From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Zach Brown <zach.brown@destroystokyo.com>
Date: Sun, 22 May 2016 20:20:55 -0500
Subject: [PATCH] Optional TNT doesn't move in water


diff --git a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
index eb04fdb172a50ec1f5b7fe78fa0e7655246abd60..6eca3f300020006f02dd36253b522db442e3cc33 100644
--- a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
+++ b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
@@ -2,7 +2,6 @@ package com.destroystokyo.paper;
 
 import java.util.List;
 
-import org.bukkit.Bukkit;
 import org.bukkit.configuration.file.YamlConfiguration;
 import org.spigotmc.SpigotWorldConfig;
 
@@ -291,4 +290,14 @@ public class PaperWorldConfig {
             );
         }
     }
+
+    public boolean preventTntFromMovingInWater;
+    private void preventTntFromMovingInWater() {
+        if (PaperConfig.version < 13) {
+            boolean oldVal = getBoolean("enable-old-tnt-cannon-behaviors", false);
+            set("prevent-tnt-from-moving-in-water", oldVal);
+        }
+        preventTntFromMovingInWater = getBoolean("prevent-tnt-from-moving-in-water", false);
+        log("Prevent TNT from moving in water: " + preventTntFromMovingInWater);
+    }
 }
diff --git a/src/main/java/net/minecraft/server/level/ServerEntity.java b/src/main/java/net/minecraft/server/level/ServerEntity.java
index fa6893055fa5617742bfb4b7eff60c8139395cb6..49c71b21b6b88bc41ca6ddf4c76186ce522ee456 100644
--- a/src/main/java/net/minecraft/server/level/ServerEntity.java
+++ b/src/main/java/net/minecraft/server/level/ServerEntity.java
@@ -66,7 +66,7 @@ public class ServerEntity {
     private boolean wasRiding;
     private boolean wasOnGround;
     // CraftBukkit start
-    private final Set<ServerPlayer> trackedPlayers;
+    final Set<ServerPlayer> trackedPlayers; // Paper - private -> package
     // Paper start
     private java.util.Map<ServerPlayer, Boolean> trackedPlayerMap = null;
 
diff --git a/src/main/java/net/minecraft/world/entity/Entity.java b/src/main/java/net/minecraft/world/entity/Entity.java
index 171697e88f5a4d8c0be2a47b67b865bbdc4dfe8c..c3aece8e5001828edea304b2a8377e9a28b34cfe 100644
--- a/src/main/java/net/minecraft/world/entity/Entity.java
+++ b/src/main/java/net/minecraft/world/entity/Entity.java
@@ -2770,6 +2770,11 @@ public abstract class Entity implements Nameable, CommandSource, net.minecraft.s
     }
 
     public boolean isPushedByFluid() {
+        // Paper start
+        return this.pushedByWater();
+    }
+    public boolean pushedByWater() {
+        // Paper end
         return true;
     }
 
diff --git a/src/main/java/net/minecraft/world/entity/item/PrimedTnt.java b/src/main/java/net/minecraft/world/entity/item/PrimedTnt.java
index 661848084fd986321ef782317934dac19ed4dce3..347ac17643de8bcb0c8496c2ea5eb18c2e4d856b 100644
--- a/src/main/java/net/minecraft/world/entity/item/PrimedTnt.java
+++ b/src/main/java/net/minecraft/world/entity/item/PrimedTnt.java
@@ -5,9 +5,13 @@ import net.minecraft.core.particles.ParticleTypes;
 import net.minecraft.nbt.CompoundTag;
 import net.minecraft.network.protocol.Packet;
 import net.minecraft.network.protocol.game.ClientboundAddEntityPacket;
+import net.minecraft.network.protocol.game.ClientboundSetEntityMotionPacket;
+import net.minecraft.network.protocol.game.ClientboundTeleportEntityPacket;
 import net.minecraft.network.syncher.EntityDataAccessor;
 import net.minecraft.network.syncher.EntityDataSerializers;
 import net.minecraft.network.syncher.SynchedEntityData;
+import net.minecraft.server.level.ChunkMap;
+import net.minecraft.server.level.ServerLevel;
 import net.minecraft.world.entity.Entity;
 import net.minecraft.world.entity.EntityDimensions;
 import net.minecraft.world.entity.EntityType;
@@ -95,7 +99,27 @@ public class PrimedTnt extends Entity {
                 this.level.addParticle(ParticleTypes.SMOKE, this.getX(), this.getY() + 0.5D, this.getZ(), 0.0D, 0.0D, 0.0D);
             }
         }
-
+        // Paper start - Optional prevent TNT from moving in water
+        if (!this.removed && this.wasTouchingWater && this.level.paperConfig.preventTntFromMovingInWater) {
+            /*
+             * Author: Jedediah Smith <jedediah@silencegreys.com>
+             */
+            // Send position and velocity updates to nearby players on every tick while the TNT is in water.
+            // This does pretty well at keeping their clients in sync with the server.
+            ChunkMap.TrackedEntity ete = ((ServerLevel)this.level).getChunkSource().chunkMap.entityMap.get(this.getId());
+            if (ete != null) {
+                ClientboundSetEntityMotionPacket velocityPacket = new ClientboundSetEntityMotionPacket(this);
+                ClientboundTeleportEntityPacket positionPacket = new ClientboundTeleportEntityPacket(this);
+
+                ete.seenBy.stream()
+                    .filter(viewer -> (viewer.getX() - this.getX()) * (viewer.getY() - this.getY()) * (viewer.getZ() - this.getZ()) < 16 * 16)
+                    .forEach(viewer -> {
+                        viewer.connection.send(velocityPacket);
+                        viewer.connection.send(positionPacket);
+                    });
+            }
+        }
+        // Paper end
     }
 
     private void explode() {
@@ -164,4 +188,11 @@ public class PrimedTnt extends Entity {
     public Packet<?> getAddEntityPacket() {
         return new ClientboundAddEntityPacket(this);
     }
+
+    // Paper start - Optional prevent TNT from moving in water
+    @Override
+    public boolean pushedByWater() {
+        return !level.paperConfig.preventTntFromMovingInWater && super.pushedByWater();
+    }
+    // Paper end
 }