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 6a2adfe51b5ea6b3290349781f41ed7818f15fe5..928139e8d0f7b65e2376d3c89d7bea294e3ed3a2 100644
--- a/src/main/java/net/minecraft/server/level/ServerChunkCache.java
+++ b/src/main/java/net/minecraft/server/level/ServerChunkCache.java
@@ -708,6 +708,11 @@ 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 b1950cd42cb7890309c1fb591110b6b9e4d37e51..03a4e114a3383ce779a6fc48747834b33b480f66 100644
--- a/src/main/java/net/minecraft/server/level/ServerLevel.java
+++ b/src/main/java/net/minecraft/server/level/ServerLevel.java
@@ -796,6 +796,13 @@ 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();
@@ -806,7 +813,7 @@ 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);
@@ -836,7 +843,7 @@ public class ServerLevel extends Level implements WorldGenLevel {
         gameprofilerfiller.popPush("iceandsnow");
         int l;
 
-        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 28e4b302284f955a73e75d0f4276d55fb51826f5..1bf1af06fbd6501e98def7997c487c425d6a1623 100644
--- a/src/main/java/net/minecraft/world/level/chunk/LevelChunk.java
+++ b/src/main/java/net/minecraft/world/level/chunk/LevelChunk.java
@@ -88,6 +88,18 @@ 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);
     }
@@ -118,6 +130,11 @@ public class LevelChunk extends ChunkAccess {
         this.fluidTicks = fluidTickScheduler;
         // CraftBukkit start
         this.bukkitChunk = new org.bukkit.craftbukkit.CraftChunk(this);
+        // Leaves start - initialize lightning tick
+        if (top.leavesmc.leaves.LeavesConfig.optimizeChunkTicking) {
+            this.lightningTick = this.level.getThreadUnsafeRandom().nextInt(100000) << 1;
+        }
+        // Leaves end - initialize lightning tick
     }
 
     public org.bukkit.Chunk bukkitChunk;
diff --git a/src/main/java/top/leavesmc/leaves/LeavesConfig.java b/src/main/java/top/leavesmc/leaves/LeavesConfig.java
index 240fe801ba2670f5986faa58b77c7902f0465fc6..64215f03789db0555422c4b0aec32c8a4504cb4d 100644
--- a/src/main/java/top/leavesmc/leaves/LeavesConfig.java
+++ b/src/main/java/top/leavesmc/leaves/LeavesConfig.java
@@ -280,6 +280,15 @@ public final class LeavesConfig {
         checkSpookySeasonOnceAnHour = getBoolean("settings.performance.check-spooky-season-once-an-hour", checkSpookySeasonOnceAnHour);
     }
 
+    public static boolean optimizeChunkTicking = true;
+    private static boolean optimizeChunkTickingLock = false;
+    private static void optimizeChunkTicking() {
+        if (!optimizeChunkTickingLock) {
+            optimizeChunkTicking = getBoolean("settings.performance.optimize-chunk-ticking", optimizeChunkTicking);
+            optimizeChunkTickingLock = true;
+        }
+    }
+
     public static final class WorldConfig {
 
         public final String worldName;