From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Fri, 13 May 2016 01:38:06 -0400
Subject: [PATCH] Entity Activation Range 2.0

Optimizes performance of Activation Range

Adds many new configurations and a new wake up inactive system

Fixes and adds new Immunities to improve gameplay behavior

Adds water Mobs to activation range config and nerfs fish
Adds flying monsters to control ghast and phantoms
Adds villagers as separate config

diff --git a/io/papermc/paper/entity/activation/ActivationRange.java b/io/papermc/paper/entity/activation/ActivationRange.java
new file mode 100644
index 0000000000000000000000000000000000000000..ade6110cc6adb1263c0359ff7e96e96b959e61f3
--- /dev/null
+++ b/io/papermc/paper/entity/activation/ActivationRange.java
@@ -0,0 +1,318 @@
+package io.papermc.paper.entity.activation;
+
+import net.minecraft.core.BlockPos;
+import net.minecraft.server.MinecraftServer;
+import net.minecraft.world.entity.Entity;
+import net.minecraft.world.entity.ExperienceOrb;
+import net.minecraft.world.entity.FlyingMob;
+import net.minecraft.world.entity.LightningBolt;
+import net.minecraft.world.entity.LivingEntity;
+import net.minecraft.world.entity.Mob;
+import net.minecraft.world.entity.ai.Brain;
+import net.minecraft.world.entity.animal.Animal;
+import net.minecraft.world.entity.animal.Bee;
+import net.minecraft.world.entity.animal.Sheep;
+import net.minecraft.world.entity.animal.horse.Llama;
+import net.minecraft.world.entity.boss.EnderDragonPart;
+import net.minecraft.world.entity.boss.enderdragon.EndCrystal;
+import net.minecraft.world.entity.boss.enderdragon.EnderDragon;
+import net.minecraft.world.entity.boss.wither.WitherBoss;
+import net.minecraft.world.entity.item.ItemEntity;
+import net.minecraft.world.entity.item.PrimedTnt;
+import net.minecraft.world.entity.monster.Creeper;
+import net.minecraft.world.entity.monster.Pillager;
+import net.minecraft.world.entity.npc.Villager;
+import net.minecraft.world.entity.player.Player;
+import net.minecraft.world.entity.projectile.AbstractArrow;
+import net.minecraft.world.entity.projectile.AbstractHurtingProjectile;
+import net.minecraft.world.entity.projectile.EyeOfEnder;
+import net.minecraft.world.entity.projectile.FireworkRocketEntity;
+import net.minecraft.world.entity.projectile.ThrowableProjectile;
+import net.minecraft.world.entity.projectile.ThrownTrident;
+import net.minecraft.world.entity.schedule.Activity;
+import net.minecraft.world.level.Level;
+import net.minecraft.world.phys.AABB;
+import org.spigotmc.SpigotWorldConfig;
+
+public final class ActivationRange {
+
+    private ActivationRange() {
+    }
+
+    static Activity[] VILLAGER_PANIC_IMMUNITIES = {
+        Activity.HIDE,
+        Activity.PRE_RAID,
+        Activity.RAID,
+        Activity.PANIC
+    };
+
+    private static int checkInactiveWakeup(final Entity entity) {
+        final Level world = entity.level();
+        final SpigotWorldConfig config = world.spigotConfig;
+        final long inactiveFor = MinecraftServer.currentTick - entity.activatedTick;
+        if (entity.activationType == ActivationType.VILLAGER) {
+            if (inactiveFor > config.wakeUpInactiveVillagersEvery && world.wakeupInactiveRemainingVillagers > 0) {
+                world.wakeupInactiveRemainingVillagers--;
+                return config.wakeUpInactiveVillagersFor;
+            }
+        } else if (entity.activationType == ActivationType.ANIMAL) {
+            if (inactiveFor > config.wakeUpInactiveAnimalsEvery && world.wakeupInactiveRemainingAnimals > 0) {
+                world.wakeupInactiveRemainingAnimals--;
+                return config.wakeUpInactiveAnimalsFor;
+            }
+        } else if (entity.activationType == ActivationType.FLYING_MONSTER) {
+            if (inactiveFor > config.wakeUpInactiveFlyingEvery && world.wakeupInactiveRemainingFlying > 0) {
+                world.wakeupInactiveRemainingFlying--;
+                return config.wakeUpInactiveFlyingFor;
+            }
+        } else if (entity.activationType == ActivationType.MONSTER || entity.activationType == ActivationType.RAIDER) {
+            if (inactiveFor > config.wakeUpInactiveMonstersEvery && world.wakeupInactiveRemainingMonsters > 0) {
+                world.wakeupInactiveRemainingMonsters--;
+                return config.wakeUpInactiveMonstersFor;
+            }
+        }
+        return -1;
+    }
+
+    static AABB maxBB = new AABB(0, 0, 0, 0, 0, 0);
+
+    /**
+     * These entities are excluded from Activation range checks.
+     *
+     * @param entity
+     * @param config
+     * @return boolean If it should always tick.
+     */
+    public static boolean initializeEntityActivationState(final Entity entity, final SpigotWorldConfig config) {
+        return (entity.activationType == ActivationType.MISC && config.miscActivationRange <= 0)
+            || (entity.activationType == ActivationType.RAIDER && config.raiderActivationRange <= 0)
+            || (entity.activationType == ActivationType.ANIMAL && config.animalActivationRange <= 0)
+            || (entity.activationType == ActivationType.MONSTER && config.monsterActivationRange <= 0)
+            || (entity.activationType == ActivationType.VILLAGER && config.villagerActivationRange <= 0)
+            || (entity.activationType == ActivationType.WATER && config.waterActivationRange <= 0)
+            || (entity.activationType == ActivationType.FLYING_MONSTER && config.flyingMonsterActivationRange <= 0)
+            || entity instanceof EyeOfEnder
+            || entity instanceof Player
+            || entity instanceof ThrowableProjectile
+            || entity instanceof EnderDragon
+            || entity instanceof EnderDragonPart
+            || entity instanceof WitherBoss
+            || entity instanceof AbstractHurtingProjectile
+            || entity instanceof LightningBolt
+            || entity instanceof PrimedTnt
