Get the basics working

connector/src/main/java/org/geysermc/connector/entity/Entity.java

@@ -56,10 +56,7 @@ import org.geysermc.connector.utils.AttributeUtils;
 import org.geysermc.connector.utils.ChunkUtils;
 import org.geysermc.connector.utils.MessageUtils;
 
-import java.util.ArrayList;
+import java.util.*;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
 
 @Getter
 @Setter
@@ -67,6 +64,8 @@ public class Entity {
     protected long entityId;
     protected long geyserId;
 
+    protected UUID javaUuid;
+
     protected String dimension;
 
     protected Vector3f position;

connector/src/main/java/org/geysermc/connector/network/session/GeyserSession.java

@@ -47,10 +47,13 @@ import com.nukkitx.protocol.bedrock.BedrockPacket;
 import com.nukkitx.protocol.bedrock.BedrockServerSession;
 import com.nukkitx.protocol.bedrock.data.*;
 import com.nukkitx.protocol.bedrock.data.command.CommandPermission;
+import com.nukkitx.protocol.bedrock.data.entity.EntityData;
+import com.nukkitx.protocol.bedrock.data.entity.EntityLinkData;
 import com.nukkitx.protocol.bedrock.packet.*;
 import it.unimi.dsi.fastutil.longs.Long2ObjectMap;
 import it.unimi.dsi.fastutil.longs.Long2ObjectMaps;
 import it.unimi.dsi.fastutil.longs.Long2ObjectOpenHashMap;
+import it.unimi.dsi.fastutil.longs.LongOpenHashSet;
 import it.unimi.dsi.fastutil.objects.Object2LongMap;
 import it.unimi.dsi.fastutil.objects.Object2LongOpenHashMap;
 import lombok.Getter;
@@ -62,6 +65,7 @@ import org.geysermc.connector.command.CommandSender;
 import org.geysermc.connector.common.AuthType;
 import org.geysermc.connector.entity.Entity;
 import org.geysermc.connector.entity.PlayerEntity;
+import org.geysermc.connector.entity.type.EntityType;
 import org.geysermc.connector.inventory.PlayerInventory;
 import org.geysermc.connector.network.remote.RemoteServer;
 import org.geysermc.connector.network.session.auth.AuthData;
@@ -261,6 +265,11 @@ public class GeyserSession implements CommandSender {
     @Setter
     private String lastSignMessage;
 
+    private Entity spectatingEntity = null;
+    private Vector3f originalPosition = null;
+    private Vector3f originalRotation = null;
+    private boolean originalOnGround = false;
+
     private MinecraftProtocol protocol;
 
     public GeyserSession(GeyserConnector connector, BedrockServerSession bedrockServerSession) {
@@ -751,4 +760,53 @@ public class GeyserSession implements CommandSender {
         adventureSettingsPacket.getSettings().addAll(flags);
         sendUpstreamPacket(adventureSettingsPacket);
     }
+
+    public void stopSpectatingEntity() {
+        playerEntity.updatePositionAndRotation(this, originalPosition.getX(), originalPosition.getY(), originalPosition.getZ(),
+                originalRotation.getZ(), originalRotation.getY(), originalOnGround);
+
+        SetEntityLinkPacket linkPacket = new SetEntityLinkPacket();
+        linkPacket.setEntityLink(new EntityLinkData(spectatingEntity.getGeyserId(), playerEntity.getGeyserId(), EntityLinkData.Type.REMOVE, false));
+        this.sendUpstreamPacket(linkPacket);
+
+        spectatingEntity.getPassengers().remove(playerEntity.getEntityId());
+
+        spectatingEntity = null;
+
+        this.sendMessage("Stopping spectating entity");
+    }
+
+    public void setSpectatingEntity(Entity entity) {
+        this.sendMessage("Starting spectating entity");
+
+        originalPosition = playerEntity.getPosition();
+        originalRotation = playerEntity.getRotation();
+        originalOnGround = playerEntity.isOnGround();
+
+        SetEntityLinkPacket linkPacket = new SetEntityLinkPacket();
+        linkPacket.setEntityLink(new EntityLinkData(entity.getGeyserId(), playerEntity.getGeyserId(),
+                EntityLinkData.Type.RIDER, false));
+
+        this.sendUpstreamPacket(linkPacket);
+
+        entity.getPassengers().add(playerEntity.getEntityId());
+
+        spectatingEntity = entity;
+    }
+
+    public void sendSpectateLocation() {
+        Vector3f pos = spectatingEntity.getPosition();
+        Vector3f rot = spectatingEntity.getRotation();
+
+        playerEntity.updatePositionAndRotation(this, pos.getX(), pos.getY(), pos.getZ(), rot.getZ(), rot.getY(), spectatingEntity.isOnGround());
+
+        SetTitlePacket setTitlePacket = new SetTitlePacket();
+        setTitlePacket.setFadeOutTime(0);
+        setTitlePacket.setFadeInTime(0);
+        setTitlePacket.setStayTime(30);
+        setTitlePacket.setText("Sending position: " + pos.getX() + " " + pos.getY() + " " + pos.getZ());
+        setTitlePacket.setType(SetTitlePacket.Type.ACTIONBAR);
+
+        this.sendUpstreamPacket(setTitlePacket);
+    }
 }

