Ender dragon Melee Attacks (#1466)

* Create and position Ender Dragon Bounding Box

Currently allows the player to "kill aura" target
the ender dragon.

* Use an entity to handle attacks for each hitbox

* Use the proper flag to make entities invisible

* Clean up and add some comments

* Ender dragon entity metadata improvements

* Add doc to segment functions

* Add changes

Co-authored-by: DoctorMacc <toy.fighter1@gmail.com>

connector/src/main/java/org/geysermc/connector/entity/living/monster/EnderDragonEntity.java

@@ -32,33 +32,60 @@ import com.nukkitx.protocol.bedrock.data.entity.EntityEventType;
 import com.nukkitx.protocol.bedrock.data.entity.EntityFlag;
 import com.nukkitx.protocol.bedrock.packet.AddEntityPacket;
 import com.nukkitx.protocol.bedrock.packet.EntityEventPacket;
+import lombok.Data;
 import org.geysermc.connector.entity.living.InsentientEntity;
 import org.geysermc.connector.entity.type.EntityType;
 import org.geysermc.connector.network.session.GeyserSession;
 
+import java.util.concurrent.ScheduledFuture;
+import java.util.concurrent.TimeUnit;
+
 public class EnderDragonEntity extends InsentientEntity {
+    /**
+     * The Ender Dragon has multiple hit boxes, which
+     * are each its own invisible entity
+     */
+    private EnderDragonPartEntity head;
+    private EnderDragonPartEntity neck;
+    private EnderDragonPartEntity body;
+    private EnderDragonPartEntity leftWing;
+    private EnderDragonPartEntity rightWing;
+    private EnderDragonPartEntity[] tail;
+
+    private EnderDragonPartEntity[] allParts;
+
+    /**
+     * A circular buffer that stores a history of
+     * y and yaw values.
+     */
+    private final Segment[] segmentHistory = new Segment[19];
+    private int latestSegment = -1;
+
+    private boolean hovering;
+
+    private ScheduledFuture<?> partPositionUpdater;
 
     public EnderDragonEntity(long entityId, long geyserId, EntityType entityType, Vector3f position, Vector3f motion, Vector3f rotation) {
         super(entityId, geyserId, entityType, position, motion, rotation);
+
+        metadata.getFlags().setFlag(EntityFlag.FIRE_IMMUNE, true);
     }
 
     @Override
     public void updateBedrockMetadata(EntityMetadata entityMetadata, GeyserSession session) {
+        // Phase
         if (entityMetadata.getId() == 15) {
-            metadata.getFlags().setFlag(EntityFlag.FIRE_IMMUNE, true);
+            int value = (int) entityMetadata.getValue();
-            switch ((int) entityMetadata.getValue()) {
+            if (value == 5) {
                 // Performing breath attack
-                case 5:
                 EntityEventPacket entityEventPacket = new EntityEventPacket();
                 entityEventPacket.setType(EntityEventType.DRAGON_FLAMING);
                 entityEventPacket.setRuntimeEntityId(geyserId);
                 entityEventPacket.setData(0);
                 session.sendUpstreamPacket(entityEventPacket);
-                case 6:
-                case 7:
-                    metadata.getFlags().setFlag(EntityFlag.SITTING, true);
-                    break;
             }
+            metadata.getFlags().setFlag(EntityFlag.SITTING, value == 5 || value == 6 || value == 7);
+            hovering = value == 10;
         }
         super.updateBedrockMetadata(entityMetadata, session);
     }
@@ -81,6 +108,118 @@ public class EnderDragonEntity extends InsentientEntity {
         valid = true;
         session.sendUpstreamPacket(addEntityPacket);
 