+            || entity instanceof net.minecraft.world.entity.item.FallingBlockEntity
+            || entity instanceof net.minecraft.world.entity.vehicle.AbstractMinecart
+            || entity instanceof net.minecraft.world.entity.vehicle.AbstractBoat
+            || entity instanceof EndCrystal
+            || entity instanceof FireworkRocketEntity
+            || entity instanceof ThrownTrident;
+    }
+
+    /**
+     * Find what entities are in range of the players in the world and set
+     * active if in range.
+     *
+     * @param world
+     */
+    public static void activateEntities(final Level world) {
+        final int miscActivationRange = world.spigotConfig.miscActivationRange;
+        final int raiderActivationRange = world.spigotConfig.raiderActivationRange;
+        final int animalActivationRange = world.spigotConfig.animalActivationRange;
+        final int monsterActivationRange = world.spigotConfig.monsterActivationRange;
+        final int waterActivationRange = world.spigotConfig.waterActivationRange;
+        final int flyingActivationRange = world.spigotConfig.flyingMonsterActivationRange;
+        final int villagerActivationRange = world.spigotConfig.villagerActivationRange;
+        world.wakeupInactiveRemainingAnimals = Math.min(world.wakeupInactiveRemainingAnimals + 1, world.spigotConfig.wakeUpInactiveAnimals);
+        world.wakeupInactiveRemainingVillagers = Math.min(world.wakeupInactiveRemainingVillagers + 1, world.spigotConfig.wakeUpInactiveVillagers);
+        world.wakeupInactiveRemainingMonsters = Math.min(world.wakeupInactiveRemainingMonsters + 1, world.spigotConfig.wakeUpInactiveMonsters);
+        world.wakeupInactiveRemainingFlying = Math.min(world.wakeupInactiveRemainingFlying + 1, world.spigotConfig.wakeUpInactiveFlying);
+
+        int maxRange = Math.max(monsterActivationRange, animalActivationRange);
+        maxRange = Math.max(maxRange, raiderActivationRange);
+        maxRange = Math.max(maxRange, miscActivationRange);
+        maxRange = Math.max(maxRange, flyingActivationRange);
+        maxRange = Math.max(maxRange, waterActivationRange);
+        maxRange = Math.max(maxRange, villagerActivationRange);
+        maxRange = Math.min((world.spigotConfig.simulationDistance << 4) - 8, maxRange);
+
+        for (final Player player : world.players()) {
+            player.activatedTick = MinecraftServer.currentTick;
+            if (world.spigotConfig.ignoreSpectatorActivation && player.isSpectator()) {
+                continue;
+            }
+
+            final int worldHeight = world.getHeight();
+            ActivationRange.maxBB = player.getBoundingBox().inflate(maxRange, worldHeight, maxRange);
+            ActivationType.MISC.boundingBox = player.getBoundingBox().inflate(miscActivationRange, worldHeight, miscActivationRange);
+            ActivationType.RAIDER.boundingBox = player.getBoundingBox().inflate(raiderActivationRange, worldHeight, raiderActivationRange);
+            ActivationType.ANIMAL.boundingBox = player.getBoundingBox().inflate(animalActivationRange, worldHeight, animalActivationRange);
+            ActivationType.MONSTER.boundingBox = player.getBoundingBox().inflate(monsterActivationRange, worldHeight, monsterActivationRange);
+            ActivationType.WATER.boundingBox = player.getBoundingBox().inflate(waterActivationRange, worldHeight, waterActivationRange);
+            ActivationType.FLYING_MONSTER.boundingBox = player.getBoundingBox().inflate(flyingActivationRange, worldHeight, flyingActivationRange);
+            ActivationType.VILLAGER.boundingBox = player.getBoundingBox().inflate(villagerActivationRange, worldHeight, villagerActivationRange);
+
+            final java.util.List<Entity> entities = world.getEntities((Entity) null, ActivationRange.maxBB, e -> true);
+            final boolean tickMarkers = world.paperConfig().entities.markers.tick;
+            for (final Entity entity : entities) {
+                if (!tickMarkers && entity instanceof net.minecraft.world.entity.Marker) {
+                    continue;
+                }
+
+                ActivationRange.activateEntity(entity);
+            }
+        }
+    }
+
+    /**
+     * Tries to activate an entity.
+     *
+     * @param entity
+     */
+    private static void activateEntity(final Entity entity) {
+        if (MinecraftServer.currentTick > entity.activatedTick) {
+            if (entity.defaultActivationState) {
+                entity.activatedTick = MinecraftServer.currentTick;
+                return;
+            }
+            if (entity.activationType.boundingBox.intersects(entity.getBoundingBox())) {
+                entity.activatedTick = MinecraftServer.currentTick;
+            }
+        }
+    }
+
+    /**
+     * If an entity is not in range, do some more checks to see if we should
+     * give it a shot.
+     *
+     * @param entity
+     * @return
+     */
+    public static int checkEntityImmunities(final Entity entity) { // return # of ticks to get immunity
+        final SpigotWorldConfig config = entity.level().spigotConfig;
+        final int inactiveWakeUpImmunity = checkInactiveWakeup(entity);
+        if (inactiveWakeUpImmunity > -1) {
+            return inactiveWakeUpImmunity;
+        }
+        if (entity.getRemainingFireTicks() > 0) {
+            return 2;
+        }
+        if (entity.activatedImmunityTick >= MinecraftServer.currentTick) {
+            return 1;
+        }
+        final long inactiveFor = MinecraftServer.currentTick - entity.activatedTick;
+        if ((entity.activationType != ActivationType.WATER && entity.isInWater() && entity.isPushedByFluid())) {
+            return 100;
+        }
+        if (!entity.onGround() || entity.getDeltaMovement().horizontalDistanceSqr() > 9.999999747378752E-6D) {
+            return 100;
+        }
+        if (!(entity instanceof final AbstractArrow arrow)) {
+            if ((!entity.onGround() && !(entity instanceof FlyingMob))) {
