
+        tracker.set(this.carrierId, carrier == null ? Util.NIL_UUID : carrier);
     }
 
     public void setCarrier(Entity carrier) {
-        entity.getDataTracker().set(CARRIER_ID, Optional.ofNullable(carrier).map(Entity::getUuid));
+        setCarrier(carrier == null ? Util.NIL_UUID : carrier.getUuid());
     }
 
     @Nullable

src/main/java/com/minelittlepony/unicopia/entity/mob/CastSpellEntity.java

@@ -12,6 +12,7 @@ import com.minelittlepony.unicopia.entity.EntityReference;
 import com.minelittlepony.unicopia.entity.MagicImmune;
 import com.minelittlepony.unicopia.entity.Physics;
 import com.minelittlepony.unicopia.network.datasync.EffectSync;
+import com.minelittlepony.unicopia.network.track.Trackable;
 
 import net.minecraft.entity.Entity;
 import net.minecraft.entity.EntityDimensions;
@@ -26,10 +27,9 @@ import net.minecraft.text.Text;
 import net.minecraft.world.World;
 
 public class CastSpellEntity extends LightEmittingEntity implements Caster<CastSpellEntity>, WeaklyOwned.Mutable<LivingEntity>, MagicImmune {
-    private static final TrackedData<Float> GRAVITY = DataTracker.registerData(CastSpellEntity.class, TrackedDataHandlerRegistry.FLOAT);
     private static final TrackedData<NbtCompound> EFFECT = DataTracker.registerData(CastSpellEntity.class, TrackedDataHandlerRegistry.NBT_COMPOUND);
 
-    private final EntityPhysics<CastSpellEntity> physics = new EntityPhysics<>(this, GRAVITY);
+    private final EntityPhysics<CastSpellEntity> physics = new EntityPhysics<>(this, Trackable.of(this).getDataTrackers().getPrimaryTracker());
 
     private final EffectSync effectDelegate = new EffectSync(this, EFFECT);
 

src/main/java/com/minelittlepony/unicopia/entity/player/Acrobatics.java

@@ -8,15 +8,15 @@ import com.minelittlepony.unicopia.client.render.PlayerPoser.Animation;
 import com.minelittlepony.unicopia.client.render.PlayerPoser.Animation.Recipient;
 import com.minelittlepony.unicopia.entity.duck.LivingEntityDuck;
 import com.minelittlepony.unicopia.entity.mob.StormCloudEntity;
+import com.minelittlepony.unicopia.network.track.DataTracker;
+import com.minelittlepony.unicopia.network.track.TrackableDataType;
 import com.minelittlepony.unicopia.util.NbtSerialisable;
 import com.minelittlepony.unicopia.util.Tickable;
+import com.minelittlepony.unicopia.util.serialization.PacketCodec;
 
 import net.minecraft.block.BlockState;
 import net.minecraft.block.Blocks;
 import net.minecraft.block.SideShapeType;
-import net.minecraft.entity.data.DataTracker;
-import net.minecraft.entity.data.TrackedData;
-import net.minecraft.entity.data.TrackedDataHandlerRegistry;
 import net.minecraft.entity.player.PlayerEntity;
 import net.minecraft.nbt.NbtCompound;
 import net.minecraft.registry.tag.BlockTags;
@@ -28,8 +28,6 @@ import net.minecraft.util.math.Vec3d;
 import net.minecraft.world.World;
 
 public class Acrobatics implements Tickable, NbtSerialisable {
-    static final TrackedData<Optional<BlockPos>> HANGING_POSITION = DataTracker.registerData(PlayerEntity.class, TrackedDataHandlerRegistry.OPTIONAL_BLOCK_POS);
-
     private int ticksHanging;
 
     private Direction attachDirection;
@@ -38,14 +36,15 @@ public class Acrobatics implements Tickable, NbtSerialisable {
     private final Pony pony;
     private final PlayerEntity entity;
 
-    public Acrobatics(Pony pony) {
+    private final DataTracker tracker;
-        this.pony = pony;
+    private final DataTracker.Entry<Optional<BlockPos>> hangingPos;
-        this.entity = pony.asEntity();
-        pony.addTicker(this::checkDislodge);
-    }
 
-    public void initDataTracker() {
+    public Acrobatics(Pony pony, DataTracker tracker) {
-        entity.getDataTracker().startTracking(HANGING_POSITION, Optional.empty());
+        this.pony = pony;
+        this.tracker = tracker;
+        this.entity = pony.asEntity();
+        this.hangingPos = tracker.startTracking(TrackableDataType.of(PacketCodec.OPTIONAL_POS), Optional.empty());
+        pony.addTicker(this::checkDislodge);
     }
 
     public boolean isImmobile() {
@@ -147,7 +146,7 @@ public class Acrobatics implements Tickable, NbtSerialisable {
     }
 
     public Optional<BlockPos> getHangingPosition() {
-        return entity.getDataTracker().get(HANGING_POSITION);
+        return tracker.get(hangingPos);
     }
 
     public boolean isHanging() {
@@ -155,13 +154,13 @@ public class Acrobatics implements Tickable, NbtSerialisable {
     }
 
     public void stopHanging() {
-        entity.getDataTracker().set(HANGING_POSITION, Optional.empty());
+        tracker.set(hangingPos, Optional.empty());
         entity.calculateDimensions();
         ticksHanging = 0;
     }
 
