SakuraMC/patches/server/0017-Replace-explosion-density-cache.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Samsuik <kfian294ma4@gmail.com>
Date: Mon, 22 Apr 2024 23:01:26 +0100
Subject: [PATCH] Replace explosion density cache


diff --git a/src/main/java/me/samsuik/sakura/explosion/density/BlockDensityCache.java b/src/main/java/me/samsuik/sakura/explosion/density/BlockDensityCache.java
new file mode 100644
index 0000000000000000000000000000000000000000..35454e122e87892099226ba8fd8d444664be9037
--- /dev/null
+++ b/src/main/java/me/samsuik/sakura/explosion/density/BlockDensityCache.java
@@ -0,0 +1,62 @@
+package me.samsuik.sakura.explosion.density;
+
+import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap;
+import net.minecraft.util.Mth;
+import net.minecraft.world.entity.Entity;
+import net.minecraft.world.phys.Vec3;
+
+/**
+ * This is a replacement for papers explosion density cache to be more lenient and efficient.
+ */
+public final class BlockDensityCache {
+    public static final float UNKNOWN_DENSITY = -1.0f;
+
+    private final Int2ObjectOpenHashMap<DensityData> densityDataMap = new Int2ObjectOpenHashMap<>();
+    private DensityData data;
+    private int key;
+    private boolean knownSource;
+
+    public float getDensity(Vec3 explosion, Entity entity) {
+        int key = getKey(explosion, entity);
+        DensityData data = this.densityDataMap.get(key);
+
+        if (data != null && data.hasPosition(explosion, entity.getBoundingBox())) {
+            return data.density();
+        } else {
+            this.knownSource = data != null && data.complete() && data.isExplosionPosition(explosion);
+            this.data = data;
+            this.key = key;
+            return UNKNOWN_DENSITY;
+        }
+    }
+
+    public float getKnownDensity(Vec3 point) {
+        if (this.knownSource && this.data.isKnownPosition(point)) {
+            return this.data.density();
+        } else {
+            return UNKNOWN_DENSITY;
+        }
+    }
+
+    public void putDensity(Vec3 explosion, Entity entity, float density) {
+        if (this.data == null || !this.data.complete()) {
+            this.densityDataMap.put(this.key, new DensityData(explosion, entity, density));
+        } else if (this.data.density() == density) {
+            this.data.expand(explosion, entity);
+        }
+    }
+
+    public void invalidate() {
+        this.densityDataMap.clear();
+    }
+
+    private static int getKey(Vec3 explosion, Entity entity) {
+        int key        = Mth.floor(explosion.x());
+        key = 31 * key + Mth.floor(explosion.y());
+        key = 31 * key + Mth.floor(explosion.z());
+        key = 31 * key + entity.getBlockX();
+        key = 31 * key + entity.getBlockY();
+        key = 31 * key + entity.getBlockZ();
+        return key;
+    }
+}
diff --git a/src/main/java/me/samsuik/sakura/explosion/density/DensityData.java b/src/main/java/me/samsuik/sakura/explosion/density/DensityData.java
new file mode 100644
index 0000000000000000000000000000000000000000..d7e24638f07f243502004970ab4ce646cbe1e436
--- /dev/null
+++ b/src/main/java/me/samsuik/sakura/explosion/density/DensityData.java
@@ -0,0 +1,47 @@
+package me.samsuik.sakura.explosion.density;
+
+import net.minecraft.world.entity.Entity;
+import net.minecraft.world.phys.AABB;
+import net.minecraft.world.phys.Vec3;
+
+public final class DensityData {
+    private AABB source;
+    private AABB known;
+    private AABB entity;
+    private final float density;
+    private final boolean complete;
+
+    public DensityData(Vec3 explosion, Entity entity, float density) {
+        this.source = new AABB(explosion, explosion);
+        this.known = new AABB(entity.position(), entity.position());
+        this.entity = entity.getBoundingBox();
+        this.density = density;
+        this.complete = Math.abs(density - 0.5f) == 0.5f;
+    }
+
+    public float density() {
+        return this.density;
+    }
+
+    public boolean complete() {
+        return this.complete;
+    }
+
+    public boolean hasPosition(Vec3 explosion, AABB entity) {
+        return this.isExplosionPosition(explosion) && this.entity.isAABBInBounds(entity);
+    }
+
+    public boolean isKnownPosition(Vec3 point) {
+        return this.entity.isVec3InBounds(point);
+    }
+
+    public boolean isExplosionPosition(Vec3 explosion) {
+        return this.source.isVec3InBounds(explosion);
+    }
+
+    public void expand(Vec3 explosion, Entity entity) {
+        this.source = this.source.expand(explosion);
+        this.known  = this.known.expand(entity.position());
+        this.entity = this.entity.minmax(entity.getBoundingBox());
+    }
+}
diff --git a/src/main/java/net/minecraft/server/MinecraftServer.java b/src/main/java/net/minecraft/server/MinecraftServer.java
index c871ef194962d1fc574a8d3d9f27dd817ead5fc9..31dd38d80c648e3f946c123878529b3393be5a91 100644
--- a/src/main/java/net/minecraft/server/MinecraftServer.java
+++ b/src/main/java/net/minecraft/server/MinecraftServer.java
@@ -1891,6 +1891,7 @@ public abstract class MinecraftServer extends ReentrantBlockableEventLoop<TickTa
             gameprofilerfiller.pop();
             worldserver.localConfig().expire(currentTick); // Sakura - add local config
             worldserver.mergeHandler.expire(currentTick); // Sakura - merge cannon entities
+            worldserver.densityCache.invalidate(); // Sakura - explosion density cache
         }
         this.isIteratingOverLevels = false; // Paper - Throw exception on world create while being ticked
 