+        head = new EnderDragonPartEntity(entityId + 1, session.getEntityCache().getNextEntityId().incrementAndGet(), EntityType.ENDER_DRAGON_PART, position, motion, rotation, 1, 1);
+        neck = new EnderDragonPartEntity(entityId + 2, session.getEntityCache().getNextEntityId().incrementAndGet(), EntityType.ENDER_DRAGON_PART, position, motion, rotation, 3, 3);
+        body = new EnderDragonPartEntity(entityId + 3, session.getEntityCache().getNextEntityId().incrementAndGet(), EntityType.ENDER_DRAGON_PART, position, motion, rotation, 5, 3);
+        leftWing = new EnderDragonPartEntity(entityId + 4, session.getEntityCache().getNextEntityId().incrementAndGet(), EntityType.ENDER_DRAGON_PART, position, motion, rotation, 4, 2);
+        rightWing = new EnderDragonPartEntity(entityId + 5, session.getEntityCache().getNextEntityId().incrementAndGet(), EntityType.ENDER_DRAGON_PART, position, motion, rotation, 4, 2);
+        tail = new EnderDragonPartEntity[3];
+        for (int i = 0; i < 3; i++) {
+            tail[i] = new EnderDragonPartEntity(entityId + 6 + i, session.getEntityCache().getNextEntityId().incrementAndGet(), EntityType.ENDER_DRAGON_PART, position, motion, rotation, 2, 2);
+        }
+
+        allParts = new EnderDragonPartEntity[]{head, neck, body, leftWing, rightWing, tail[0], tail[1], tail[2]};
+
+        for (EnderDragonPartEntity part : allParts) {
+            session.getEntityCache().spawnEntity(part);
+        }
+
+        for (int i = 0; i < segmentHistory.length; i++) {
+            segmentHistory[i] = new Segment();
+            segmentHistory[i].yaw = rotation.getZ();
+            segmentHistory[i].y = position.getY();
+        }
+
+        partPositionUpdater = session.getConnector().getGeneralThreadPool().scheduleAtFixedRate(() -> {
+            pushSegment();
+            updateBoundingBoxes(session);
+        }, 0, 50, TimeUnit.MILLISECONDS);
+
         session.getConnector().getLogger().debug("Spawned entity " + entityType + " at location " + position + " with id " + geyserId + " (java id " + entityId + ")");
     }
+
+    @Override
+    public boolean despawnEntity(GeyserSession session) {
+        partPositionUpdater.cancel(true);
+
+        for (EnderDragonPartEntity part : allParts) {
+            part.despawnEntity(session);
+        }
+        return super.despawnEntity(session);
+    }
+
+    /**
+     * Updates the positions of the Ender Dragon's multiple bounding boxes
+     *
+     * @param session GeyserSession.
+     */
+    private void updateBoundingBoxes(GeyserSession session) {
+        Vector3f facingDir = Vector3f.createDirectionDeg(0, rotation.getZ());
+        Segment baseSegment = getSegment(5);
+        // Used to angle the head, neck, and tail when the dragon flies up/down
+        float pitch = (float) Math.toRadians(10 * (baseSegment.getY() - getSegment(10).getY()));
+        float pitchXZ = (float) Math.cos(pitch);
+        float pitchY = (float) Math.sin(pitch);
+
+        // Lowers the head when the dragon sits/hovers
+        float headDuck;
+        if (hovering || metadata.getFlags().getFlag(EntityFlag.SITTING)) {
+            headDuck = -1f;
+        } else {
+            headDuck = baseSegment.y - getSegment(0).y;
+        }
+
+        head.setPosition(facingDir.up(pitchY).mul(pitchXZ, 1, -pitchXZ).mul(6.5f).up(headDuck));
+        neck.setPosition(facingDir.up(pitchY).mul(pitchXZ, 1, -pitchXZ).mul(5.5f).up(headDuck));
+        body.setPosition(facingDir.mul(0.5f, 0f, -0.5f));
+
+        Vector3f wingPos = Vector3f.createDirectionDeg(0, 90f - rotation.getZ()).mul(4.5f).up(2f);
+        rightWing.setPosition(wingPos);
+        leftWing.setPosition(wingPos.mul(-1, 1, -1)); // Mirror horizontally
+
+        Vector3f tailBase = facingDir.mul(1.5f);
+        for (int i = 0; i < tail.length; i++) {
+            float distance = (i + 1) * 2f;
+            // Curls the tail when the dragon turns
+            Segment targetSegment = getSegment(12 + 2 * i);
+            float angle = rotation.getZ() + targetSegment.yaw - baseSegment.yaw;
+
+            float tailYOffset = targetSegment.y - baseSegment.y - (distance + 1.5f) * pitchY + 1.5f;
+            tail[i].setPosition(Vector3f.createDirectionDeg(0, angle).mul(distance).add(tailBase).mul(-pitchXZ, 1, pitchXZ).up(tailYOffset));
+        }
+        // Send updated positions
+        for (EnderDragonPartEntity part : allParts) {
+             part.moveAbsolute(session, part.getPosition().add(position), Vector3f.ZERO, false, false);
+        }
+    }
+
+    /**
+     * Store the current yaw and y into the circular buffer
+     */
+    private void pushSegment() {
+        latestSegment = (latestSegment + 1) % segmentHistory.length;
+        segmentHistory[latestSegment].yaw = rotation.getZ();
+        segmentHistory[latestSegment].y = position.getY();
+    }
+
+    /**
+     * Gets the previous yaw and y
+     * Used to curl the tail and pitch the head and tail up/down
+     *
+     * @param index Number of ticks in the past
+     * @return Segment with the yaw and y
+     */
+    private Segment getSegment(int index) {
+        index = (latestSegment - index) % segmentHistory.length;
+        if (index < 0) {
+            index += segmentHistory.length;
+        }
+        return segmentHistory[index];
+    }
+
+    @Data
+    private static class Segment {
+        private float yaw;
+        private float y;
+    }
 }

