PaperMC/Spigot-Server-Patches/0030-Configurable-async-light-updates.patch

From 3737e9c22597fdd788f00c58af11937a76d8d613 Mon Sep 17 00:00:00 2001
From: Byteflux <byte@byteflux.net>
Date: Wed, 2 Mar 2016 00:52:31 -0600
Subject: [PATCH] Configurable async light updates


diff --git a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
index 17619b6..ef5c960 100644
--- a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
+++ b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
@@ -161,4 +161,9 @@ public class PaperWorldConfig {
 
     }
 
+    public boolean useAsyncLighting;
+    private void useAsyncLighting() {
+        useAsyncLighting = false; //getBoolean( "use-async-lighting", false );
+        log("World async lighting: " + useAsyncLighting);
+    }
 }
diff --git a/src/main/java/net/minecraft/server/Chunk.java b/src/main/java/net/minecraft/server/Chunk.java
index cde4124..5df38be 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; // Paper
+
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
@@ -44,6 +46,10 @@ public class Chunk {
     private int w;
     private ConcurrentLinkedQueue<BlockPosition> x;
     protected gnu.trove.map.hash.TObjectIntHashMap<Class> entityCount = new gnu.trove.map.hash.TObjectIntHashMap<Class>(); // Spigot
+    // Paper start - Asynchronous light updates
+    public AtomicInteger pendingLightUpdates = new AtomicInteger();
+    public long lightUpdateTime;
+    // Paper end
 
     // CraftBukkit start - Neighbor loaded cache for chunk lighting and entity ticking
     private int neighbors = 0x1 << 12;
@@ -278,7 +284,7 @@ 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));
             }
 
             this.r = true;
@@ -991,7 +997,7 @@ public class Chunk {
 
     public void b(boolean flag) {
         if (this.l && !this.world.worldProvider.m() && !flag) {
-            this.h(this.world.isClientSide);
+            this.recheckGaps(this.world.isClientSide); // Paper - Asynchronous lighting updates
         }
 
         this.q = true;
@@ -1012,6 +1018,23 @@ public class Chunk {
 
     }
 
+    /**
+     * Paper- Recheck gaps asynchronously
+     */
+    public void recheckGaps(final boolean isClientSide) {
+        if (!world.paperConfig.useAsyncLighting) {
+            this.h(this.world.isClientSide);
+            return;
+        }
+
+        world.lightingExecutor.submit(new Runnable() {
+            @Override
+            public void run() {
+                Chunk.this.h(isClientSide);
+            }
+        });
+    }
+
     public boolean isReady() {
         // Spigot Start
         /*
diff --git a/src/main/java/net/minecraft/server/ChunkProviderServer.java b/src/main/java/net/minecraft/server/ChunkProviderServer.java
index 83857a6..49288c9 100644
--- a/src/main/java/net/minecraft/server/ChunkProviderServer.java
+++ b/src/main/java/net/minecraft/server/ChunkProviderServer.java
@@ -46,6 +46,12 @@ public class ChunkProviderServer implements IChunkProvider {
     }
 
     public void queueUnload(int i, int j) {
+        // Paper start - Asynchronous lighting updates
+        Chunk chunk = chunks.get(LongHash.toLong(i, j));
+        if (chunk != null && chunk.world.paperConfig.useAsyncLighting && (chunk.pendingLightUpdates.get() > 0 || chunk.world.getTime() - chunk.lightUpdateTime < 20)) {
+            return;
+        }
+        // Paper end
         if (this.world.worldProvider.c(i, j)) {
             // CraftBukkit start
             this.unloadQueue.add(i, j);
diff --git a/src/main/java/net/minecraft/server/World.java b/src/main/java/net/minecraft/server/World.java
index b1cf8cc..a062013 100644
--- a/src/main/java/net/minecraft/server/World.java
+++ b/src/main/java/net/minecraft/server/World.java
@@ -29,6 +29,12 @@ import org.bukkit.event.entity.CreatureSpawnEvent.SpawnReason;
 import org.bukkit.generator.ChunkGenerator;
 // CraftBukkit end
 
