From f7e6aa36cb060a0db52599ebe618f400952b819c Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Tue, 20 Dec 2016 15:15:11 -0500
Subject: [PATCH] Bound Treasure Maps to World Border

Make it so a Treasure Map does not target a structure outside of the
World Border, where players are not even able to reach.

This also would help the case where a players close to the border, and one
that is outside happens to be closer, but unreachable, yet another reachable
one is in border that would of been missed.

diff --git a/src/main/java/net/minecraft/server/StructureGenerator.java b/src/main/java/net/minecraft/server/StructureGenerator.java
index 464e1e101a..7b2eace75c 100644
--- a/src/main/java/net/minecraft/server/StructureGenerator.java
+++ b/src/main/java/net/minecraft/server/StructureGenerator.java
@@ -103,6 +103,7 @@ public abstract class StructureGenerator<C extends WorldGenFeatureConfiguration>
 
                             if (flag1 || flag2) {
                                 ChunkCoordIntPair chunkcoordintpair = this.a(chunkgenerator, seededrandom, j, k, i1, j1);
+                                if (!world.getWorldBorder().isChunkInBounds(chunkcoordintpair.x, chunkcoordintpair.z)) { continue; } // Paper
                                 StructureStart structurestart = world.getChunkAt(chunkcoordintpair.x, chunkcoordintpair.z, ChunkStatus.STRUCTURE_STARTS).a(this.b());
 
                                 if (structurestart != null && structurestart.e()) {
diff --git a/src/main/java/net/minecraft/server/WorldBorder.java b/src/main/java/net/minecraft/server/WorldBorder.java
index 77b805f3ae..1e622a0434 100644
--- a/src/main/java/net/minecraft/server/WorldBorder.java
+++ b/src/main/java/net/minecraft/server/WorldBorder.java
@@ -24,6 +24,18 @@ public class WorldBorder {
         return (double) (blockposition.getX() + 1) > this.c() && (double) blockposition.getX() < this.e() && (double) (blockposition.getZ() + 1) > this.d() && (double) blockposition.getZ() < this.f();
     }
 
+    // Paper start
+    private final BlockPosition.MutableBlockPosition mutPos = new BlockPosition.MutableBlockPosition();
+    public boolean isBlockInBounds(int chunkX, int chunkZ) {
+        this.mutPos.setValues(chunkX, 64, chunkZ);
+        return this.isInBounds(this.mutPos);
+    }
+    public boolean isChunkInBounds(int chunkX, int chunkZ) {
+        this.mutPos.setValues(((chunkX << 4) + 15), 64, (chunkZ << 4) + 15);
+        return this.isInBounds(this.mutPos);
+    }
+    // Paper end
+
     public boolean isInBounds(ChunkCoordIntPair chunkcoordintpair) {
         return (double) chunkcoordintpair.f() > this.c() && (double) chunkcoordintpair.d() < this.e() && (double) chunkcoordintpair.g() > this.d() && (double) chunkcoordintpair.e() < this.f();
     }
-- 
2.21.0