Add NETWORK serialization attribute

src/main/java/io/wispforest/owo/serialization/CodecUtils.java

@@ -271,6 +271,8 @@ public T decode(B buf) {
                         ? SerializationContext.attributes(RegistriesAttribute.of(registryByteBuf.getRegistryManager()))
                         : SerializationContext.empty();
 
+                ctx = ctx.withAttributes(MinecraftSerializationAttributes.NETWORK);
+
                 return endec.decode(ctx, ByteBufDeserializer.of(buf));
             }
 
@@ -280,6 +282,8 @@ public void encode(B buf, T value) {
                         ? SerializationContext.attributes(RegistriesAttribute.of(registryByteBuf.getRegistryManager()))
                         : SerializationContext.empty();
 
+                ctx = ctx.withAttributes(MinecraftSerializationAttributes.NETWORK);
+
                 endec.encode(ctx, ByteBufSerializer.of(buf), value);
             }
         };

src/main/java/io/wispforest/owo/serialization/MinecraftSerializationAttributes.java

@@ -0,0 +1,14 @@
+package io.wispforest.owo.serialization;
+
+import io.wispforest.endec.SerializationAttribute;
+
+public final class MinecraftSerializationAttributes {
+    private MinecraftSerializationAttributes() { }
+
+    /**
+     * This format will be sent over the network.
+     * <p>
+     * Registries and block states can be represented as integer IDs.
+     */
+    public static final SerializationAttribute.Marker NETWORK = SerializationAttribute.marker("network");
+}

src/main/java/io/wispforest/owo/serialization/endec/MinecraftEndecs.java

@@ -1,14 +1,20 @@
 package io.wispforest.owo.serialization.endec;
 
 import com.mojang.datafixers.util.Function3;
-import io.wispforest.endec.Endec;
-import io.wispforest.endec.SerializationAttributes;
+import io.wispforest.endec.*;
 import io.wispforest.endec.impl.ReflectiveEndecBuilder;
 import io.wispforest.endec.impl.StructEndecBuilder;
 import io.wispforest.owo.serialization.CodecUtils;
+import io.wispforest.owo.serialization.MinecraftSerializationAttributes;
+import net.fabricmc.fabric.api.event.registry.RegistryAttribute;
+import net.fabricmc.fabric.api.event.registry.RegistryAttributeHolder;
 import net.fabricmc.fabric.api.networking.v1.PacketByteBufs;
+import net.minecraft.block.Block;
+import net.minecraft.block.BlockState;
+import net.minecraft.item.Item;
 import net.minecraft.item.ItemStack;
 import net.minecraft.network.PacketByteBuf;
+import net.minecraft.registry.Registries;
 import net.minecraft.registry.Registry;
 import net.minecraft.registry.RegistryKey;
 import net.minecraft.registry.tag.TagKey;
@@ -87,6 +93,11 @@ private MinecraftEndecs() {}
                     : BlockHitResult.createMissed(pos, side, blockPos)
     );
 
+    public static final Endec<BlockState> BLOCK_STATE = Endec.ifAttr(
+            MinecraftSerializationAttributes.NETWORK, Endec.VAR_INT.xmap(Block.STATE_IDS::get, Block.STATE_IDS::getRawId)
+        )
+        .orElse(CodecUtils.toEndec(BlockState.CODEC));
+
     // --- Constructors for MC types ---
 
     public static ReflectiveEndecBuilder addDefaults(ReflectiveEndecBuilder builder) {
@@ -105,11 +116,39 @@ public static ReflectiveEndecBuilder addDefaults(ReflectiveEndecBuilder builder)
 
         builder.register(BLOCK_HIT_RESULT, BlockHitResult.class);
 
