From 0e76f067787f47458049e16499ba476dbac629e5 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 fbe769eb3..d2a542354 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;
 
@@ -327,4 +326,14 @@ 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/Entity.java b/src/main/java/net/minecraft/server/Entity.java
index 14b6439c2..724e85aa3 100644
--- a/src/main/java/net/minecraft/server/Entity.java
+++ b/src/main/java/net/minecraft/server/Entity.java
@@ -1108,6 +1108,11 @@ public abstract class Entity implements ICommandListener {
     }
 
     public boolean aq() {
+        return this.doWaterMovement();
+    }
+
+    public boolean doWaterMovement() {
+        // Paper end
         if (this.bJ() instanceof EntityBoat) {
             this.inWater = false;
         } else if (this.world.a(this.getBoundingBox().grow(0.0D, -0.4000000059604645D, 0.0D).shrink(0.001D), Material.WATER, this)) {
@@ -2532,6 +2537,11 @@ public abstract class Entity implements ICommandListener {
     }
 
     public boolean bo() {
+        return this.pushedByWater();
+    }
+
+    public boolean pushedByWater() {
+        // Paper end
         return true;
     }
 
diff --git a/src/main/java/net/minecraft/server/EntityTNTPrimed.java b/src/main/java/net/minecraft/server/EntityTNTPrimed.java
index bb0904f86..50811852a 100644
--- a/src/main/java/net/minecraft/server/EntityTNTPrimed.java
+++ b/src/main/java/net/minecraft/server/EntityTNTPrimed.java
@@ -147,4 +147,49 @@ public class EntityTNTPrimed extends Entity {
     public int getFuseTicks() {
         return this.c;
     }
+
+    // Paper start - Optional prevent TNT from moving in water
+    @Override
+    public boolean pushedByWater() {
+        return !world.paperConfig.preventTntFromMovingInWater && super.pushedByWater();
+    }
+
+    /**
+     * Author: Jedediah Smith <jedediah@silencegreys.com>
+     */
+    @Override
+    public boolean doWaterMovement() {
+        if (!world.paperConfig.preventTntFromMovingInWater) return super.doWaterMovement();
+
+        // Preserve velocity while calling the super method
+        double oldMotX = this.motX;
+        double oldMotY = this.motY;
+        double oldMotZ = this.motZ;
+
+        super.doWaterMovement();
+
+        this.motX = oldMotX;
+        this.motY = oldMotY;
+        this.motZ = oldMotZ;
+
+        if (this.inWater) {
+            // 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.
+            EntityTrackerEntry ete = ((WorldServer) this.getWorld()).getTracker().trackedEntities.get(this.getId());
+            if (ete != null) {
+                PacketPlayOutEntityVelocity velocityPacket = new PacketPlayOutEntityVelocity(this);
+                PacketPlayOutEntityTeleport positionPacket = new PacketPlayOutEntityTeleport(this);
+
+                ete.trackedPlayers.stream()
+                        .filter(viewer -> (viewer.locX - this.locX) * (viewer.locY - this.locY) * (viewer.locZ - this.locZ) < 16 * 16)
+                        .forEach(viewer -> {
+                    viewer.playerConnection.sendPacket(velocityPacket);
+                    viewer.playerConnection.sendPacket(positionPacket);
+                });
+            }
+        }
+
+        return this.inWater;
+    }
+    // Paper end
 }
-- 
2.13.1