+                return 10;
+            }
+        } else if (!arrow.isInGround()) {
+            return 1;
+        }
+        // special cases.
+        if (entity instanceof final LivingEntity living) {
+            if (living.onClimbable() || living.jumping || living.hurtTime > 0 || !living.activeEffects.isEmpty() || living.isFreezing()) {
+                return 1;
+            }
+            if (entity instanceof final Mob mob && mob.getTarget() != null) {
+                return 20;
+            }
+            if (entity instanceof final Bee bee) {
+                final BlockPos movingTarget = bee.getMovingTarget();
+                if (bee.isAngry() ||
+                    (bee.getHivePos() != null && bee.getHivePos().equals(movingTarget)) ||
+                    (bee.getSavedFlowerPos() != null && bee.getSavedFlowerPos().equals(movingTarget))
+                ) {
+                    return 20;
+                }
+            }
+            if (entity instanceof final Villager villager) {
+                final Brain<Villager> behaviorController = villager.getBrain();
+
+                if (config.villagersActiveForPanic) {
+                    for (final Activity activity : VILLAGER_PANIC_IMMUNITIES) {
+                        if (behaviorController.isActive(activity)) {
+                            return 20 * 5;
+                        }
+                    }
+                }
+
+                if (config.villagersWorkImmunityAfter > 0 && inactiveFor >= config.villagersWorkImmunityAfter) {
+                    if (behaviorController.isActive(Activity.WORK)) {
+                        return config.villagersWorkImmunityFor;
+                    }
+                }
+            }
+            if (entity instanceof final Llama llama && llama.inCaravan()) {
+                return 1;
+            }
+            if (entity instanceof final Animal animal) {
+                if (animal.isBaby() || animal.isInLove()) {
+                    return 5;
+                }
+                if (entity instanceof final Sheep sheep && sheep.isSheared()) {
+                    return 1;
+                }
+            }
+            if (entity instanceof final Creeper creeper && creeper.isIgnited()) { // isExplosive
+                return 20;
+            }
+            if (entity instanceof final Mob mob && mob.targetSelector.hasTasks()) {
+                return 0;
+            }
+            if (entity instanceof final Pillager pillager) {
+                // TODO:?
+            }
+        }
+        // SPIGOT-6644: Otherwise the target refresh tick will be missed
+        if (entity instanceof ExperienceOrb) {
+            return 20;
+        }
+        return -1;
+    }
+
+    /**
+     * Checks if the entity is active for this tick.
+     *
+     * @param entity
+     * @return
+     */
+    public static boolean checkIfActive(final Entity entity) {
+        // Never safe to skip fireworks or item gravity
+        if (entity instanceof FireworkRocketEntity || (entity instanceof ItemEntity && (entity.tickCount + entity.getId()) % 4 == 0)) { // Needed for item gravity, see ItemEntity tick
+            return true;
+        }
+        // special case always immunities
+        // immunize brand-new entities, dead entities, and portal scenarios
+        if (entity.defaultActivationState || entity.tickCount < 20 * 10 || !entity.isAlive() || (entity.portalProcess != null && !entity.portalProcess.hasExpired()) || entity.portalCooldown > 0) {
+            return true;
+        }
+        // immunize leashed entities
+        if (entity instanceof final Mob mob && mob.getLeashHolder() instanceof Player) {
+            return true;
+        }
+
+        boolean isActive = entity.activatedTick >= MinecraftServer.currentTick;
+        entity.isTemporarilyActive = false;
+
+        // Should this entity tick?
+        if (!isActive) {
+            if ((MinecraftServer.currentTick - entity.activatedTick - 1) % 20 == 0) {
+                // Check immunities every 20 ticks.
+                final int immunity = checkEntityImmunities(entity);
+                if (immunity >= 0) {
+                    entity.activatedTick = MinecraftServer.currentTick + immunity;
+                } else {
+                    entity.isTemporarilyActive = true;
+                }
+                isActive = true;
+            }
+        }
+        // removed the original's dumb tick skipping for active entities
+        return isActive;
+    }
+}
diff --git a/net/minecraft/server/level/ChunkMap.java b/net/minecraft/server/level/ChunkMap.java
index d95413af04121fe91ca0f3b0c70025b9808acef9..ad665c7535c615d2b03a3e7864be435f933235dd 100644
--- a/net/minecraft/server/level/ChunkMap.java
+++ b/net/minecraft/server/level/ChunkMap.java
@@ -4,7 +4,6 @@ import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Iterables;
 import com.google.common.collect.Lists;
 import com.google.common.collect.Queues;
-import com.google.common.collect.Sets;
 import com.google.common.collect.ImmutableList.Builder;
 import com.mojang.datafixers.DataFixer;
 import com.mojang.logging.LogUtils;
@@ -19,7 +18,6 @@ import it.unimi.dsi.fastutil.longs.LongIterator;
 import it.unimi.dsi.fastutil.longs.LongLinkedOpenHashSet;
 import it.unimi.dsi.fastutil.longs.LongOpenHashSet;
 import it.unimi.dsi.fastutil.longs.LongSet;
-import it.unimi.dsi.fastutil.longs.Long2ObjectMap.Entry;
 import java.io.IOException;
 import java.io.Writer;
 import java.nio.file.Path;
@@ -95,7 +93,6 @@ import net.minecraft.world.level.levelgen.structure.StructureStart;
 import net.minecraft.world.level.levelgen.structure.templatesystem.StructureTemplateManager;
 import net.minecraft.world.level.storage.DimensionDataStorage;
 import net.minecraft.world.level.storage.LevelStorageSource;
-import net.minecraft.world.phys.Vec3;
 import org.apache.commons.lang3.mutable.MutableBoolean;
 import org.slf4j.Logger;
 
