papermc/Spigot-Server-Patches/0042-Configurable-async-light-updates.patch

From cc4cc3c5874b1cdd1f1a1e5488d6b729f3b303ec Mon Sep 17 00:00:00 2001
From: Byteflux <byte@byteflux.net>
Date: Wed, 1 Jul 2015 00:18:10 -0700
Subject: [PATCH] Configurable async light updates


diff --git a/src/main/java/net/minecraft/server/Chunk.java b/src/main/java/net/minecraft/server/Chunk.java
index 7242d45..ab4de94 100644
--- a/src/main/java/net/minecraft/server/Chunk.java
+++ b/src/main/java/net/minecraft/server/Chunk.java
@@ -11,6 +11,8 @@ import java.util.Map;
 import java.util.Random;
 import java.util.concurrent.Callable;
 import java.util.concurrent.ConcurrentLinkedQueue;
+import java.util.concurrent.atomic.AtomicInteger; // PaperSpigot
+
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
@@ -43,6 +45,10 @@ public class Chunk {
     private int v;
     private ConcurrentLinkedQueue<BlockPosition> w;
     protected gnu.trove.map.hash.TObjectIntHashMap<Class> entityCount = new gnu.trove.map.hash.TObjectIntHashMap<Class>(); // Spigot
+    // PaperSpigot start - Asynchronous light updates
+    public AtomicInteger pendingLightUpdates = new AtomicInteger();
+    public long lightUpdateTime;
+    // PaperSpigot end
 
     // CraftBukkit start - Neighbor loaded cache for chunk lighting and entity ticking
     private int neighbors = 0x1 << 12;
@@ -274,7 +280,7 @@ public class Chunk {
     private void a(int i, int j, int k, int l) {
         if (l > k && this.world.areChunksLoaded(new BlockPosition(i, 0, j), 16)) {
             for (int i1 = k; i1 < l; ++i1) {
-                this.world.c(EnumSkyBlock.SKY, new BlockPosition(i, i1, j));
+                this.world.updateLight(EnumSkyBlock.SKY, new BlockPosition(i, i1, j)); // PaperSpigot - Asynchronous lighting updates
             }
 
             this.q = true;
diff --git a/src/main/java/net/minecraft/server/ChunkProviderServer.java b/src/main/java/net/minecraft/server/ChunkProviderServer.java
index 975d666..ae0f276 100644
--- a/src/main/java/net/minecraft/server/ChunkProviderServer.java
+++ b/src/main/java/net/minecraft/server/ChunkProviderServer.java
@@ -53,6 +53,12 @@ public class ChunkProviderServer implements IChunkProvider {
     }
 
     public void queueUnload(int i, int j) {
+        // PaperSpigot start - Asynchronous lighting updates
+        Chunk chunk = chunks.get(LongHash.toLong(i, j));
+        if (chunk != null && chunk.world.paperSpigotConfig.useAsyncLighting && (chunk.pendingLightUpdates.get() > 0 || chunk.world.getTime() - chunk.lightUpdateTime < 20)) {
+            return;
+        }
+        // PaperSpigot end
         if (this.world.worldProvider.e()) {
             if (!this.world.c(i, j)) {
                 // CraftBukkit start
diff --git a/src/main/java/net/minecraft/server/World.java b/src/main/java/net/minecraft/server/World.java
index b681a9f..8ee0cec 100644
--- a/src/main/java/net/minecraft/server/World.java
+++ b/src/main/java/net/minecraft/server/World.java
@@ -18,6 +18,12 @@ import org.bukkit.generator.ChunkGenerator;
 import java.util.*;
 import java.util.concurrent.Callable;
 
+// PaperSpigot start
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import com.google.common.util.concurrent.ThreadFactoryBuilder;
+// PaperSpigot end
+
 // CraftBukkit start
 // CraftBukkit end
 
@@ -126,6 +132,7 @@ public abstract class World implements IBlockAccess {
     public static boolean haveWeSilencedAPhysicsCrash;
     public static String blockLocation;
     private int tileTickPosition;
+    private ExecutorService lightingExecutor; // PaperSpigot - Asynchronous lighting updates
 
     public static long chunkToKey(int x, int z)
     {
@@ -493,7 +500,7 @@ public abstract class World implements IBlockAccess {
 
         if (!this.worldProvider.o()) {
             for (i1 = k; i1 <= l; ++i1) {
-                this.c(EnumSkyBlock.SKY, new BlockPosition(i, i1, j));
+                this.updateLight(EnumSkyBlock.SKY, new BlockPosition(i, i1, j)); // PaperSpigot - Asynchronous lighting updates
             }
         }
 
@@ -2308,10 +2315,10 @@ public abstract class World implements IBlockAccess {
         boolean flag = false;
 
         if (!this.worldProvider.o()) {
-            flag |= this.c(EnumSkyBlock.SKY, blockposition);
+            flag |= this.updateLight(EnumSkyBlock.SKY, blockposition); // PaperSpigot - Asynchronous lighting updates
         }
 
