chunk granularity

adapters/bukkit/nms/v26_2_R1/src/main/java/art/arcane/iris/core/nms/v26_2_R1/CustomBiomeSource.java

@@ -1,6 +1,7 @@
 package art.arcane.iris.core.nms.v26_2_R1;
 
 import art.arcane.iris.platform.bukkit.BukkitWorldBinding;
+import com.mojang.datafixers.util.Pair;
 import com.mojang.serialization.MapCodec;
 import art.arcane.iris.spi.IrisLogging;
 import art.arcane.iris.engine.data.cache.AtomicCache;
@@ -13,6 +14,7 @@ import art.arcane.iris.engine.object.IrisDimension;
 import art.arcane.iris.util.project.context.IrisContext;
 import art.arcane.volmlib.util.collection.KMap;
 import art.arcane.volmlib.util.math.RNG;
+import net.minecraft.core.BlockPos;
 import net.minecraft.core.Holder;
 import net.minecraft.core.QuartPos;
 import net.minecraft.core.Registry;
@@ -20,6 +22,7 @@ import net.minecraft.core.RegistryAccess;
 import net.minecraft.core.registries.Registries;
 import net.minecraft.resources.Identifier;
 import net.minecraft.resources.ResourceKey;
+import net.minecraft.util.RandomSource;
 import net.minecraft.world.level.biome.Biome;
 import net.minecraft.world.level.biome.BiomeSource;
 import net.minecraft.world.level.biome.Climate;
@@ -40,10 +43,14 @@ import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Optional;
 import java.util.Set;
+import java.util.function.Predicate;
 import java.util.stream.Stream;
 
 public class CustomBiomeSource extends BiomeSource {
     private static final int NOISE_BIOME_CACHE_MAX = 262144;
+    private static final int STRONGHOLD_RING_SEARCH_Y = 0;
+    private static final int STRONGHOLD_RING_SEARCH_RADIUS = 112;
+    private static final int STRONGHOLD_RING_SEARCH_QUART_STEP = 4;
 
     private final long seed;
     private final Engine engine;
@@ -309,6 +316,30 @@ public class CustomBiomeSource extends BiomeSource {
         }
     }
 
+    @Override
+    public Pair<BlockPos, Holder<Biome>> findBiomeHorizontal(
+            int x,
+            int y,
+            int z,
+            int searchRadius,
+            Predicate<Holder<Biome>> allowed,
+            RandomSource random,
+            Climate.Sampler sampler
+    ) {
+        int quartStep = horizontalBiomeSearchQuartStep(y, searchRadius);
+        if (quartStep == 1) {
+            return super.findBiomeHorizontal(x, y, z, searchRadius, allowed, random, sampler);
+        }
+        return super.findBiomeHorizontal(
+                x, y, z, searchRadius, quartStep, allowed, random, false, sampler);
+    }
+
+    static int horizontalBiomeSearchQuartStep(int blockY, int searchRadius) {
+        return blockY == STRONGHOLD_RING_SEARCH_Y && searchRadius == STRONGHOLD_RING_SEARCH_RADIUS
+                ? STRONGHOLD_RING_SEARCH_QUART_STEP
+                : 1;
+    }
+
     @Override
     public Set<Holder<Biome>> getBiomesWithin(int x, int y, int z, int radius, Climate.Sampler sampler) {
         GenerationSessionLease lease = tryAcquireGenerationLease("bukkit_biomes_within");

adapters/bukkit/nms/v26_2_R1/src/test/java/art/arcane/iris/core/nms/v26_2_R1/CustomBiomeSourceStructureContractTest.java

@@ -37,4 +37,16 @@ public class CustomBiomeSourceStructureContractTest {
         assertTrue(source.contains("catch (GenerationSessionException e)"));
         assertTrue(source.contains("e.isExpectedTeardown()"));
     }
+
+    @Test
+    public void strongholdRingSearchSamplesOneQuartColumnPerChunk() throws IOException {
+        String source = Files.readString(Path.of(System.getProperty("iris.customBiomeSource")));
+
+        assertTrue(source.contains("private static final int STRONGHOLD_RING_SEARCH_Y = 0"));
+        assertTrue(source.contains("private static final int STRONGHOLD_RING_SEARCH_RADIUS = 112"));
+        assertTrue(source.contains("private static final int STRONGHOLD_RING_SEARCH_QUART_STEP = 4"));
+        assertTrue(source.contains("x, y, z, searchRadius, quartStep, allowed, random, false, sampler"));
+        assertTrue(source.contains(
+                "return super.findBiomeHorizontal(x, y, z, searchRadius, allowed, random, sampler)"));
+    }
 }

adapters/modded-common/src/main/java/art/arcane/iris/modded/IrisModdedBiomeSource.java