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

@@ -36,6 +36,7 @@ import com.github.steveice10.mc.protocol.packet.ingame.client.player.ClientPlaye
 import com.github.steveice10.mc.protocol.packet.ingame.client.player.ClientPlayerInteractEntityPacket;
 import com.github.steveice10.mc.protocol.packet.ingame.client.player.ClientPlayerPlaceBlockPacket;
 import com.github.steveice10.mc.protocol.packet.ingame.client.player.ClientPlayerUseItemPacket;
+import com.github.steveice10.mc.protocol.packet.ingame.client.world.ClientSpectatePacket;
 import com.nukkitx.math.vector.Vector3f;
 import com.nukkitx.math.vector.Vector3i;
 import com.nukkitx.protocol.bedrock.data.LevelEventType;
@@ -45,6 +46,7 @@ import com.nukkitx.protocol.bedrock.packet.ContainerOpenPacket;
 import com.nukkitx.protocol.bedrock.packet.InventorySlotPacket;
 import com.nukkitx.protocol.bedrock.packet.InventoryTransactionPacket;
 import com.nukkitx.protocol.bedrock.packet.LevelEventPacket;
+import org.geysermc.connector.GeyserConnector;
 import org.geysermc.connector.entity.CommandBlockMinecartEntity;
 import org.geysermc.connector.entity.Entity;
 import org.geysermc.connector.entity.ItemFrameEntity;
@@ -242,6 +244,15 @@ public class BedrockInventoryTransactionTranslator extends PacketTranslator<Inve
                 //https://wiki.vg/Protocol#Interact_Entity
                 switch (packet.getActionType()) {
                     case 0: //Interact
+                        if (session.getGameMode() == GameMode.SPECTATOR) {
+                            if (entity.getJavaUuid() == null) {
+                                GeyserConnector.getInstance().getLogger().warning("DEBUG: Tried to spectate entity with no Java UUID");
+                                return;
+                            }
+                            session.sendDownstreamPacket(new ClientSpectatePacket(entity.getJavaUuid()));
+                            return;
+                        }
+
                         if (entity instanceof CommandBlockMinecartEntity) {
                             // The UI is handled client-side on Java Edition
                             // Ensure OP permission level and gamemode is appropriate

connector/src/main/java/org/geysermc/connector/network/translators/bedrock/entity/player/BedrockInteractTranslator.java

@@ -25,6 +25,7 @@
 
 package org.geysermc.connector.network.translators.bedrock.entity.player;
 
+import com.github.steveice10.mc.protocol.data.game.entity.player.GameMode;
 import com.nukkitx.protocol.bedrock.data.entity.EntityData;
 import com.nukkitx.protocol.bedrock.data.entity.EntityDataMap;
 import com.nukkitx.protocol.bedrock.data.entity.EntityFlag;
@@ -76,6 +77,10 @@ public class BedrockInteractTranslator extends PacketTranslator<InteractPacket>
                 ClientPlayerStatePacket sneakPacket = new ClientPlayerStatePacket((int) entity.getEntityId(), PlayerState.START_SNEAKING);
                 session.sendDownstreamPacket(sneakPacket);
                 session.setRidingVehicleEntity(null);
+
+                if (session.getGameMode() == GameMode.SPECTATOR && session.getSpectatingEntity() != null) {
+                    //session.stopSpectatingEntity();
+                }
                 break;
             case MOUSEOVER:
                 // Handle the buttons for mobile - "Mount", etc; and the suggestions for console - "ZL: Mount", etc

connector/src/main/java/org/geysermc/connector/network/translators/java/JavaSwitchCameraTranslator.java