     public void startHanging(BlockPos pos) {
-        entity.getDataTracker().set(HANGING_POSITION, Optional.of(pos));
+        tracker.set(hangingPos, Optional.of(pos));
         entity.teleport(pos.getX() + 0.5, pos.getY() - 1, pos.getZ() + 0.5);
         entity.setVelocity(Vec3d.ZERO);
         entity.setSneaking(false);
@@ -202,6 +201,6 @@ public class Acrobatics implements Tickable, NbtSerialisable {
     @Override
     public void fromNBT(NbtCompound compound) {
         ticksHanging = compound.getInt("ticksHanging");
-        pony.asEntity().getDataTracker().set(HANGING_POSITION, NbtSerialisable.BLOCK_POS.readOptional("hangingPosition", compound));
+        tracker.set(hangingPos, NbtSerialisable.BLOCK_POS.readOptional("hangingPosition", compound));
     }
 }

src/main/java/com/minelittlepony/unicopia/entity/player/ManaContainer.java

@@ -3,11 +3,13 @@ package com.minelittlepony.unicopia.entity.player;
 import java.util.HashMap;
 import java.util.Map;
 
+import com.minelittlepony.unicopia.network.track.DataTracker;
+import com.minelittlepony.unicopia.network.track.TrackableDataType;
 import com.minelittlepony.unicopia.util.Copyable;
 import com.minelittlepony.unicopia.util.NbtSerialisable;
 import com.minelittlepony.unicopia.util.Tickable;
+import com.minelittlepony.unicopia.util.serialization.PacketCodec;
 
-import net.minecraft.entity.data.TrackedData;
 import net.minecraft.nbt.NbtCompound;
 import net.minecraft.util.math.MathHelper;
 
@@ -23,14 +25,14 @@ class ManaContainer implements MagicReserves, Tickable, NbtSerialisable, Copyabl
     private final BarInst xp;
     private final BarInst charge;
 
-    public ManaContainer(Pony pony) {
+    public ManaContainer(Pony pony, DataTracker tracker) {
         this.pony = pony;
-        this.energy = addBar("energy", new BarInst(Pony.ENERGY, 100F, 0));
+        this.energy = addBar("energy", new BarInst(tracker, 100F, 0));
-        this.exhaustion = addBar("exhaustion", new BarInst(Pony.EXHAUSTION, 100F, 0));
+        this.exhaustion = addBar("exhaustion", new BarInst(tracker, 100F, 0));
-        this.exertion = addBar("exertion", new BarInst(Pony.EXERTION, 10F, 0));
+        this.exertion = addBar("exertion", new BarInst(tracker, 10F, 0));
-        this.xp = addBar("xp", new BarInst(Pony.XP, 1F, 0));
+        this.xp = addBar("xp", new BarInst(tracker, 1F, 0));
-        this.mana = addBar("mana", new XpCollectingBar(Pony.MANA, 100F, 1));
+        this.mana = addBar("mana", new XpCollectingBar(tracker, 100F, 1));
-        this.charge = addBar("charge", new BarInst(Pony.CHARGE, 10F, 0) {
+        this.charge = addBar("charge", new BarInst(tracker, 10F, 0) {
             @Override
             protected float applyLimits(float value) {
                 return Math.max(0, value);
@@ -38,10 +40,6 @@ class ManaContainer implements MagicReserves, Tickable, NbtSerialisable, Copyabl
         });
     }
 
-    public void initDataTracker() {
-        bars.values().forEach(BarInst::initDataTracker);
-    }
-
     protected BarInst addBar(String name, BarInst bar) {
         bars.put(name, bar);
         return bar;
@@ -130,9 +128,8 @@ class ManaContainer implements MagicReserves, Tickable, NbtSerialisable, Copyabl
     }
 
     class XpCollectingBar extends BarInst {
-
+        XpCollectingBar(DataTracker tracker, float max, float initial) {
-        XpCollectingBar(TrackedData<Float> marker, float max, float initial) {
+            super(tracker, max, initial);
-            super(marker, max, initial);
         }
 
         @Override
@@ -156,29 +153,26 @@ class ManaContainer implements MagicReserves, Tickable, NbtSerialisable, Copyabl
     }
 
     class BarInst implements Bar, NbtSerialisable {
-
+        private final DataTracker tracker;
-        private final TrackedData<Float> marker;
+        private final DataTracker.Entry<Float> marker;
         private final float max;
 
         private float trailingValue;
         private float prevTrailingValue;
         private float prevValue;
 
-        BarInst(TrackedData<Float> marker, float max, float initial) {
+        BarInst(DataTracker tracker, float max, float initial) {
-            this.marker = marker;
+            this.tracker = tracker;
             this.max = max;
             this.trailingValue = initial;
             this.prevTrailingValue = initial;
             this.prevValue = initial;
-        }
+            this.marker = tracker.startTracking(TrackableDataType.of(PacketCodec.FLOAT), max * trailingValue);
-
-        public void initDataTracker() {
-            pony.asEntity().getDataTracker().startTracking(marker, max * trailingValue);
         }
 
         @Override
         public float get() {
-            return applyLimits(pony.asEntity().getDataTracker().get(marker));
+            return applyLimits(tracker.get(marker));
         }
 
