fix: Fix feature generation

Uses a workaround that returns a dummy `ProtoChunk` in `ChunkRegion#getChunk` to prevent issues due to missing `null` checks.
This means there are issues at chunk borders, where features will get cut off. A potential solution for this is to store features' block modifications in the save data, and apply these block modifications on top of world generation chunk data.

common/src/main/java/io/github/steveplays28/noisium/mixin/server/world/ServerEntityManagerMixin.java

@@ -9,7 +9,6 @@
 import org.spongepowered.asm.mixin.injection.Inject;
 import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
 
-// TODO: Disable vanilla's ServerEntityManager's save method
 @Mixin(value = ServerEntityManager.class, priority = 500)
 public class ServerEntityManagerMixin<T extends EntityLike> {
 	@Inject(method = "stopTracking", at = @At(value = "HEAD"), cancellable = true)
@@ -21,4 +20,10 @@ public class ServerEntityManagerMixin<T extends EntityLike> {
 			}
 		}
 	}
+
+	@Inject(method = "save", at = @At(value = "HEAD"), cancellable = true)
+	private void noisium$cancelSave(CallbackInfo ci) {
+		// TODO: Invoke an entity manager save event that's used in NoisiumServerWorldEntityTracker
+		ci.cancel();
+	}
 }

common/src/main/java/io/github/steveplays28/noisium/mixin/server/world/ServerWorldMixin.java

@@ -51,8 +51,13 @@ public abstract class ServerWorldMixin implements NoisiumServerWorldExtension {
 	private NoisiumServerWorldEntityTracker noisium$serverWorldEntityManager;
 
 	@Inject(method = "<init>", at = @At(value = "TAIL"))
-	private void noisium$constructorCreateServerWorldChunkManager(MinecraftServer server, Executor workerExecutor, LevelStorage.Session session, ServerWorldProperties properties, RegistryKey<World> worldKey, DimensionOptions dimensionOptions, WorldGenerationProgressListener worldGenerationProgressListener, boolean debugWorld, long seed, List<?> spawners, boolean shouldTickTime, RandomSequencesState randomSequencesState, CallbackInfo ci, @Local DataFixer dataFixer) {
+	private void noisium$constructorCreateServerWorldChunkManager(MinecraftServer server, Executor workerExecutor, LevelStorage.Session session, ServerWorldProperties serverWorldProperties, RegistryKey<World> worldKey, DimensionOptions dimensionOptions, WorldGenerationProgressListener worldGenerationProgressListener, boolean debugWorld, long seed, List<?> spawners, boolean shouldTickTime, RandomSequencesState randomSequencesState, CallbackInfo ci, @Local DataFixer dataFixer) {
+		@SuppressWarnings("DataFlowIssue")
 		var serverWorld = ((ServerWorld) (Object) this);
+		// DEBUG
+		if (serverWorld.getRegistryKey() != World.OVERWORLD) {
+			return;
+		}
 
 		this.noisium$serverWorldChunkManager = new NoisiumServerWorldChunkManager(
 				serverWorld, dimensionOptions.chunkGenerator(), session.getWorldDirectory(worldKey), dataFixer);

common/src/main/java/io/github/steveplays28/noisium/mixin/world/ChunkRegionMixin.java