-        flag |= this.c(EnumSkyBlock.BLOCK, blockposition);
+        flag |= this.updateLight(EnumSkyBlock.BLOCK, blockposition); // PaperSpigot - Asynchronous lighting updates
         return flag;
     }
 
@@ -2358,10 +2365,10 @@ public abstract class World implements IBlockAccess {
         }
     }
 
-    public boolean c(EnumSkyBlock enumskyblock, BlockPosition blockposition) {
+    public boolean c(EnumSkyBlock enumskyblock, BlockPosition blockposition, Chunk chunk, List<Chunk> neighbors) { // PaperSpigot
         // CraftBukkit start - Use neighbor cache instead of looking up
-        Chunk chunk = this.getChunkIfLoaded(blockposition.getX() >> 4, blockposition.getZ() >> 4);
-        if (chunk == null || !chunk.areNeighborsLoaded(1) /*!this.areChunksLoaded(blockposition, 17, false)*/) {
+        //Chunk chunk = this.getChunkIfLoaded(blockposition.getX() >> 4, blockposition.getZ() >> 4);
+        if (chunk == null /*|| !chunk.areNeighborsLoaded(1)*/ /*!this.areChunksLoaded(blockposition, 17, false)*/) {
             // CraftBukkit end
             return false;
         } else {
@@ -2479,11 +2486,66 @@ public abstract class World implements IBlockAccess {
                 }
             }
 
+            // PaperSpigot start - Asynchronous light updates
+            if (chunk.world.paperSpigotConfig.useAsyncLighting) {
+                chunk.pendingLightUpdates.decrementAndGet();
+                if (neighbors != null) {
+                    for (Chunk neighbor : neighbors) {
+                        neighbor.pendingLightUpdates.decrementAndGet();
+                    }
+                }
+            }
+            // PaperSpigot end
             this.methodProfiler.b();
             return true;
         }
     }
 
+    /**
+     * PaperSpigot - Asynchronous lighting updates
+     */
+    public boolean updateLight(final EnumSkyBlock enumskyblock, final BlockPosition position) {
+        int x = position.getX();
+        int z = position.getZ();
+        final Chunk chunk = this.getChunkIfLoaded(x >> 4, z >> 4);
+        if (chunk == null || (!chunk.world.paperSpigotConfig.useAsyncLighting && !chunk.areNeighborsLoaded(1))) {
+            return false;
+        }
+
+        if (!chunk.world.paperSpigotConfig.useAsyncLighting) {
+            return this.c(enumskyblock, position, chunk, null);
+        }
+
+        if (lightingExecutor == null) {
+            lightingExecutor = Executors.newSingleThreadExecutor(new ThreadFactoryBuilder().setNameFormat("PaperSpigot - Lighting Thread").build());
+        }
+
+        chunk.pendingLightUpdates.incrementAndGet();
+        chunk.lightUpdateTime = chunk.world.getTime();
+
+        final List<Chunk> neighbors = new ArrayList<Chunk>();
+        for (int cx = (x >> 4) - 1; cx < (x >> 4) + 1; ++cx) {
+            for (int cz = (z >> 4) - 1; cz < (z >> 4) + 1; ++cz) {
+                if (this.chunkProvider.isChunkLoaded(cx, cz)) {
+                    Chunk neighbor = this.getChunkAt(cx, cz);
+                    if (neighbor != chunk) {
+                        neighbor.pendingLightUpdates.incrementAndGet();
+                        neighbor.lightUpdateTime = chunk.world.getTime();
+                        neighbors.add(neighbor);
+                    }
+                }
+            }
+        }
+
+        lightingExecutor.submit(new Runnable() {
+            @Override
+            public void run() {
+                World.this.c(enumskyblock, position, chunk, neighbors);
+            }
+        });
+        return true;
+    }
+
     public boolean a(boolean flag) {
         return false;
     }
diff --git a/src/main/java/org/github/paperspigot/PaperSpigotWorldConfig.java b/src/main/java/org/github/paperspigot/PaperSpigotWorldConfig.java
index bcd8b65..fa9ae6c 100644
--- a/src/main/java/org/github/paperspigot/PaperSpigotWorldConfig.java
+++ b/src/main/java/org/github/paperspigot/PaperSpigotWorldConfig.java
@@ -244,4 +244,11 @@ public class PaperSpigotWorldConfig
         log( "WorldServer TickNextTick cap set at " + tickNextTickCap );
         log( "WorldServer TickNextTickList cap always processes redstone: " + tickNextTickListCapIgnoresRedstone );
     }
+
+    public boolean useAsyncLighting;
+    private void useAsyncLighting()
+    {
+        useAsyncLighting = getBoolean( "use-async-lighting", false );
+        log( "World async lighting: " + useAsyncLighting );
+    }
 }
-- 
1.9.5.msysgit.1