diff --git a/net/minecraft/server/level/ServerLevel.java b/net/minecraft/server/level/ServerLevel.java
index f45fb8ddb08d82ce76018b5a5c4fce5b3b319559..12f0dc36c5adcdbd9e1dad5f8512ac184da3960f 100644
--- a/net/minecraft/server/level/ServerLevel.java
+++ b/net/minecraft/server/level/ServerLevel.java
@@ -551,6 +551,7 @@ public class ServerLevel extends Level implements ServerEntityGetter, WorldGenLe
                 profilerFiller.pop();
             }
 
+            io.papermc.paper.entity.activation.ActivationRange.activateEntities(this); // Paper - EAR
             this.entityTickList
                 .forEach(
                     entity -> {
@@ -980,12 +981,15 @@ public class ServerLevel extends Level implements ServerEntityGetter, WorldGenLe
         entity.totalEntityAge++; // Paper - age-like counter for all entities
         profilerFiller.push(() -> BuiltInRegistries.ENTITY_TYPE.getKey(entity.getType()).toString());
         profilerFiller.incrementCounter("tickNonPassenger");
+        final boolean isActive = io.papermc.paper.entity.activation.ActivationRange.checkIfActive(entity); // Paper - EAR 2
+        if (isActive) { // Paper - EAR 2
         entity.tick();
         entity.postTick(); // CraftBukkit
+        } else {entity.inactiveTick();} // Paper - EAR 2
         profilerFiller.pop();
 
         for (Entity entity1 : entity.getPassengers()) {
-            this.tickPassenger(entity, entity1);
+            this.tickPassenger(entity, entity1, isActive); // Paper - EAR 2
         }
         // Paper start - log detailed entity tick information
         } finally {
@@ -996,7 +1000,7 @@ public class ServerLevel extends Level implements ServerEntityGetter, WorldGenLe
         // Paper end - log detailed entity tick information
     }
 
-    private void tickPassenger(Entity ridingEntity, Entity passengerEntity) {
+    private void tickPassenger(Entity ridingEntity, Entity passengerEntity, final boolean isActive) { // Paper - EAR 2
         if (passengerEntity.isRemoved() || passengerEntity.getVehicle() != ridingEntity) {
             passengerEntity.stopRiding();
         } else if (passengerEntity instanceof Player || this.entityTickList.contains(passengerEntity)) {
@@ -1006,12 +1010,21 @@ public class ServerLevel extends Level implements ServerEntityGetter, WorldGenLe
             ProfilerFiller profilerFiller = Profiler.get();
             profilerFiller.push(() -> BuiltInRegistries.ENTITY_TYPE.getKey(passengerEntity.getType()).toString());
             profilerFiller.incrementCounter("tickPassenger");
+            // Paper start - EAR 2
+            if (isActive) {
             passengerEntity.rideTick();
             passengerEntity.postTick(); // CraftBukkit
+            } else {
+                passengerEntity.setDeltaMovement(Vec3.ZERO);
+                passengerEntity.inactiveTick();
+                // copied from inside of if (isPassenger()) of passengerTick, but that ifPassenger is unnecessary
+                ridingEntity.positionRider(passengerEntity);
+            }
+            // Paper end - EAR 2
             profilerFiller.pop();
 
             for (Entity entity : passengerEntity.getPassengers()) {
-                this.tickPassenger(passengerEntity, entity);
+                this.tickPassenger(passengerEntity, entity, isActive); // Paper - EAR 2
             }
         }
     }
diff --git a/net/minecraft/world/entity/AgeableMob.java b/net/minecraft/world/entity/AgeableMob.java
index a9f01e616ef6b0d74caf57cd68eb371a4fd30fd5..179f4e4b9b1eb57f78bbb2f9fa34b11ea79b7a88 100644
--- a/net/minecraft/world/entity/AgeableMob.java
+++ b/net/minecraft/world/entity/AgeableMob.java
@@ -126,6 +126,23 @@ public abstract class AgeableMob extends PathfinderMob {
         super.onSyncedDataUpdated(key);
     }
 