diff --git a/src/main/java/net/minecraft/world/level/Level.java b/src/main/java/net/minecraft/world/level/Level.java
index d036cdcc17b8429c986946a020cb34cd6ced322e..b45ad0125cd5c116126e8ffb893585970ea3b960 100644
--- a/src/main/java/net/minecraft/world/level/Level.java
+++ b/src/main/java/net/minecraft/world/level/Level.java
@@ -842,6 +842,7 @@ public abstract class Level implements LevelAccessor, AutoCloseable, ca.spottedl
     }
     // Paper end - optimise random ticking
     public final me.samsuik.sakura.entity.merge.EntityMergeHandler mergeHandler = new me.samsuik.sakura.entity.merge.EntityMergeHandler(); // Sakura - merge cannon entities
+    public final me.samsuik.sakura.explosion.density.BlockDensityCache densityCache = new me.samsuik.sakura.explosion.density.BlockDensityCache(); // Sakura - explosion density cache
 
     protected Level(WritableLevelData worlddatamutable, ResourceKey<Level> resourcekey, RegistryAccess iregistrycustom, Holder<DimensionType> holder, boolean flag, boolean flag1, long i, int j, org.bukkit.generator.ChunkGenerator gen, org.bukkit.generator.BiomeProvider biomeProvider, org.bukkit.World.Environment env, java.util.function.Function<org.spigotmc.SpigotWorldConfig, io.papermc.paper.configuration.WorldConfiguration> paperWorldConfigCreator, java.util.function.Supplier<me.samsuik.sakura.configuration.WorldConfiguration> sakuraWorldConfigCreator, java.util.concurrent.Executor executor) { // Sakura - sakura configuration files // Paper - create paper world config & Anti-Xray
         // Paper start - getblock optimisations - cache world height/sections
diff --git a/src/main/java/net/minecraft/world/level/ServerExplosion.java b/src/main/java/net/minecraft/world/level/ServerExplosion.java
index a92be80081178cc302a7f0b646bad7daa28f7c66..10432b31acd047ac2aa8581f2ee863254ec8d1eb 100644
--- a/src/main/java/net/minecraft/world/level/ServerExplosion.java
+++ b/src/main/java/net/minecraft/world/level/ServerExplosion.java
@@ -297,7 +297,12 @@ public class ServerExplosion implements Explosion {
                             Math.fma(dz, diffZ, offZ)
                     );
 