@@ -25,7 +25,9 @@ import art.arcane.iris.engine.object.IrisBiome;
 import art.arcane.iris.engine.object.IrisBiomeCustom;
 import art.arcane.iris.util.project.context.IrisContext;
 import art.arcane.volmlib.util.math.RNG;
+import com.mojang.datafixers.util.Pair;
 import com.mojang.serialization.MapCodec;
+import net.minecraft.core.BlockPos;
 import net.minecraft.core.Holder;
 import net.minecraft.core.HolderLookup;
 import net.minecraft.core.QuartPos;
@@ -34,6 +36,7 @@ import net.minecraft.core.registries.Registries;
 import net.minecraft.resources.Identifier;
 import net.minecraft.resources.ResourceKey;
 import net.minecraft.server.MinecraftServer;
+import net.minecraft.util.RandomSource;
 import net.minecraft.world.level.biome.Biome;
 import net.minecraft.world.level.biome.BiomeSource;
 import net.minecraft.world.level.biome.Climate;
@@ -49,10 +52,14 @@ import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.atomic.AtomicLong;
 import java.util.concurrent.atomic.AtomicReferenceArray;
+import java.util.function.Predicate;
 import java.util.stream.Stream;
 
 final class IrisModdedBiomeSource extends BiomeSource {
     private static final int UNRESOLVED_WARN_KEYS_MAX = 256;
+    private static final int STRONGHOLD_RING_SEARCH_Y = 0;
+    private static final int STRONGHOLD_RING_SEARCH_RADIUS = 112;
+    private static final int STRONGHOLD_RING_SEARCH_QUART_STEP = 4;
 
     private final BiomeSource serializedSource;
     private final Set<String> warnedUnresolvedBiomeKeys = ConcurrentHashMap.newKeySet();
@@ -554,6 +561,12 @@ final class IrisModdedBiomeSource extends BiomeSource {
         return radius == 29 && blockY == minHeight + fluidHeight;
     }
 
+    static int horizontalBiomeSearchQuartStep(int blockY, int searchRadius) {
+        return blockY == STRONGHOLD_RING_SEARCH_Y && searchRadius == STRONGHOLD_RING_SEARCH_RADIUS
+                ? STRONGHOLD_RING_SEARCH_QUART_STEP
+                : 1;
+    }
+
     private static boolean isReady(Engine engine) {
         return engine != null && !engine.isClosed() && engine.getComplex() != null;
     }
@@ -861,6 +874,24 @@ final class IrisModdedBiomeSource extends BiomeSource {
             return resolved;
         }
 
+        @Override
+        public Pair<BlockPos, Holder<Biome>> findBiomeHorizontal(
+                int x,
+                int y,
+                int z,
+                int searchRadius,
+                Predicate<Holder<Biome>> allowed,
+                RandomSource random,
+                Climate.Sampler sampler
+        ) {
+            int quartStep = horizontalBiomeSearchQuartStep(y, searchRadius);
+            if (quartStep == 1) {
+                return super.findBiomeHorizontal(x, y, z, searchRadius, allowed, random, sampler);
+            }
+            return super.findBiomeHorizontal(
+                    x, y, z, searchRadius, quartStep, allowed, random, false, sampler);
+        }
+
         @Override
         public Set<Holder<Biome>> getBiomesWithin(int x, int y, int z, int radius, Climate.Sampler sampler) {
             return super.getBiomesWithin(x, y, z, radius, sampler);

adapters/modded-common/src/test/java/art/arcane/iris/modded/IrisModdedStructureParityTest.java

@@ -13,6 +13,9 @@ import net.minecraft.server.Bootstrap;
 import org.junit.BeforeClass;
 import org.junit.Test;
 
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
 import java.util.List;
 import java.util.Set;
 import java.util.concurrent.CountDownLatch;
@@ -56,6 +59,19 @@ public class IrisModdedStructureParityTest {
         assertFalse(IrisModdedBiomeSource.isMonumentSurfaceBiomeQuery(50, 28, -256, 306));
     }
 
+    @Test
+    public void strongholdRingSearchSamplesOneQuartColumnPerChunk() throws IOException {
+        assertEquals(4, IrisModdedBiomeSource.horizontalBiomeSearchQuartStep(0, 112));
+        assertEquals(1, IrisModdedBiomeSource.horizontalBiomeSearchQuartStep(1, 112));
+        assertEquals(1, IrisModdedBiomeSource.horizontalBiomeSearchQuartStep(0, 111));
+        String source = Files.readString(Path.of(
+                System.getProperty("iris.moddedCommonSources"),
+                "art/arcane/iris/modded/IrisModdedBiomeSource.java"));
+        assertTrue(source.contains("x, y, z, searchRadius, quartStep, allowed, random, false, sampler"));
+        assertTrue(source.contains(
+                "return super.findBiomeHorizontal(x, y, z, searchRadius, allowed, random, sampler)"));
+    }
+
     @Test
     public void spawnHeightMatchesPaperFixedSpawnClamp() {
         assertEquals(96, ModdedDimensionMetadata.clampSpawnHeight(-64, 384));