         @Override
@@ -197,7 +191,7 @@ class ManaContainer implements MagicReserves, Tickable, NbtSerialisable, Copyabl
         }
 
         private void load(float value) {
-            pony.asEntity().getDataTracker().set(marker, value);
+            tracker.set(marker, value);
         }
 
         protected float getInitial(float initial) {

src/main/java/com/minelittlepony/unicopia/entity/player/PlayerLevelStore.java

@@ -1,8 +1,10 @@
 package com.minelittlepony.unicopia.entity.player;
 
 import com.minelittlepony.unicopia.ability.magic.Levelled;
+import com.minelittlepony.unicopia.network.track.DataTracker;
+import com.minelittlepony.unicopia.network.track.TrackableDataType;
+import com.minelittlepony.unicopia.util.serialization.PacketCodec;
 
-import net.minecraft.entity.data.TrackedData;
 import net.minecraft.sound.*;
 import net.minecraft.util.math.MathHelper;
 
@@ -10,15 +12,17 @@ class PlayerLevelStore implements Levelled.LevelStore {
 
     private final Pony pony;
 
-    private final TrackedData<Integer> dataEntry;
+    private final DataTracker tracker;
+    private final DataTracker.Entry<Integer> dataEntry;
 
     private final boolean upgradeMana;
 
     private final SoundEvent levelUpSound;
 
-    PlayerLevelStore(Pony pony, TrackedData<Integer> dataEntry, boolean upgradeMana, SoundEvent levelUpSound) {
+    PlayerLevelStore(Pony pony, DataTracker tracker, boolean upgradeMana, SoundEvent levelUpSound) {
         this.pony = pony;
-        this.dataEntry = dataEntry;
+        this.tracker = tracker;
+        this.dataEntry = tracker.startTracking(TrackableDataType.of(PacketCodec.INT), 0);
         this.upgradeMana = upgradeMana;
         this.levelUpSound = levelUpSound;
     }
@@ -41,11 +45,11 @@ class PlayerLevelStore implements Levelled.LevelStore {
 
     @Override
     public int get() {
-        return pony.asEntity().getDataTracker().get(dataEntry);
+        return tracker.get(dataEntry);
     }
 
     @Override
     public void set(int level) {
-        pony.asEntity().getDataTracker().set(dataEntry, MathHelper.clamp(level, 0, getMax()));
+        tracker.set(dataEntry, MathHelper.clamp(level, 0, getMax()));
     }
 }

src/main/java/com/minelittlepony/unicopia/entity/player/PlayerPhysics.java

@@ -25,6 +25,7 @@ import com.minelittlepony.unicopia.item.UItems;
 import com.minelittlepony.unicopia.item.enchantment.UEnchantments;
 import com.minelittlepony.unicopia.network.Channel;
 import com.minelittlepony.unicopia.network.MsgPlayerFlightControlsInput;
+import com.minelittlepony.unicopia.network.track.DataTracker;
 import com.minelittlepony.unicopia.particle.*;
 import com.minelittlepony.unicopia.projectile.ProjectileUtil;
 import com.minelittlepony.unicopia.server.world.BlockDestructionManager;
@@ -97,8 +98,8 @@ public class PlayerPhysics extends EntityPhysics<PlayerEntity> implements Tickab
     private Lerp updraft = new Lerp(0);
     private Lerp windStrength = new Lerp(0);
 
-    public PlayerPhysics(Pony pony) {
+    public PlayerPhysics(Pony pony, DataTracker tracker) {
-        super(pony.asEntity(), Creature.GRAVITY);
+        super(pony.asEntity(), tracker);
         this.pony = pony;
         dimensions = new PlayerDimensions(pony, this);
     }

src/main/java/com/minelittlepony/unicopia/entity/player/Pony.java

@@ -34,6 +34,8 @@ import com.minelittlepony.unicopia.item.enchantment.UEnchantments;
 import com.minelittlepony.unicopia.util.*;
 import com.minelittlepony.unicopia.network.*;
 import com.minelittlepony.unicopia.network.datasync.EffectSync.UpdateCallback;
+import com.minelittlepony.unicopia.network.track.DataTracker;
+import com.minelittlepony.unicopia.network.track.TrackableDataType;
 import com.minelittlepony.unicopia.server.world.UGameRules;
 import com.minelittlepony.common.util.animation.LinearInterpolator;
 import com.google.common.collect.Streams;
@@ -46,9 +48,6 @@ import net.minecraft.entity.*;
 import net.minecraft.entity.attribute.DefaultAttributeContainer;
 import net.minecraft.entity.damage.DamageSource;
 import net.minecraft.entity.damage.DamageTypes;
-import net.minecraft.entity.data.DataTracker;
-import net.minecraft.entity.data.TrackedData;
-import net.minecraft.entity.data.TrackedDataHandlerRegistry;
 import net.minecraft.entity.effect.StatusEffectInstance;
 import net.minecraft.entity.mob.HostileEntity;
 import net.minecraft.entity.player.PlayerEntity;
@@ -71,28 +70,14 @@ import net.minecraft.world.GameMode;
 import net.minecraft.world.GameRules;
 
