fix pedestal block multiplayer sync issues

src/main/java/net/kaupenjoe/tutorialmod/TutorialMod.java

@@ -17,6 +17,7 @@
 import net.kaupenjoe.tutorialmod.entity.custom.MantisEntity;
 import net.kaupenjoe.tutorialmod.item.ModItemGroups;
 import net.kaupenjoe.tutorialmod.item.ModItems;
+import net.kaupenjoe.tutorialmod.networking.ModPayloads;
 import net.kaupenjoe.tutorialmod.particle.ModParticles;
 import net.kaupenjoe.tutorialmod.potion.ModPotions;
 import net.kaupenjoe.tutorialmod.recipe.ModRecipes;
@@ -70,6 +71,8 @@ public void onInitialize() {
 		ModBlockEntities.registerBlockEntities();
 		ModScreenHandlers.registerScreenHandlers();
 
+		ModPayloads.registerModPayloads();
+
 		ModRecipes.registerRecipes();
 
 		FuelRegistry.INSTANCE.add(ModItems.STARLIGHT_ASHES, 600);

src/main/java/net/kaupenjoe/tutorialmod/TutorialModClient.java

@@ -2,14 +2,17 @@
 
 import net.fabricmc.api.ClientModInitializer;
 import net.fabricmc.fabric.api.blockrenderlayer.v1.BlockRenderLayerMap;
+import net.fabricmc.fabric.api.client.networking.v1.ClientPlayNetworking;
 import net.fabricmc.fabric.api.client.particle.v1.ParticleFactoryRegistry;
 import net.fabricmc.fabric.api.client.rendering.v1.EntityModelLayerRegistry;
 import net.fabricmc.fabric.api.client.rendering.v1.EntityRendererRegistry;
 import net.kaupenjoe.tutorialmod.block.ModBlocks;
 import net.kaupenjoe.tutorialmod.block.entity.ModBlockEntities;
+import net.kaupenjoe.tutorialmod.block.entity.custom.PedestalBlockEntity;
 import net.kaupenjoe.tutorialmod.block.entity.renderer.PedestalBlockEntityRenderer;
 import net.kaupenjoe.tutorialmod.entity.ModEntities;
 import net.kaupenjoe.tutorialmod.entity.client.*;
+import net.kaupenjoe.tutorialmod.networking.custom.SyncPedestalBlockEntityS2CPayload;
 import net.kaupenjoe.tutorialmod.particle.ModParticles;
 import net.kaupenjoe.tutorialmod.particle.PinkGarnetParticle;
 import net.kaupenjoe.tutorialmod.screen.ModScreenHandlers;
@@ -49,5 +52,7 @@ public void onInitializeClient() {
         HandledScreens.register(ModScreenHandlers.PEDESTAL_SCREEN_HANDLER, PedestalScreen::new);
 
         HandledScreens.register(ModScreenHandlers.GROWTH_CHAMBER_SCREEN_HANDLER, GrowthChamberScreen::new);
+
+        ClientPlayNetworking.registerGlobalReceiver(SyncPedestalBlockEntityS2CPayload.ID, PedestalBlockEntity::onSyncPacket);
     }
 }

src/main/java/net/kaupenjoe/tutorialmod/block/entity/custom/PedestalBlockEntity.java

@@ -1,11 +1,17 @@
 package net.kaupenjoe.tutorialmod.block.entity.custom;
 
+import net.fabricmc.fabric.api.client.networking.v1.ClientPlayNetworking;
+import net.fabricmc.fabric.api.networking.v1.PlayerLookup;
+import net.fabricmc.fabric.api.networking.v1.ServerPlayNetworking;
 import net.fabricmc.fabric.api.screenhandler.v1.ExtendedScreenHandlerFactory;
 import net.kaupenjoe.tutorialmod.block.entity.ImplementedInventory;
 import net.kaupenjoe.tutorialmod.block.entity.ModBlockEntities;
+import net.kaupenjoe.tutorialmod.networking.custom.SyncPedestalBlockEntityS2CPayload;
 import net.kaupenjoe.tutorialmod.screen.custom.PedestalScreenHandler;
+import net.minecraft.block.Block;
 import net.minecraft.block.BlockState;
 import net.minecraft.block.entity.BlockEntity;
+import net.minecraft.client.world.ClientWorld;
 import net.minecraft.entity.player.PlayerEntity;
 import net.minecraft.entity.player.PlayerInventory;
 import net.minecraft.inventory.Inventories;
@@ -17,9 +23,11 @@
 import net.minecraft.registry.RegistryWrapper;
 import net.minecraft.screen.ScreenHandler;
 import net.minecraft.server.network.ServerPlayerEntity;
+import net.minecraft.server.world.ServerWorld;
 import net.minecraft.text.Text;
 import net.minecraft.util.collection.DefaultedList;
 import net.minecraft.util.math.BlockPos;
+import net.minecraft.world.World;
 import org.jetbrains.annotations.Nullable;
 
 public class PedestalBlockEntity extends BlockEntity implements ImplementedInventory, ExtendedScreenHandlerFactory<BlockPos> {
@@ -30,6 +38,31 @@ public PedestalBlockEntity(BlockPos pos, BlockState state) {
         super(ModBlockEntities.PEDESTAL_BE, pos, state);
     }
 