+// Paper start
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import com.google.common.util.concurrent.ThreadFactoryBuilder;
+// Paper end
+
 public abstract class World implements IBlockAccess {
 
     private int a = 63;
@@ -134,6 +140,7 @@ public abstract class World implements IBlockAccess {
     private org.spigotmc.TickLimiter entityLimiter;
     private org.spigotmc.TickLimiter tileLimiter;
     private int tileTickPosition;
+    public ExecutorService lightingExecutor = Executors.newSingleThreadExecutor(new ThreadFactoryBuilder().setNameFormat("Paper - Lighting Thread").build()); // Paper - Asynchronous lighting updates
 
     public CraftWorld getWorld() {
         return this.world;
@@ -476,7 +483,7 @@ public abstract class World implements IBlockAccess {
 
         if (!this.worldProvider.m()) {
             for (i1 = k; i1 <= l; ++i1) {
-                this.c(EnumSkyBlock.SKY, new BlockPosition(i, i1, j));
+                this.updateLight(EnumSkyBlock.SKY, new BlockPosition(i, i1, j)); // Paper - Asynchronous lighting updates
             }
         }
 
@@ -2244,10 +2251,10 @@ public abstract class World implements IBlockAccess {
         boolean flag = false;
 
         if (!this.worldProvider.m()) {
-            flag |= this.c(EnumSkyBlock.SKY, blockposition);
+            flag |= this.updateLight(EnumSkyBlock.SKY, blockposition); // Paper - Asynchronous lighting updates
         }
 
-        flag |= this.c(EnumSkyBlock.BLOCK, blockposition);
+        flag |= this.updateLight(EnumSkyBlock.BLOCK, blockposition); // Paper - Asynchronous lighting updates
         return flag;
     }
 
@@ -2297,10 +2304,15 @@ public abstract class World implements IBlockAccess {
         }
     }
 
+    // Paper start - Asynchronous lighting updates
     public boolean c(EnumSkyBlock enumskyblock, BlockPosition blockposition) {
+        return this.c(enumskyblock, blockposition, null, null);
+    }
+
+    public boolean c(EnumSkyBlock enumskyblock, BlockPosition blockposition, Chunk chunk, List<Chunk> neighbors) { // Paper
         // 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 {
@@ -2371,6 +2383,17 @@ public abstract class World implements IBlockAccess {
                 i = 0;
             }
 
+            // Paper start - Asynchronous light updates
+            if (chunk.world.paperConfig.useAsyncLighting) {
+                chunk.pendingLightUpdates.decrementAndGet();
+                if (neighbors != null) {
+                    for (Chunk neighbor : neighbors) {
+                        neighbor.pendingLightUpdates.decrementAndGet();
+                    }
+                }
+            }
+            // Paper end
+
             this.methodProfiler.b();
             this.methodProfiler.a("checkedPosition < toCheckCount");
 
@@ -2425,6 +2448,52 @@ public abstract class World implements IBlockAccess {
         }
     }
 
+    /**
+     * Paper - 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.areNeighborsLoaded(1)) {
+            return false;
+        }
+
+        if (!chunk.world.paperConfig.useAsyncLighting) {
+            return this.c(enumskyblock, position, chunk, null);
+        }
+
+        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 (cx != x >> 4 && cz != z >> 4) {
+                    Chunk neighbor = this.getChunkIfLoaded(cx, cz);
+                    if (neighbor != null) {
+                        neighbor.pendingLightUpdates.incrementAndGet();
+                        neighbor.lightUpdateTime = chunk.world.getTime();
+                        neighbors.add(neighbor);
+                    }
+                }
+            }
+        }
+
+        if (!Bukkit.isPrimaryThread()) {
+            return this.c(enumskyblock, position, chunk, neighbors);
+        }
+
+        lightingExecutor.submit(new Runnable() {
+            @Override
+            public void run() {
+                World.this.c(enumskyblock, position, chunk, neighbors);
+            }
+        });
+        return true;
+    }
+
     public boolean a(boolean flag) {
         return false;
     }
-- 
2.7.3