Leash fixes (#567)

* Leash fixes

- Adds visuals for leash string by translating ServerEntityAttachPacket
- Updates position offset for lead knots, making them properly appear on fences

* Add basic description of JavaEntityAttachTranslator

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

@@ -0,0 +1,39 @@
+/*
+ * 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;
+
+import com.nukkitx.math.vector.Vector3f;
+import org.geysermc.connector.entity.type.EntityType;
+
+public class LeashKnotEntity extends Entity {
+
+    public LeashKnotEntity(long entityId, long geyserId, EntityType entityType, Vector3f position, Vector3f motion, Vector3f rotation) {
+        // Position is incorrect by default
+        super(entityId, geyserId, entityType, position.add(0.5f, 0.25f, 0.5f), motion, rotation);
+    }
+
+}

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

@@ -121,7 +121,7 @@ public enum EntityType {
     FIREBALL(ItemedFireballEntity.class, 85, 1.0f),
     POTION(ThrowableEntity.class, 86, 0.25f),
     ENDER_PEARL(ThrowableEntity.class, 87, 0.25f),
-    LEASH_KNOT(Entity.class, 88, 0.5f, 0.375f),
+    LEASH_KNOT(LeashKnotEntity.class, 88, 0.5f, 0.375f),
     WITHER_SKULL(Entity.class, 89, 0.3125f),
     BOAT(Entity.class, 90, 0.7f, 1.6f, 1.6f, 0.35f),
     WITHER_SKULL_DANGEROUS(Entity.class, 91, 0f),

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

@@ -0,0 +1,81 @@
+/*
+ * 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.entity;
+
+import com.github.steveice10.mc.protocol.packet.ingame.server.entity.ServerEntityAttachPacket;
+import com.nukkitx.protocol.bedrock.data.EntityData;
+import com.nukkitx.protocol.bedrock.data.EntityEventType;
+import com.nukkitx.protocol.bedrock.data.EntityFlag;
+import com.nukkitx.protocol.bedrock.packet.EntityEventPacket;
+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;
+
+/**
+ * Called when a leash is attached, removed or updated from an entity
+ */
+@Translator(packet = ServerEntityAttachPacket.class)
+public class JavaEntityAttachTranslator extends PacketTranslator<ServerEntityAttachPacket> {
+
+    @Override
+    public void translate(ServerEntityAttachPacket packet, GeyserSession session) {
+
+        Entity holderId;
+        if (packet.getEntityId() == session.getPlayerEntity().getEntityId()) {
+            holderId = session.getPlayerEntity();
+        } else {
+            holderId = session.getEntityCache().getEntityByJavaId(packet.getEntityId());
+            if (holderId == null) {
+                return;
+            }
+        }
+
+        Entity attachedToId;
+        if (packet.getAttachedToId() == session.getPlayerEntity().getEntityId()) {
+            attachedToId = session.getPlayerEntity();
+        } else {
+            attachedToId = session.getEntityCache().getEntityByJavaId(packet.getAttachedToId());
+            if ((attachedToId == null || packet.getAttachedToId() == 0)) {
+                // Is not being leashed
+                holderId.getMetadata().getFlags().setFlag(EntityFlag.LEASHED, false);
+                holderId.getMetadata().put(EntityData.LEAD_HOLDER_EID, 0);
+                holderId.updateBedrockMetadata(session);
+                EntityEventPacket eventPacket = new EntityEventPacket();
+                eventPacket.setRuntimeEntityId(holderId.getGeyserId());
+                eventPacket.setType(EntityEventType.REMOVE_LEASH);
+                eventPacket.setData(0);
+                session.sendUpstreamPacket(eventPacket);
+                return;
+            }
+        }
+
+        holderId.getMetadata().getFlags().setFlag(EntityFlag.LEASHED, true);
+        holderId.getMetadata().put(EntityData.LEAD_HOLDER_EID, attachedToId.getGeyserId());
+        holderId.updateBedrockMetadata(session);
+    }
+}