From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Gabriele C <sgdc3.mail@gmail.com>
Date: Mon, 22 Oct 2018 17:34:10 +0200
Subject: [PATCH] Add option to prevent players from moving into unloaded
 chunks #1551


diff --git a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
index 8c50036896602ab6b00979351918878d08c9c75e..a4b20f8616b6fe2046e7a5f00306565b59cd570d 100644
--- a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
+++ b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
@@ -426,4 +426,9 @@ public class PaperWorldConfig {
         waterOverLavaFlowSpeed = getInt("water-over-lava-flow-speed", 5);
         log("Water over lava flow speed: " + waterOverLavaFlowSpeed);
     }
+
+    public boolean preventMovingIntoUnloadedChunks = false;
+    private void preventMovingIntoUnloadedChunks() {
+        preventMovingIntoUnloadedChunks = getBoolean("prevent-moving-into-unloaded-chunks", false);
+    }
 }
diff --git a/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java b/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java
index a7ee0d00e2688bf84efd25c1c4d679213a783b1b..02d072816d7599204dd8f4d7b2da1a4598c7d984 100644
--- a/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java
+++ b/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java
@@ -498,9 +498,9 @@ public class ServerGamePacketListenerImpl implements ServerPlayerConnection, Ser
                 double d0 = entity.getX();
                 double d1 = entity.getY();
                 double d2 = entity.getZ();
-                double d3 = ServerGamePacketListenerImpl.clampHorizontal(packet.getX());
-                double d4 = ServerGamePacketListenerImpl.clampVertical(packet.getY());
-                double d5 = ServerGamePacketListenerImpl.clampHorizontal(packet.getZ());
+                double d3 = ServerGamePacketListenerImpl.clampHorizontal(packet.getX()); final double toX = d3; // Paper - OBFHELPER
+                double d4 = ServerGamePacketListenerImpl.clampVertical(packet.getY()); final double toY = d4; // Paper - OBFHELPER
+                double d5 = ServerGamePacketListenerImpl.clampHorizontal(packet.getZ()); final double toZ = d5; // Paper - OBFHELPER
                 float f = Mth.wrapDegrees(packet.getYRot());
                 float f1 = Mth.wrapDegrees(packet.getXRot());
                 double d6 = d3 - this.vehicleFirstGoodX;
@@ -535,6 +535,16 @@ public class ServerGamePacketListenerImpl implements ServerPlayerConnection, Ser
                 }
                 speed *= 2f; // TODO: Get the speed of the vehicle instead of the player
 
+                // Paper start - Prevent moving into unloaded chunks
+                if (player.level.paperConfig.preventMovingIntoUnloadedChunks && (
+                    !worldserver.areChunksLoadedForMove(this.player.getBoundingBox().expandTowards(new Vec3(toX, toY, toZ).subtract(this.player.position()))) ||
+                        !worldserver.areChunksLoadedForMove(entity.getBoundingBox().expandTowards(new Vec3(toX, toY, toZ).subtract(entity.position())))
+                    )) {
+                    this.connection.send(new ClientboundMoveVehiclePacket(entity));
+                    return;
+                }
+                // Paper end
+
                 if (d10 - d9 > Math.max(100.0D, Math.pow((double) (org.spigotmc.SpigotConfig.movedTooQuicklyMultiplier * (float) i * speed), 2)) && !this.isSingleplayerOwner()) {
                 // CraftBukkit end
                     ServerGamePacketListenerImpl.LOGGER.warn("{} (vehicle of {}) moved too quickly! {},{},{}", new Object[]{entity.getName().getString(), this.player.getName().getString(), d6, d7, d8});
@@ -1149,9 +1159,9 @@ public class ServerGamePacketListenerImpl implements ServerPlayerConnection, Ser
                     this.allowedPlayerTicks = 20; // CraftBukkit
                 } else {
                     this.awaitingTeleportTime = this.tickCount;
-                    double d0 = ServerGamePacketListenerImpl.clampHorizontal(packet.getX(this.player.getX()));
-                    double d1 = ServerGamePacketListenerImpl.clampVertical(packet.getY(this.player.getY()));
-                    double d2 = ServerGamePacketListenerImpl.clampHorizontal(packet.getZ(this.player.getZ()));
+                    double d0 = ServerGamePacketListenerImpl.clampHorizontal(packet.getX(this.player.getX())); final double toX = d0; // Paper - OBFHELPER
+                    double d1 = ServerGamePacketListenerImpl.clampVertical(packet.getY(this.player.getY())); final double toY = d1;
+                    double d2 = ServerGamePacketListenerImpl.clampHorizontal(packet.getZ(this.player.getZ())); final double toZ = d2; // Paper - OBFHELPER
                     float f = Mth.wrapDegrees(packet.getYRot(this.player.getYRot()));
                     float f1 = Mth.wrapDegrees(packet.getXRot(this.player.getXRot()));
 
@@ -1207,6 +1217,12 @@ public class ServerGamePacketListenerImpl implements ServerPlayerConnection, Ser
                             } else {
                                 speed = this.player.getAbilities().walkingSpeed * 10f;
                             }
+                            // Paper start - Prevent moving into unloaded chunks
+                            if (player.level.paperConfig.preventMovingIntoUnloadedChunks && (this.player.getX() != toX || this.player.getZ() != toZ) && !worldserver.areChunksLoadedForMove(this.player.getBoundingBox().expandTowards(new Vec3(toX, toY, toZ).subtract(this.player.position())))) {
+                                this.internalTeleport(this.player.getX(), this.player.getY(), this.player.getZ(), this.player.getYRot(), this.player.getXRot(), Collections.emptySet(), true);
+                                return;
+                            }
+                            // Paper end
 
                             if (!this.player.isChangingDimension() && (!this.player.getLevel().getGameRules().getBoolean(GameRules.RULE_DISABLE_ELYTRA_MOVEMENT_CHECK) || !this.player.isFallFlying())) {
                                 float f2 = this.player.isFallFlying() ? 300.0F : 100.0F;