@@ -0,0 +1,71 @@
+package io.github.steveplays28.noisium.mixin.world;
+
+import net.minecraft.registry.RegistryKeys;
+import net.minecraft.server.world.ServerWorld;
+import net.minecraft.util.math.ChunkPos;
+import net.minecraft.world.ChunkRegion;
+import net.minecraft.world.StructureWorldAccess;
+import net.minecraft.world.chunk.Chunk;
+import net.minecraft.world.chunk.ChunkStatus;
+import net.minecraft.world.chunk.ProtoChunk;
+import net.minecraft.world.chunk.UpgradeData;
+import org.jetbrains.annotations.Nullable;
+import org.spongepowered.asm.mixin.Final;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Overwrite;
+import org.spongepowered.asm.mixin.Shadow;
+
+import java.util.List;
+
+@Mixin(ChunkRegion.class)
+public abstract class ChunkRegionMixin implements StructureWorldAccess {
+
+	@Shadow
+	@Final
+	private ServerWorld world;
+
+	@Shadow
+	@Final
+	private ChunkPos lowerCorner;
+
+	@Shadow
+	@Final
+	private List<Chunk> chunks;
+
+	@Shadow
+	@Final
+	private int width;
+
+	/**
+	 * @return The loaded {@link Chunk} at the specified chunk position, or a dummy {@link ProtoChunk} if the specified chunk position isn't loaded.
+	 * @author Steveplays28
+	 * @reason Workaround for there not being {@code null} checks when the specified chunk position isn't in this {@link ChunkRegion}'s bounds.
+	 */
+	@Overwrite
+	public @Nullable Chunk getChunk(int chunkPosX, int chunkPosZ, ChunkStatus leastChunkStatus, boolean create) {
+		if (!this.isChunkLoaded(chunkPosX, chunkPosZ)) {
+			// TODO: Replace the ProtoChunk instances with null and add null checks where needed using ASM
+			var protoChunk = new ProtoChunk(
+					new ChunkPos(chunkPosX, chunkPosZ), UpgradeData.NO_UPGRADE_DATA, this.world, this.world.getRegistryManager().get(
+					RegistryKeys.BIOME), null);
+			protoChunk.setLightingProvider(world.getLightingProvider());
+			protoChunk.setStatus(ChunkStatus.FULL);
+			return protoChunk;
+		}
+
+		int i = chunkPosX - this.lowerCorner.x;
+		int j = chunkPosZ - this.lowerCorner.z;
+		var chunk = (Chunk) this.chunks.get(i + j * this.width);
+		if (chunk.getStatus().isAtLeast(leastChunkStatus)) {
+			return chunk;
+		}
+
+		// TODO: Replace the ProtoChunk instances with null and add null checks where needed using ASM
+		var protoChunk = new ProtoChunk(
+				new ChunkPos(chunkPosX, chunkPosZ), UpgradeData.NO_UPGRADE_DATA, this.world, this.world.getRegistryManager().get(
+				RegistryKeys.BIOME), null);
+		protoChunk.setLightingProvider(world.getLightingProvider());
+		protoChunk.setStatus(ChunkStatus.FULL);
+		return protoChunk;
+	}
+}

common/src/main/java/io/github/steveplays28/noisium/mixin/world/gen/chunk/ChunkGeneratorMixin.java

@@ -1,46 +1,69 @@
 package io.github.steveplays28.noisium.mixin.world.gen.chunk;
 
-import com.llamalad7.mixinextras.injector.v2.WrapWithCondition;
-import com.llamalad7.mixinextras.sugar.Local;
+import it.unimi.dsi.fastutil.ints.IntArraySet;
+import it.unimi.dsi.fastutil.ints.IntSet;
+import it.unimi.dsi.fastutil.objects.ObjectArraySet;
+import net.minecraft.SharedConstants;
 import net.minecraft.registry.Registries;
+import net.minecraft.registry.Registry;
 import net.minecraft.registry.RegistryKeys;
 import net.minecraft.registry.entry.RegistryEntry;
+import net.minecraft.registry.entry.RegistryEntryList;
 import net.minecraft.server.network.DebugInfoSender;
 import net.minecraft.structure.StructureStart;
 import net.minecraft.util.crash.CrashException;
 import net.minecraft.util.crash.CrashReport;
 import net.minecraft.util.crash.CrashReportSection;
+import net.minecraft.util.math.BlockBox;
+import net.minecraft.util.math.BlockPos;
 import net.minecraft.util.math.ChunkPos;
 import net.minecraft.util.math.ChunkSectionPos;
+import net.minecraft.util.math.random.ChunkRandom;
+import net.minecraft.util.math.random.RandomSeed;
+import net.minecraft.util.math.random.Xoroshiro128PlusPlusRandom;
 import net.minecraft.world.StructureWorldAccess;
 import net.minecraft.world.biome.Biome;
+import net.minecraft.world.biome.GenerationSettings;
+import net.minecraft.world.biome.source.BiomeSource;
 import net.minecraft.world.chunk.Chunk;
 import net.minecraft.world.chunk.ChunkSection;
+import net.minecraft.world.gen.GenerationStep;
 import net.minecraft.world.gen.StructureAccessor;
 import net.minecraft.world.gen.chunk.ChunkGenerator;
+import net.minecraft.world.gen.feature.PlacedFeature;
+import net.minecraft.world.gen.feature.util.PlacedFeatureIndexer;
+import net.minecraft.world.gen.structure.Structure;
+import org.spongepowered.asm.mixin.Final;
 import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Overwrite;
+import org.spongepowered.asm.mixin.Shadow;
 import org.spongepowered.asm.mixin.injection.At;
 import org.spongepowered.asm.mixin.injection.Inject;
 import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
 