 public class Pony extends Living<PlayerEntity> implements Copyable<Pony>, UpdateCallback {
-    private static final TrackedData<String> RACE = DataTracker.registerData(PlayerEntity.class, TrackedDataHandlerRegistry.STRING);
-    private static final TrackedData<String> SUPPRESSED_RACE = DataTracker.registerData(PlayerEntity.class, TrackedDataHandlerRegistry.STRING);
-
-    static final TrackedData<Float> ENERGY = DataTracker.registerData(PlayerEntity.class, TrackedDataHandlerRegistry.FLOAT);
-    static final TrackedData<Float> EXHAUSTION = DataTracker.registerData(PlayerEntity.class, TrackedDataHandlerRegistry.FLOAT);
-    static final TrackedData<Float> EXERTION = DataTracker.registerData(PlayerEntity.class, TrackedDataHandlerRegistry.FLOAT);
-    static final TrackedData<Float> MANA = DataTracker.registerData(PlayerEntity.class, TrackedDataHandlerRegistry.FLOAT);
-    static final TrackedData<Float> XP = DataTracker.registerData(PlayerEntity.class, TrackedDataHandlerRegistry.FLOAT);
-    static final TrackedData<Float> CHARGE = DataTracker.registerData(PlayerEntity.class, TrackedDataHandlerRegistry.FLOAT);
-    static final TrackedData<Integer> LEVEL = DataTracker.registerData(PlayerEntity.class, TrackedDataHandlerRegistry.INTEGER);
-    static final TrackedData<Integer> CORRUPTION = DataTracker.registerData(PlayerEntity.class, TrackedDataHandlerRegistry.INTEGER);
-
     static final int INITIAL_SUN_IMMUNITY = 20;
 
-    private static final TrackedData<NbtCompound> EFFECT = DataTracker.registerData(PlayerEntity.class, TrackedDataHandlerRegistry.NBT_COMPOUND);
-
     private final AbilityDispatcher powers = new AbilityDispatcher(this);
-    private final PlayerPhysics gravity = addTicker(new PlayerPhysics(this));
+    private final PlayerPhysics gravity = addTicker(new PlayerPhysics(this, tracker));
     private final PlayerCharmTracker charms = new PlayerCharmTracker(this);
     private final PlayerCamera camera = new PlayerCamera(this);
     private final TraitDiscovery discoveries = new TraitDiscovery(this);
-    private final Acrobatics acrobatics = new Acrobatics(this);
+    private final Acrobatics acrobatics = new Acrobatics(this, tracker);
     private final CorruptionHandler corruptionHandler = new CorruptionHandler(this);
 
     private final Map<String, Integer> advancementProgress = new HashMap<>();
@@ -121,11 +106,16 @@ public class Pony extends Living<PlayerEntity> implements Copyable<Pony>, Update
     private int animationMaxDuration;
     private int animationDuration;
 
+    private DataTracker.Entry<Race> race;
+    private DataTracker.Entry<Race> suppressedRace;
+
     public Pony(PlayerEntity player) {
-        super(player, EFFECT);
+        super(player);
-        this.levels = new PlayerLevelStore(this, LEVEL, true, USounds.Vanilla.ENTITY_PLAYER_LEVELUP);
+        race = this.tracker.startTracking(TrackableDataType.of(Race.PACKET_CODEC), Race.HUMAN);
-        this.corruption = new PlayerLevelStore(this, CORRUPTION, false, USounds.ENTITY_PLAYER_CORRUPTION);
+        suppressedRace = this.tracker.startTracking(TrackableDataType.of(Race.PACKET_CODEC), Race.HUMAN);
-        this.mana = addTicker(new ManaContainer(this));
+        this.levels = new PlayerLevelStore(this, tracker, true, USounds.Vanilla.ENTITY_PLAYER_LEVELUP);
+        this.corruption = new PlayerLevelStore(this, tracker, false, USounds.ENTITY_PLAYER_CORRUPTION);
+        this.mana = addTicker(new ManaContainer(this, tracker));
 
         addTicker(this::updateAnimations);
         addTicker(this::updateBatPonyAbilities);
@@ -134,17 +124,6 @@ public class Pony extends Living<PlayerEntity> implements Copyable<Pony>, Update
         addTicker(corruptionHandler);
     }
 
-    @Override
-    public void initDataTracker() {
-        super.initDataTracker();
-        acrobatics.initDataTracker();
-        mana.initDataTracker();
-        entity.getDataTracker().startTracking(LEVEL, 0);
-        entity.getDataTracker().startTracking(CORRUPTION, 0);
-        entity.getDataTracker().startTracking(RACE, Race.DEFAULT_ID);
-        entity.getDataTracker().startTracking(SUPPRESSED_RACE, Race.DEFAULT_ID);
-    }
-
     public static void registerAttributes(DefaultAttributeContainer.Builder builder) {
         builder.add(UEntityAttributes.EXTRA_MINING_SPEED);
         builder.add(UEntityAttributes.ENTITY_GRAVITY_MODIFIER);
@@ -218,7 +197,7 @@ public class Pony extends Living<PlayerEntity> implements Copyable<Pony>, Update
      */
     @Override
     public Race getSpecies() {
-        return Race.fromName(entity.getDataTracker().get(RACE), Race.HUMAN);
+        return tracker.get(race);
     }
 
