[26.1] Expose debug renderer/subscription flag registration

patches/net/minecraft/client/multiplayer/ClientDebugSubscriber.java.patch

@@ -0,0 +1,11 @@
+--- a/net/minecraft/client/multiplayer/ClientDebugSubscriber.java
++++ b/net/minecraft/client/multiplayer/ClientDebugSubscriber.java
+@@ -64,6 +_,8 @@
+             addFlag(subscriptions, DebugSubscriptions.VILLAGE_SECTIONS, SharedConstants.DEBUG_VILLAGE_SECTIONS);
+         }
+
++        // Neo: Allow requesting custom subscriptions
++        net.neoforged.neoforge.common.NeoForge.EVENT_BUS.post(new net.neoforged.neoforge.client.event.AddDebugSubscriptionFlagsEvent((subscription, flag) -> addFlag(subscriptions, subscription, flag)));
+         return subscriptions;
+     }
+

patches/net/minecraft/client/renderer/debug/DebugRenderer.java.patch

@@ -0,0 +1,12 @@
+--- a/net/minecraft/client/renderer/debug/DebugRenderer.java
++++ b/net/minecraft/client/renderer/debug/DebugRenderer.java
+@@ -137,6 +_,9 @@
+         }
+
+         this.renderers.add(new ChunkCullingDebugRenderer(minecraft));
++
++        // Neo: Allow registering custom debug renderers
++        net.neoforged.fml.ModLoader.postEvent(new net.neoforged.neoforge.client.event.RegisterDebugRenderersEvent(factory -> renderers.add(factory.apply(minecraft))));
+     }
+
+     public void emitGizmos(Frustum frustum, double camX, double camY, double camZ, float partialTicks) {

src/client/java/net/neoforged/neoforge/client/event/AddDebugSubscriptionFlagsEvent.java

@@ -0,0 +1,78 @@
+/*
+ * Copyright (c) NeoForged and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
+package net.neoforged.neoforge.client.event;
+
+import it.unimi.dsi.fastutil.objects.ObjectBooleanBiConsumer;
+import java.util.function.Supplier;
+import net.minecraft.client.multiplayer.ClientDebugSubscriber;
+import net.minecraft.util.debug.DebugSubscription;
+import net.neoforged.bus.api.Event;
+import net.neoforged.fml.LogicalSide;
+import net.neoforged.fml.loading.FMLEnvironment;
+import org.jetbrains.annotations.ApiStatus;
+
+/**
+ * This event allows mods to register client-side {@linkplain DebugSubscription debug subscription} flags.
+ * <p>
+ * These flags are used to determine when subscriptions are allowed to register and store debug renderer values.
+ * If no flag is registered for a given debug subscription then it will be treated as a {@code always-disabled} flag and no debug values will be stored for it.
+ * <p>
+ * This event is fired once per tick during {@linkplain ClientDebugSubscriber#requestedSubscriptions()}.
+ * <p>
+ * This event is fired on the {@linkplain LogicalSide#CLIENT logical client}.
+ *
+ * @apiNote Each {@linkplain DebugSubscription debug subscription} should only be registered once.
+ */
+public final class AddDebugSubscriptionFlagsEvent extends Event {
+    private final ObjectBooleanBiConsumer<DebugSubscription<?>> registrar;
+
+    @ApiStatus.Internal
+    public AddDebugSubscriptionFlagsEvent(ObjectBooleanBiConsumer<DebugSubscription<?>> registrar) {
+        this.registrar = registrar;
+    }
+
+    /**
+     * Register a new flag for the given {@linkplain DebugSubscription debug subscription}.
+     *
+     * @param subscription {@linkplain DebugSubscription debug subscription} to register flag for.
+     * @param flag         Flag used to conditionally enable or disable the given {@linkplain DebugSubscription debug subscription}.
+     */
+    public void addFlag(DebugSubscription<?> subscription, boolean flag) {
+        registrar.accept(subscription, flag);
+    }
+
+    /**
+     * Register a new flag for the given {@linkplain DebugSubscription debug subscription}.
+     *
+     * @param subscription {@linkplain DebugSubscription Debug subscription} to register flag for.
+     * @param flag         Flag used to conditionally enable or disable the given {@linkplain DebugSubscription debug subscription}.
+     */
+    public void addFlag(Supplier<? extends DebugSubscription<?>> subscription, boolean flag) {
+        addFlag(subscription.get(), flag);
+    }
+
+    /**
+     * Mark the given {@linkplain DebugSubscription debug subscription} as only active in dev.
+     * <p>
+     * Using this method will mark your {@linkplain DebugSubscription debug subscription} as only being enabled in dev a.k.a when {@linkplain FMLEnvironment#isProduction()} == {@code false}.
+     *
+     * @param subscription {@linkplain DebugSubscription debug subscription} to register flag for.
+     */
+    public void addActiveInDev(DebugSubscription<?> subscription) {
+        addFlag(subscription, !FMLEnvironment.isProduction());
+    }
+
+    /**
+     * Mark the given {@linkplain DebugSubscription debug subscription} as only active in dev.
+     * <p>
+     * Using this method will mark your {@linkplain DebugSubscription debug subscription} as only being enabled in dev a.k.a when {@linkplain FMLEnvironment#isProduction()} == {@code false}.
+     *
+     * @param subscription {@linkplain DebugSubscription Debug subscription} to register flag for.
+     */
+    public void addActiveInDev(Supplier<? extends DebugSubscription<?>> subscription) {
+        addActiveInDev(subscription.get());
+    }
+}

