Lerp entity steps

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

@@ -35,7 +35,12 @@ import org.cloudburstmc.math.vector.Vector3f;
 import org.cloudburstmc.protocol.bedrock.data.entity.EntityDataTypes;
 import org.cloudburstmc.protocol.bedrock.data.entity.EntityEventType;
 import org.cloudburstmc.protocol.bedrock.data.entity.EntityFlag;
-import org.cloudburstmc.protocol.bedrock.packet.*;
+import org.cloudburstmc.protocol.bedrock.packet.AddEntityPacket;
+import org.cloudburstmc.protocol.bedrock.packet.EntityEventPacket;
+import org.cloudburstmc.protocol.bedrock.packet.MoveEntityAbsolutePacket;
+import org.cloudburstmc.protocol.bedrock.packet.MoveEntityDeltaPacket;
+import org.cloudburstmc.protocol.bedrock.packet.RemoveEntityPacket;
+import org.cloudburstmc.protocol.bedrock.packet.SetEntityDataPacket;
 import org.geysermc.geyser.api.entity.type.GeyserEntity;
 import org.geysermc.geyser.entity.EntityDefinition;
 import org.geysermc.geyser.entity.GeyserDirtyMetadata;
@@ -55,7 +60,11 @@ import org.geysermc.mcprotocollib.protocol.data.game.entity.metadata.type.IntEnt
 import org.geysermc.mcprotocollib.protocol.data.game.entity.player.Hand;
 import org.geysermc.mcprotocollib.protocol.data.game.entity.type.EntityType;
 
-import java.util.*;
+import java.util.Collections;
+import java.util.EnumSet;
+import java.util.List;
+import java.util.Optional;
+import java.util.UUID;
 
 @Getter
 @Setter
@@ -218,11 +227,15 @@ public class Entity implements GeyserEntity {
         valid = false;
     }
 
-    public void moveRelative(double relX, double relY, double relZ, float yaw, float pitch, boolean isOnGround) {
+    protected void moveRelative(double relX, double relY, double relZ, float yaw, float pitch, boolean isOnGround) {
         moveRelative(relX, relY, relZ, yaw, pitch, getHeadYaw(), isOnGround);
     }
 
     public void moveRelative(double relX, double relY, double relZ, float yaw, float pitch, float headYaw, boolean isOnGround) {
+        moveRelativeRaw(relX, relY, relZ, yaw, pitch, headYaw, isOnGround);
+    }
+
+    protected void moveRelativeRaw(double relX, double relY, double relZ, float yaw, float pitch, float headYaw, boolean isOnGround) {
         position = Vector3f.from(position.getX() + relX, position.getY() + relY, position.getZ() + relZ);
 
         MoveEntityDeltaPacket moveEntityPacket = new MoveEntityDeltaPacket();
@@ -266,6 +279,10 @@ public class Entity implements GeyserEntity {
     }
 
     public void moveAbsolute(Vector3f position, float yaw, float pitch, float headYaw, boolean isOnGround, boolean teleported) {
+        moveAbsoluteRaw(position, yaw, pitch, headYaw, isOnGround, teleported);
+    }
+
+    protected void moveAbsoluteRaw(Vector3f position, float yaw, float pitch, float headYaw, boolean isOnGround, boolean teleported) {
         setPosition(position);
         // Setters are intentional so it can be overridden in places like AbstractArrowEntity
         setYaw(yaw);

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

@@ -38,6 +38,7 @@ import org.cloudburstmc.protocol.bedrock.data.inventory.ContainerId;
 import org.cloudburstmc.protocol.bedrock.data.inventory.ItemData;
 import org.cloudburstmc.protocol.bedrock.packet.MobArmorEquipmentPacket;
 import org.cloudburstmc.protocol.bedrock.packet.MobEquipmentPacket;
+import org.cloudburstmc.protocol.bedrock.packet.MoveEntityDeltaPacket;
 import org.cloudburstmc.protocol.bedrock.packet.UpdateAttributesPacket;
 import org.geysermc.geyser.entity.EntityDefinition;
 import org.geysermc.geyser.entity.attribute.GeyserAttributeType;
@@ -69,7 +70,7 @@ import java.util.*;
 