     /**
@@ -242,7 +221,7 @@ public class Pony extends Living<PlayerEntity> implements Copyable<Pony>, Update
     public void setSpecies(Race race) {
         race = race.validate(entity);
         Race current = getSpecies();
-        entity.getDataTracker().set(RACE, race.getId().toString());
+        tracker.set(this.race, race);
         if (race != current) {
             clearSuppressedRace();
         }
@@ -255,7 +234,7 @@ public class Pony extends Living<PlayerEntity> implements Copyable<Pony>, Update
     }
 
     public void setSuppressedRace(Race race) {
-        entity.getDataTracker().set(SUPPRESSED_RACE, race.validate(entity).getId().toString());
+        tracker.set(suppressedRace, race.validate(entity));
     }
 
     public void clearSuppressedRace() {
@@ -263,7 +242,7 @@ public class Pony extends Living<PlayerEntity> implements Copyable<Pony>, Update
     }
 
     public Race getSuppressedRace() {
-        return Race.fromName(entity.getDataTracker().get(SUPPRESSED_RACE), Race.UNSET);
+        return tracker.get(suppressedRace);
     }
 
     public TraitDiscovery getDiscoveries() {

src/main/java/com/minelittlepony/unicopia/mixin/MixinEntity.java

@@ -11,6 +11,8 @@ import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
 import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;
 
 import com.minelittlepony.unicopia.entity.duck.LavaAffine;
+import com.minelittlepony.unicopia.network.track.DataTrackerManager;
+import com.minelittlepony.unicopia.network.track.Trackable;
 import com.minelittlepony.unicopia.EquinePredicates;
 import com.minelittlepony.unicopia.Race;
 import com.minelittlepony.unicopia.ability.magic.Caster;
@@ -19,11 +21,11 @@ import com.minelittlepony.unicopia.entity.Living;
 import com.minelittlepony.unicopia.entity.duck.EntityDuck;
 
 import net.minecraft.entity.Entity;
-import net.minecraft.entity.EntityType;
 import net.minecraft.entity.ItemEntity;
 import net.minecraft.entity.MovementType;
 import net.minecraft.entity.Entity.PositionUpdater;
 import net.minecraft.entity.Entity.RemovalReason;
+import net.minecraft.entity.EntityType;
 import net.minecraft.fluid.Fluid;
 import net.minecraft.item.ItemStack;
 import net.minecraft.registry.tag.TagKey;
@@ -31,10 +33,12 @@ import net.minecraft.util.math.Vec3d;
 import net.minecraft.world.World;
 
 @Mixin(Entity.class)
-abstract class MixinEntity implements EntityDuck {
+abstract class MixinEntity implements EntityDuck, Trackable {
     @Nullable
     private transient Caster<?> host;
 
+    private DataTrackerManager dataTrackerManager;
+
     @Override
     @Nullable
     public Caster<?> getHost() {
@@ -46,6 +50,14 @@ abstract class MixinEntity implements EntityDuck {
         this.host = host;
     }
 
+    @Override
+    public DataTrackerManager getDataTrackers() {
+        if (dataTrackerManager == null) {
+            dataTrackerManager = new DataTrackerManager((Entity)(Object)this);
+        }
+        return dataTrackerManager;
+    }
+
     @Override
     @Accessor("submergedFluidTag")
     public abstract Set<TagKey<Fluid>> getSubmergedFluidTags();
@@ -104,6 +116,13 @@ abstract class MixinEntity implements EntityDuck {
         }
     }
 
+    @Inject(method = "tick()V", at = @At("RETURN"))
+    private void afterTick(CallbackInfo info) {
+        if (dataTrackerManager != null) {
+            dataTrackerManager.tick();
+        }
+    }
+
     @Inject(method = "updatePassengerPosition(Lnet/minecraft/entity/Entity;Lnet/minecraft/entity/Entity$PositionUpdater;)V",
             at = @At("HEAD"),
             cancellable = true

src/main/java/com/minelittlepony/unicopia/network/Channel.java

@@ -2,6 +2,7 @@ package com.minelittlepony.unicopia.network;
 
 import com.minelittlepony.unicopia.*;
 import com.minelittlepony.unicopia.entity.player.Pony;
+import com.minelittlepony.unicopia.network.track.MsgTrackedValues;
 import com.minelittlepony.unicopia.server.world.UnicopiaWorldProperties;
 import com.minelittlepony.unicopia.server.world.ZapAppleStageStore;
 import com.sollace.fabwork.api.packets.*;
@@ -31,6 +32,7 @@ public interface Channel {
 
     S2CPacketType<MsgServerResources> SERVER_RESOURCES = SimpleNetworking.serverToClient(Unicopia.id("resources"), MsgServerResources::new);
 
+    S2CPacketType<MsgTrackedValues> SERVER_TRACKED_ENTITY_DATA = SimpleNetworking.serverToClient(Unicopia.id("tracked_entity_date"), MsgTrackedValues::new);
     S2CPacketType<MsgOtherPlayerCapabilities> SERVER_OTHER_PLAYER_CAPABILITIES = SimpleNetworking.serverToClient(Unicopia.id("other_player_capabilities"), MsgOtherPlayerCapabilities::new);
     S2CPacketType<MsgPlayerAnimationChange> SERVER_PLAYER_ANIMATION_CHANGE = SimpleNetworking.serverToClient(Unicopia.id("other_player_animation_change"), MsgPlayerAnimationChange::new);
     S2CPacketType<MsgSkyAngle> SERVER_SKY_ANGLE = SimpleNetworking.serverToClient(Unicopia.id("sky_angle"), MsgSkyAngle::new);