src/client/java/net/neoforged/neoforge/client/event/RegisterDebugRenderersEvent.java

@@ -0,0 +1,49 @@
+/*
+ * Copyright (c) NeoForged and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
+package net.neoforged.neoforge.client.event;
+
+import java.util.function.Consumer;
+import java.util.function.Function;
+import net.minecraft.client.Minecraft;
+import net.minecraft.client.renderer.debug.DebugRenderer;
+import net.neoforged.bus.api.Event;
+import net.neoforged.fml.LogicalSide;
+import net.neoforged.fml.event.IModBusEvent;
+import org.jetbrains.annotations.ApiStatus;
+
+/**
+ * This event allows mods to register custom {@link DebugRenderer.SimpleDebugRenderer}s.
+ * <p>
+ * This event is fired during {@link DebugRenderer#refreshRendererList()}.
+ * <p>
+ * This event is fired on the mod-specific event bus, only on the {@linkplain LogicalSide#CLIENT logical client}.
+ */
+public final class RegisterDebugRenderersEvent extends Event implements IModBusEvent {
+    private final Consumer<Function<Minecraft, DebugRenderer.SimpleDebugRenderer>> registrar;
+
+    @ApiStatus.Internal
+    public RegisterDebugRenderersEvent(Consumer<Function<Minecraft, DebugRenderer.SimpleDebugRenderer>> registrar) {
+        this.registrar = registrar;
+    }
+
+    /**
+     * Registers the given debug renderer
+     *
+     * @param factory Factory used to construct the debug renderer
+     */
+    public void register(Function<Minecraft, DebugRenderer.SimpleDebugRenderer> factory) {
+        registrar.accept(factory);
+    }
+
+    /**
+     * Registers the given debug renderer
+     *
+     * @param renderer Debug renderer to be registered
+     */
+    public void register(DebugRenderer.SimpleDebugRenderer renderer) {
+        register(client -> renderer);
+    }
+}