 @Getter
 @Setter
-public class LivingEntity extends Entity {
+public class LivingEntity extends Entity implements Tickable {
 
     protected ItemData helmet = ItemData.AIR;
     protected ItemData chestplate = ItemData.AIR;
@@ -102,6 +103,11 @@ public class LivingEntity extends Entity {
     @Setter(AccessLevel.NONE)
     private float attributeScale;
 
+    private float lerpX;
+    private float lerpY;
+    private float lerpZ;
+    private int lerpSteps;
+
     public LivingEntity(GeyserSession session, int entityId, long geyserId, UUID uuid, EntityDefinition<?> definition, Vector3f position, Vector3f motion, float yaw, float pitch, float headYaw) {
         super(session, entityId, geyserId, uuid, definition, position, motion, yaw, pitch, headYaw);
     }
@@ -277,6 +283,40 @@ public class LivingEntity extends Entity {
         return new AttributeData(GeyserAttributeType.HEALTH.getBedrockIdentifier(), 0f, this.maxHealth, (float) Math.ceil(this.health), this.maxHealth);
     }
 
+    @Override
+    public void tick() {
+        lerpSteps();
+    }
+
+    protected void lerpSteps() {
+        if (this.lerpSteps > 0) {
+            float time = 1.0f / this.lerpSteps;
+            float lerpXTotal = lerp(time, this.position.getX(), this.lerpX);
+            float lerpYTotal = lerp(time, this.position.getY(), this.lerpY);
+            float lerpZTotal = lerp(time, this.position.getZ(), this.lerpZ);
+            setPosition(Vector3f.from(lerpXTotal, lerpYTotal, lerpZTotal));
+
+            MoveEntityDeltaPacket moveEntityPacket = new MoveEntityDeltaPacket();
+            moveEntityPacket.setRuntimeEntityId(geyserId);
+            moveEntityPacket.setX(position.getX());
+            moveEntityPacket.getFlags().add(MoveEntityDeltaPacket.Flag.HAS_X);
+            moveEntityPacket.setY(position.getY());
+            moveEntityPacket.getFlags().add(MoveEntityDeltaPacket.Flag.HAS_Y);
+            moveEntityPacket.setZ(position.getZ());
+            moveEntityPacket.getFlags().add(MoveEntityDeltaPacket.Flag.HAS_Z);
+            if (this.onGround) {
+                moveEntityPacket.getFlags().add(MoveEntityDeltaPacket.Flag.ON_GROUND);
+            }
+            session.sendUpstreamPacket(moveEntityPacket);
+
+            this.lerpSteps--;
+        }
+    }
+
+    private static float lerp(float time, float a, float b) {
+        return a + time * (b - a);
+    }
+
     @Override
     public boolean isAlive() {
         return this.valid && health > 0f;
@@ -304,7 +344,27 @@ public class LivingEntity extends Entity {
             clientVehicle.getVehicleComponent().moveRelative(relX, relY, relZ);
         }
 
-        super.moveRelative(relX, relY, relZ, yaw, pitch, headYaw, isOnGround);
+        // Logic analogous to Java Edition 1.21.
+        if (relX != 0 || relY != 0 || relZ != 0) {
+            this.lerpX = this.position.getX() + (float) relX;
+            this.lerpY = this.position.getY() + (float) relY;
+            this.lerpZ = this.position.getZ() + (float) relZ;
+            this.lerpSteps = 3;
+        }
+
+        // Rotation lerping does not seem to be an issue with Bedrock Edition as of 1.21.22
+
+        super.moveRelative(0, 0, 0, yaw, pitch, headYaw, isOnGround);
+    }
+
+    @Override
+    public void moveAbsolute(Vector3f position, float yaw, float pitch, float headYaw, boolean isOnGround, boolean teleported) {
+        this.lerpX = position.getX();
+        this.lerpY = position.getY();
+        this.lerpZ = position.getZ();
+        this.lerpSteps = 3;
+
+        super.moveAbsolute(this.position, yaw, pitch, headYaw, isOnGround, teleported);
     }
 
