初步多线程支持

src/main/java/me/cortex/voxy/server/DirtyUpdateService.java

@@ -33,6 +33,17 @@ public class DirtyUpdateService {
             section.acquire();
             this.dirtyQueue.add(new DirtySection(world, section, updateFlags, neighborMsk));
             // Logger.info("Section dirty: " + section.lvl + " " + section.x + " " + section.y + " " + section.z);
+            int lvl = section.lvl;
+            int sx = section.x;
+            int sz = section.z;
+            int m = (1 << (lvl + 1)) - 1;
+            for (int dx = 0; dx <= m; dx++) {
+                for (int dz = 0; dz <= m; dz++) {
+                    int absX = (sx << (lvl + 1)) | dx;
+                    int absZ = (sz << (lvl + 1)) | dz;
+                    this.instance.getVisibleBandCache().invalidate(absX, absZ);
+                }
+            }
         }
     }
 
@@ -121,7 +132,8 @@ public class DirtyUpdateService {
                 int absZ = (int) it[1];
                 int minAbsY = (sy << (lvl + 1));
                 int maxAbsY = minAbsY + m;
-                int[] yList = VisibleBandUtil.computeVisibleBands(matchLevel, dirty.world, absX, absZ);
+                int[] yList = this.instance.getVisibleBandCache().getOrSchedule(matchLevel, dirty.world, absX, absZ);
+                if (yList == null) continue;
                 for (int i = 0; i < yList.length && perPlayerBudget > 0; i++) {
                     int absY = yList[i];
                     if (absY < minAbsY || absY > maxAbsY) continue;

src/main/java/me/cortex/voxy/server/PlayerLodTracker.java

@@ -109,8 +109,11 @@ public class PlayerLodTracker {
                 long key = (((long)x) << 32) ^ (z & 0xffffffffL);
                 var prog = state.sentColumns.computeIfAbsent(key, k -> new ColumnProgress());
                 if (prog.yList == null) {
-                    prog.yList = VisibleBandUtil.computeVisibleBands(level, engine, x, z);
-                    prog.nextIdx = 0;
+                    int[] ys = this.instance.getVisibleBandCache().getOrSchedule(level, engine, x, z);
+                    if (ys != null) {
+                        prog.yList = ys;
+                        prog.nextIdx = 0;
+                    }
                 }
                 // defer processing to global prioritized loop
             }
@@ -139,8 +142,13 @@ public class PlayerLodTracker {
                 var prog = state.sentColumns.get(key);
                 if (prog == null) continue;
                 if (prog.yList == null) {
-                    prog.yList = VisibleBandUtil.computeVisibleBands(level, engine, cx, cz);
-                    prog.nextIdx = 0;
+                    int[] ys = this.instance.getVisibleBandCache().getOrSchedule(level, engine, cx, cz);
+                    if (ys != null) {
+                        prog.yList = ys;
+                        prog.nextIdx = 0;
+                    } else {
+                        continue;
+                    }
                 }
                 budget.addAndGet(-processVerticalList(player, engine, cx, cz, prog, budget.get()));
             }

src/main/java/me/cortex/voxy/server/VisibleBandCache.java

@@ -0,0 +1,39 @@
+package me.cortex.voxy.server;
+
+import me.cortex.voxy.common.world.WorldEngine;
+import net.minecraft.server.level.ServerLevel;
+
+import java.util.concurrent.ConcurrentHashMap;
+
+final class VisibleBandCache {
+    private final VoxyServerInstance instance;
+    private final ConcurrentHashMap<Long, int[]> cache = new ConcurrentHashMap<>();
+    private final ConcurrentHashMap<Long, Boolean> pending = new ConcurrentHashMap<>();
+
+    VisibleBandCache(VoxyServerInstance instance) {
+        this.instance = instance;
+    }
+
+    int[] getOrSchedule(ServerLevel level, WorldEngine engine, int chunkX, int chunkZ) {
+        long key = (((long) chunkX) << 32) ^ (chunkZ & 0xffffffffL);
+        int[] ys = cache.get(key);
+        if (ys != null) return ys;
+        if (pending.putIfAbsent(key, Boolean.TRUE) == null) {
+            this.instance.getThreadPool().execute(() -> {
+                try {
+                    int[] result = VisibleBandUtil.computeVisibleBands(level, engine, chunkX, chunkZ);
+                    cache.put(key, result);
+                } finally {
+                    pending.remove(key);
+                }
+            });
+        }
+        return null;
+    }
+
+    void invalidate(int chunkX, int chunkZ) {
+        long key = (((long) chunkX) << 32) ^ (chunkZ & 0xffffffffL);
+        cache.remove(key);
+        pending.remove(key);
+    }
+}

src/main/java/me/cortex/voxy/server/VoxyServerInstance.java

@@ -21,6 +21,7 @@ public class VoxyServerInstance extends VoxyInstance {
 
     private final DirtyUpdateService dirtyUpdateService;
     private final PlayerLodTracker playerLodTracker;
+    private final VisibleBandCache visibleBandCache;
 
     public VoxyServerInstance(MinecraftServer server) {
         super();
@@ -35,6 +36,7 @@ public class VoxyServerInstance extends VoxyInstance {
         
         this.dirtyUpdateService = new DirtyUpdateService(this);
         this.playerLodTracker = new PlayerLodTracker(this);
+        this.visibleBandCache = new VisibleBandCache(this);
         
         // Start a service to tick the dirty service
         this.threadPool.serviceManager.createServiceNoCleanup(() -> this.dirtyUpdateService::tick, VoxyServerConfig.CONFIG.dirtyUpdateDelay * 50, "DirtyUpdateService");
@@ -110,4 +112,8 @@ public class VoxyServerInstance extends VoxyInstance {
     public UnifiedServiceThreadPool getThreadPool() {
         return this.threadPool;
     }
+    
+    VisibleBandCache getVisibleBandCache() {
+        return this.visibleBandCache;
+    }
 }