+    // Paper start - EAR 2
+    @Override
+    public void inactiveTick() {
+        super.inactiveTick();
+        if (this.level().isClientSide || this.ageLocked) { // CraftBukkit
+            this.refreshDimensions();
+        } else {
+            int age = this.getAge();
+            if (age < 0) {
+                this.setAge(++age);
+            } else if (age > 0) {
+                this.setAge(--age);
+            }
+        }
+    }
+    // Paper end - EAR 2
+
     @Override
     public void aiStep() {
         super.aiStep();
diff --git a/net/minecraft/world/entity/AreaEffectCloud.java b/net/minecraft/world/entity/AreaEffectCloud.java
index 24735284fda151414d99faad401d25ba60995f9a..23b342cc31c7e72ade0e1ccad86a9ccf34380f13 100644
--- a/net/minecraft/world/entity/AreaEffectCloud.java
+++ b/net/minecraft/world/entity/AreaEffectCloud.java
@@ -128,6 +128,16 @@ public class AreaEffectCloud extends Entity implements TraceableEntity {
         this.duration = duration;
     }
 
+    // Paper start - EAR 2
+    @Override
+    public void inactiveTick() {
+        super.inactiveTick();
+        if (this.tickCount >= this.waitTime + this.duration) {
+            this.discard(org.bukkit.event.entity.EntityRemoveEvent.Cause.DESPAWN); // CraftBukkit - add Bukkit remove cause
+        }
+    }
+    // Paper end - EAR 2
+
     @Override
     public void tick() {
         super.tick();
diff --git a/net/minecraft/world/entity/Entity.java b/net/minecraft/world/entity/Entity.java
index 2facc7ad69bfe28c2f928a026ba5ab37387ab039..6256d7f8f4ee8bd4e3673b4e069af5cc0069c8f2 100644
--- a/net/minecraft/world/entity/Entity.java
+++ b/net/minecraft/world/entity/Entity.java
@@ -381,6 +381,15 @@ public abstract class Entity implements SyncedDataHolder, Nameable, EntityAccess
     private final int despawnTime; // Paper - entity despawn time limit
     public int totalEntityAge; // Paper - age-like counter for all entities
     public final io.papermc.paper.entity.activation.ActivationType activationType = io.papermc.paper.entity.activation.ActivationType.activationTypeFor(this); // Paper - EAR 2/tracking ranges
+    // Paper start - EAR 2
+    public final boolean defaultActivationState;
+    public long activatedTick = Integer.MIN_VALUE;
+    public boolean isTemporarilyActive;
+    public long activatedImmunityTick = Integer.MIN_VALUE;
+
+    public void inactiveTick() {
+    }
+    // Paper end - EAR 2
 
     public void setOrigin(@javax.annotation.Nonnull org.bukkit.Location location) {
         this.origin = location.toVector();
@@ -414,6 +423,13 @@ public abstract class Entity implements SyncedDataHolder, Nameable, EntityAccess
         this.position = Vec3.ZERO;
         this.blockPosition = BlockPos.ZERO;
         this.chunkPosition = ChunkPos.ZERO;
+        // Paper start - EAR 2
+        if (level != null) {
+            this.defaultActivationState = io.papermc.paper.entity.activation.ActivationRange.initializeEntityActivationState(this, level.spigotConfig);
+        } else {
+            this.defaultActivationState = false;
+        }
+        // Paper end - EAR 2
         SynchedEntityData.Builder builder = new SynchedEntityData.Builder(this);
         builder.define(DATA_SHARED_FLAGS_ID, (byte)0);
         builder.define(DATA_AIR_SUPPLY_ID, this.getMaxAirSupply());
@@ -978,6 +994,8 @@ public abstract class Entity implements SyncedDataHolder, Nameable, EntityAccess
         } else {
             this.wasOnFire = this.isOnFire();
             if (type == MoverType.PISTON) {
+                this.activatedTick = Math.max(this.activatedTick, MinecraftServer.currentTick + 20); // Paper - EAR 2
+                this.activatedImmunityTick = Math.max(this.activatedImmunityTick, MinecraftServer.currentTick + 20);   // Paper - EAR 2
                 movement = this.limitPistonMovement(movement);
                 if (movement.equals(Vec3.ZERO)) {
                     return;
@@ -991,6 +1009,13 @@ public abstract class Entity implements SyncedDataHolder, Nameable, EntityAccess
                 this.stuckSpeedMultiplier = Vec3.ZERO;
                 this.setDeltaMovement(Vec3.ZERO);
             }
+            // Paper start - ignore movement changes while inactive.
+            if (isTemporarilyActive && !(this instanceof ItemEntity) && movement == getDeltaMovement() && type == MoverType.SELF) {
+                setDeltaMovement(Vec3.ZERO);
+                profilerFiller.pop();
+                return;
+            }
+            // Paper end
 
             movement = this.maybeBackOffFromEdge(movement, type);
             Vec3 vec3 = this.collide(movement);
diff --git a/net/minecraft/world/entity/LivingEntity.java b/net/minecraft/world/entity/LivingEntity.java
index e0c310d970a687945b6a771b4ecb94044128c33c..4546aca8e2e144ec207653c713fc49f849908827 100644
--- a/net/minecraft/world/entity/LivingEntity.java
+++ b/net/minecraft/world/entity/LivingEntity.java
@@ -3103,6 +3103,14 @@ public abstract class LivingEntity extends Entity implements Attackable {
         return false;
     }
 