src/main/java/com/minelittlepony/unicopia/network/track/DataTracker.java

@@ -0,0 +1,143 @@
+package com.minelittlepony.unicopia.network.track;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+import java.util.function.Consumer;
+
+import org.jetbrains.annotations.Nullable;
+
+import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap;
+import it.unimi.dsi.fastutil.ints.IntOpenHashSet;
+import it.unimi.dsi.fastutil.ints.IntSet;
+import it.unimi.dsi.fastutil.objects.ObjectArrayList;
+import net.minecraft.network.PacketByteBuf;
+
+public class DataTracker {
+    private final List<Pair<?>> codecs = new ObjectArrayList<>();
+    private final Int2ObjectOpenHashMap<Consumer<?>> loadCallbacks = new Int2ObjectOpenHashMap<>();
+    private final Int2ObjectOpenHashMap<Runnable> writethroughCallback = new Int2ObjectOpenHashMap<>();
+    private IntSet dirtyIndices = new IntOpenHashSet();
+
+    private final DataTrackerManager manager;
+    private boolean initial = true;
+
+    final int id;
+
+    public DataTracker(DataTrackerManager manager, int id) {
+        this.manager = manager;
+        this.id = id;
+    }
+
+    public <T> Entry<T> startTracking(TrackableDataType<T> type, T initialValue) {
+        Entry<T> entry = new Entry<>(codecs.size());
+        codecs.add(new Pair<>(entry.id(), type, initialValue));
+        return entry;
+    }
+
+    public <T> void onReceive(Entry<T> entry, Consumer<T> loadCallback) {
+        loadCallbacks.put(entry.id(), loadCallback);
+    }
+
+    public <T> void onBeforeSend(Entry<T> entry, Runnable action) {
+        writethroughCallback.put(entry.id(), action);
+    }
+
+    @SuppressWarnings("unchecked")
+    private <T> Pair<T> getPair(Entry<T> entry) {
+        return (Pair<T>)codecs.get(entry.id());
+    }
+
+    public <T> T get(Entry<T> entry) {
+        return getPair(entry).value;
+    }
+
+    public <T> void set(Entry<T> entry, T value) {
+        if (manager.isClient) {
+            return;
+        }
+
+        Pair<T> pair = getPair(entry);
+        if (!Objects.equals(pair.value, value)) {
+            pair.value = value;
+            dirtyIndices.add(entry.id());
+        }
+    }
+
+    @Nullable
+    MsgTrackedValues.TrackerEntries getDirtyPairs() {
+        writethroughCallback.values().forEach(Runnable::run);
+
+        if (initial) {
+            initial = false;
+            dirtyIndices = new IntOpenHashSet();
+            return new MsgTrackedValues.TrackerEntries(id, true, codecs);
+        }
+
+        if (dirtyIndices.isEmpty()) {
+            return null;
+        }
+
+        IntSet toSend = dirtyIndices;
+        dirtyIndices = new IntOpenHashSet();
+        List<Pair<?>> pairs = new ArrayList<>();
+        for (int i : toSend) {
+            pairs.add(codecs.get(i));
+        }
+        return new MsgTrackedValues.TrackerEntries(id, false, pairs);
+    }
+
+    @SuppressWarnings("unchecked")
+    void load(boolean wipe, List<Pair<?>> values) {
+        if (wipe) {
+            codecs.clear();
+            codecs.addAll(values);
+            for (var value : values) {
+                Consumer<?> callback = loadCallbacks.get(value.id);
+                if (callback != null) {
+                    ((Consumer<Object>)callback).accept(value.value);
+                }
+            }
+        } else {
+            values.forEach(value -> {
+                if (value.id >= 0 && value.id < codecs.size()) {
+                    if (codecs.get(value.id).type == value.type) {
+                        codecs.set(value.id, value);
+                        Consumer<?> callback = loadCallbacks.get(value.id);
+                        if (callback != null) {
+                            ((Consumer<Object>)callback).accept(value.value);
+                        }
+                    }
+                }
+            });
+        }
+    }
+
+    public void close() {
+        manager.closeTracker(id);
+    }
+
+    public record Entry<T>(int id) {}
+    static class Pair<T> {
+        private final TrackableDataType<T> type;
+        public final int id;
+        public T value;
+
+        public Pair(int id, TrackableDataType<T> type, T value) {
+            this.id = id;
+            this.type = type;
+            this.value = value;
+        }
+
+        public Pair(PacketByteBuf buffer) {
+            this.id = buffer.readInt();
+            this.type = TrackableDataType.of(buffer.readInt());
+            this.value = type.read(buffer);
+        }
+
+        public void write(PacketByteBuf buffer) {
+            buffer.writeInt(id);
+            type.write(buffer, value);
+        }
+    }
+}