     @Override

core/src/main/java/org/geysermc/geyser/entity/type/living/animal/PigEntity.java

@@ -101,6 +101,8 @@ public class PigEntity extends AnimalEntity implements Tickable, ClientVehicle {
 
     @Override
     public void tick() {
+        super.tick();
+
         PlayerEntity player = getPlayerPassenger();
         if (player == null) {
             return;

core/src/main/java/org/geysermc/geyser/entity/type/living/animal/SnifferEntity.java

@@ -101,6 +101,8 @@ public class SnifferEntity extends AnimalEntity implements Tickable {
 
     @Override
     public void tick() {
+        super.tick();
+
         // The java client renders digging particles on its own, but bedrock does not
         if (digTicks > 0 && --digTicks < DIG_START && digTicks % 5 == 0) {
             Vector3f rot = Vector3f.createDirectionDeg(0, -getYaw()).mul(2.25f);

core/src/main/java/org/geysermc/geyser/entity/type/living/animal/StriderEntity.java

@@ -148,6 +148,8 @@ public class StriderEntity extends AnimalEntity implements Tickable, ClientVehic
 
     @Override
     public void tick() {
+        super.tick();
+
         PlayerEntity player = getPlayerPassenger();
         if (player == null) {
             return;

core/src/main/java/org/geysermc/geyser/entity/type/living/monster/EnderDragonEntity.java

@@ -162,6 +162,8 @@ public class EnderDragonEntity extends MobEntity implements Tickable {
 
     @Override
     public void tick() {
+        super.tick();
+
         effectTick();
         if (!getFlag(EntityFlag.NO_AI) && isAlive()) {
             pushSegment();

core/src/main/java/org/geysermc/geyser/entity/type/living/monster/ShulkerEntity.java

@@ -75,6 +75,18 @@ public class ShulkerEntity extends GolemEntity {
         }
     }
 
+    // As of 1.21, Java Edition does not lerp shulker steps.
+
+    @Override
+    public void moveRelative(double relX, double relY, double relZ, float yaw, float pitch, float headYaw, boolean isOnGround) {
+        moveRelativeRaw(relX, relY, relZ, yaw, pitch, headYaw, isOnGround);
+    }
+
+    @Override
+    public void moveAbsolute(Vector3f position, float yaw, float pitch, float headYaw, boolean isOnGround, boolean teleported) {
+        moveAbsoluteRaw(position, yaw, pitch, headYaw, isOnGround, teleported);
+    }
+
     @Override
     protected boolean isEnemy() {
         return true;

core/src/main/java/org/geysermc/geyser/entity/type/living/monster/WardenEntity.java

@@ -73,6 +73,8 @@ public class WardenEntity extends MonsterEntity implements Tickable {
 
     @Override
     public void tick() {
+        super.tick();
+
         if (++tickCount % heartBeatDelay == 0 && !silent) {
             // We have to do these calculations because they're clientside on Java Edition but we mute entities
             // to prevent hearing their step sounds

core/src/main/java/org/geysermc/geyser/translator/protocol/java/entity/JavaSetEntityMotionTranslator.java

@@ -25,7 +25,6 @@
 
 package org.geysermc.geyser.translator.protocol.java.entity;
 
-import org.geysermc.mcprotocollib.protocol.packet.ingame.clientbound.entity.ClientboundSetEntityMotionPacket;
 import org.cloudburstmc.math.vector.Vector3f;
 import org.cloudburstmc.protocol.bedrock.packet.SetEntityMotionPacket;
 import org.geysermc.geyser.entity.type.Entity;
@@ -34,6 +33,7 @@ import org.geysermc.geyser.entity.type.living.animal.horse.AbstractHorseEntity;
 import org.geysermc.geyser.session.GeyserSession;
 import org.geysermc.geyser.translator.protocol.PacketTranslator;
 import org.geysermc.geyser.translator.protocol.Translator;
+import org.geysermc.mcprotocollib.protocol.packet.ingame.clientbound.entity.ClientboundSetEntityMotionPacket;
 
 @Translator(packet = ClientboundSetEntityMotionPacket.class)
 public class JavaSetEntityMotionTranslator extends PacketTranslator<ClientboundSetEntityMotionPacket> {