stamps and notes

src/main/java/me/cortex/voxy/client/core/rendering/SectionUpdateRouter.java

@@ -4,18 +4,21 @@ import it.unimi.dsi.fastutil.longs.Long2ByteOpenHashMap;
 import me.cortex.voxy.common.world.WorldEngine;
 import me.cortex.voxy.common.world.WorldSection;
 
+import java.util.concurrent.locks.StampedLock;
 import java.util.function.LongConsumer;
 
 import static me.cortex.voxy.common.world.WorldEngine.UPDATE_TYPE_BLOCK_BIT;
 
 public class SectionUpdateRouter implements ISectionWatcher {
-    private static final int SLICES = 1<<8;
+    private static final int SLICES = 1<<4;
     public interface IChildUpdate {void accept(WorldSection section);}
 
     private final Long2ByteOpenHashMap[] slices = new Long2ByteOpenHashMap[SLICES];
+    private final StampedLock[] locks = new StampedLock[SLICES];
     {
         for (int i = 0; i < this.slices.length; i++) {
             this.slices[i] = new Long2ByteOpenHashMap();
+            this.locks[i] = new StampedLock();
         }
     }
 
@@ -35,17 +38,34 @@ public class SectionUpdateRouter implements ISectionWatcher {
     }
 
     public boolean watch(long position, int types) {
-        var set = this.slices[getSliceIndex(position)];
+        int idx = getSliceIndex(position);
+        var set = this.slices[idx];
+        var lock = this.locks[idx];
         byte delta = 0;
-        synchronized (set) {
-            byte current = 0;
-            if (set.containsKey(position)) {
-                current = set.get(position);
-            }
+        {
+            long stamp = lock.readLock();
+            byte current = set.getOrDefault(position, (byte) 0);
             delta = (byte) (current&types);
             current |= (byte) types;
             delta ^= (byte) (current&types);
+            if (delta != 0) {//Was change
+                long ws = lock.tryConvertToWriteLock(stamp);
+                if (ws == 0) {
+                    lock.unlockRead(stamp);
+                    stamp = lock.writeLock();
+                    //We need to recompute as we failed to acquire an immediate write lock
+                    current = set.getOrDefault(position, (byte) 0);
+                    delta = (byte) (current&types);
+                    current |= (byte) types;
+                    delta ^= (byte) (current&types);
+                    if (delta != 0)
                         set.put(position, current);
+                } else {
+                    stamp = ws;
+                    set.put(position, current);
+                }
+            }
+            lock.unlock(stamp);
         }
         if ((delta&UPDATE_TYPE_BLOCK_BIT)!=0) {
             //If we added it, immediately invoke for an update
@@ -58,38 +78,67 @@ public class SectionUpdateRouter implements ISectionWatcher {
         return this.unwatch(WorldEngine.getWorldSectionId(lvl, x, y, z), types);
     }
 
-    public boolean unwatch(long position, int types) {
-        var set = this.slices[getSliceIndex(position)];
-        synchronized (set) {
-            if (!set.containsKey(position)) {
-                throw new IllegalStateException("Section pos not in map!! " + WorldEngine.pprintPos(position));
+    public boolean unwatch(long position, int types) {//Types is types to unwatch
+        int idx = getSliceIndex(position);
+        var set = this.slices[idx];
+        var lock = this.locks[idx];
+
+        long stamp = lock.readLock();
+
+        byte current = set.getOrDefault(position, (byte)0);
+        if (current == 0) {
+            throw new IllegalStateException("Section pos not in map " + WorldEngine.pprintPos(position));
         }
-            byte current = set.get(position);
-            byte delta = (byte) (current&types);
+        boolean removed = false;
+        if ((current&types) != 0) {//Was change
+            long ws = lock.tryConvertToWriteLock(stamp);
+            if (ws == 0) {//failed to get write lock, need to unlock, get write, then redo
+                lock.unlockRead(stamp);
+                stamp = lock.writeLock();
+
+                current = set.getOrDefault(position, (byte)0);
+                if (current == 0) {
+                    throw new IllegalStateException("Section pos not in map " + WorldEngine.pprintPos(position));
+                }
+            } else {
+                stamp = ws;
+            }
+
+            if ((current&types) != 0) {
                 current &= (byte) ~types;
                 if (current == 0) {
                     set.remove(position);
-                return true;
-            }
+                    removed = true;
+                } else {
                     set.put(position, current);
-            return false;
                 }
             }
+        }
+        lock.unlock(stamp);
+        return removed;
+    }
 
     public int get(long position) {
-        var set = this.slices[getSliceIndex(position)];
-        synchronized (set) {
-            return set.getOrDefault(position, (byte) 0);
-        }
+        int idx = getSliceIndex(position);
+        var set = this.slices[idx];
+        var lock = this.locks[idx];
+        long stamp = lock.readLock();
+        int ret = set.getOrDefault(position, (byte) 0);
+        lock.unlockRead(stamp);
+        return ret;
     }
 
     public void forwardEvent(WorldSection section, int type) {
         final long position = section.key;
-        var set = this.slices[getSliceIndex(position)];
-        byte types = 0;
-        synchronized (set) {
-            types = set.getOrDefault(position, (byte)0);
-        }
+
+        int idx = getSliceIndex(position);
+        var set = this.slices[idx];
+        var lock = this.locks[idx];
+
+        long stamp = lock.readLock();
+        byte types = set.getOrDefault(position, (byte) 0);
+        lock.unlockRead(stamp);
+
         if (types!=0) {
             if ((type&WorldEngine.UPDATE_TYPE_CHILD_EXISTENCE_BIT)!=0) {
                 this.childUpdateCallback.accept(section);

src/main/java/me/cortex/voxy/client/core/rendering/building/RenderDataFactory45.java

@@ -331,6 +331,7 @@ public class RenderDataFactory45 {
         }
     }
 
+    //TODO: add neighbor face culling
     private void generateYZOpaqueInnerGeometry(int axis) {
         for (int layer = 0; layer < 31; layer++) {
             this.blockMesher.auxiliaryPosition = layer;

src/main/java/me/cortex/voxy/common/config/storage/inmemory/MemoryStorageBackend.java

@@ -16,6 +16,7 @@ import org.lwjgl.system.MemoryUtil;
 import java.nio.ByteBuffer;
 import java.util.function.LongConsumer;
 
+//TODO: replace synchronize with StampedLock
 public class MemoryStorageBackend extends StorageBackend {
     private final Long2ObjectMap<MemoryBuffer>[] maps;
     private final Int2ObjectMap<ByteBuffer> idMappings = new Int2ObjectOpenHashMap<>();

src/main/java/me/cortex/voxy/common/world/ActiveSectionTracker.java

@@ -18,7 +18,7 @@ public class ActiveSectionTracker {
     //Loaded section world cache, TODO: get rid of VolatileHolder and use something more sane
 
     private final Long2ObjectOpenHashMap<VolatileHolder<WorldSection>>[] loadedSectionCache;
-    private final ReentrantLock[] locks;
+    private final ReentrantLock[] locks;//TODO: replace with StampedLocks
     private final SectionLoader loader;
 
     private final int lruSize;