src/main/java/com/minelittlepony/unicopia/network/track/DataTrackerManager.java

@@ -0,0 +1,83 @@
+package com.minelittlepony.unicopia.network.track;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import com.minelittlepony.unicopia.network.Channel;
+import com.minelittlepony.unicopia.util.Tickable;
+
+import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap;
+import it.unimi.dsi.fastutil.ints.IntOpenHashSet;
+import it.unimi.dsi.fastutil.ints.IntSet;
+import net.minecraft.entity.Entity;
+
+public class DataTrackerManager implements Tickable {
+    private final Entity entity;
+    final boolean isClient;
+    private final Int2ObjectOpenHashMap<DataTracker> trackers = new Int2ObjectOpenHashMap<>();
+
+    private IntSet discardedTrackers = new IntOpenHashSet();
+    private int nextId = 0;
+
+    private final DataTracker primaryTracker = checkoutTracker();
+
+    public DataTrackerManager(Entity entity) {
+        this.entity = entity;
+        this.isClient = entity.getWorld().isClient;
+    }
+
+    public DataTracker getPrimaryTracker() {
+        return primaryTracker;
+    }
+
+    public DataTracker checkoutTracker() {
+        DataTracker tracker = new DataTracker(this, nextId++);
+        trackers.put(tracker.id, tracker);
+        return tracker;
+    }
+
+    void closeTracker(int id) {
+        if (id <= 0) {
+            return;
+        }
+
+        trackers.remove(id);
+        if (!isClient) {
+            discardedTrackers.add(id);
+        }
+    }
+
+    @Override
+    public void tick() {
+        if (isClient) {
+            return;
+        }
+
+        List<MsgTrackedValues.TrackerEntries> toTransmit = new ArrayList<>();
+
+        for (var entry : trackers.int2ObjectEntrySet()) {
+            MsgTrackedValues.TrackerEntries dirtyPairs = entry.getValue().getDirtyPairs();
+            if (dirtyPairs != null) {
+                toTransmit.add(dirtyPairs);
+            }
+        }
+
+        if (!toTransmit.isEmpty() || !discardedTrackers.isEmpty()) {
+            MsgTrackedValues packet = new MsgTrackedValues(entity.getId(), toTransmit, discardedTrackers.toIntArray());
+            discardedTrackers = new IntOpenHashSet();
+            Channel.SERVER_TRACKED_ENTITY_DATA.sendToSurroundingPlayers(packet, entity);
+        }
+    }
+
+    void load(MsgTrackedValues packet) {
+        for (int id : packet.removedTrackers()) {
+            closeTracker(id);
+        }
+        for (var update : packet.updatedTrackers()) {
+            DataTracker tracker = trackers.get(update.id());
+            if (tracker != null) {
+                tracker.load(update.wipe(), update.values());
+            }
+        }
+    }
+}

src/main/java/com/minelittlepony/unicopia/network/track/MsgTrackedValues.java

@@ -0,0 +1,46 @@
+package com.minelittlepony.unicopia.network.track;
+
+import java.util.ArrayList;
+import java.util.List;
+import com.sollace.fabwork.api.packets.HandledPacket;
+
+import net.minecraft.entity.Entity;
+import net.minecraft.entity.player.PlayerEntity;
+import net.minecraft.network.PacketByteBuf;
+
+public record MsgTrackedValues(
+        int owner,
+        List<TrackerEntries> updatedTrackers,
+        int[] removedTrackers
+) implements HandledPacket<PlayerEntity> {
+    public MsgTrackedValues(PacketByteBuf buffer) {
+        this(buffer.readInt(), buffer.readCollection(ArrayList::new, TrackerEntries::new), buffer.readIntArray());
+    }
+
+    @Override
+    public void toBuffer(PacketByteBuf buffer) {
+        buffer.writeInt(owner);
+        buffer.writeCollection(updatedTrackers, (buf, tracker) -> tracker.write(buf));
+        buffer.writeIntArray(removedTrackers);
+    }
+
+    @Override
+    public void handle(PlayerEntity sender) {
+        Entity entity = sender.getWorld().getEntityById(owner);
+        if (entity instanceof Trackable trackable) {
+            trackable.getDataTrackers().load(this);
+        }
+    }
+
+    public record TrackerEntries(int id, boolean wipe, List<DataTracker.Pair<?>> values) {
+        public TrackerEntries(PacketByteBuf buffer) {
+            this(buffer.readInt(), buffer.readBoolean(), buffer.readCollection(ArrayList::new, DataTracker.Pair::new));
+        }
+
+        public void write(PacketByteBuf buffer) {
+            buffer.writeInt(id);
+            buffer.writeBoolean(wipe);
+            buffer.writeCollection(values, (buf, pair) -> pair.write(buf));
+        }
+    }
+}

src/main/java/com/minelittlepony/unicopia/network/track/Trackable.java

@@ -0,0 +1,12 @@
+package com.minelittlepony.unicopia.network.track;
+
+import net.minecraft.entity.Entity;
+
+public interface Trackable {
+
+    DataTrackerManager getDataTrackers();
+
+    static Trackable of(Entity entity) {
+        return (Trackable)entity;
+    }
+}

src/main/java/com/minelittlepony/unicopia/network/track/TrackableDataType.java

@@ -0,0 +1,38 @@
+package com.minelittlepony.unicopia.network.track;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import com.google.common.collect.Interner;
+import com.google.common.collect.Interners;
+import com.minelittlepony.unicopia.util.serialization.PacketCodec;
+
+import net.minecraft.network.PacketByteBuf;
+
+public record TrackableDataType<T>(int id, PacketCodec<T> codec) {
+    private static final List<TrackableDataType<?>> REGISTRY = new ArrayList<>();
+    private static final Interner<TrackableDataType<?>> INTERNER = Interners.newStrongInterner();
+
+    @SuppressWarnings("unchecked")
+    public static <T> TrackableDataType<T> of(int id) {
+        return (TrackableDataType<T>)REGISTRY.get(id);
+    }
+
+    public static <T> TrackableDataType<T> of(PacketCodec<T> codec) {
+        @SuppressWarnings("unchecked")
+        TrackableDataType<T> type = (TrackableDataType<T>) INTERNER.intern(new TrackableDataType<>(REGISTRY.size(), codec));
+        if (type.id() == REGISTRY.size()) {
+            REGISTRY.add(type);
+        }
+        return type;
+    }
+
+    public T read(PacketByteBuf buffer) {
+        return codec().read(buffer);
+    }
+
+    public void write(PacketByteBuf buffer, T value) {
+        buffer.writeInt(id());
+        codec().write(buffer, value);
+    }
+}