-import java.util.Set;
-import java.util.function.Consumer;
-import java.util.stream.Stream;
+import java.util.*;
+import java.util.function.Function;
+import java.util.function.Supplier;
+import java.util.stream.Collectors;
 
 @Mixin(ChunkGenerator.class)
-public class ChunkGeneratorMixin {
-	@WrapWithCondition(method = "generateFeatures", at = @At(value = "INVOKE", target = "Ljava/util/stream/Stream;forEach(Ljava/util/function/Consumer;)V"))
-	private static boolean noisium$cancelChunkPosStreamToFixAnInfiniteLoop(Stream<ChunkPos> stream, Consumer<?> consumer) {
-		return false;
-	}
+public abstract class ChunkGeneratorMixin {
+	@Shadow
+	@Final
+	private Supplier<List<PlacedFeatureIndexer.IndexedFeatures>> indexedFeaturesListSupplier;
 
-	@Inject(method = "generateFeatures", at = @At(value = "INVOKE", target = "Lnet/minecraft/util/math/ChunkPos;stream(Lnet/minecraft/util/math/ChunkPos;I)Ljava/util/stream/Stream;", shift = At.Shift.BEFORE))
-	private void noisium$addChunkSectionBiomeContainersToSet(StructureWorldAccess world, Chunk chunk, StructureAccessor structureAccessor, CallbackInfo ci, @Local Set<RegistryEntry<Biome>> set) {
-		for (ChunkSection chunkSection : chunk.getSectionArray()) {
-			chunkSection.getBiomeContainer().forEachValue(set::add);
-		}
+	@Shadow
+	private static BlockBox getBlockBoxForChunk(Chunk chunk) {
+		throw new RuntimeException();
 	}
 
+	@Shadow
+	@Final
+	private Function<RegistryEntry<Biome>, GenerationSettings> generationSettingsGetter;
+
+	@Shadow
+	public abstract BiomeSource getBiomeSource();
+
 	/**
 	 * Replaces {@link ChunkGenerator#addStructureReferences} with a simpler one, that only checks the center chunk, instead of iterating outwards.
 	 * This fixes an infinite loop with {@link io.github.steveplays28.noisium.server.world.NoisiumServerWorldChunkManager}.
@@ -95,4 +118,119 @@ public class ChunkGeneratorMixin {
 
