From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: MrHua269 <mrhua269@gmail.com>
Date: Fri, 1 May 2026 21:47:48 +0800
Subject: [PATCH] Pufferfish: Reduce projectile chunk loading

A part of Pufferfish(https://github.com/Pufferfish-gg/Pufferfish)
Co-authored-by: Paul Sauve <paul@technove.co>
Original patch: https://github.com/pufferfish-gg/Pufferfish/blob/ver/1.21/pufferfish-server/minecraft-patches/features/0006-Reduce-projectile-chunk-loading.patch
Original license(GPL-3.0): https://github.com/pufferfish-gg/Pufferfish/blob/ver/1.21/PATCH-LICENSE

diff --git a/io/papermc/paper/threadedregions/RegionizedWorldData.java b/io/papermc/paper/threadedregions/RegionizedWorldData.java
index 5a72d922af1af3a4e2314b8fa441787e7875ed77..1d393b97d09083eee5e21e00be5223741b5b7819 100644
--- a/io/papermc/paper/threadedregions/RegionizedWorldData.java
+++ b/io/papermc/paper/threadedregions/RegionizedWorldData.java
@@ -408,6 +408,10 @@ public final class RegionizedWorldData {
 
     private RegionizedServer.WorldLevelData tickData;
 
+    // Shiroha start - Pufferfish - Reduce projectile chunk loading
+    public long pufferfish$loadedThisTick = 0L;
+    public long pufferfish$loadedTick = 0L;
+    // Shiroha end
     // connections
     public final List<Connection> connections = new ArrayList<>();
 
diff --git a/net/minecraft/world/entity/projectile/Projectile.java b/net/minecraft/world/entity/projectile/Projectile.java
index 721e3b083846fd363a31311196bc4c681969215c..cc3aebbd42a876fcc982a9bf1c3dc1bd11f3a4e0 100644
--- a/net/minecraft/world/entity/projectile/Projectile.java
+++ b/net/minecraft/world/entity/projectile/Projectile.java
@@ -58,6 +58,38 @@ public abstract class Projectile extends Entity implements TraceableEntity {
         this.setOwner(EntityReference.of(owner));
     }
 
+    // Pufferfish start
+    private int loadedLifetime = 0;
+    @Override
+    public void setPos(double x, double y, double z) {
+        var currRegionData = io.papermc.paper.threadedregions.TickRegionScheduler.getCurrentRegionizedWorldData();
+        // we might run this on a chunk system worker(chunk gen), so skip this check if no world data was fetched
+        if (currRegionData == null || currRegionData.world != this.level()) {
+            return;
+        }
+        long currentTick = currRegionData.getRedstoneGameTime();
+        if (currRegionData.pufferfish$loadedTick != currentTick) {
+            currRegionData.pufferfish$loadedTick = currentTick;
+            currRegionData.pufferfish$loadedThisTick = 0L;
+        }
+        int previousX = Mth.floor(this.getX()) >> 4, previousZ = Mth.floor(this.getZ()) >> 4;
+        int newX = Mth.floor(x) >> 4, newZ = Mth.floor(z) >> 4;
+        if (previousX != newX || previousZ != newZ) {
+            boolean isLoaded = ((net.minecraft.server.level.ServerChunkCache) this.level().getChunkSource()).getChunkAtIfLoadedImmediately(newX, newZ) != null;
+            if (!isLoaded) {
+                if (currRegionData.pufferfish$loadedThisTick > io.nanachiyo0721.shiroha.config.modules.optimizations.ProjectileChunkReduceConfig.maxProjectileLoadsPerTick) {
+                    if (++this.loadedLifetime > io.nanachiyo0721.shiroha.config.modules.optimizations.ProjectileChunkReduceConfig.maxProjectileLoadsPerProjectile) {
+                        this.discard();
+                    }
+                    return;
+                }
+                currRegionData.pufferfish$loadedThisTick++;
+            }
+        }
+        super.setPos(x, y, z);
+    }
+    // Pufferfish end
+
     // Folia start - region threading
     // In general, this is an entire mess. At the time of writing, there are fifty usages of getOwner.
     // Usage of this function is to avoid concurrency issues, even if it sacrifices behavior.