Paper/Spigot-Server-Patches/0031-Lighting-Queue.patch

From cf551879a447edab9e7fbbdbe01190b3663ad0dc Mon Sep 17 00:00:00 2001
From: Byteflux <byte@byteflux.net>
Date: Wed, 2 Mar 2016 00:52:31 -0600
Subject: [PATCH] Lighting Queue


diff --git a/src/main/java/co/aikar/timings/MinecraftTimings.java b/src/main/java/co/aikar/timings/MinecraftTimings.java
index 0f8315c..5afdc2c 100644
--- a/src/main/java/co/aikar/timings/MinecraftTimings.java
+++ b/src/main/java/co/aikar/timings/MinecraftTimings.java
@@ -17,6 +17,7 @@ public final class MinecraftTimings {
     public static final Timing timeUpdateTimer = Timings.ofSafe("Time Update");
     public static final Timing serverCommandTimer = Timings.ofSafe("Server Command");
     public static final Timing worldSaveTimer = Timings.ofSafe("World Save");
+    public static final Timing lightingQueueTimer = Timings.ofSafe("Lighting Queue");
 
     public static final Timing tickEntityTimer = Timings.ofSafe("## tickEntity");
     public static final Timing tickTileEntityTimer = Timings.ofSafe("## tickTileEntity");
diff --git a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
index 7c0e61f..8e3a0f3 100644
--- a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
+++ b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
@@ -155,4 +155,10 @@ public class PaperWorldConfig {
         netherVoidTopDamage = getBoolean( "nether-ceiling-void-damage", false );
         log("Top of the nether void damage: " + netherVoidTopDamage);
     }
+
+    public boolean queueLightUpdates;
+    private void queueLightUpdates() {
+        queueLightUpdates = getBoolean("queue-light-updates", false);
+        log("Lighting Queue enabled: " + queueLightUpdates);
+    }
 }
diff --git a/src/main/java/net/minecraft/server/Chunk.java b/src/main/java/net/minecraft/server/Chunk.java
index cde4124..3b5e8c2 100644
--- a/src/main/java/net/minecraft/server/Chunk.java
+++ b/src/main/java/net/minecraft/server/Chunk.java
@@ -44,6 +44,7 @@ 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
+    public int lightUpdates; // Paper - Number of queued light updates for this chunk
 
     // CraftBukkit start - Neighbor loaded cache for chunk lighting and entity ticking
     private int neighbors = 0x1 << 12;
@@ -226,6 +227,22 @@ public class Chunk {
     private void h(boolean flag) {
         this.world.methodProfiler.a("recheckGaps");
         if (this.world.areChunksLoaded(new BlockPosition(this.locX * 16 + 8, 0, this.locZ * 16 + 8), 16)) {
+            // Paper start - Queue light update
+            if (!world.paperConfig.queueLightUpdates) {
+                recheckGaps(flag);
+            } else {
+                ++lightUpdates;
+                world.getServer().getServer().lightingQueue.add(() -> {
+                    recheckGaps(flag);
+                    --lightUpdates;
+                });
+            }
+        }
+    }
+
+    private void recheckGaps(boolean flag) {
+        if (true) {
+            // Paper end
             for (int i = 0; i < 16; ++i) {
                 for (int j = 0; j < 16; ++j) {
                     if (this.h[i + j * 16]) {
@@ -476,7 +493,7 @@ public class Chunk {
             } else {
                 if (flag) {
                     this.initLighting();
-                } else {
+                } else if (!world.paperConfig.queueLightUpdates) { // Paper
                     int j1 = iblockdata.c();
                     int k1 = iblockdata1.c();
 
@@ -491,6 +508,28 @@ public class Chunk {
                     if (j1 != k1 && (j1 < k1 || this.getBrightness(EnumSkyBlock.SKY, blockposition) > 0 || this.getBrightness(EnumSkyBlock.BLOCK, blockposition) > 0)) {
                         this.d(i, k);
                     }
+                    // Paper start - Queue light update
+                } else {
+                    int j1 = iblockdata.c();
+                    int k1 = iblockdata1.c();
+
+                    ++lightUpdates;
+                    world.getServer().getServer().lightingQueue.add(() -> {
+                        if (j1 > 0) {
+                            if (j >= i1) {
+                                this.c(i, j + 1, k);
+                            }
+                        } else if (j == i1 - 1) {
+                            this.c(i, j, k);
+                        }
+
+                        if (j1 != k1 && (j1 < k1 || this.getBrightness(EnumSkyBlock.SKY, blockposition) > 0 || this.getBrightness(EnumSkyBlock.BLOCK, blockposition) > 0)) {
+                            this.d(i, k);
+                        }
+
+                        --lightUpdates;
+                    });
+                    // Paper end
                 }
 