-                    if (!this.clipsAnything(from, source, context, blockCache, blockPos)) {
+                    // Sakura start - replace density cache
+                    final float density = this.level.densityCache.getKnownDensity(from);
+                    if (density != me.samsuik.sakura.explosion.density.BlockDensityCache.UNKNOWN_DENSITY) {
+                        missedRays += (int) density;
+                    } else if (!this.clipsAnything(from, source, context, blockCache, blockPos)) {
+                        // Sakura end - replace density cache
                         ++missedRays;
                     }
                 }
@@ -377,7 +382,16 @@ public class ServerExplosion implements Explosion {
                         double d10 = Mth.lerp(d7, axisalignedbb.minZ, axisalignedbb.maxZ);
                         Vec3 vec3d1 = new Vec3(d8 + d3, d9, d10 + d4);
 
-                        if (entity.level().clip(new ClipContext(vec3d1, pos, ClipContext.Block.COLLIDER, ClipContext.Fluid.NONE, entity)).getType() == HitResult.Type.MISS) {
+                        // Sakura start - replace density cache
+                        final net.minecraft.world.phys.HitResult.Type hitResult;
+                        final float density = entity.level().densityCache.getKnownDensity(vec3d1);
+                        if (density != me.samsuik.sakura.explosion.density.BlockDensityCache.UNKNOWN_DENSITY) {
+                            hitResult = density != 0.0f ? net.minecraft.world.phys.HitResult.Type.MISS : net.minecraft.world.phys.HitResult.Type.BLOCK;
+                        } else {
+                            hitResult = entity.level().clip(new ClipContext(vec3d1, pos, ClipContext.Block.COLLIDER, ClipContext.Fluid.NONE, entity)).getType();
+                        }
+                        if (hitResult == HitResult.Type.MISS) {
+                            // Sakura end - replace density cache
                             ++i;
                         }
 
@@ -691,6 +705,12 @@ public class ServerExplosion implements Explosion {
             return;
         }
         // CraftBukkit end
+        // Sakura start - explosion density cache
+        if (!positions.isEmpty() && !this.level.paperConfig().environment.optimizeExplosions) {
+            this.level.densityCache.invalidate();
+        }
+        // Sakura end - explosion density cache
+
         Iterator iterator = positions.iterator();
 
         while (iterator.hasNext()) {
@@ -864,14 +884,12 @@ public class ServerExplosion implements Explosion {
 
     // Paper start - Optimize explosions
     private float getBlockDensity(Vec3 vec3d, Entity entity) {
-        if (!this.level.paperConfig().environment.optimizeExplosions) {
-            return this.getSeenFraction(vec3d, entity, this.directMappedBlockCache, this.mutablePos); // Paper - collision optimisations
-        }
-        CacheKey key = new CacheKey(this, entity.getBoundingBox());
-        Float blockDensity = this.level.explosionDensityCache.get(key);
-        if (blockDensity == null) {
+        // Sakura start - replace density cache
+        float blockDensity = this.level.densityCache.getDensity(vec3d, entity);
+        if (blockDensity == me.samsuik.sakura.explosion.density.BlockDensityCache.UNKNOWN_DENSITY) {
             blockDensity = this.getSeenFraction(vec3d, entity, this.directMappedBlockCache, this.mutablePos); // Paper - collision optimisations
-            this.level.explosionDensityCache.put(key, blockDensity);
+            this.level.densityCache.putDensity(vec3d, entity, blockDensity);
+            // Sakura end - replace density cache
         }
 
         return blockDensity;
diff --git a/src/main/java/net/minecraft/world/level/block/BasePressurePlateBlock.java b/src/main/java/net/minecraft/world/level/block/BasePressurePlateBlock.java
index c2eb63de04fc48bd2cc1aad8d9cba272c0829c80..0d9f944a3777ac3a0f569832468c5c97b0fdf488 100644
--- a/src/main/java/net/minecraft/world/level/block/BasePressurePlateBlock.java
+++ b/src/main/java/net/minecraft/world/level/block/BasePressurePlateBlock.java
@@ -109,6 +109,11 @@ public abstract class BasePressurePlateBlock extends Block {
         if (output != j) {
             BlockState iblockdata1 = this.setSignalForState(state, j);
 