tests/src/main/java/net/neoforged/neoforge/debug/CustomDebugSubscriberTest.java

@@ -0,0 +1,136 @@
+/*
+ * Copyright (c) NeoForged and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
+package net.neoforged.neoforge.debug;
+
+import com.mojang.serialization.MapCodec;
+import net.minecraft.client.Minecraft;
+import net.minecraft.client.renderer.culling.Frustum;
+import net.minecraft.client.renderer.debug.DebugRenderer;
+import net.minecraft.core.BlockPos;
+import net.minecraft.core.registries.Registries;
+import net.minecraft.gizmos.Gizmos;
+import net.minecraft.network.codec.ByteBufCodecs;
+import net.minecraft.resources.Identifier;
+import net.minecraft.server.level.ServerLevel;
+import net.minecraft.util.CommonColors;
+import net.minecraft.util.debug.DebugSubscription;
+import net.minecraft.util.debug.DebugValueAccess;
+import net.minecraft.world.InteractionResult;
+import net.minecraft.world.entity.player.Player;
+import net.minecraft.world.level.Level;
+import net.minecraft.world.level.block.BaseEntityBlock;
+import net.minecraft.world.level.block.entity.BlockEntity;
+import net.minecraft.world.level.block.entity.BlockEntityType;
+import net.minecraft.world.level.block.state.BlockState;
+import net.minecraft.world.level.storage.ValueInput;
+import net.minecraft.world.level.storage.ValueOutput;
+import net.minecraft.world.phys.BlockHitResult;
+import net.neoforged.api.distmarker.Dist;
+import net.neoforged.neoforge.client.event.AddDebugSubscriptionFlagsEvent;
+import net.neoforged.neoforge.client.event.RegisterDebugRenderersEvent;
+import net.neoforged.neoforge.common.NeoForge;
+import net.neoforged.neoforge.registries.DeferredHolder;
+import net.neoforged.testframework.DynamicTest;
+import net.neoforged.testframework.annotation.ForEachTest;
+import net.neoforged.testframework.annotation.TestHolder;
+import net.neoforged.testframework.registration.RegistrationHelper;
+
+@ForEachTest(groups = "custom_debug_subscribers", side = Dist.CLIENT)
+public interface CustomDebugSubscriberTest {
+    @TestHolder(description = "Renders debug info for a new block entity using debug renderers and subscribers", enabledByDefault = true)
+    static void testDebugSubscriptions(DynamicTest test, RegistrationHelper reg) {
+        var id = "debug_subscription";
+        var registryName = Identifier.fromNamespaceAndPath(reg.modId(), id);
+        var blockEntityType = DeferredHolder.create(Registries.BLOCK_ENTITY_TYPE, registryName);
+
+        // register our custom debug subscription
+        var debugSubscription = reg.registrar(Registries.DEBUG_SUBSCRIPTION).register(id, () -> new DebugSubscription<>(ByteBufCodecs.VAR_INT, 200));
+
+        final class DebugBlockEntity extends BlockEntity {
+            private int counter = 0;
+
+            private DebugBlockEntity(BlockPos pos, BlockState blockState) {
+                super(blockEntityType.value(), pos, blockState);
+            }
+
+            public void incrementCounter() {
+                counter++;
+                setChanged();
+            }
+
+            @Override
+            protected void saveAdditional(ValueOutput output) {
+                super.saveAdditional(output);
+                output.putInt("counter", counter);
+            }
+
+            @Override
+            protected void loadAdditional(ValueInput input) {
+                super.loadAdditional(input);
+                counter = input.getIntOr("counter", 0);
+            }
+
+            @Override
+            public void registerDebugValues(ServerLevel level, Registration registration) {
+                // mark this entity for displaying debug info for our subscription
+                registration.register(debugSubscription.value(), () -> counter);
+            }
+        }
+
+        // generic block for our block entity
+        final class DebugBlock extends BaseEntityBlock {
+            private DebugBlock(Properties properties) {
+                super(properties);
+            }
+
+            @Override
+            protected MapCodec<? extends BaseEntityBlock> codec() {
+                return null;
+            }
+
+            @Override
+            protected InteractionResult useWithoutItem(BlockState blockState, Level level, BlockPos pos, Player player, BlockHitResult hitResult) {
+                if (!(level.getBlockEntity(pos) instanceof DebugBlockEntity blockEntity)) {
+                    return InteractionResult.FAIL;
+                }
+
+                blockEntity.incrementCounter();
+                return InteractionResult.SUCCESS;
+            }
+
+            @Override
+            public BlockEntity newBlockEntity(BlockPos pos, BlockState blockState) {
+                return new DebugBlockEntity(pos, blockState);
+            }
+        }
+
+        var block = reg.blocks().registerBlock(id, DebugBlock::new);
+        reg.items().registerSimpleBlockItem(block);
+        reg.registrar(Registries.BLOCK_ENTITY_TYPE).register(id, () -> new BlockEntityType<>(DebugBlockEntity::new, block.value()));
+
+        // debug renderer used to render counters above our block entities
+        final class DebugCountRenderer implements DebugRenderer.SimpleDebugRenderer {
+            private DebugCountRenderer(Minecraft client) {}
+
+            @Override
+            public void emitGizmos(double camX, double camY, double camZ, DebugValueAccess valueAccess, Frustum frustum, float partialTicks) {
+                // list is populated via 'DebugBlockEntity.registerDebugValues'
+                // while we are using block entities this, you can also register subscribers for entities and chunks too
+                valueAccess.forEachBlock(debugSubscription.value(), (pos, count) -> {
+                    Gizmos.billboardTextOverBlock(count + "", pos, 0, CommonColors.WHITE, .5F);
+                });
+            }
+        }
+
+        // mark our subscriber as only being active in dev
+        NeoForge.EVENT_BUS.addListener(AddDebugSubscriptionFlagsEvent.class, event -> event.addActiveInDev(debugSubscription.value()));
+
+        // register our debug renderer
+        reg.eventListeners().accept((RegisterDebugRenderersEvent event) -> event.register(DebugCountRenderer::new));
+
+        test.pass();
+    }
+}