                 TileEntity tileentity;
@@ -1314,4 +1353,29 @@ public class Chunk {
 
         private EnumTileEntityState() {}
     }
+
+    // Paper start
+    public boolean hasLightUpdates() {
+        if (world.paperConfig.queueLightUpdates) {
+            if (lightUpdates > 0) {
+                return true;
+            }
+
+            for (int x = locX - 2; x <= locX + 2; ++x) {
+                for (int z = locZ - 2; z <= locZ + 2; ++z) {
+                    if ((x == 0 && z == 0) || (x == locX && z == locZ)) {
+                        continue;
+                    }
+
+                    Chunk chunk = world.getChunkIfLoaded(x, z);
+                    if (chunk != null && chunk.lightUpdates > 0) {
+                        return true;
+                    }
+                }
+            }
+        }
+
+        return false;
+    }
+    // Paper end
 }
diff --git a/src/main/java/net/minecraft/server/ChunkProviderServer.java b/src/main/java/net/minecraft/server/ChunkProviderServer.java
index 7d3adde..54c83f3 100644
--- a/src/main/java/net/minecraft/server/ChunkProviderServer.java
+++ b/src/main/java/net/minecraft/server/ChunkProviderServer.java
@@ -288,6 +288,7 @@ public class ChunkProviderServer implements IChunkProvider {
                 long chunkcoordinates = this.unloadQueue.popFirst();
                 Chunk chunk = this.chunks.get(chunkcoordinates);
                 if (chunk == null) continue;
+                if (chunk.hasLightUpdates()) continue; // Paper - Don't unload chunks with pending light updates.
 
                 ChunkUnloadEvent event = new ChunkUnloadEvent(chunk.bukkitChunk);
                 server.getPluginManager().callEvent(event);
diff --git a/src/main/java/net/minecraft/server/MinecraftServer.java b/src/main/java/net/minecraft/server/MinecraftServer.java
index cd784a0..75f2605 100644
--- a/src/main/java/net/minecraft/server/MinecraftServer.java
+++ b/src/main/java/net/minecraft/server/MinecraftServer.java
@@ -47,6 +47,11 @@ import org.bukkit.craftbukkit.CraftServer;
 // CraftBukkit end
 import co.aikar.timings.MinecraftTimings; // Paper
 
+// Paper start
+import java.util.LinkedList;
+import java.util.Queue;
+// Paper end
+
 public abstract class MinecraftServer implements Runnable, ICommandListener, IAsyncTaskHandler, IMojangStatistics {
 
     public static final Logger LOGGER = LogManager.getLogger();
@@ -113,6 +118,7 @@ public abstract class MinecraftServer implements Runnable, ICommandListener, IAs
     public final Thread primaryThread;
     public java.util.Queue<Runnable> processQueue = new java.util.concurrent.ConcurrentLinkedQueue<Runnable>();
     public int autosavePeriod;
+    public final Queue<Runnable> lightingQueue = new LinkedList<Runnable>(); // Paper - Queued light updates
     // CraftBukkit end
 
     public MinecraftServer(OptionSet options, Proxy proxy, DataConverterManager dataconvertermanager, YggdrasilAuthenticationService yggdrasilauthenticationservice, MinecraftSessionService minecraftsessionservice, GameProfileRepository gameprofilerepository, UserCache usercache) {
@@ -760,6 +766,34 @@ public abstract class MinecraftServer implements Runnable, ICommandListener, IAs
         this.methodProfiler.b();
         this.methodProfiler.b();
 
+        // Paper start - Flush light updates
+        if (!lightingQueue.isEmpty()) {
+            MinecraftTimings.lightingQueueTimer.startTiming();
+
+            int updatesThisTick = 0;
+            long cachedTime = System.currentTimeMillis();
+            long startTime = cachedTime - (this.h[this.ticks % 100] / 1000000);
+            int maxTickTimeCap = MathHelper.floor((TICK_TIME / 1000000) * 0.8);
+            int maxTickTime = Math.max(0, (int) (maxTickTimeCap - (cachedTime - startTime)));
+            Runnable lightUpdate;
+
+            while (maxTickTime > 0 && (lightUpdate = lightingQueue.poll()) != null) {
+                lightUpdate.run();
+                if (++updatesThisTick % 10 == 0) {
+                    long currentTime = System.currentTimeMillis();
+                    if (currentTime - cachedTime > maxTickTime) {
+                        break;
+                    }
+
+                    cachedTime = currentTime;
+                    maxTickTime = Math.max(0, (int) (maxTickTimeCap - (currentTime - startTime)));
+                }
+            }
+
+            MinecraftTimings.lightingQueueTimer.stopTiming();
+        }
+        // Paper end
+
         org.spigotmc.WatchdogThread.tick(); // Spigot
         co.aikar.timings.TimingsManager.FULL_SERVER_TICK.stopTiming(); // Paper
     }
diff --git a/src/main/java/net/minecraft/server/World.java b/src/main/java/net/minecraft/server/World.java
index 3b84e27..1793995 100644
--- a/src/main/java/net/minecraft/server/World.java
+++ b/src/main/java/net/minecraft/server/World.java
@@ -379,7 +379,17 @@ public abstract class World implements IBlockAccess {
             } else {
                 if (iblockdata.c() != iblockdata1.c() || iblockdata.d() != iblockdata1.d()) {
                     this.methodProfiler.a("checkLight");
-                    this.w(blockposition);
+                    // Paper start - Queue light update
+                    if (!paperConfig.queueLightUpdates) {
+                        this.w(blockposition);
+                    } else {
+                        ++chunk.lightUpdates;
+                        getMinecraftServer().lightingQueue.add(() -> {
+                            this.w(blockposition);
+                            --chunk.lightUpdates;
+                        });
+                    }
+                    // Paper end
                     this.methodProfiler.b();
                 }
 
-- 
2.8.1