+    // Paper start - EAR 2
+    @Override
+    public void inactiveTick() {
+        super.inactiveTick();
+        ++this.noActionTime; // Above all the floats
+    }
+    // Paper end - EAR 2
+
     @Override
     public void tick() {
         super.tick();
diff --git a/net/minecraft/world/entity/Mob.java b/net/minecraft/world/entity/Mob.java
index e12b47ca5eeb842bae606c0c7a8e3e4cf7d468a9..e330bf990e4874baed1b21cd8c9b44d66ec5b823 100644
--- a/net/minecraft/world/entity/Mob.java
+++ b/net/minecraft/world/entity/Mob.java
@@ -215,6 +215,19 @@ public abstract class Mob extends LivingEntity implements EquipmentUser, Leashab
         return this.lookControl;
     }
 
+    // Paper start
+    @Override
+    public void inactiveTick() {
+        super.inactiveTick();
+        if (this.goalSelector.inactiveTick()) {
+            this.goalSelector.tick();
+        }
+        if (this.targetSelector.inactiveTick()) {
+            this.targetSelector.tick();
+        }
+    }
+    // Paper end
+
     public MoveControl getMoveControl() {
         return this.getControlledVehicle() instanceof Mob mob ? mob.getMoveControl() : this.moveControl;
     }
diff --git a/net/minecraft/world/entity/PathfinderMob.java b/net/minecraft/world/entity/PathfinderMob.java
index 0caf50ec50f056b83a20bbc6a2fe0144593aef39..af59a700755654eb68d6bf57d0712c4a2ac6c09b 100644
--- a/net/minecraft/world/entity/PathfinderMob.java
+++ b/net/minecraft/world/entity/PathfinderMob.java
@@ -17,6 +17,8 @@ public abstract class PathfinderMob extends Mob {
         super(entityType, level);
     }
 
+    public BlockPos movingTarget; public BlockPos getMovingTarget() { return movingTarget; } // Paper
+
     public float getWalkTargetValue(BlockPos pos) {
         return this.getWalkTargetValue(pos, this.level());
     }
diff --git a/net/minecraft/world/entity/ai/goal/GoalSelector.java b/net/minecraft/world/entity/ai/goal/GoalSelector.java
index 9338e63cc28413f5559bb0122ef5e04a84bd51d1..eeba224bd575451ba6023df65ef9d9b97f7f1c71 100644
--- a/net/minecraft/world/entity/ai/goal/GoalSelector.java
+++ b/net/minecraft/world/entity/ai/goal/GoalSelector.java
@@ -25,6 +25,7 @@ public class GoalSelector {
     private final Map<Goal.Flag, WrappedGoal> lockedFlags = new EnumMap<>(Goal.Flag.class);
     private final Set<WrappedGoal> availableGoals = new ObjectLinkedOpenHashSet<>();
     private final EnumSet<Goal.Flag> disabledFlags = EnumSet.noneOf(Goal.Flag.class);
+    private int curRate; // Paper - EAR 2
 
     public void addGoal(int priority, Goal goal) {
         this.availableGoals.add(new WrappedGoal(priority, goal));
@@ -35,6 +36,22 @@ public class GoalSelector {
         this.availableGoals.removeIf(wrappedGoal -> filter.test(wrappedGoal.getGoal()));
     }
 
+    // Paper start - EAR 2
+    public boolean inactiveTick() {
+        this.curRate++;
+        return this.curRate % 3 == 0; // TODO newGoalRate was already unused in 1.20.4, check if this is correct
+    }
+
+    public boolean hasTasks() {
+        for (WrappedGoal task : this.availableGoals) {
+            if (task.isRunning()) {
+                return true;
+            }
+        }
+        return false;
+    }
+    // Paper end - EAR 2
+
     public void removeGoal(Goal goal) {
         for (WrappedGoal wrappedGoal : this.availableGoals) {
             if (wrappedGoal.getGoal() == goal && wrappedGoal.isRunning()) {
diff --git a/net/minecraft/world/entity/ai/goal/MoveToBlockGoal.java b/net/minecraft/world/entity/ai/goal/MoveToBlockGoal.java
index 789fea258d70e60d38271ebb31270562dc7eb3ab..d0ab3db7bbd2942db19f473474371b20ce822608 100644
--- a/net/minecraft/world/entity/ai/goal/MoveToBlockGoal.java
+++ b/net/minecraft/world/entity/ai/goal/MoveToBlockGoal.java
@@ -23,6 +23,14 @@ public abstract class MoveToBlockGoal extends Goal {
     public MoveToBlockGoal(PathfinderMob mob, double speedModifier, int searchRange) {
         this(mob, speedModifier, searchRange, 1);
     }
+    // Paper start - activation range improvements
+    @Override
+    public void stop() {
+        super.stop();
+        this.blockPos = BlockPos.ZERO;
+        this.mob.movingTarget = null;
+    }
+    // Paper end
 
     public MoveToBlockGoal(PathfinderMob mob, double speedModifier, int searchRange, int verticalSearchRange) {
         this.mob = mob;
@@ -113,6 +121,7 @@ public abstract class MoveToBlockGoal extends Goal {
                         mutableBlockPos.setWithOffset(blockPos, i4, i2 - 1, i5);
                         if (this.mob.isWithinRestriction(mutableBlockPos) && this.isValidTarget(this.mob.level(), mutableBlockPos)) {
                             this.blockPos = mutableBlockPos;
+                            this.mob.movingTarget = mutableBlockPos == BlockPos.ZERO ? null : mutableBlockPos.immutable(); // Paper
                             return true;
                         }
                     }
diff --git a/net/minecraft/world/entity/item/ItemEntity.java b/net/minecraft/world/entity/item/ItemEntity.java
index 8b034b6bda937b25dbb3d09b8293fed6d7dc512c..52a7ed0d991758bad0dcedcb7f97fb15ac6c6d04 100644
--- a/net/minecraft/world/entity/item/ItemEntity.java
+++ b/net/minecraft/world/entity/item/ItemEntity.java
@@ -124,6 +124,29 @@ public class ItemEntity extends Entity implements TraceableEntity {
         return 0.04;
     }
 