src/main/java/com/minelittlepony/unicopia/projectile/MagicBeamEntity.java

@@ -19,6 +19,7 @@ import com.minelittlepony.unicopia.entity.MagicImmune;
 import com.minelittlepony.unicopia.entity.Physics;
 import com.minelittlepony.unicopia.entity.mob.UEntities;
 import com.minelittlepony.unicopia.network.datasync.EffectSync;
+import com.minelittlepony.unicopia.network.track.Trackable;
 
 import net.minecraft.entity.Entity;
 import net.minecraft.entity.EntityType;
@@ -31,13 +32,11 @@ import net.minecraft.util.math.Vec3d;
 import net.minecraft.world.World;
 
 public class MagicBeamEntity extends MagicProjectileEntity implements Caster<MagicBeamEntity>, MagicImmune {
-    private static final TrackedData<Float> GRAVITY = DataTracker.registerData(MagicBeamEntity.class, TrackedDataHandlerRegistry.FLOAT);
-    private static final TrackedData<Boolean> HYDROPHOBIC = DataTracker.registerData(MagicBeamEntity.class, TrackedDataHandlerRegistry.BOOLEAN);
     private static final TrackedData<NbtCompound> EFFECT = DataTracker.registerData(MagicBeamEntity.class, TrackedDataHandlerRegistry.NBT_COMPOUND);
+    private static final TrackedData<Boolean> HYDROPHOBIC = DataTracker.registerData(MagicBeamEntity.class, TrackedDataHandlerRegistry.BOOLEAN);
 
     private final EffectSync effectDelegate = new EffectSync(this, EFFECT);
-
+    private final EntityPhysics<MagicProjectileEntity> physics = new EntityPhysics<>(this, Trackable.of(this).getDataTrackers().getPrimaryTracker());
-    private final EntityPhysics<MagicProjectileEntity> physics = new EntityPhysics<>(this, GRAVITY);
 
     public MagicBeamEntity(EntityType<MagicBeamEntity> type, World world) {
         super(type, world);
@@ -55,10 +54,10 @@ public class MagicBeamEntity extends MagicProjectileEntity implements Caster<Mag
     @Override
     protected void initDataTracker() {
         super.initDataTracker();
-        getDataTracker().startTracking(GRAVITY, 1F);
         getDataTracker().startTracking(HYDROPHOBIC, false);
         getDataTracker().startTracking(EFFECT, new NbtCompound());
     }
+
     @Override
     public void tick() {
         super.tick();

src/main/java/com/minelittlepony/unicopia/util/serialization/PacketCodec.java

@@ -1,25 +1,36 @@
 package com.minelittlepony.unicopia.util.serialization;
 
 import java.util.Optional;
+import java.util.UUID;
 import java.util.function.BiConsumer;
 import java.util.function.BiFunction;
 import java.util.function.Function;
 import java.util.function.Supplier;
 
+import net.minecraft.nbt.NbtCompound;
 import net.minecraft.network.PacketByteBuf;
 import net.minecraft.registry.Registry;
 import net.minecraft.util.Identifier;
+import net.minecraft.util.math.BlockPos;
 import net.minecraft.util.math.MathHelper;
 
 public record PacketCodec<T>(PacketByteBuf.PacketReader<T> reader, PacketByteBuf.PacketWriter<T> writer) {
+    public static final PacketCodec<Boolean> BOOLEAN = new PacketCodec<>(PacketByteBuf::readBoolean, PacketByteBuf::writeBoolean);
     public static final PacketCodec<Float> FLOAT = new PacketCodec<>(PacketByteBuf::readFloat, PacketByteBuf::writeFloat);
     public static final PacketCodec<Integer> INT = new PacketCodec<>(PacketByteBuf::readInt, PacketByteBuf::writeInt);
     public static final PacketCodec<Byte> BYTE = new PacketCodec<>(PacketByteBuf::readByte, (b, v) -> b.writeByte(v));
     public static final PacketCodec<Long> LONG = new PacketCodec<>(PacketByteBuf::readLong, PacketByteBuf::writeLong);
     public static final PacketCodec<String> STRING = new PacketCodec<>(PacketByteBuf::readString, PacketByteBuf::writeString);
+    public static final PacketCodec<UUID> UUID = new PacketCodec<>(PacketByteBuf::readUuid, PacketByteBuf::writeUuid);
+    public static final PacketCodec<Optional<UUID>> OPTIONAL_UUID = UUID.asOptional();
 
     public static final PacketCodec<Identifier> IDENTIFIER = STRING.xMap(Identifier::new, Identifier::toString);
 
+    public static final PacketCodec<NbtCompound> NBT = new PacketCodec<>(PacketByteBuf::readNbt, PacketByteBuf::writeNbt);
+
+    public static final PacketCodec<BlockPos> POS = new PacketCodec<>(PacketByteBuf::readBlockPos, PacketByteBuf::writeBlockPos);
+    public static final PacketCodec<Optional<BlockPos>> OPTIONAL_POS = POS.asOptional();
+
     public static final <T> PacketCodec<T> ofRegistry(Registry<T> registry) {
         return INT.xMap(registry::get, registry::getRawId);
     }