Create FakeEntityImpl.java

1.19.4 nms

nms/v1_19_R3/src/main/java/de/epiceric/shopchest/nms/v1_19_R3/FakeEntityImpl.java

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+package de.epiceric.shopchest.nms.v1_19_R3;
+
+import de.epiceric.shopchest.nms.FakeEntity;
+import net.minecraft.network.protocol.Packet;
+import net.minecraft.network.protocol.game.ClientboundAddEntityPacket;
+import net.minecraft.network.protocol.game.ClientboundRemoveEntitiesPacket;
+import net.minecraft.network.protocol.game.ClientboundSetEntityDataPacket;
+import net.minecraft.network.syncher.EntityDataAccessor;
+import net.minecraft.network.syncher.SynchedEntityData;
+import net.minecraft.world.entity.Entity;
+import net.minecraft.world.entity.EntityType;
+import net.minecraft.world.phys.Vec3;
+import org.bukkit.Location;
+import org.bukkit.craftbukkit.v1_19_R3.entity.CraftPlayer;
+import org.bukkit.entity.Player;
+
+import java.lang.reflect.Field;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.UUID;
+import java.util.concurrent.atomic.AtomicInteger;
+
+public abstract class FakeEntityImpl<T> implements FakeEntity {
+
+    private final static AtomicInteger ENTITY_COUNTER;
+    private final static EntityDataAccessor<Boolean> DATA_NO_GRAVITY;
+    private final static EntityDataAccessor<Boolean> DATA_SILENT;
+
+    static {
+        try {
+            final Field entityCounterField = Entity.class.getDeclaredField("c"); // ENTITY_COUNTER
+            entityCounterField.setAccessible(true);
+            ENTITY_COUNTER = (AtomicInteger) entityCounterField.get(null);
+            final Field dataNoGravityField = Entity.class.getDeclaredField("aP"); // DATA_NO_GRAVITY
+            dataNoGravityField.setAccessible(true);
+            DATA_NO_GRAVITY = forceCast(dataNoGravityField.get(null));
+            final Field dataSilentField = Entity.class.getDeclaredField("aO"); // DATA_SILENT
+            dataSilentField.setAccessible(true);
+            DATA_SILENT = forceCast(dataSilentField.get(null));
+        } catch (ReflectiveOperationException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    protected final int entityId;
+
+    public FakeEntityImpl() {
+        entityId = ENTITY_COUNTER.incrementAndGet();
+    }
+
+    @SuppressWarnings("unchecked")
+    protected static <T> T forceCast(Object o) {
+        return (T) o;
+    }
+
+    @Override
+    public int getEntityId() {
+        return entityId;
+    }
+
+    protected void sendPacket(Packet<?> packet, Iterable<Player> receivers) {
+        for (Player receiver : receivers) {
+            ((CraftPlayer) receiver).getHandle().connection.send(packet);
+        }
+    }
+
+    @Override
+    public void spawn(UUID uuid, Location location, Iterable<Player> receivers) {
+        final ClientboundAddEntityPacket spawnPacket = new ClientboundAddEntityPacket(
+                entityId,
+                uuid,
+                location.getX(),
+                location.getY() + getSpawnOffSet(),
+                location.getZ(),
+                0f,
+                0f,
+                getEntityType(),
+                0,
+                Vec3.ZERO,
+                0d
+        );
+        sendPacket(spawnPacket, receivers);
+    }
+
+    @Override
+    public void remove(Iterable<Player> receivers) {
+        final ClientboundRemoveEntitiesPacket removePacket = new ClientboundRemoveEntitiesPacket(entityId);
+        sendPacket(removePacket, receivers);
+    }
+
+    protected void sendData(Iterable<Player> receivers, T data) {
+        // Create packet
+        final List<SynchedEntityData.DataValue<?>> packedItems = new LinkedList<>();
+        final ClientboundSetEntityDataPacket dataPacket = new ClientboundSetEntityDataPacket(entityId, packedItems);
+
+        // Setup data
+        packedItems.add(SynchedEntityData.DataValue.create(DATA_NO_GRAVITY, true));
+        packedItems.add(SynchedEntityData.DataValue.create(DATA_SILENT, true));
+        addSpecificData(packedItems, data);
+
+        // Send packet
+        sendPacket(dataPacket, receivers);
+    }
+
+    protected abstract EntityType<?> getEntityType();
+
+    protected float getSpawnOffSet() {
+        return 0f;
+    }
+
+    protected abstract int getDataItemCount();
+
+    protected abstract void addSpecificData(List<SynchedEntityData.DataValue<?>> packedItems, T data);
+
+}