+    // Paper start - EAR 2
+    @Override
+    public void inactiveTick() {
+        super.inactiveTick();
+        if (this.pickupDelay > 0 && this.pickupDelay != 32767) {
+            this.pickupDelay--;
+        }
+        if (this.age != -32768) {
+            this.age++;
+        }
+
+        if (!this.level().isClientSide && this.age >= this.despawnRate) {// Paper - Alternative item-despawn-rate
+            // CraftBukkit start - fire ItemDespawnEvent
+            if (org.bukkit.craftbukkit.event.CraftEventFactory.callItemDespawnEvent(this).isCancelled()) {
+                this.age = 0;
+                return;
+            }
+            // CraftBukkit end
+            this.discard(org.bukkit.event.entity.EntityRemoveEvent.Cause.DESPAWN); // CraftBukkit - add Bukkit remove cause
+        }
+    }
+    // Paper end - EAR 2
+
     @Override
     public void tick() {
         if (this.getItem().isEmpty()) {
diff --git a/net/minecraft/world/entity/npc/Villager.java b/net/minecraft/world/entity/npc/Villager.java
index 27568a1604d2dd5d46e836bbc25431929e218aa1..2b83262e4a13eae86df82913ce4f3121e3631a43 100644
--- a/net/minecraft/world/entity/npc/Villager.java
+++ b/net/minecraft/world/entity/npc/Villager.java
@@ -265,11 +265,35 @@ public class Villager extends AbstractVillager implements ReputationEventHandler
         return this.assignProfessionWhenSpawned;
     }
 
+    // Paper start - EAR 2
+    @Override
+    public void inactiveTick() {
+        // SPIGOT-3874, SPIGOT-3894, SPIGOT-3846, SPIGOT-5286 :(
+        if (this.getUnhappyCounter() > 0) {
+            this.setUnhappyCounter(this.getUnhappyCounter() - 1);
+        }
+        if (this.isEffectiveAi()) {
+            if (this.level().spigotConfig.tickInactiveVillagers) {
+                this.customServerAiStep(this.level().getMinecraftWorld());
+            } else {
+                this.customServerAiStep(this.level().getMinecraftWorld(), true);
+            }
+        }
+        maybeDecayGossip();
+        super.inactiveTick();
+    }
+    // Paper end - EAR 2
+
     @Override
     protected void customServerAiStep(ServerLevel level) {
+        // Paper start - EAR 2
+        this.customServerAiStep(level, false);
+    }
+    protected void customServerAiStep(ServerLevel level, final boolean inactive) {
+        // Paper end - EAR 2
         ProfilerFiller profilerFiller = Profiler.get();
         profilerFiller.push("villagerBrain");
-        this.getBrain().tick(level, this);
+        if (!inactive) this.getBrain().tick(level, this); // Paper - EAR 2
         profilerFiller.pop();
         if (this.assignProfessionWhenSpawned) {
             this.assignProfessionWhenSpawned = false;
@@ -293,7 +317,7 @@ public class Villager extends AbstractVillager implements ReputationEventHandler
             this.lastTradedPlayer = null;
         }
 
-        if (!this.isNoAi() && this.random.nextInt(100) == 0) {
+        if (!inactive && !this.isNoAi() && this.random.nextInt(100) == 0) { // Paper - EAR 2
             Raid raidAt = level.getRaidAt(this.blockPosition());
             if (raidAt != null && raidAt.isActive() && !raidAt.isOver()) {
                 level.broadcastEntityEvent(this, (byte)42);
@@ -303,6 +327,7 @@ public class Villager extends AbstractVillager implements ReputationEventHandler
         if (this.getVillagerData().getProfession() == VillagerProfession.NONE && this.isTrading()) {
             this.stopTrading();
         }
+        if (inactive) return; // Paper - EAR 2
 
         super.customServerAiStep(level);
     }
diff --git a/net/minecraft/world/entity/projectile/Arrow.java b/net/minecraft/world/entity/projectile/Arrow.java
index c1e09e701757a300183b62d343ded03033e63aa7..56574f8ef879159edc0114da09300143a2c79a35 100644
--- a/net/minecraft/world/entity/projectile/Arrow.java
+++ b/net/minecraft/world/entity/projectile/Arrow.java
@@ -66,6 +66,16 @@ public class Arrow extends AbstractArrow {
         builder.define(ID_EFFECT_COLOR, -1);
     }
 