connector/src/main/java/org/geysermc/connector/entity/living/monster/EnderDragonPartEntity.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright (c) 2019-2020 GeyserMC. http://geysermc.org
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * @author GeyserMC
+ * @link https://github.com/GeyserMC/Geyser
+ */
+
+package org.geysermc.connector.entity.living.monster;
+
+import com.nukkitx.math.vector.Vector3f;
+import com.nukkitx.protocol.bedrock.data.entity.EntityData;
+import com.nukkitx.protocol.bedrock.data.entity.EntityFlag;
+import org.geysermc.connector.entity.Entity;
+import org.geysermc.connector.entity.type.EntityType;
+
+public class EnderDragonPartEntity extends Entity {
+    public EnderDragonPartEntity(long entityId, long geyserId, EntityType entityType, Vector3f position, Vector3f motion, Vector3f rotation, float width, float height) {
+        super(entityId, geyserId, entityType, position, motion, rotation);
+
+        metadata.put(EntityData.BOUNDING_BOX_WIDTH, width);
+        metadata.put(EntityData.BOUNDING_BOX_HEIGHT, height);
+        metadata.getFlags().setFlag(EntityFlag.INVISIBLE, true);
+    }
+}

connector/src/main/java/org/geysermc/connector/entity/type/EntityType.java

@@ -86,7 +86,7 @@ public enum EntityType {
     ELDER_GUARDIAN(ElderGuardianEntity.class, 50, 1.9975f),
     NPC(PlayerEntity.class, 51, 1.8f, 0.6f, 0.6f, 1.62f),
     WITHER(WitherEntity.class, 52, 3.5f, 0.9f),
-    ENDER_DRAGON(EnderDragonEntity.class, 53, 4f, 13f),
+    ENDER_DRAGON(EnderDragonEntity.class, 53, 0f, 0f),
     SHULKER(ShulkerEntity.class, 54, 1f, 1f),
     ENDERMITE(MonsterEntity.class, 55, 0.3f, 0.4f),
     AGENT(Entity.class, 56, 0f),
@@ -166,7 +166,12 @@ public enum EntityType {
     /**
      * Not an entity in Bedrock, so we replace it with a Pillager
      */
-    ILLUSIONER(AbstractIllagerEntity.class, 114, 1.8f, 0.6f, 0.6f, 1.62f, "minecraft:pillager");
+    ILLUSIONER(AbstractIllagerEntity.class, 114, 1.8f, 0.6f, 0.6f, 1.62f, "minecraft:pillager"),
+
+    /**
+     * Not an entity in Bedrock, but used for the Ender Dragon's multiple hitboxes
+     */
+    ENDER_DRAGON_PART(EnderDragonPartEntity.class, 32, 0, 0, 0, 0, "minecraft:armor_stand");
 
     private static final EntityType[] VALUES = values();
 

connector/src/main/java/org/geysermc/connector/network/translators/bedrock/BedrockInventoryTransactionTranslator.java

@@ -49,6 +49,7 @@ import org.geysermc.connector.entity.CommandBlockMinecartEntity;
 import org.geysermc.connector.entity.Entity;
 import org.geysermc.connector.entity.ItemFrameEntity;
 import org.geysermc.connector.entity.living.merchant.AbstractMerchantEntity;
+import org.geysermc.connector.entity.type.EntityType;
 import org.geysermc.connector.inventory.Inventory;
 import org.geysermc.connector.network.session.GeyserSession;
 import org.geysermc.connector.network.translators.PacketTranslator;
@@ -251,9 +252,17 @@ public class BedrockInventoryTransactionTranslator extends PacketTranslator<Inve
                         }
                         break;
                     case 1: //Attack
+                        if (entity.getEntityType() == EntityType.ENDER_DRAGON) {
+                            // Redirects the attack to its body entity, this only happens when
+                            // attacking the underbelly of the ender dragon
+                            ClientPlayerInteractEntityPacket attackPacket = new ClientPlayerInteractEntityPacket((int) entity.getEntityId() + 3,
+                                    InteractAction.ATTACK, session.isSneaking());
+                            session.sendDownstreamPacket(attackPacket);
+                        } else {
                             ClientPlayerInteractEntityPacket attackPacket = new ClientPlayerInteractEntityPacket((int) entity.getEntityId(),
                                     InteractAction.ATTACK, session.isSneaking());
                             session.sendDownstreamPacket(attackPacket);
+                        }
                         break;
                 }
                 break;