 		ci.cancel();
 	}
+
+	/**
+	 * @author Steveplays28
+	 * @reason TODO
+	 */
+	@Overwrite
+	public void generateFeatures(StructureWorldAccess world, Chunk chunk, StructureAccessor structureAccessor) {
+		ChunkPos chunkPos = chunk.getPos();
+		if (SharedConstants.isOutsideGenerationArea(chunkPos)) {
+			return;
+		}
+
+		ChunkSectionPos chunkSectionPos = ChunkSectionPos.from(chunkPos, world.getBottomSectionCoord());
+		BlockPos blockPos = chunkSectionPos.getMinPos();
+		Registry<Structure> registry = world.getRegistryManager().get(RegistryKeys.STRUCTURE);
+		Map<Integer, List<Structure>> map = registry.stream().collect(
+				Collectors.groupingBy((structureType) -> structureType.getFeatureGenerationStep().ordinal()));
+		List<PlacedFeatureIndexer.IndexedFeatures> indexedFeatures = this.indexedFeaturesListSupplier.get();
+		ChunkRandom chunkRandom = new ChunkRandom(new Xoroshiro128PlusPlusRandom(RandomSeed.getSeed()));
+		long l = chunkRandom.setPopulationSeed(world.getSeed(), blockPos.getX(), blockPos.getZ());
+		Set<RegistryEntry<Biome>> biomeRegistryEntries = new ObjectArraySet<>();
+		for (ChunkSection chunkSection : chunk.getSectionArray()) {
+			chunkSection.getBiomeContainer().forEachValue(biomeRegistryEntries::add);
+		}
+		biomeRegistryEntries.retainAll(this.getBiomeSource().getBiomes());
+		int indexedFeaturesSize = indexedFeatures.size();
+
+		try {
+			Registry<PlacedFeature> placedFeatureRegistry = world.getRegistryManager().get(RegistryKeys.PLACED_FEATURE);
+			int j = Math.max(GenerationStep.Feature.values().length, indexedFeaturesSize);
+
+			for (int indexedFeatureIndex = 0; indexedFeatureIndex < j; ++indexedFeatureIndex) {
+				int m = 0;
+				CrashReportSection crashReportSection;
+				if (structureAccessor.shouldGenerateStructures()) {
+					List<Structure> list2 = map.getOrDefault(indexedFeatureIndex, Collections.emptyList());
+
+					for (var biomeRegistryEntriesIterator = list2.iterator(); biomeRegistryEntriesIterator.hasNext(); ++m) {
+						Structure structure = biomeRegistryEntriesIterator.next();
+						chunkRandom.setDecoratorSeed(l, m, indexedFeatureIndex);
+						Supplier<String> currentlyGeneratingStructureNameSupplier = () -> {
+							var placedFeatureNameOptional = registry.getKey(structure).map(Object::toString);
+							Objects.requireNonNull(structure);
+							return placedFeatureNameOptional.orElseGet(structure::toString);
+						};
+
+						try {
+							world.setCurrentlyGeneratingStructureName(currentlyGeneratingStructureNameSupplier);
+							//noinspection DataFlowIssue
+							structureAccessor.getStructureStarts(chunkSectionPos, structure).forEach((start) -> start.place(
+									world, structureAccessor, (ChunkGenerator) (Object) this, chunkRandom,
+									getBlockBoxForChunk(chunk), chunkPos
+							));
+						} catch (Exception e) {
+							CrashReport crashReport = CrashReport.create(e, "Feature placement");
+							crashReportSection = crashReport.addElement("Feature");
+							Objects.requireNonNull(currentlyGeneratingStructureNameSupplier);
+							crashReportSection.add("Description", currentlyGeneratingStructureNameSupplier::get);
+							throw new CrashException(crashReport);
+						}
+					}
+				}
+
+				if (indexedFeatureIndex < indexedFeaturesSize) {
+					IntSet placedFeatureIndexMappings = new IntArraySet();
+
+					for (RegistryEntry<Biome> biomeRegistryEntry : biomeRegistryEntries) {
+						List<RegistryEntryList<PlacedFeature>> placedFeatureRegistryEntries = this.generationSettingsGetter.apply(
+								biomeRegistryEntry).getFeatures();
+						if (indexedFeatureIndex < placedFeatureRegistryEntries.size()) {
+							RegistryEntryList<PlacedFeature> registryEntryList = placedFeatureRegistryEntries.get(indexedFeatureIndex);
+							PlacedFeatureIndexer.IndexedFeatures indexedFeature = indexedFeatures.get(indexedFeatureIndex);
+							registryEntryList.stream().map(RegistryEntry::value).forEach(
+									(placedFeature) -> placedFeatureIndexMappings.add(
+											indexedFeature.indexMapping().applyAsInt(placedFeature)));
+						}
+					}
+
+					int placedFeatureIndexMappingsSize = placedFeatureIndexMappings.size();
+					int[] placedFeatureIndexMappingsArray = placedFeatureIndexMappings.toIntArray();
+					Arrays.sort(placedFeatureIndexMappingsArray);
+					PlacedFeatureIndexer.IndexedFeatures indexedFeature = indexedFeatures.get(indexedFeatureIndex);
+
+					for (int o = 0; o < placedFeatureIndexMappingsSize; ++o) {
+						int p = placedFeatureIndexMappingsArray[o];
+						PlacedFeature placedFeature = indexedFeature.features().get(p);
+						Supplier<String> currentlyGeneratingStructureNameSupplier = () -> {
+							var placedFeatureNameOptional = placedFeatureRegistry.getKey(placedFeature).map(Object::toString);
+							Objects.requireNonNull(placedFeature);
+							return placedFeatureNameOptional.orElseGet(placedFeature::toString);
+						};
+						chunkRandom.setDecoratorSeed(l, p, indexedFeatureIndex);
+
+						try {
+							world.setCurrentlyGeneratingStructureName(currentlyGeneratingStructureNameSupplier);
+							//noinspection DataFlowIssue
+							placedFeature.generate(world, (ChunkGenerator) (Object) this, chunkRandom, blockPos);
+						} catch (Exception e) {
+							CrashReport crashReport = CrashReport.create(e, "Feature placement");
+							crashReportSection = crashReport.addElement("Feature");
+							Objects.requireNonNull(currentlyGeneratingStructureNameSupplier);
+							crashReportSection.add("Description", currentlyGeneratingStructureNameSupplier::get);
+							throw new CrashException(crashReport);
+						}
+					}
+				}
+			}
+
+			world.setCurrentlyGeneratingStructureName(null);
+		} catch (Exception var31) {
+			CrashReport crashReport3 = CrashReport.create(var31, "Biome decoration");
+			crashReport3.addElement("Generation").add("CenterX", chunkPos.x).add("CenterZ", chunkPos.z).add("Seed", l);
+			throw new CrashException(crashReport3);
+		}
+	}
 }

common/src/main/java/io/github/steveplays28/noisium/server/player/NoisiumServerPlayerChunkLoader.java