@@ -0,0 +1,54 @@
+/*
+ * 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.network.translators.java;
+
+import com.github.steveice10.mc.protocol.packet.ingame.server.ServerSwitchCameraPacket;
+import org.geysermc.connector.entity.Entity;
+import org.geysermc.connector.network.session.GeyserSession;
+import org.geysermc.connector.network.translators.PacketTranslator;
+import org.geysermc.connector.network.translators.Translator;
+
+@Translator(packet = ServerSwitchCameraPacket.class)
+public class JavaSwitchCameraTranslator extends PacketTranslator<ServerSwitchCameraPacket> {
+
+    @Override
+    public void translate(ServerSwitchCameraPacket packet, GeyserSession session) {
+        Entity entity = session.getEntityCache().getEntityByJavaId(packet.getCameraEntityId());
+        if (session.getPlayerEntity().getEntityId() == packet.getCameraEntityId()) {
+            entity = session.getPlayerEntity();
+        }
+
+        if (entity == null)
+            return;
+
+        if (session.getSpectatingEntity() != null && session.getPlayerEntity().getGeyserId() == entity.getGeyserId()) {
+            session.stopSpectatingEntity();
+            return;
+        }
+
+        session.setSpectatingEntity(entity);
+    }
+}

connector/src/main/java/org/geysermc/connector/network/translators/java/entity/JavaEntityPositionRotationTranslator.java

@@ -43,5 +43,9 @@ public class JavaEntityPositionRotationTranslator extends PacketTranslator<Serve
         if (entity == null) return;
 
         entity.updatePositionAndRotation(session, packet.getMoveX(), packet.getMoveY(), packet.getMoveZ(), packet.getYaw(), packet.getPitch(), packet.isOnGround());
+
+        if (session.getSpectatingEntity() != null && session.getSpectatingEntity().getGeyserId() == entity.getGeyserId()) {
+            session.sendSpectateLocation();
+        }
     }
 }

connector/src/main/java/org/geysermc/connector/network/translators/java/entity/JavaEntityPositionTranslator.java

@@ -44,5 +44,9 @@ public class JavaEntityPositionTranslator extends PacketTranslator<ServerEntityP
         if (entity == null) return;
 
         entity.moveRelative(session, packet.getMoveX(), packet.getMoveY(), packet.getMoveZ(), entity.getRotation(), packet.isOnGround());
+
+        if (session.getSpectatingEntity() != null && session.getSpectatingEntity().getGeyserId() == entity.getGeyserId()) {
+            session.sendSpectateLocation();
+        }
     }
 }

connector/src/main/java/org/geysermc/connector/network/translators/java/entity/spawn/JavaSpawnEntityTranslator.java

@@ -83,6 +83,7 @@ public class JavaSpawnEntityTranslator extends PacketTranslator<ServerSpawnEntit
                         type, position, motion, rotation
                 );
             }
+            entity.setJavaUuid(packet.getUuid());
             session.getEntityCache().spawnEntity(entity);
         } catch (NoSuchMethodException | InstantiationException | IllegalAccessException | InvocationTargetException ex) {
             ex.printStackTrace();

connector/src/main/java/org/geysermc/connector/network/translators/java/entity/spawn/JavaSpawnLivingEntityTranslator.java

@@ -61,6 +61,7 @@ public class JavaSpawnLivingEntityTranslator extends PacketTranslator<ServerSpaw
             Entity entity = entityConstructor.newInstance(packet.getEntityId(), session.getEntityCache().getNextEntityId().incrementAndGet(),
                     type, position, motion, rotation
             );
+            entity.setJavaUuid(packet.getUuid());
             session.getEntityCache().spawnEntity(entity);
         } catch (NoSuchMethodException | InstantiationException | IllegalAccessException | InvocationTargetException ex) {
             ex.printStackTrace();

connector/src/main/java/org/geysermc/connector/network/translators/java/entity/spawn/JavaSpawnPaintingTranslator.java

@@ -51,6 +51,7 @@ public class JavaSpawnPaintingTranslator extends PacketTranslator<ServerSpawnPai
                     .setPaintingName(PaintingType.getByPaintingType(packet.getPaintingType()))
                     .setDirection(packet.getDirection().ordinal());
 
+            entity.setJavaUuid(packet.getUuid());
             session.getEntityCache().spawnEntity(entity);
         });
     }

connector/src/main/java/org/geysermc/connector/network/translators/java/entity/spawn/JavaSpawnPlayerTranslator.java

@@ -50,6 +50,7 @@ public class JavaSpawnPlayerTranslator extends PacketTranslator<ServerSpawnPlaye
         }
 
         entity.setEntityId(packet.getEntityId());
+        entity.setJavaUuid(packet.getUuid());
         entity.setPosition(position);
         entity.setRotation(rotation);
         session.getEntityCache().cacheEntity(entity);