+            // Sakura start - explosion density cache
+            if (!world.paperConfig().environment.optimizeExplosions) {
+                world.densityCache.invalidate();
+            }
+            // Sakura end - explosion density cache
             world.setBlock(pos, iblockdata1, 2);
             this.updateNeighbours(world, pos);
             world.setBlocksDirty(pos, state, iblockdata1);
diff --git a/src/main/java/net/minecraft/world/level/block/TripWireHookBlock.java b/src/main/java/net/minecraft/world/level/block/TripWireHookBlock.java
index c2589f42c467ca672417c24076313da51bb2dcbb..5ae5ef6edf3a6e2b8be9ce11ca46c7714accc4f3 100644
--- a/src/main/java/net/minecraft/world/level/block/TripWireHookBlock.java
+++ b/src/main/java/net/minecraft/world/level/block/TripWireHookBlock.java
@@ -175,6 +175,11 @@ public class TripWireHookBlock extends Block {
                 blockposition1 = pos.relative(enumdirection, j);
                 Direction enumdirection1 = enumdirection.getOpposite();
 
+                // Sakura start - explosion density cache
+                if (!world.paperConfig().environment.optimizeExplosions) {
+                    world.densityCache.invalidate();
+                }
+                // Sakura end - explosion density cache
                 world.setBlock(blockposition1, (BlockState) iblockdata3.setValue(TripWireHookBlock.FACING, enumdirection1), 3);
                 TripWireHookBlock.notifyNeighbors(block, world, blockposition1, enumdirection1);
                 TripWireHookBlock.emitState(world, blockposition1, flag4, flag5, flag2, flag3);
diff --git a/src/main/java/net/minecraft/world/phys/AABB.java b/src/main/java/net/minecraft/world/phys/AABB.java
index 6cf6d4ec7b9e43c7b2b4c0e2fb080964ff588130..a867ec0347038c7246af3f3377eceda17e695ec3 100644
--- a/src/main/java/net/minecraft/world/phys/AABB.java
+++ b/src/main/java/net/minecraft/world/phys/AABB.java
@@ -551,4 +551,28 @@ public class AABB {
     public static AABB ofSize(Vec3 center, double dx, double dy, double dz) {
         return new AABB(center.x - dx / 2.0, center.y - dy / 2.0, center.z - dz / 2.0, center.x + dx / 2.0, center.y + dy / 2.0, center.z + dz / 2.0);
     }
+
+    // Sakura start - explosion density cache
+    public final boolean isAABBInBounds(AABB bb) {
+        return this.minX <= bb.minX && this.maxX >= bb.maxX
+            && this.minY <= bb.minY && this.maxY >= bb.maxY
+            && this.minZ <= bb.minZ && this.maxZ >= bb.maxZ;
+    }
+
+    public final boolean isVec3InBounds(Vec3 p) {
+        return this.minX <= p.x && this.maxX >= p.x
+            && this.minY <= p.y && this.maxY >= p.y
+            && this.minZ <= p.z && this.maxZ >= p.z;
+    }
+
+    public final AABB expand(Vec3 pos) {
+        double minX = Math.min(this.minX, pos.x);
+        double minY = Math.min(this.minY, pos.y);
+        double minZ = Math.min(this.minZ, pos.z);
+        double maxX = Math.max(this.maxX, pos.x);
+        double maxY = Math.max(this.maxY, pos.y);
+        double maxZ = Math.max(this.maxZ, pos.z);
+        return new AABB(minX, minY, minZ, maxX, maxY, maxZ);
+    }
+    // Sakura end - explosion density cache
 }