+        builder.register(ofRegistry(Registries.ITEM), Item.class)
+               .register(ofRegistry(Registries.BLOCK), Block.class);
+
+        builder.register(BLOCK_STATE, BlockState.class);
+
         return builder;
     }
 
     public static <T> Endec<T> ofRegistry(Registry<T> registry) {
-        return IDENTIFIER.xmap(registry::get, registry::getId);
+        Endec<T> idEndec = IDENTIFIER.xmap(registry::get, registry::getId);
+        Endec<T> rawIdEndec = Endec.VAR_INT.xmap(registry::get, registry::getRawId);
+
+        return new Endec<>() {
+            @Override
+            public void encode(SerializationContext ctx, Serializer<?> serializer, T value) {
+                if (RegistryAttributeHolder.get(registry).hasAttribute(RegistryAttribute.SYNCED)
+                    && ctx.hasAttribute(MinecraftSerializationAttributes.NETWORK)) {
+                    rawIdEndec.encode(ctx, serializer, value);
+                } else {
+                    idEndec.encode(ctx, serializer, value);
+                }
+            }
+
+            @Override
+            public T decode(SerializationContext ctx, Deserializer<?> deserializer) {
+                if (RegistryAttributeHolder.get(registry).hasAttribute(RegistryAttribute.SYNCED)
+                    && ctx.hasAttribute(MinecraftSerializationAttributes.NETWORK)) {
+                    return rawIdEndec.decode(ctx, deserializer);
+                } else {
+                    return idEndec.decode(ctx, deserializer);
+                }
+            }
+        };
     }
 
     public static <T> Endec<TagKey<T>> unprefixedTagKey(RegistryKey<? extends Registry<T>> registry) {

src/testmod/java/io/wispforest/uwu/network/DispatchedSubclassThree.java

@@ -0,0 +1,12 @@
+package io.wispforest.uwu.network;
+
+import net.minecraft.block.Block;
+import net.minecraft.block.BlockState;
+import net.minecraft.item.Item;
+
+public record DispatchedSubclassThree(Item item, Block block, BlockState state) implements DispatchedInterface {
+    @Override
+    public String getName() {
+        return "three";
+    }
+}

src/testmod/java/io/wispforest/uwu/network/UwuNetworkExample.java

@@ -1,17 +1,20 @@
 package io.wispforest.uwu.network;
 
 import io.wispforest.endec.impl.RecordEndec;
-import io.wispforest.endec.impl.ReflectiveEndecBuilder;
 import io.wispforest.owo.network.OwoNetChannel;
 import io.wispforest.endec.Endec;
 import io.wispforest.endec.StructEndec;
 import net.fabricmc.api.EnvType;
 import net.fabricmc.api.Environment;
 import net.fabricmc.fabric.api.client.event.lifecycle.v1.ClientTickEvents;
 import net.fabricmc.fabric.api.client.keybinding.v1.KeyBindingHelper;
+import net.minecraft.block.Blocks;
+import net.minecraft.block.HorizontalFacingBlock;
 import net.minecraft.client.option.KeyBinding;
+import net.minecraft.item.Items;
 import net.minecraft.text.Text;
 import net.minecraft.util.Identifier;
+import net.minecraft.util.math.Direction;
 import org.lwjgl.glfw.GLFW;
 
 import java.util.HashMap;
@@ -28,6 +31,7 @@ public static void init() {
 
         REGISTRY.put("one", RecordEndec.create(CHANNEL.builder(), DispatchedSubclassOne.class));
         REGISTRY.put("two", RecordEndec.create(CHANNEL.builder(), DispatchedSubclassTwo.class));
+        REGISTRY.put("three", RecordEndec.create(CHANNEL.builder(), DispatchedSubclassThree.class));
 
         CHANNEL.registerClientbound(StringPacket.class, (message, access) -> {
             access.player().sendMessage(Text.of(message.value()), false);
@@ -67,6 +71,11 @@ public static void init() {
 
                     CHANNEL.clientHandle().send(new MaldingPacket(new DispatchedSubclassOne("base")));
                     CHANNEL.clientHandle().send(new MaldingPacket(new DispatchedSubclassTwo(20)));
+                    CHANNEL.clientHandle().send(new MaldingPacket(new DispatchedSubclassThree(
+                        Items.ACACIA_BOAT,
+                        Blocks.DRAGON_EGG,
+                        Blocks.OAK_STAIRS.getDefaultState().with(HorizontalFacingBlock.FACING, Direction.EAST)
+                    )));
 
                     CHANNEL.clientHandle().send(new NullablePacket(null, null));
                     CHANNEL.clientHandle().send(new NullablePacket("Weeee", null));