+    public static void sendSyncPacket(World world, BlockPos blockpos, DefaultedList<ItemStack> inventory) {
+        if (world.isClient()) return;
+        SyncPedestalBlockEntityS2CPayload payload = new SyncPedestalBlockEntityS2CPayload(blockpos, inventory);
+
+        for (ServerPlayerEntity serverPlayerEntity : PlayerLookup.world((ServerWorld) world)) {
+            ServerPlayNetworking.send(serverPlayerEntity, payload);
+        }
+    }
+
+    public static void onSyncPacket(SyncPedestalBlockEntityS2CPayload payload, ClientPlayNetworking.Context context) {
+        ClientWorld world = context.client().world;
+
+        if (world == null) return; // Ensure the world is not null
+
+        // Retrieve the BlockEntity at the specified BlockPos
+        BlockEntity blockEntity = world.getBlockEntity(payload.blockPos());
+        if (blockEntity instanceof PedestalBlockEntity pedestalBlockEntity) {
+            // Update the BlockEntity's inventory with the payload data
+            pedestalBlockEntity.setStack(0, payload.inventory().getFirst());
+
+            // Mark the BlockEntity for re-rendering (optional, if needed)
+            world.updateListeners(payload.blockPos(), blockEntity.getCachedState(), blockEntity.getCachedState(), Block.NOTIFY_ALL);
+        }
+    }
+
     @Override
     public DefaultedList<ItemStack> getItems() {
         return inventory;
@@ -82,4 +115,16 @@ public Packet<ClientPlayPacketListener> toUpdatePacket() {
     public NbtCompound toInitialChunkDataNbt(RegistryWrapper.WrapperLookup registryLookup) {
         return createNbt(registryLookup);
     }
+
+    @Override
+    public void markDirty() {
+        super.markDirty();
+        syncInventory();
+    }
+
+    public void syncInventory() {
+        if (this.world != null && !this.world.isClient) {
+            sendSyncPacket(this.world, this.pos, this.inventory);
+        }
+    }
 }

src/main/java/net/kaupenjoe/tutorialmod/networking/ModPayloads.java

@@ -0,0 +1,12 @@
+package net.kaupenjoe.tutorialmod.networking;
+
+import net.fabricmc.fabric.api.networking.v1.PayloadTypeRegistry;
+import net.kaupenjoe.tutorialmod.TutorialMod;
+import net.kaupenjoe.tutorialmod.networking.custom.SyncPedestalBlockEntityS2CPayload;
+
+public class ModPayloads {
+    public static void registerModPayloads() {
+        PayloadTypeRegistry.playS2C().register(SyncPedestalBlockEntityS2CPayload.ID, SyncPedestalBlockEntityS2CPayload.CODEC);
+        TutorialMod.LOGGER.info("Registering Mod Payloads for " + TutorialMod.MOD_ID);
+    }
+}

src/main/java/net/kaupenjoe/tutorialmod/networking/custom/SyncPedestalBlockEntityS2CPayload.java

@@ -0,0 +1,56 @@
+package net.kaupenjoe.tutorialmod.networking.custom;
+
+import net.kaupenjoe.tutorialmod.TutorialMod;
+import net.minecraft.item.ItemStack;
+import net.minecraft.network.RegistryByteBuf;
+import net.minecraft.network.codec.PacketCodec;
+import net.minecraft.network.packet.CustomPayload;
+import net.minecraft.util.Identifier;
+import net.minecraft.util.collection.DefaultedList;
+import net.minecraft.util.math.BlockPos;
+
+public record SyncPedestalBlockEntityS2CPayload(BlockPos blockPos, DefaultedList<ItemStack> inventory) implements CustomPayload {
+    public static final Identifier SYNC_PEDESTAL_BLOCK_ENTITY_PAYLOAD_ID = Identifier.of(TutorialMod.MOD_ID, "sync_pedestal_block_entity");
+    public static final CustomPayload.Id<SyncPedestalBlockEntityS2CPayload> ID = new CustomPayload.Id<>(SYNC_PEDESTAL_BLOCK_ENTITY_PAYLOAD_ID);
+
+    // Define a PacketCodec for DefaultedList<ItemStack>
+    public static final PacketCodec<RegistryByteBuf, DefaultedList<ItemStack>> ITEM_STACK_LIST_CODEC = new PacketCodec<>() {
+        @Override
+        public DefaultedList<ItemStack> decode(RegistryByteBuf buf) {
+            // Read the size of the list
+            int size = buf.readVarInt();
+            // Create a DefaultedList with the specified size
+            DefaultedList<ItemStack> list = DefaultedList.ofSize(size, ItemStack.EMPTY);
+            // Read each ItemStack from the buffer
+            for (int i = 0; i < size; i++) {
+                // Decode the ItemStack, allowing empty stacks
+                ItemStack stack = ItemStack.OPTIONAL_PACKET_CODEC.decode(buf);
+                list.set(i, stack);
+            }
+            return list;
+        }
+
+        @Override
+        public void encode(RegistryByteBuf buf, DefaultedList<ItemStack> list) {
+            // Write the size of the list
+            buf.writeVarInt(list.size());
+            // Write each ItemStack to the buffer
+            for (ItemStack stack : list) {
+                // Encode the ItemStack, allowing empty stacks
+                ItemStack.OPTIONAL_PACKET_CODEC.encode(buf, stack);
+            }
+        }
+    };
+
+    // Define the PacketCodec for SyncPedestalBlockEntityS2CPayload
+    public static final PacketCodec<RegistryByteBuf, SyncPedestalBlockEntityS2CPayload> CODEC = PacketCodec.tuple(
+            BlockPos.PACKET_CODEC, SyncPedestalBlockEntityS2CPayload::blockPos, // Handle BlockPos
+            ITEM_STACK_LIST_CODEC, SyncPedestalBlockEntityS2CPayload::inventory, // Handle DefaultedList<ItemStack>
+            SyncPedestalBlockEntityS2CPayload::new // Constructor
+    );
+
+    @Override
+    public Id<? extends CustomPayload> getId() {
+        return ID;
+    }
+}