From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: violetc <58360096+s-yh-china@users.noreply.github.com>
Date: Sun, 14 Aug 2022 11:01:17 +0800
Subject: [PATCH] Optimize random calls in chunk ticking

This patch is Powered by Pufferfish(https://github.com/pufferfish-gg/Pufferfish)

diff --git a/src/main/java/net/minecraft/server/level/ServerChunkCache.java b/src/main/java/net/minecraft/server/level/ServerChunkCache.java
index 488a253e218409b5f0b4a872cee0928578fa7582..a55ed382125310dfdfaeb7e80de2634a8d67f929 100644
--- a/src/main/java/net/minecraft/server/level/ServerChunkCache.java
+++ b/src/main/java/net/minecraft/server/level/ServerChunkCache.java
@@ -553,6 +553,11 @@ public class ServerChunkCache extends ChunkSource {
             ProfilerFiller gameprofilerfiller = this.level.getProfiler();
 
             gameprofilerfiller.push("pollingChunks");
+            // Leaves start - reset ice & snow tick random
+            if (top.leavesmc.leaves.LeavesConfig.optimizeChunkTicking) {
+                this.level.resetIceAndSnowTick();
+            }
+            // Leaves end - reset ice & snow tick random
             int k = this.level.getGameRules().getInt(GameRules.RULE_RANDOMTICKING);
             boolean flag1 = level.ticksPerSpawnCategory.getLong(org.bukkit.entity.SpawnCategory.ANIMAL) != 0L && worlddata.getGameTime() % level.ticksPerSpawnCategory.getLong(org.bukkit.entity.SpawnCategory.ANIMAL) == 0L; // CraftBukkit
 
diff --git a/src/main/java/net/minecraft/server/level/ServerLevel.java b/src/main/java/net/minecraft/server/level/ServerLevel.java
index b6ad64f0bed9459aa2ecb4f80b71653691a8359f..bf05f321373c9cb5d42fd6cace010a75dc98b90a 100644
--- a/src/main/java/net/minecraft/server/level/ServerLevel.java
+++ b/src/main/java/net/minecraft/server/level/ServerLevel.java
@@ -937,6 +937,13 @@ public class ServerLevel extends Level implements WorldGenLevel {
     // private final io.papermc.paper.util.math.ThreadUnsafeRandom randomTickRandom = new io.papermc.paper.util.math.ThreadUnsafeRandom(this.random.nextLong()); // Leaves - moved to super
     // Paper end
 
+    // Leaves start - reset ice & snow tick random
+    private int currentIceAndSnowTick = 0;
+    protected void resetIceAndSnowTick() {
+        this.currentIceAndSnowTick = this.randomTickRandom.nextInt(16);
+    }
+    // Leaves end - reset ice & snow tick random
+
     public void tickChunk(LevelChunk chunk, int randomTickSpeed) {
         ChunkPos chunkcoordintpair = chunk.getPos();
         boolean flag = this.isRaining();
@@ -947,7 +954,7 @@ public class ServerLevel extends Level implements WorldGenLevel {
         gameprofilerfiller.push("thunder");
         final BlockPos.MutableBlockPos blockposition = this.chunkTickMutablePosition; // Paper - use mutable to reduce allocation rate, final to force compile fail on change
 
-        if (!this.paperConfig().environment.disableThunder && flag && this.isThundering() && this.spigotConfig.thunderChance > 0 && this.random.nextInt(this.spigotConfig.thunderChance) == 0) { // Spigot // Paper - disable thunder
+        if (!this.paperConfig().environment.disableThunder && flag && this.isThundering() && this.spigotConfig.thunderChance > 0 && (top.leavesmc.leaves.LeavesConfig.optimizeChunkTicking ? chunk.shouldDoLightning(this.random) : this.random.nextInt(this.spigotConfig.thunderChance) == 0)) { // Spigot // Paper - disable thunder // Leaves - replace random with shouldDoLightning
             blockposition.set(this.findLightningTargetAround(this.getBlockRandomPos(j, 0, k, 15))); // Paper
             if (this.isRainingAt(blockposition)) {
                 DifficultyInstance difficultydamagescaler = this.getCurrentDifficultyAt(blockposition);
@@ -978,7 +985,7 @@ public class ServerLevel extends Level implements WorldGenLevel {
         int l;
         int i1;
 
-        if (!this.paperConfig().environment.disableIceAndSnow && this.random.nextInt(16) == 0) { // Paper - Disable ice and snow
+        if (!this.paperConfig().environment.disableIceAndSnow && (top.leavesmc.leaves.LeavesConfig.optimizeChunkTicking ? (this.currentIceAndSnowTick++ & 15) == 0 : this.random.nextInt(16) == 0)) { // Paper - Disable ice and snow // Paper - optimise random ticking  // Leaves - optimize further random ticking
             // Paper start - optimise chunk ticking
             this.getRandomBlockPosition(j, 0, k, 15, blockposition);
             int normalY = chunk.getHeight(Heightmap.Types.MOTION_BLOCKING, blockposition.getX() & 15, blockposition.getZ() & 15) + 1;
diff --git a/src/main/java/net/minecraft/world/level/chunk/LevelChunk.java b/src/main/java/net/minecraft/world/level/chunk/LevelChunk.java
index 4ff0d2fc9fd76e92e64abd69f2c9e299aa08ac32..cc224af0139a6e3adefd22cbfa0cd519735b7191 100644
--- a/src/main/java/net/minecraft/world/level/chunk/LevelChunk.java
+++ b/src/main/java/net/minecraft/world/level/chunk/LevelChunk.java
@@ -85,6 +85,18 @@ public class LevelChunk extends ChunkAccess {
     private final LevelChunkTicks<Block> blockTicks;
     private final LevelChunkTicks<Fluid> fluidTicks;
 
+    // Leaves start - instead of using a random every time the chunk is ticked, define when lightning strikes preemptively
+    private int lightningTick;
+    // shouldDoLightning compiles down to 29 bytes, which with the default of 35 byte inlining should guarantee an inline
+    public final boolean shouldDoLightning(net.minecraft.util.RandomSource random) {
+        if (this.lightningTick-- <= 0) {
+            this.lightningTick = random.nextInt(this.level.spigotConfig.thunderChance) << 1;
+            return true;
+        }
+        return false;
+    }
+    // Leaves end - instead of using a random every time the chunk is ticked, define when lightning strikes preemptively
+
     public LevelChunk(Level world, ChunkPos pos) {
         this(world, pos, UpgradeData.EMPTY, new LevelChunkTicks<>(), new LevelChunkTicks<>(), 0L, (LevelChunkSection[]) null, (LevelChunk.PostLoadProcessor) null, (BlendingData) null);
     }
@@ -112,6 +124,12 @@ public class LevelChunk extends ChunkAccess {
         this.postLoad = entityLoader;
         this.blockTicks = blockTickScheduler;
         this.fluidTicks = fluidTickScheduler;
+        
+        // Leaves start - initialize lightning tick
+        if (top.leavesmc.leaves.LeavesConfig.optimizeChunkTicking) {
+            this.lightningTick = this.level.getThreadUnsafeRandom().nextInt(100000) << 1;
+        }
+        // Leaves end - initialize lightning tick
     }
 
     // CraftBukkit start