@@ -10,6 +10,7 @@
 import net.minecraft.util.math.ChunkPos;
 import net.minecraft.util.math.ChunkSectionPos;
 import net.minecraft.util.math.Vec3d;
+import net.minecraft.world.World;
 import net.minecraft.world.chunk.WorldChunk;
 import org.jetbrains.annotations.NotNull;
 
@@ -35,8 +36,15 @@ public NoisiumServerPlayerChunkLoader() {
 		PlayerEvent.PLAYER_JOIN.register(player -> previousPlayerPositions.put(player.getId(), player.getPos()));
 		PlayerEvent.PLAYER_QUIT.register(player -> previousPlayerPositions.remove(player.getId()));
 		TickEvent.ServerLevelTick.SERVER_LEVEL_POST.register(
-				instance -> tick(
-						instance, ((NoisiumServerWorldExtension) instance).noisium$getServerWorldChunkManager()::getChunksInRadiusAsync));
+				instance -> {
+					// DEBUG
+					if (instance.getRegistryKey() != World.OVERWORLD) {
+						return;
+					}
+
+					tick(
+							instance, ((NoisiumServerWorldExtension) instance).noisium$getServerWorldChunkManager()::getChunksInRadiusAsync);
+				});
 	}
 
 	// TODO: Enable ticking/update chunk tracking in ServerEntityManager
@@ -51,7 +59,7 @@ private void tick(@NotNull ServerWorld serverWorld, @NotNull BiFunction<ChunkPos
 			var player = players.get(i);
 			var playerBlockPos = player.getBlockPos();
 			if (!playerBlockPos.isWithinDistance(previousPlayerPositions.get(player.getId()), 16d)) {
-				var worldChunks = worldChunksSupplier.apply(new ChunkPos(playerBlockPos), 2);
+				var worldChunks = worldChunksSupplier.apply(new ChunkPos(playerBlockPos), 6);
 
 				ChunkUtil.sendWorldChunksToPlayerAsync(serverWorld, new ArrayList<>(worldChunks.values()));
 				CompletableFuture.runAsync(() -> player.networkHandler.sendPacket(

common/src/main/java/io/github/steveplays28/noisium/server/world/NoisiumServerWorldChunkManager.java

@@ -82,7 +82,13 @@ public NoisiumServerWorldChunkManager(@NotNull ServerWorld serverWorld, @NotNull
 
 		NoisiumServerChunkEvent.LIGHT_UPDATE.register(this::onLightUpdateAsync);
 		NoisiumServerChunkEvent.BLOCK_CHANGE.register(this::onBlockChange);
-		TickEvent.SERVER_LEVEL_POST.register(instance -> ((ServerLightingProvider) serverWorld.getLightingProvider()).tick());
+		TickEvent.SERVER_LEVEL_POST.register(instance -> {
+			if (!instance.equals(serverWorld)) {
+				return;
+			}
+
+			((ServerLightingProvider) serverWorld.getLightingProvider()).tick();
+		});
 	}
 
 	/**
@@ -317,7 +323,7 @@ private void onBlockChange(@NotNull BlockPos blockPos, @NotNull BlockState oldBl
 
 		protoChunk.setStatus(ChunkStatus.CARVERS);
 		chunkGenerator.carve(
-				chunkRegion, serverWorld.getSeed(), noiseConfig, chunkRegion.getBiomeAccess(), chunkRegionStructureAccessor, protoChunk,
+				chunkRegion, chunkRegion.getSeed(), noiseConfig, chunkRegion.getBiomeAccess(), chunkRegionStructureAccessor, protoChunk,
 				GenerationStep.Carver.AIR
 		);
 

common/src/main/resources/noisium-common.mixins.json

@@ -18,6 +18,7 @@
     "server.world.ServerEntityManagerMixin",
     "server.world.ServerWorldMixin",
     "server.world.ThreadedAnvilChunkStorageMixin",
+    "world.ChunkRegionMixin",
     "world.WorldMixin",
     "world.chunk.WorldChunkMixin",
     "world.gen.chunk.ChunkGeneratorMixin",