From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: hayanesuru <hayanesuru@outlook.jp>
Date: Tue, 3 Jun 2025 15:16:32 +0900
Subject: [PATCH] optimise ChunkGenerator#getMobsAt

inline fillStartsForStructure

diff --git a/net/minecraft/world/level/StructureManager.java b/net/minecraft/world/level/StructureManager.java
index 3399922d79a713484e16beb6e4e9985c284ddfb5..fbe93098ce0366054a6da857cd808af1431b6612 100644
--- a/net/minecraft/world/level/StructureManager.java
+++ b/net/minecraft/world/level/StructureManager.java
@@ -78,7 +78,7 @@ public class StructureManager {
 
     public void fillStartsForStructure(Structure structure, LongSet structureRefs, Consumer<StructureStart> startConsumer) {
         for (long l : structureRefs) {
-            SectionPos sectionPos = SectionPos.of(new ChunkPos(l), this.level.getMinSectionY());
+            SectionPos sectionPos = SectionPos.of(ChunkPos.getX(l), this.level.getMinSectionY(), ChunkPos.getZ(l)); // Leaf - optimise ChunkGenerator#getMobsAt
             StructureStart startForStructure = this.getStartForStructure(
                 sectionPos, structure, this.level.getChunk(sectionPos.x(), sectionPos.z(), ChunkStatus.STRUCTURE_STARTS)
             );
@@ -178,8 +178,8 @@ public class StructureManager {
     }
 
     public Map<Structure, LongSet> getAllStructuresAt(BlockPos pos) {
-        SectionPos sectionPos = SectionPos.of(pos);
-        return this.level.getChunk(sectionPos.x(), sectionPos.z(), ChunkStatus.STRUCTURE_REFERENCES).getAllReferences();
+        //SectionPos sectionPos = SectionPos.of(pos); // Leaf - optimise ChunkGenerator#getMobsAt
+        return this.level.getChunk(pos.getX() >> 4, pos.getZ() >> 4, ChunkStatus.STRUCTURE_REFERENCES).getAllReferences(); // Leaf - optimise ChunkGenerator#getMobsAt
     }
 
     public StructureCheckResult checkStructurePresence(ChunkPos chunkPos, Structure structure, StructurePlacement placement, boolean skipKnownStructures) {
diff --git a/net/minecraft/world/level/chunk/ChunkGenerator.java b/net/minecraft/world/level/chunk/ChunkGenerator.java
index e1ebbfab87aed9cc633f2fedb1e6edeca4ddc2ec..11c7c299d4affb9e78488590e7db939efe6e3dd9 100644
--- a/net/minecraft/world/level/chunk/ChunkGenerator.java
+++ b/net/minecraft/world/level/chunk/ChunkGenerator.java
@@ -496,18 +496,20 @@ public abstract class ChunkGenerator {
             Structure structure = entry.getKey();
             StructureSpawnOverride structureSpawnOverride = structure.spawnOverrides().get(category);
             if (structureSpawnOverride != null) {
-                MutableBoolean mutableBoolean = new MutableBoolean(false);
-                Predicate<StructureStart> predicate = structureSpawnOverride.boundingBox() == StructureSpawnOverride.BoundingBoxType.PIECE
-                    ? structureStart -> structureManager.structureHasPieceAt(pos, structureStart)
-                    : structureStart -> structureStart.getBoundingBox().isInside(pos);
-                structureManager.fillStartsForStructure(structure, entry.getValue(), structureStart -> {
-                    if (mutableBoolean.isFalse() && predicate.test(structureStart)) {
-                        mutableBoolean.setTrue();
+                // Leaf start - optimise ChunkGenerator#getMobsAt
+                for (long l : entry.getValue()) {
+                    StructureStart startForStructure = structureManager.getStartForStructure(
+                        null, structure, structureManager.level.getChunk(ChunkPos.getX(l), ChunkPos.getZ(l), ChunkStatus.STRUCTURE_STARTS)
+                    );
+                    if (startForStructure != null && startForStructure.isValid()) {
+                        if (structureSpawnOverride.boundingBox() == StructureSpawnOverride.BoundingBoxType.PIECE
+                            ? structureManager.structureHasPieceAt(pos, startForStructure)
+                            : startForStructure.getBoundingBox().isInside(pos)) {
+                            return structureSpawnOverride.spawns();
+                        }
                     }
-                });
-                if (mutableBoolean.isTrue()) {
-                    return structureSpawnOverride.spawns();
                 }
+                // Leaf end - optimise ChunkGenerator#getMobsAt
             }
         }