+    // Paper start - EAR 2
+    @Override
+    public void inactiveTick() {
+        if (this.isInGround()) {
+            this.life++;
+        }
+        super.inactiveTick();
+    }
+    // Paper end
+
     @Override
     public void tick() {
         super.tick();
diff --git a/net/minecraft/world/entity/projectile/FireworkRocketEntity.java b/net/minecraft/world/entity/projectile/FireworkRocketEntity.java
index a3e4605a81eeaca77cc3a3ab937b75a415d83037..c7ae41b2cbc1eb85a6eb9c16813bd326fb8f49f0 100644
--- a/net/minecraft/world/entity/projectile/FireworkRocketEntity.java
+++ b/net/minecraft/world/entity/projectile/FireworkRocketEntity.java
@@ -102,6 +102,21 @@ public class FireworkRocketEntity extends Projectile implements ItemSupplier {
         return super.shouldRender(x, y, z) && !this.isAttachedToEntity();
     }
 
+    // Paper start - EAR 2
+    @Override
+    public void inactiveTick() {
+        this.life++;
+        if (this.life > this.lifetime && this.level() instanceof ServerLevel serverLevel) {
+            // Paper start - Call FireworkExplodeEvent
+            if (org.bukkit.craftbukkit.event.CraftEventFactory.callFireworkExplodeEvent(this)) {
+                this.explode(serverLevel);
+            }
+            // Paper end - Call FireworkExplodeEvent
+        }
+        super.inactiveTick();
+    }
+    // Paper end - EAR 2
+
     @Override
     public void tick() {
         super.tick();
diff --git a/net/minecraft/world/entity/vehicle/MinecartHopper.java b/net/minecraft/world/entity/vehicle/MinecartHopper.java
index c553cf0592dfa606dbbb1e6854d3377b9feb5efb..8341e7f01606fca90e69384c16fc19bb9e20d1b7 100644
--- a/net/minecraft/world/entity/vehicle/MinecartHopper.java
+++ b/net/minecraft/world/entity/vehicle/MinecartHopper.java
@@ -47,6 +47,7 @@ public class MinecartHopper extends AbstractMinecartContainer implements Hopper
         if (flag != this.isEnabled()) {
             this.setEnabled(flag);
         }
+        this.immunize(); // Paper
     }
 
     public boolean isEnabled() {
@@ -100,11 +101,13 @@ public class MinecartHopper extends AbstractMinecartContainer implements Hopper
 
     public boolean suckInItems() {
         if (HopperBlockEntity.suckInItems(this.level(), this)) {
+            this.immunize(); // Paper
             return true;
         } else {
             for (ItemEntity itemEntity : this.level()
                 .getEntitiesOfClass(ItemEntity.class, this.getBoundingBox().inflate(0.25, 0.0, 0.25), EntitySelector.ENTITY_STILL_ALIVE)) {
                 if (HopperBlockEntity.addItem(this, itemEntity)) {
+                    this.immunize(); // Paper
                     return true;
                 }
             }
@@ -139,4 +142,11 @@ public class MinecartHopper extends AbstractMinecartContainer implements Hopper
     public AbstractContainerMenu createMenu(int id, Inventory playerInventory) {
         return new HopperMenu(id, playerInventory, this);
     }
+
+    // Paper start
+    public void immunize() {
+        this.activatedImmunityTick = Math.max(this.activatedImmunityTick, net.minecraft.server.MinecraftServer.currentTick + 20);
+    }
+    // Paper end
+
 }
diff --git a/net/minecraft/world/level/Level.java b/net/minecraft/world/level/Level.java
index 32f184288f6065259c921293922c1b0163df4dc4..0f346faa82b988e86834c38837f6f11bea7f31c6 100644
--- a/net/minecraft/world/level/Level.java
+++ b/net/minecraft/world/level/Level.java
@@ -153,6 +153,12 @@ public abstract class Level implements LevelAccessor, AutoCloseable {
     public Map<BlockPos, BlockEntity> capturedTileEntities = new java.util.LinkedHashMap<>(); // Paper - Retain block place order when capturing blockstates
     public List<net.minecraft.world.entity.item.ItemEntity> captureDrops;
     public final it.unimi.dsi.fastutil.objects.Object2LongOpenHashMap<SpawnCategory> ticksPerSpawnCategory = new it.unimi.dsi.fastutil.objects.Object2LongOpenHashMap<>();
+    // Paper start
+    public int wakeupInactiveRemainingAnimals;
+    public int wakeupInactiveRemainingFlying;
+    public int wakeupInactiveRemainingMonsters;
+    public int wakeupInactiveRemainingVillagers;
+    // Paper end
     public boolean populating;
     public final org.spigotmc.SpigotWorldConfig spigotConfig; // Spigot
     // Paper start - add paper world config
diff --git a/net/minecraft/world/level/block/piston/PistonMovingBlockEntity.java b/net/minecraft/world/level/block/piston/PistonMovingBlockEntity.java
index ce880bd45fbda4829d17de8507034b3a39c68cbb..ee2f8e8deb35059824b5730a1442f383dc79f01c 100644
--- a/net/minecraft/world/level/block/piston/PistonMovingBlockEntity.java
+++ b/net/minecraft/world/level/block/piston/PistonMovingBlockEntity.java
@@ -149,6 +149,10 @@ public class PistonMovingBlockEntity extends BlockEntity {
                                 }
 
                                 entity.setDeltaMovement(d1, d2, d3);
+                                // Paper - EAR items stuck in slime pushed by a piston
+                                entity.activatedTick = Math.max(entity.activatedTick, net.minecraft.server.MinecraftServer.currentTick + 10);
+                                entity.activatedImmunityTick = Math.max(entity.activatedImmunityTick, net.minecraft.server.MinecraftServer.currentTick + 10);
+                                // Paper end
                                 break;
                             }
                         }
